[automerge] Import MDD logging 2p: 980a37b132

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/mobile-data-download/+/19682334

Bug: 219636547
Change-Id: Ic00af798a8e27c2eb870c74a294249238968ba8f

17 files changed, 1952 insertions, 361 deletions

diff --git a/java/com/google/android/libraries/mobiledatadownload/internal/SharedPreferencesFileGroupsMetadata.java b/java/com/google/android/libraries/mobiledatadownload/internal/SharedPreferencesFileGroupsMetadata.java
index bc407fd..9b1ba9a 100644
--- a/java/com/google/android/libraries/mobiledatadownload/internal/SharedPreferencesFileGroupsMetadata.java
+++ b/java/com/google/android/libraries/mobiledatadownload/internal/SharedPreferencesFileGroupsMetadata.java
@@ -36,6 +36,7 @@ import com.google.errorprone.annotations.CheckReturnValue;
 import com.google.mobiledatadownload.internal.MetadataProto.DataFileGroupInternal;
 import com.google.mobiledatadownload.internal.MetadataProto.GroupKey;
 import com.google.mobiledatadownload.internal.MetadataProto.GroupKeyProperties;
+
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
@@ -54,7 +55,7 @@ public final class SharedPreferencesFileGroupsMetadata implements FileGroupsMeta
   private static final String TAG = "SharedPreferencesFileGroupsMetadata";
   private static final String MDD_FILE_GROUPS = FileGroupsMetadataUtil.MDD_FILE_GROUPS;
   private static final String MDD_FILE_GROUP_KEY_PROPERTIES =
-      FileGroupsMetadataUtil.MDD_FILE_GROUP_KEY_PROPERTIES;
+          FileGroupsMetadataUtil.MDD_FILE_GROUP_KEY_PROPERTIES;
 
   // TODO(b/144033163): Migrate the Garbage Collector File to PDS.
   @VisibleForTesting static final String MDD_GARBAGE_COLLECTION_FILE = "gms_icing_mdd_garbage_file";
@@ -67,11 +68,11 @@ public final class SharedPreferencesFileGroupsMetadata implements FileGroupsMeta
 
   @Inject
   SharedPreferencesFileGroupsMetadata(
-      @ApplicationContext Context context,
-      TimeSource timeSource,
-      SilentFeedback silentFeedback,
-      @InstanceId Optional<String> instanceId,
-      @SequentialControlExecutor Executor sequentialControlExecutor) {
+          @ApplicationContext Context context,
+          TimeSource timeSource,
+          SilentFeedback silentFeedback,
+          @InstanceId Optional<String> instanceId,
+          @SequentialControlExecutor Executor sequentialControlExecutor) {
     this.context = context;
     this.timeSource = timeSource;
     this.silentFeedback = silentFeedback;
@@ -86,66 +87,66 @@ public final class SharedPreferencesFileGroupsMetadata implements FileGroupsMeta
 
   @Override
   public ListenableFuture<@NullableType DataFileGroupInternal> read(GroupKey groupKey) {
-    String serializedGroupKey = FileGroupsMetadataUtil.getSerializedGroupKey(groupKey, context);
+    String serializedGroupKey = FileGroupsMetadataUtil.getSerializedGroupKey(groupKey);
 
     SharedPreferences prefs =
-        SharedPreferencesUtil.getSharedPreferences(context, MDD_FILE_GROUPS, instanceId);
+            SharedPreferencesUtil.getSharedPreferences(context, MDD_FILE_GROUPS, instanceId);
     DataFileGroupInternal fileGroup =
-        SharedPreferencesUtil.readProto(prefs, serializedGroupKey, DataFileGroupInternal.parser());
+            SharedPreferencesUtil.readProto(prefs, serializedGroupKey, DataFileGroupInternal.parser());
 
     return Futures.immediateFuture(fileGroup);
   }
 
   @Override
   public ListenableFuture<Boolean> write(GroupKey groupKey, DataFileGroupInternal fileGroup) {
-    String serializedGroupKey = FileGroupsMetadataUtil.getSerializedGroupKey(groupKey, context);
+    String serializedGroupKey = FileGroupsMetadataUtil.getSerializedGroupKey(groupKey);
 
     SharedPreferences prefs =
-        SharedPreferencesUtil.getSharedPreferences(context, MDD_FILE_GROUPS, instanceId);
+            SharedPreferencesUtil.getSharedPreferences(context, MDD_FILE_GROUPS, instanceId);
     return Futures.immediateFuture(
-        SharedPreferencesUtil.writeProto(prefs, serializedGroupKey, fileGroup));
+            SharedPreferencesUtil.writeProto(prefs, serializedGroupKey, fileGroup));
   }
 
   @Override
   public ListenableFuture<Boolean> remove(GroupKey groupKey) {
-    String serializedGroupKey = FileGroupsMetadataUtil.getSerializedGroupKey(groupKey, context);
+    String serializedGroupKey = FileGroupsMetadataUtil.getSerializedGroupKey(groupKey);
 
     SharedPreferences prefs =
-        SharedPreferencesUtil.getSharedPreferences(context, MDD_FILE_GROUPS, instanceId);
+            SharedPreferencesUtil.getSharedPreferences(context, MDD_FILE_GROUPS, instanceId);
     return Futures.immediateFuture(SharedPreferencesUtil.removeProto(prefs, serializedGroupKey));
   }
 
   @Override
   public ListenableFuture<@NullableType GroupKeyProperties> readGroupKeyProperties(
-      GroupKey groupKey) {
-    String serializedGroupKey = FileGroupsMetadataUtil.getSerializedGroupKey(groupKey, context);
+          GroupKey groupKey) {
+    String serializedGroupKey = FileGroupsMetadataUtil.getSerializedGroupKey(groupKey);
 
     SharedPreferences prefs =
-        SharedPreferencesUtil.getSharedPreferences(
-            context, MDD_FILE_GROUP_KEY_PROPERTIES, instanceId);
+            SharedPreferencesUtil.getSharedPreferences(
+                    context, MDD_FILE_GROUP_KEY_PROPERTIES, instanceId);
     GroupKeyProperties groupKeyProperties =
-        SharedPreferencesUtil.readProto(prefs, serializedGroupKey, GroupKeyProperties.parser());
+            SharedPreferencesUtil.readProto(prefs, serializedGroupKey, GroupKeyProperties.parser());
 
     return Futures.immediateFuture(groupKeyProperties);
   }
 
   @Override
   public ListenableFuture<Boolean> writeGroupKeyProperties(
-      GroupKey groupKey, GroupKeyProperties groupKeyProperties) {
-    String serializedGroupKey = FileGroupsMetadataUtil.getSerializedGroupKey(groupKey, context);
+          GroupKey groupKey, GroupKeyProperties groupKeyProperties) {
+    String serializedGroupKey = FileGroupsMetadataUtil.getSerializedGroupKey(groupKey);
 
     SharedPreferences prefs =
-        SharedPreferencesUtil.getSharedPreferences(
-            context, MDD_FILE_GROUP_KEY_PROPERTIES, instanceId);
+            SharedPreferencesUtil.getSharedPreferences(
+                    context, MDD_FILE_GROUP_KEY_PROPERTIES, instanceId);
     return Futures.immediateFuture(
-        SharedPreferencesUtil.writeProto(prefs, serializedGroupKey, groupKeyProperties));
+            SharedPreferencesUtil.writeProto(prefs, serializedGroupKey, groupKeyProperties));
   }
 
   @Override
   public ListenableFuture<List<GroupKey>> getAllGroupKeys() {
     List<GroupKey> groupKeyList = new ArrayList<>();
     SharedPreferences prefs =
-        SharedPreferencesUtil.getSharedPreferences(context, MDD_FILE_GROUPS, instanceId);
+            SharedPreferencesUtil.getSharedPreferences(context, MDD_FILE_GROUPS, instanceId);
     SharedPreferences.Editor editor = null;
     for (String serializedGroupKey : prefs.getAll().keySet()) {
       try {
@@ -175,36 +176,36 @@ public final class SharedPreferencesFileGroupsMetadata implements FileGroupsMeta
   @Override
   public ListenableFuture<List<Pair<GroupKey, DataFileGroupInternal>>> getAllFreshGroups() {
     return Futures.transformAsync(
-        getAllGroupKeys(),
-        groupKeyList -> {
-          List<ListenableFuture<@NullableType DataFileGroupInternal>> groupReadFutures =
-              new ArrayList<>();
-          for (GroupKey key : groupKeyList) {
-            groupReadFutures.add(read(key));
-          }
-          return Futures.whenAllComplete(groupReadFutures)
-              .callAsync(
-                  () -> {
-                    List<Pair<GroupKey, DataFileGroupInternal>> retrievedGroups = new ArrayList<>();
-                    for (int i = 0; i < groupKeyList.size(); i++) {
-                      GroupKey key = groupKeyList.get(i);
-                      DataFileGroupInternal group = Futures.getDone(groupReadFutures.get(i));
-                      if (group == null) {
-                        continue;
-                      }
-                      retrievedGroups.add(Pair.create(key, group));
-                    }
-                    return Futures.immediateFuture(retrievedGroups);
-                  },
-                  sequentialControlExecutor);
-        },
-        sequentialControlExecutor);
+            getAllGroupKeys(),
+            groupKeyList -> {
+              List<ListenableFuture<@NullableType DataFileGroupInternal>> groupReadFutures =
+                      new ArrayList<>();
+              for (GroupKey key : groupKeyList) {
+                groupReadFutures.add(read(key));
+              }
+              return Futures.whenAllComplete(groupReadFutures)
+                      .callAsync(
+                              () -> {
+                                List<Pair<GroupKey, DataFileGroupInternal>> retrievedGroups = new ArrayList<>();
+                                for (int i = 0; i < groupKeyList.size(); i++) {
+                                  GroupKey key = groupKeyList.get(i);
+                                  DataFileGroupInternal group = Futures.getDone(groupReadFutures.get(i));
+                                  if (group == null) {
+                                    continue;
+                                  }
+                                  retrievedGroups.add(Pair.create(key, group));
+                                }
+                                return Futures.immediateFuture(retrievedGroups);
+                              },
+                              sequentialControlExecutor);
+            },
+            sequentialControlExecutor);
   }
 
   @Override
   public ListenableFuture<Boolean> removeAllGroupsWithKeys(List<GroupKey> keys) {
     SharedPreferences prefs =
-        SharedPreferencesUtil.getSharedPreferences(context, MDD_FILE_GROUPS, instanceId);
+            SharedPreferencesUtil.getSharedPreferences(context, MDD_FILE_GROUPS, instanceId);
     SharedPreferences.Editor editor = prefs.edit();
     for (GroupKey key : keys) {
       LogUtil.d("%s: Removing group %s %s", TAG, key.getGroupName(), key.getOwnerPackage());
@@ -216,8 +217,8 @@ public final class SharedPreferencesFileGroupsMetadata implements FileGroupsMeta
   @Override
   public ListenableFuture<List<DataFileGroupInternal>> getAllStaleGroups() {
     return Futures.immediateFuture(
-        FileGroupsMetadataUtil.getAllStaleGroups(
-            FileGroupsMetadataUtil.getGarbageCollectorFile(context, instanceId)));
+            FileGroupsMetadataUtil.getAllStaleGroups(
+                    FileGroupsMetadataUtil.getGarbageCollectorFile(context, instanceId)));
   }
 
   @Override
@@ -226,8 +227,8 @@ public final class SharedPreferencesFileGroupsMetadata implements FileGroupsMeta
 
     long currentTimeSeconds = timeSource.currentTimeMillis() / 1000;
     fileGroup =
-        FileGroupUtil.setStaleExpirationDate(
-            fileGroup, currentTimeSeconds + fileGroup.getStaleLifetimeSecs());
+            FileGroupUtil.setStaleExpirationDate(
+                    fileGroup, currentTimeSeconds + fileGroup.getStaleLifetimeSecs());
 
     List<DataFileGroupInternal> fileGroups = new ArrayList<>();
     fileGroups.add(fileGroup);
@@ -275,12 +276,12 @@ public final class SharedPreferencesFileGroupsMetadata implements FileGroupsMeta
   @Override
   public ListenableFuture<Void> clear() {
     SharedPreferences prefs =
-        SharedPreferencesUtil.getSharedPreferences(context, MDD_FILE_GROUPS, instanceId);
+            SharedPreferencesUtil.getSharedPreferences(context, MDD_FILE_GROUPS, instanceId);
     prefs.edit().clear().commit();
 
     SharedPreferences activatedGroupPrefs =
-        SharedPreferencesUtil.getSharedPreferences(
-            context, MDD_FILE_GROUP_KEY_PROPERTIES, instanceId);
+            SharedPreferencesUtil.getSharedPreferences(
+                    context, MDD_FILE_GROUP_KEY_PROPERTIES, instanceId);
     activatedGroupPrefs.edit().clear().commit();
 
     return removeAllStaleGroups();
diff --git a/java/com/google/android/libraries/mobiledatadownload/internal/dagger/MainMddLibModule.java b/java/com/google/android/libraries/mobiledatadownload/internal/dagger/MainMddLibModule.java
index 18c23f0..04ab285 100644
--- a/java/com/google/android/libraries/mobiledatadownload/internal/dagger/MainMddLibModule.java
+++ b/java/com/google/android/libraries/mobiledatadownload/internal/dagger/MainMddLibModule.java
@@ -16,6 +16,7 @@
 package com.google.android.libraries.mobiledatadownload.internal.dagger;
 
 import android.content.Context;
+
 import com.google.android.libraries.mobiledatadownload.AccountSource;
 import com.google.android.libraries.mobiledatadownload.ExperimentationConfig;
 import com.google.android.libraries.mobiledatadownload.Flags;
@@ -33,156 +34,164 @@ import com.google.android.libraries.mobiledatadownload.internal.experimentation.
 import com.google.android.libraries.mobiledatadownload.internal.experimentation.NoOpDownloadStageManager;
 import com.google.android.libraries.mobiledatadownload.internal.logging.EventLogger;
 import com.google.android.libraries.mobiledatadownload.internal.logging.LoggingStateStore;
-import com.google.android.libraries.mobiledatadownload.internal.logging.NoOpLoggingState;
+import com.google.android.libraries.mobiledatadownload.internal.logging.SharedPreferencesLoggingState;
 import com.google.android.libraries.mobiledatadownload.internal.util.FuturesUtil;
 import com.google.android.libraries.mobiledatadownload.monitor.DownloadProgressMonitor;
 import com.google.android.libraries.mobiledatadownload.monitor.NetworkUsageMonitor;
 import com.google.common.base.Optional;
-import dagger.Module;
-import dagger.Provides;
+
+import java.security.SecureRandom;
 import java.util.concurrent.Executor;
+
 import javax.inject.Singleton;
 
+import dagger.Module;
+import dagger.Provides;
+
 /** Module for MDD Lib dependencies */
 @Module
 public class MainMddLibModule {
-  /** The version of MDD library. Same as mdi_download module version. */
-  // TODO(b/122271766): Figure out how to update this automatically.
-  // LINT.IfChange
-  public static final int MDD_LIB_VERSION = 422883838;
-  // LINT.ThenChange(<internal>)
-
-  private final SynchronousFileStorage fileStorage;
-  private final NetworkUsageMonitor networkUsageMonitor;
-  private final EventLogger eventLogger;
-  private final Optional<DownloadProgressMonitor> downloadProgressMonitorOptional;
-  private final Optional<SilentFeedback> silentFeedbackOptional;
-  private final Optional<String> instanceId;
-  private final Optional<AccountSource> accountSourceOptional;
-  private final Flags flags;
-  private final Optional<ExperimentationConfig> experimentationConfigOptional;
-
-  public MainMddLibModule(
-      SynchronousFileStorage fileStorage,
-      NetworkUsageMonitor networkUsageMonitor,
-      EventLogger eventLogger,
-      Optional<DownloadProgressMonitor> downloadProgressMonitorOptional,
-      Optional<SilentFeedback> silentFeedbackOptional,
-      Optional<String> instanceId,
-      Optional<AccountSource> accountSourceOptional,
-      Flags flags,
-      Optional<ExperimentationConfig> experimentationConfigOptional) {
-    this.fileStorage = fileStorage;
-    this.networkUsageMonitor = networkUsageMonitor;
-    this.eventLogger = eventLogger;
-    this.downloadProgressMonitorOptional = downloadProgressMonitorOptional;
-    this.silentFeedbackOptional = silentFeedbackOptional;
-    this.instanceId = instanceId;
-    this.accountSourceOptional = accountSourceOptional;
-    this.flags = flags;
-    this.experimentationConfigOptional = experimentationConfigOptional;
-  }
-
-  @Provides
-  @Singleton
-  static FileGroupsMetadata provideFileGroupsMetadata(
-      SharedPreferencesFileGroupsMetadata fileGroupsMetadata) {
-    return fileGroupsMetadata;
-  }
-
-  @Provides
-  @Singleton
-  static SharedFilesMetadata provideSharedFilesMetadata(
-      SharedPreferencesSharedFilesMetadata sharedFilesMetadata) {
-    return sharedFilesMetadata;
-  }
-
-  @Provides
-  @Singleton
-  EventLogger provideEventLogger() {
-    return eventLogger;
-  }
-
-  @Provides
-  @Singleton
-  SilentFeedback providesSilentFeedback() {
-    if (this.silentFeedbackOptional.isPresent()) {
-      return this.silentFeedbackOptional.get();
-    } else {
-      return (throwable, description, args) -> {
-        // No-op SilentFeedback.
-      };
-    }
-  }
-
-  @Provides
-  @Singleton
-  Optional<AccountSource> provideAccountSourceOptional(@ApplicationContext Context context) {
-    return this.accountSourceOptional;
-  }
-
-  @Provides
-  @Singleton
-  static TimeSource provideTimeSource() {
-    return System::currentTimeMillis;
-  }
-
-  @Provides
-  @Singleton
-  @InstanceId
-  Optional<String> provideInstanceId() {
-    return this.instanceId;
-  }
-
-  @Provides
-  @Singleton
-  NetworkUsageMonitor provideNetworkUsageMonitor() {
-    return this.networkUsageMonitor;
-  }
-
-  @Provides
-  @Singleton
-  // TODO: We don't need to have @Singleton here and few other places in this class
-  // since it comes from the this instance. We should remove this since it could increase APK size.
-  Optional<DownloadProgressMonitor> provideDownloadProgressMonitor() {
-    return this.downloadProgressMonitorOptional;
-  }
-
-  @Provides
-  @Singleton
-  SynchronousFileStorage provideSynchronousFileStorage() {
-    return this.fileStorage;
-  }
-
-  @Provides
-  @Singleton
-  Flags provideFlags() {
-    return this.flags;
-  }
-
-  @Provides
-  Optional<ExperimentationConfig> provideExperimentationConfigOptional() {
-    return this.experimentationConfigOptional;
-  }
-
-  @Provides
-  @Singleton
-  static FuturesUtil provideFuturesUtil(@SequentialControlExecutor Executor sequentialExecutor) {
-    return new FuturesUtil(sequentialExecutor);
-  }
-
-  @Provides
-  @Singleton
-  static LoggingStateStore provideLoggingStateStore() {
-    return new NoOpLoggingState();
-  }
-
-  @Provides
-  static DownloadStageManager provideDownloadStageManager(
-      FileGroupsMetadata fileGroupsMetadata,
-      Optional<ExperimentationConfig> experimentationConfigOptional,
-      @SequentialControlExecutor Executor executor,
-      Flags flags) {
-    return new NoOpDownloadStageManager();
-  }
+    /** The version of MDD library. Same as mdi_download module version. */
+    // TODO(b/122271766): Figure out how to update this automatically.
+    public static final int MDD_LIB_VERSION = 422883838;
+
+    private final SynchronousFileStorage fileStorage;
+    private final NetworkUsageMonitor networkUsageMonitor;
+    private final EventLogger eventLogger;
+    private final Optional<DownloadProgressMonitor> downloadProgressMonitorOptional;
+    private final Optional<SilentFeedback> silentFeedbackOptional;
+    private final Optional<String> instanceId;
+    private final Optional<AccountSource> accountSourceOptional;
+    private final Flags flags;
+    private final Optional<ExperimentationConfig> experimentationConfigOptional;
+
+    public MainMddLibModule(
+            SynchronousFileStorage fileStorage,
+            NetworkUsageMonitor networkUsageMonitor,
+            EventLogger eventLogger,
+            Optional<DownloadProgressMonitor> downloadProgressMonitorOptional,
+            Optional<SilentFeedback> silentFeedbackOptional,
+            Optional<String> instanceId,
+            Optional<AccountSource> accountSourceOptional,
+            Flags flags,
+            Optional<ExperimentationConfig> experimentationConfigOptional) {
+        this.fileStorage = fileStorage;
+        this.networkUsageMonitor = networkUsageMonitor;
+        this.eventLogger = eventLogger;
+        this.downloadProgressMonitorOptional = downloadProgressMonitorOptional;
+        this.silentFeedbackOptional = silentFeedbackOptional;
+        this.instanceId = instanceId;
+        this.accountSourceOptional = accountSourceOptional;
+        this.flags = flags;
+        this.experimentationConfigOptional = experimentationConfigOptional;
+    }
+
+    @Provides
+    @Singleton
+    static FileGroupsMetadata provideFileGroupsMetadata(
+            SharedPreferencesFileGroupsMetadata fileGroupsMetadata) {
+        return fileGroupsMetadata;
+    }
+
+    @Provides
+    @Singleton
+    static SharedFilesMetadata provideSharedFilesMetadata(
+            SharedPreferencesSharedFilesMetadata sharedFilesMetadata) {
+        return sharedFilesMetadata;
+    }
+
+    @Provides
+    @Singleton
+    EventLogger provideEventLogger() {
+        return eventLogger;
+    }
+
+    @Provides
+    @Singleton
+    SilentFeedback providesSilentFeedback() {
+        if (this.silentFeedbackOptional.isPresent()) {
+            return this.silentFeedbackOptional.get();
+        } else {
+            return (throwable, description, args) -> {
+                // No-op SilentFeedback.
+            };
+        }
+    }
+
+    @Provides
+    @Singleton
+    Optional<AccountSource> provideAccountSourceOptional(@ApplicationContext Context context) {
+        return this.accountSourceOptional;
+    }
+
+    @Provides
+    @Singleton
+    static TimeSource provideTimeSource() {
+        return System::currentTimeMillis;
+    }
+
+    @Provides
+    @Singleton
+    @InstanceId
+    Optional<String> provideInstanceId() {
+        return this.instanceId;
+    }
+
+    @Provides
+    @Singleton
+    NetworkUsageMonitor provideNetworkUsageMonitor() {
+        return this.networkUsageMonitor;
+    }
+
+    @Provides
+    @Singleton
+        // TODO(b/243706147): We don't need to have @Singleton here and few other places in this
+        //  class since it comes from the this instance. We should remove this since it could
+        //  increase APK size.
+    Optional<DownloadProgressMonitor> provideDownloadProgressMonitor() {
+        return this.downloadProgressMonitorOptional;
+    }
+
+    @Provides
+    @Singleton
+    SynchronousFileStorage provideSynchronousFileStorage() {
+        return this.fileStorage;
+    }
+
+    @Provides
+    @Singleton
+    Flags provideFlags() {
+        return this.flags;
+    }
+
+    @Provides
+    Optional<ExperimentationConfig> provideExperimentationConfigOptional() {
+        return this.experimentationConfigOptional;
+    }
+
+    @Provides
+    @Singleton
+    static FuturesUtil provideFuturesUtil(@SequentialControlExecutor Executor sequentialExecutor) {
+        return new FuturesUtil(sequentialExecutor);
+    }
+
+    @Provides
+    @Singleton
+    static LoggingStateStore provideLoggingStateStore(
+            @ApplicationContext Context context,
+            @InstanceId Optional<String> instanceId,
+            TimeSource timeSource,
+            @SequentialControlExecutor Executor sequentialExecutor) {
+        return SharedPreferencesLoggingState.createFromContext(
+                context, instanceId, timeSource, sequentialExecutor, new SecureRandom());
+    }
+
+    @Provides
+    static DownloadStageManager provideDownloadStageManager(
+            FileGroupsMetadata fileGroupsMetadata,
+            Optional<ExperimentationConfig> experimentationConfigOptional,
+            @SequentialControlExecutor Executor executor,
+            Flags flags) {
+        return new NoOpDownloadStageManager();
+    }
 }
diff --git a/java/com/google/android/libraries/mobiledatadownload/internal/logging/EventLogger.java b/java/com/google/android/libraries/mobiledatadownload/internal/logging/EventLogger.java
index e1ed276..8271ac3 100644
--- a/java/com/google/android/libraries/mobiledatadownload/internal/logging/EventLogger.java
+++ b/java/com/google/android/libraries/mobiledatadownload/internal/logging/EventLogger.java
@@ -18,6 +18,8 @@ package com.google.android.libraries.mobiledatadownload.internal.logging;
 import com.google.auto.value.AutoValue;
 import com.google.common.util.concurrent.AsyncCallable;
 import com.google.common.util.concurrent.ListenableFuture;
+import com.google.mobiledatadownload.LogProto.DataDownloadFileGroupStats;
+import com.google.mobiledatadownload.LogProto.MddFileGroupStatus;
 import java.util.List;
 
 /** Interface for remote logging. */
@@ -28,11 +30,11 @@ public interface EventLogger {
 
   /** Log an mdd event with an associated file group. */
   void logEventSampled(
-      int eventCode,
-      String fileGroupName,
-      int fileGroupVersionNumber,
-      long buildId,
-      String variantId);
+          int eventCode,
+          String fileGroupName,
+          int fileGroupVersionNumber,
+          long buildId,
+          String variantId);
 
   /**
    * Log an mdd event. This not sampled. Caller should make sure this method is called after
@@ -50,18 +52,19 @@ public interface EventLogger {
    *     failure if the callable fails or if there is an error when logging.
    */
   ListenableFuture<Void> logMddFileGroupStats(
-      AsyncCallable<List<FileGroupStatusWithDetails>> buildFileGroupStats);
+          AsyncCallable<List<FileGroupStatusWithDetails>> buildFileGroupStats);
 
   /** Simple wrapper class for MDD file group stats and details. */
   @AutoValue
   abstract class FileGroupStatusWithDetails {
-    abstract Void fileGroupStatus();
+    abstract MddFileGroupStatus fileGroupStatus();
 
-    abstract Void fileGroupDetails();
+    abstract DataDownloadFileGroupStats fileGroupDetails();
 
-    static FileGroupStatusWithDetails create(Void fileGroupStatus, Void fileGroupDetails) {
+    static FileGroupStatusWithDetails create(
+            MddFileGroupStatus fileGroupStatus, DataDownloadFileGroupStats fileGroupDetails) {
       return new AutoValue_EventLogger_FileGroupStatusWithDetails(
-          fileGroupStatus, fileGroupDetails);
+              fileGroupStatus, fileGroupDetails);
     }
   }
 
@@ -93,12 +96,12 @@ public interface EventLogger {
 
   /** Log the network savings of MDD download features */
   void logMddNetworkSavings(
-      Void fileGroupDetails,
-      int code,
-      long fullFileSize,
-      long downloadedFileSize,
-      String fileId,
-      int deltaIndex);
+          Void fileGroupDetails,
+          int code,
+          long fullFileSize,
+          long downloadedFileSize,
+          String fileId,
+          int deltaIndex);
 
   /** Log mdd download result events. */
   void logMddDownloadResult(int code, Void fileGroupDetails);
@@ -114,4 +117,4 @@ public interface EventLogger {
 
   /** Log mdd usage event. */
   void logMddUsageEvent(Void fileGroupDetails, Void usageEventLog);
-}
+}
\ No newline at end of file
diff --git a/java/com/google/android/libraries/mobiledatadownload/internal/logging/FileGroupStatsLogger.java b/java/com/google/android/libraries/mobiledatadownload/internal/logging/FileGroupStatsLogger.java
index 3803c33..6ef267b 100644
--- a/java/com/google/android/libraries/mobiledatadownload/internal/logging/FileGroupStatsLogger.java
+++ b/java/com/google/android/libraries/mobiledatadownload/internal/logging/FileGroupStatsLogger.java
@@ -15,15 +15,22 @@
  */
 package com.google.android.libraries.mobiledatadownload.internal.logging;
 
+import static com.google.common.util.concurrent.Futures.immediateFuture;
+
 import android.util.Pair;
 import com.google.android.libraries.mobiledatadownload.internal.FileGroupManager;
+import com.google.android.libraries.mobiledatadownload.internal.FileGroupManager.GroupDownloadStatus;
 import com.google.android.libraries.mobiledatadownload.internal.FileGroupsMetadata;
 import com.google.android.libraries.mobiledatadownload.internal.annotations.SequentialControlExecutor;
+import com.google.android.libraries.mobiledatadownload.internal.util.FileGroupUtil;
 import com.google.android.libraries.mobiledatadownload.tracing.PropagatedFutures;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.mobiledatadownload.internal.MetadataProto.DataFileGroupInternal;
 import com.google.mobiledatadownload.internal.MetadataProto.GroupKey;
+import com.google.mobiledatadownload.LogEnumsProto.MddFileGroupDownloadStatus;
+import com.google.mobiledatadownload.LogProto.DataDownloadFileGroupStats;
+import com.google.mobiledatadownload.LogProto.MddFileGroupStatus;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.Executor;
@@ -43,10 +50,10 @@ public class FileGroupStatsLogger {
 
   @Inject
   public FileGroupStatsLogger(
-      FileGroupManager fileGroupManager,
-      FileGroupsMetadata fileGroupsMetadata,
-      EventLogger eventLogger,
-      @SequentialControlExecutor Executor sequentialControlExecutor) {
+          FileGroupManager fileGroupManager,
+          FileGroupsMetadata fileGroupsMetadata,
+          EventLogger eventLogger,
+          @SequentialControlExecutor Executor sequentialControlExecutor) {
     this.fileGroupManager = fileGroupManager;
     this.fileGroupsMetadata = fileGroupsMetadata;
     this.eventLogger = eventLogger;
@@ -59,36 +66,80 @@ public class FileGroupStatsLogger {
   }
 
   private ListenableFuture<List<EventLogger.FileGroupStatusWithDetails>> buildFileGroupStatusList(
-      int daysSinceLastLog) {
+          int daysSinceLastLog) {
     return PropagatedFutures.transformAsync(
-        fileGroupsMetadata.getAllFreshGroups(),
-        downloadedAndPendingGroups -> {
-          List<ListenableFuture<EventLogger.FileGroupStatusWithDetails>> futures =
-              new ArrayList<>();
-          for (Pair<GroupKey, DataFileGroupInternal> pair : downloadedAndPendingGroups) {
-            GroupKey groupKey = pair.first;
-            DataFileGroupInternal dataFileGroup = pair.second;
-            if (dataFileGroup == null) {
-              continue;
-            }
+            fileGroupsMetadata.getAllFreshGroups(),
+            downloadedAndPendingGroups -> {
+              List<ListenableFuture<EventLogger.FileGroupStatusWithDetails>> futures =
+                      new ArrayList<>();
+              for (Pair<GroupKey, DataFileGroupInternal> pair : downloadedAndPendingGroups) {
+                GroupKey groupKey = pair.first;
+                DataFileGroupInternal dataFileGroup = pair.second;
+                if (dataFileGroup == null) {
+                  continue;
+                }
 
-            Void fileGroupDetails = null;
+                DataDownloadFileGroupStats fileGroupDetails =
+                        DataDownloadFileGroupStats.newBuilder()
+                                .setFileGroupName(groupKey.getGroupName())
+                                .setOwnerPackage(groupKey.getOwnerPackage())
+                                .setFileGroupVersionNumber(dataFileGroup.getFileGroupVersionNumber())
+                                .setFileCount(dataFileGroup.getFileCount())
+                                .setInlineFileCount(FileGroupUtil.getInlineFileCount(dataFileGroup))
+                                .setHasAccount(!groupKey.getAccount().isEmpty())
+                                .setBuildId(dataFileGroup.getBuildId())
+                                .setVariantId(dataFileGroup.getVariantId())
+                                .build();
 
-            futures.add(
-                PropagatedFutures.transform(
-                    buildFileGroupStatus(dataFileGroup, groupKey, daysSinceLastLog),
-                    fileGroupStatus ->
-                        EventLogger.FileGroupStatusWithDetails.create(
-                            fileGroupStatus, fileGroupDetails),
-                    sequentialControlExecutor));
-          }
-          return Futures.allAsList(futures);
-        },
-        sequentialControlExecutor);
+                futures.add(
+                        PropagatedFutures.transform(
+                                buildFileGroupStatus(dataFileGroup, groupKey, daysSinceLastLog),
+                                fileGroupStatus ->
+                                        EventLogger.FileGroupStatusWithDetails.create(
+                                                fileGroupStatus, fileGroupDetails),
+                                sequentialControlExecutor));
+              }
+              return Futures.allAsList(futures);
+            },
+            sequentialControlExecutor);
   }
 
-  private ListenableFuture<Void> buildFileGroupStatus(
-      DataFileGroupInternal dataFileGroup, GroupKey groupKey, int daysSinceLastLog) {
-    return Futures.immediateVoidFuture();
+  private ListenableFuture<MddFileGroupStatus> buildFileGroupStatus(
+          DataFileGroupInternal dataFileGroup, GroupKey groupKey, int daysSinceLastLog) {
+    MddFileGroupStatus.Builder fileGroupStatus =
+            MddFileGroupStatus.newBuilder().setDaysSinceLastLog(daysSinceLastLog);
+    if (dataFileGroup.getBookkeeping().hasGroupNewFilesReceivedTimestamp()) {
+      fileGroupStatus.setGroupAddedTimestampInSeconds(
+              dataFileGroup.getBookkeeping().getGroupNewFilesReceivedTimestamp() / 1000);
+    } else {
+      fileGroupStatus.setGroupAddedTimestampInSeconds(-1);
+    }
+
+    if (groupKey.getDownloaded()) {
+      fileGroupStatus.setFileGroupDownloadStatus(MddFileGroupDownloadStatus.Code.COMPLETE);
+      if (dataFileGroup.getBookkeeping().hasGroupDownloadedTimestampInMillis()) {
+        fileGroupStatus.setGroupDownloadedTimestampInSeconds(
+                dataFileGroup.getBookkeeping().getGroupDownloadedTimestampInMillis() / 1000);
+      } else {
+        fileGroupStatus.setGroupDownloadedTimestampInSeconds(-1);
+      }
+      return immediateFuture(fileGroupStatus.build());
+    } else {
+      fileGroupStatus.setGroupDownloadedTimestampInSeconds(-1);
+      return PropagatedFutures.transform(
+              fileGroupManager.getFileGroupDownloadStatus(dataFileGroup),
+              status -> {
+                if (status == GroupDownloadStatus.DOWNLOADED || status == GroupDownloadStatus.PENDING) {
+                  // Log pending even if verify returns downloaded, as it will be marked as
+                  // completed in the next periodic task.
+                  fileGroupStatus.setFileGroupDownloadStatus(MddFileGroupDownloadStatus.Code.PENDING);
+                } else {
+                  // TODO(b/73490689): Log the reason for failure along with this.
+                  fileGroupStatus.setFileGroupDownloadStatus(MddFileGroupDownloadStatus.Code.FAILED);
+                }
+                return fileGroupStatus.build();
+              },
+              sequentialControlExecutor);
+    }
   }
-}
+}
\ No newline at end of file
diff --git a/java/com/google/android/libraries/mobiledatadownload/internal/logging/LogSampler.java b/java/com/google/android/libraries/mobiledatadownload/internal/logging/LogSampler.java
index 212dec5..6e6ac72 100644
--- a/java/com/google/android/libraries/mobiledatadownload/internal/logging/LogSampler.java
+++ b/java/com/google/android/libraries/mobiledatadownload/internal/logging/LogSampler.java
@@ -23,6 +23,9 @@ import com.google.android.libraries.mobiledatadownload.tracing.PropagatedFluentF
 import com.google.common.base.Optional;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.errorprone.annotations.CheckReturnValue;
+import com.google.mobiledatadownload.LogProto.StableSamplingInfo;
+import com.google.protobuf.Timestamp;
+
 import java.util.Random;
 
 /** Class responsible for sampling events. */
@@ -58,8 +61,8 @@ public final class LogSampler {
    *     Optional if the event should not be logged. If the event should be logged, the returned
    *     Void should be attached to the log event.
    */
-  public ListenableFuture<Optional<Void>> shouldLog(
-      long sampleInterval, Optional<LoggingStateStore> loggingStateStore) {
+  public ListenableFuture<Optional<StableSamplingInfo>> shouldLog(
+          long sampleInterval, Optional<LoggingStateStore> loggingStateStore) {
     if (sampleInterval == 0L) {
       return immediateFuture(Optional.absent());
     } else if (sampleInterval < 0L) {
@@ -78,9 +81,10 @@ public final class LogSampler {
    * @return if the event should be sampled, returns the Void with stable_sampling_used = false.
    *     Otherwise, returns an empty Optional.
    */
-  private ListenableFuture<Optional<Void>> shouldLogPerEvent(long sampleInterval) {
+  private ListenableFuture<Optional<StableSamplingInfo>> shouldLogPerEvent(long sampleInterval) {
     if (shouldSamplePerEvent(sampleInterval)) {
-      return immediateFuture(Optional.absent());
+      return immediateFuture(
+              Optional.of(StableSamplingInfo.newBuilder().setStableSamplingUsed(false).build()));
     } else {
       return immediateFuture(Optional.absent());
     }
@@ -103,24 +107,33 @@ public final class LogSampler {
    * @return if the event should be sampled, returns the Void with stable_sampling_used = true and
    *     all other fields populated. Otherwise, returns an empty Optional.
    */
-  private ListenableFuture<Optional<Void>> shouldLogDeviceStable(
-      long sampleInterval, LoggingStateStore loggingStateStore) {
+  private ListenableFuture<Optional<StableSamplingInfo>> shouldLogDeviceStable(
+          long sampleInterval, LoggingStateStore loggingStateStore) {
     return PropagatedFluentFuture.from(loggingStateStore.getStableSamplingInfo())
-        .transform(
-            samplingInfo -> {
-              boolean invalidSamplingRateUsed = ((100 % sampleInterval) != 0);
-              if (invalidSamplingRateUsed) {
-                LogUtil.e(
-                    "Bad sample interval (1 percent cohort will not log): %d", sampleInterval);
-              }
+            .transform(
+                    samplingInfo -> {
+                      boolean invalidSamplingRateUsed = ((100 % sampleInterval) != 0);
+                      if (invalidSamplingRateUsed) {
+                        LogUtil.e(
+                                "Bad sample interval (1 percent cohort will not log): %d", sampleInterval);
+                      }
 
-              if (!isPartOfSample(samplingInfo.getStableLogSamplingSalt(), sampleInterval)) {
-                return Optional.absent();
-              }
+                      if (!isPartOfSample(samplingInfo.getStableLogSamplingSalt(), sampleInterval)) {
+                        return Optional.absent();
+                      }
 
-              return Optional.absent();
-            },
-            directExecutor());
+                      return Optional.of(
+                              StableSamplingInfo.newBuilder()
+                                      .setStableSamplingUsed(true)
+                                      .setStableSamplingFirstEnabledTimestampMs(
+                                              toMillis(samplingInfo.getLogSamplingSaltSetTimestamp()))
+                                      .setPartOfAlwaysLoggingGroup(
+                                              isPartOfSample(
+                                                      samplingInfo.getStableLogSamplingSalt(), /*sampleInterval=*/ 100))
+                                      .setInvalidSamplingRateUsed(invalidSamplingRateUsed)
+                                      .build());
+                    },
+                    directExecutor());
   }
 
   /**
@@ -130,4 +143,10 @@ public final class LogSampler {
   private boolean isPartOfSample(long randomNumber, long sampleInterval) {
     return randomNumber % sampleInterval == 0;
   }
-}
+
+  // Copy from com.google.protobuf.util.Timestamps
+  // TODO(b/243397277) Remove toMillis.
+  private static long toMillis(Timestamp timestamp) {
+    return timestamp.getSeconds() * 1000L + (long)timestamp.getNanos() / 1000000L;
+  }
+}
\ No newline at end of file
diff --git a/java/com/google/android/libraries/mobiledatadownload/internal/logging/MddEventLogger.java b/java/com/google/android/libraries/mobiledatadownload/internal/logging/MddEventLogger.java
index c2b4984..1b11bb4 100644
--- a/java/com/google/android/libraries/mobiledatadownload/internal/logging/MddEventLogger.java
+++ b/java/com/google/android/libraries/mobiledatadownload/internal/logging/MddEventLogger.java
@@ -29,6 +29,11 @@ import com.google.common.util.concurrent.AsyncCallable;
 import com.google.common.util.concurrent.FluentFuture;
 import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.ListenableFuture;
+import com.google.mobiledatadownload.LogEnumsProto.MddClientEvent.Code;
+import com.google.mobiledatadownload.LogProto.AndroidClientInfo;
+import com.google.mobiledatadownload.LogProto.MddDeviceInfo;
+import com.google.mobiledatadownload.LogProto.MddLogData;
+import com.google.mobiledatadownload.LogProto.StableSamplingInfo;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
@@ -50,7 +55,7 @@ public final class MddEventLogger implements EventLogger {
   private Optional<LoggingStateStore> loggingStateStore = Optional.absent();
 
   public MddEventLogger(
-      Context context, Logger logger, int moduleVersion, LogSampler logSampler, Flags flags) {
+          Context context, Logger logger, int moduleVersion, LogSampler logSampler, Flags flags) {
     this.context = context;
     this.logger = logger;
     this.moduleVersion = moduleVersion;
@@ -78,11 +83,11 @@ public final class MddEventLogger implements EventLogger {
 
   @Override
   public void logEventSampled(
-      int eventCode,
-      String fileGroupName,
-      int fileGroupVersionNumber,
-      long buildId,
-      String variantId) {
+          int eventCode,
+          String fileGroupName,
+          int fileGroupVersionNumber,
+          long buildId,
+          String variantId) {
 
     Void dataDownloadFileGroupStats = null;
   }
@@ -110,43 +115,48 @@ public final class MddEventLogger implements EventLogger {
 
   @Override
   public ListenableFuture<Void> logMddFileGroupStats(
-      AsyncCallable<List<EventLogger.FileGroupStatusWithDetails>> buildFileGroupStats) {
+          AsyncCallable<List<EventLogger.FileGroupStatusWithDetails>> buildFileGroupStats) {
     return lazySampleAndSendLogEvent(
-        0,
-        () ->
-            PropagatedFutures.transform(
-                buildFileGroupStats.call(),
-                fileGroupStatusAndDetailsList -> {
-                  List<Void> allIcingLogData = new ArrayList<>();
-
-                  for (FileGroupStatusWithDetails fileGroupStatusAndDetails :
-                      fileGroupStatusAndDetailsList) {
-                    allIcingLogData.add(null);
-                  }
-                  return allIcingLogData;
-                },
-                directExecutor()),
-        flags.groupStatsLoggingSampleInterval());
+            Code.DATA_DOWNLOAD_FILE_GROUP_STATUS,
+            () ->
+                    PropagatedFutures.transform(
+                            buildFileGroupStats.call(),
+                            fileGroupStatusAndDetailsList -> {
+                              List<MddLogData> allMddLogData = new ArrayList<>();
+
+                              for (FileGroupStatusWithDetails fileGroupStatusAndDetails :
+                                      fileGroupStatusAndDetailsList) {
+                                allMddLogData.add(
+                                        MddLogData.newBuilder()
+                                                .setMddFileGroupStatus(fileGroupStatusAndDetails.fileGroupStatus())
+                                                .setDataDownloadFileGroupStats(
+                                                        fileGroupStatusAndDetails.fileGroupDetails())
+                                                .build());
+                              }
+                              return allMddLogData;
+                            },
+                            directExecutor()),
+            flags.groupStatsLoggingSampleInterval());
   }
 
   @Override
   public ListenableFuture<Void> logMddStorageStats(AsyncCallable<Void> buildStorageStats) {
     return lazySampleAndSendLogEvent(
-        0,
-        () ->
-            PropagatedFutures.transform(
-                buildStorageStats.call(), storageStats -> Arrays.asList(), directExecutor()),
-        flags.storageStatsLoggingSampleInterval());
+            Code.EVENT_CODE_UNSPECIFIED,
+            () ->
+                    PropagatedFutures.transform(
+                            buildStorageStats.call(), storageStats -> Arrays.asList(), directExecutor()),
+            flags.storageStatsLoggingSampleInterval());
   }
 
   @Override
   public ListenableFuture<Void> logMddNetworkStats(AsyncCallable<Void> buildNetworkStats) {
     return lazySampleAndSendLogEvent(
-        0,
-        () ->
-            PropagatedFutures.transform(
-                buildNetworkStats.call(), networkStats -> Arrays.asList(), directExecutor()),
-        flags.networkStatsLoggingSampleInterval());
+            Code.EVENT_CODE_UNSPECIFIED,
+            () ->
+                    PropagatedFutures.transform(
+                            buildNetworkStats.call(), networkStats -> Arrays.asList(), directExecutor()),
+            flags.networkStatsLoggingSampleInterval());
   }
 
   @Override
@@ -157,12 +167,12 @@ public final class MddEventLogger implements EventLogger {
 
   @Override
   public void logMddNetworkSavings(
-      Void fileGroupDetails,
-      int code,
-      long fullFileSize,
-      long downloadedFileSize,
-      String fileId,
-      int deltaIndex) {
+          Void fileGroupDetails,
+          int code,
+          long fullFileSize,
+          long downloadedFileSize,
+          String fileId,
+          int deltaIndex) {
     Void logData = null;
 
     sampleAndSendLogEvent(0, logData, flags.mddDefaultSampleInterval());
@@ -213,63 +223,92 @@ public final class MddEventLogger implements EventLogger {
    * constructs the log event lazy. This is useful if constructing the log event is expensive.
    */
   private ListenableFuture<Void> lazySampleAndSendLogEvent(
-      int eventCode, AsyncCallable<List<Void>> buildStats, int sampleInterval) {
+          Code eventCode, AsyncCallable<List<MddLogData>> buildStats, int sampleInterval) {
     return PropagatedFutures.transformAsync(
-        logSampler.shouldLog(sampleInterval, loggingStateStore),
-        samplingInfoOptional -> {
-          if (!samplingInfoOptional.isPresent()) {
-            return immediateVoidFuture();
-          }
-
-          return FluentFuture.from(buildStats.call())
-              .transform(
-                  icingLogDataList -> {
-                    if (icingLogDataList != null) {
-                      for (Void icingLogData : icingLogDataList) {
-                        processAndSendEvent(
-                            eventCode, null, sampleInterval, samplingInfoOptional.get());
-                      }
-                    }
-                    return null;
-                  },
-                  directExecutor());
-        },
-        directExecutor());
+            logSampler.shouldLog(sampleInterval, loggingStateStore),
+            samplingInfoOptional -> {
+              if (!samplingInfoOptional.isPresent()) {
+                return immediateVoidFuture();
+              }
+
+              return FluentFuture.from(buildStats.call())
+                      .transform(
+                              icingLogDataList -> {
+                                if (icingLogDataList != null) {
+                                  for (MddLogData icingLogData : icingLogDataList) {
+                                    processAndSendEvent(
+                                            eventCode,
+                                            icingLogData.toBuilder(),
+                                            sampleInterval,
+                                            samplingInfoOptional.get());
+                                  }
+                                }
+                                return null;
+                              },
+                              directExecutor());
+            },
+            directExecutor());
   }
 
   private void sampleAndSendLogEvent(int eventCode, Void logData, long sampleInterval) {
     PropagatedFutures.addCallback(
-        logSampler.shouldLog(sampleInterval, loggingStateStore),
-        new FutureCallback<Optional<Void>>() {
-          @Override
-          public void onSuccess(Optional<Void> stableSamplingInfo) {
-            if (stableSamplingInfo.isPresent()) {
-              processAndSendEvent(eventCode, logData, sampleInterval, stableSamplingInfo.get());
-            }
-          }
-
-          @Override
-          public void onFailure(Throwable t) {
-            LogUtil.e(t, "%s: failure when sampling log!", TAG);
-          }
-        },
-        directExecutor());
+            logSampler.shouldLog(sampleInterval, loggingStateStore),
+            new FutureCallback<Optional<StableSamplingInfo>>() {
+              @Override
+              public void onSuccess(Optional<StableSamplingInfo> stableSamplingInfo) {
+                if (stableSamplingInfo.isPresent()) {
+                  processAndSendEvent(
+                          Code.EVENT_CODE_UNSPECIFIED,
+                          MddLogData.newBuilder(),
+                          sampleInterval,
+                          stableSamplingInfo.get());
+                }
+              }
+
+              @Override
+              public void onFailure(Throwable t) {
+                LogUtil.e(t, "%s: failure when sampling log!", TAG);
+              }
+            },
+            directExecutor());
   }
 
   /** Adds all transforms common to all logs and sends the event to Logger. */
   private void processAndSendEventWithoutStableSampling(
-      int eventCode, Void logData, long sampleInterval) {
-    processAndSendEvent(eventCode, logData, sampleInterval, null);
+          int eventCode, Void logData, long sampleInterval) {
+    processAndSendEvent(
+            Code.EVENT_CODE_UNSPECIFIED,
+            MddLogData.newBuilder(),
+            sampleInterval,
+            StableSamplingInfo.newBuilder().setStableSamplingUsed(false).build());
   }
 
   /** Adds all transforms common to all logs and sends the event to Logger. */
   private void processAndSendEvent(
-      int eventCode, Void logData, long sampleInterval, Void stableSamplingInfo) {}
+          Code eventCode,
+          MddLogData.Builder logData,
+          long sampleInterval,
+          StableSamplingInfo stableSamplingInfo) {
+    if (eventCode.equals(Code.EVENT_CODE_UNSPECIFIED)) {
+      LogUtil.e("%s: unspecified code used, skipping event log", TAG);
+      // return early for unspecified codes.
+      return;
+    }
+    logData
+            .setSamplingInterval(sampleInterval)
+            .setDeviceInfo(MddDeviceInfo.newBuilder().setDeviceStorageLow(isDeviceStorageLow(context)))
+            .setAndroidClientInfo(
+                    AndroidClientInfo.newBuilder()
+                            .setHostPackageName(hostPackageName)
+                            .setModuleVersion(moduleVersion))
+            .setStableSamplingInfo(stableSamplingInfo);
+    logger.log(logData.build(), eventCode.getNumber());
+  }
 
   /** Returns whether the device is in low storage state. */
   private static boolean isDeviceStorageLow(Context context) {
     // Check if the system says storage is low, by reading the sticky intent.
     return context.registerReceiver(null, new IntentFilter(Intent.ACTION_DEVICE_STORAGE_LOW))
-        != null;
+            != null;
   }
-}
+}
\ No newline at end of file
diff --git a/java/com/google/android/libraries/mobiledatadownload/internal/logging/SharedPreferencesLoggingState.java b/java/com/google/android/libraries/mobiledatadownload/internal/logging/SharedPreferencesLoggingState.java
new file mode 100644
index 0000000..e4debc5
--- /dev/null
+++ b/java/com/google/android/libraries/mobiledatadownload/internal/logging/SharedPreferencesLoggingState.java
@@ -0,0 +1,367 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.libraries.mobiledatadownload.internal.logging;
+
+import static com.google.android.libraries.mobiledatadownload.internal.MddConstants.SPLIT_CHAR;
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import androidx.annotation.VisibleForTesting;
+import com.google.android.libraries.mobiledatadownload.TimeSource;
+import com.google.android.libraries.mobiledatadownload.internal.util.FileGroupsMetadataUtil;
+import com.google.android.libraries.mobiledatadownload.internal.util.FileGroupsMetadataUtil.GroupKeyDeserializationException;
+import com.google.android.libraries.mobiledatadownload.internal.util.SharedPreferencesUtil;
+import com.google.android.libraries.mobiledatadownload.tracing.PropagatedExecutionSequencer;
+import com.google.common.base.Optional;
+import com.google.common.base.Splitter;
+import com.google.common.base.Supplier;
+import com.google.common.base.Suppliers;
+import com.google.common.primitives.Ints;
+import com.google.common.util.concurrent.ListenableFuture;
+import com.google.mobiledatadownload.internal.MetadataProto.FileGroupLoggingState;
+import com.google.mobiledatadownload.internal.MetadataProto.GroupKey;
+import com.google.mobiledatadownload.internal.MetadataProto.SamplingInfo;
+import com.google.protobuf.Timestamp;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Calendar;
+import java.util.GregorianCalendar;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Random;
+import java.util.Set;
+import java.util.TimeZone;
+import java.util.concurrent.Executor;
+
+/** LoggingStateStore that uses SharedPreferences for storage. */
+public final class SharedPreferencesLoggingState implements LoggingStateStore {
+
+    private static final String SHARED_PREFS_NAME = "LoggingState";
+
+    private static final String LAST_MAINTENANCE_RUN_SECS_KEY = "last_maintenance_secs";
+
+    @VisibleForTesting static final String SALT_KEY = "stable_log_sampling_salt";
+    private static final String SALT_TIMESTAMP_MILLIS_KEY = "log_sampling_salt_set_timestamp_millis";
+
+    private final Supplier<SharedPreferences> sharedPrefs;
+    private final Executor backgroundExecutor;
+    private final TimeSource timeSource;
+    private final Random random;
+
+    // Serialize access to SharedPref keys to avoid clobbering.
+    private final PropagatedExecutionSequencer futureSerializer =
+            PropagatedExecutionSequencer.create();
+
+    /**
+     * Constructs a new instance.
+     *
+     * @param sharedPrefs may be called multiple times, so memoization is recommended. The returned
+     *     instance must be exclusive to {@link SharedPreferencesLoggingState} since {@link #clear}
+     *     may clear the data at any time.
+     */
+    public static SharedPreferencesLoggingState create(
+            Supplier<SharedPreferences> sharedPrefs,
+            TimeSource timeSource,
+            Executor backgroundExecutor,
+            Random random) {
+        return new SharedPreferencesLoggingState(sharedPrefs, timeSource, backgroundExecutor, random);
+    }
+
+    /** Constructs a new instance. */
+    public static SharedPreferencesLoggingState createFromContext(
+            Context context,
+            Optional<String> instanceIdOptional,
+            TimeSource timeSource,
+            Executor backgroundExecutor,
+            Random random) {
+        // Avoid calling getSharedPreferences on the main thread.
+        Supplier<SharedPreferences> sharedPrefs =
+                Suppliers.memoize(
+                        () ->
+                                SharedPreferencesUtil.getSharedPreferences(
+                                        context, SHARED_PREFS_NAME, instanceIdOptional));
+        return new SharedPreferencesLoggingState(sharedPrefs, timeSource, backgroundExecutor, random);
+    }
+
+    private SharedPreferencesLoggingState(
+            Supplier<SharedPreferences> sharedPrefs,
+            TimeSource timeSource,
+            Executor backgroundExecutor,
+            Random random) {
+        this.sharedPrefs = sharedPrefs;
+        this.timeSource = timeSource;
+        this.backgroundExecutor = backgroundExecutor;
+        this.random = random;
+    }
+
+    /** Data fields for each Entry persisted in SharedPreferences. */
+    private enum Key {
+        CELLULAR_USAGE("cu"),
+        WIFI_USAGE("wu");
+
+        final String sharedPrefsSuffix;
+
+        Key(String sharedPrefsSuffix) {
+            this.sharedPrefsSuffix = sharedPrefsSuffix;
+        }
+    }
+
+    /** Bridge between FileGroupLoggingState and its SharedPreferences representation. */
+    private static final class Entry {
+
+        final GroupKey groupKey;
+        final long buildId;
+        final int fileGroupVersionNumber;
+
+        /** Prefix used in SharedPreference keys. */
+        final String spKeyPrefix;
+
+        static Entry fromLoggingState(FileGroupLoggingState loggingState) {
+            return new Entry(
+                    /* groupKey= */ loggingState.getGroupKey(),
+                    /* buildId= */ loggingState.getBuildId(),
+                    /* fileGroupVersionNumber= */ loggingState.getFileGroupVersionNumber());
+        }
+
+        /**
+         * @throws IllegalArgumentException if the key can't be parsed
+         */
+        static Entry fromSpKey(String spKey) {
+            List<String> parts = Splitter.on(SPLIT_CHAR).splitToList(spKey);
+            try {
+                return new Entry(
+                        /* groupKey= */ FileGroupsMetadataUtil.deserializeGroupKey(parts.get(0)),
+                        /* buildId= */ Long.parseLong(parts.get(1)),
+                        /* fileGroupVersionNumber= */ Integer.parseInt(parts.get(2)));
+            } catch (GroupKeyDeserializationException | ArrayIndexOutOfBoundsException e) {
+                throw new IllegalArgumentException("Failed to parse SharedPrefs key: " + spKey, e);
+            }
+        }
+
+        private Entry(GroupKey groupKey, long buildId, int fileGroupVersionNumber) {
+            this.groupKey = groupKey;
+            this.buildId = buildId;
+            this.fileGroupVersionNumber = fileGroupVersionNumber;
+            this.spKeyPrefix =
+                    FileGroupsMetadataUtil.getSerializedGroupKey(groupKey)
+                            + SPLIT_CHAR
+                            + buildId
+                            + SPLIT_CHAR
+                            + fileGroupVersionNumber;
+        }
+
+        String getSharedPrefsKey(Key key) {
+            return spKeyPrefix + SPLIT_CHAR + key.sharedPrefsSuffix;
+        }
+    }
+
+    @Override
+    public ListenableFuture<Optional<Integer>> getAndResetDaysSinceLastMaintenance() {
+        return futureSerializer.submit(
+                () -> {
+                    long currentTimestamp = timeSource.currentTimeMillis();
+
+                    Optional<Integer> daysSinceLastMaintenance;
+                    boolean hasEverDoneMaintenance =
+                            sharedPrefs.get().contains(LAST_MAINTENANCE_RUN_SECS_KEY);
+                    if (hasEverDoneMaintenance) {
+                        long persistedTimestamp = sharedPrefs.get().getLong(LAST_MAINTENANCE_RUN_SECS_KEY, 0);
+                        long currentStartOfDay = truncateTimestampToStartOfDay(currentTimestamp);
+                        long previousStartOfDay = truncateTimestampToStartOfDay(persistedTimestamp);
+                        // Note: ignore MillisTo_Days java optional suggestion because Duration is api
+                        // 26+.
+                        daysSinceLastMaintenance =
+                                Optional.of(
+                                        Ints.saturatedCast(
+                                                MILLISECONDS.toDays(currentStartOfDay - previousStartOfDay)));
+                    } else {
+                        daysSinceLastMaintenance = Optional.absent();
+                    }
+
+                    SharedPreferences.Editor editor = sharedPrefs.get().edit();
+                    editor.putLong(LAST_MAINTENANCE_RUN_SECS_KEY, currentTimestamp);
+                    commitOrThrow(editor);
+
+                    return daysSinceLastMaintenance;
+                },
+                backgroundExecutor);
+    }
+
+    @Override
+    public ListenableFuture<Void> incrementDataUsage(FileGroupLoggingState dataUsageIncrements) {
+        return futureSerializer.submit(
+                () -> {
+                    Entry entry = Entry.fromLoggingState(dataUsageIncrements);
+
+                    long currentCellarUsage =
+                            sharedPrefs.get().getLong(entry.getSharedPrefsKey(Key.CELLULAR_USAGE), 0);
+                    long currentWifiUsage =
+                            sharedPrefs.get().getLong(entry.getSharedPrefsKey(Key.WIFI_USAGE), 0);
+                    long updatedCellarUsage = currentCellarUsage + dataUsageIncrements.getCellularUsage();
+                    long updatedWifiUsage = currentWifiUsage + dataUsageIncrements.getWifiUsage();
+
+                    SharedPreferences.Editor editor = sharedPrefs.get().edit();
+                    editor.putLong(entry.getSharedPrefsKey(Key.CELLULAR_USAGE), updatedCellarUsage);
+                    editor.putLong(entry.getSharedPrefsKey(Key.WIFI_USAGE), updatedWifiUsage);
+
+                    return commitOrThrow(editor);
+                },
+                backgroundExecutor);
+    }
+
+    @Override
+    public ListenableFuture<List<FileGroupLoggingState>> getAndResetAllDataUsage() {
+        return futureSerializer.submit(
+                () -> {
+                    List<FileGroupLoggingState> allLoggingStates = new ArrayList<>();
+                    Set<String> allLoggingStateKeys = new HashSet<>();
+                    SharedPreferences.Editor editor = sharedPrefs.get().edit();
+
+                    for (String key : sharedPrefs.get().getAll().keySet()) {
+                        Entry entry;
+                        try {
+                            entry = Entry.fromSpKey(key);
+                        } catch (IllegalArgumentException e) {
+                            continue; // This isn't a LoggingState entry
+                        }
+                        if (allLoggingStateKeys.contains(entry.spKeyPrefix)) {
+                            continue;
+                        }
+                        allLoggingStateKeys.add(entry.spKeyPrefix);
+
+                        FileGroupLoggingState loggingState =
+                                FileGroupLoggingState.newBuilder()
+                                        .setGroupKey(entry.groupKey)
+                                        .setBuildId(entry.buildId)
+                                        .setFileGroupVersionNumber(entry.fileGroupVersionNumber)
+                                        .setCellularUsage(
+                                                sharedPrefs.get().getLong(entry.getSharedPrefsKey(Key.CELLULAR_USAGE), 0))
+                                        .setWifiUsage(
+                                                sharedPrefs.get().getLong(entry.getSharedPrefsKey(Key.WIFI_USAGE), 0))
+                                        .build();
+                        allLoggingStates.add(loggingState);
+
+                        editor.remove(entry.getSharedPrefsKey(Key.CELLULAR_USAGE));
+                        editor.remove(entry.getSharedPrefsKey(Key.WIFI_USAGE));
+                    }
+                    commitOrThrow(editor);
+
+                    return allLoggingStates;
+                },
+                backgroundExecutor);
+    }
+
+    @Override
+    public ListenableFuture<Void> clear() {
+        return futureSerializer.submit(
+                () -> {
+                    SharedPreferences.Editor editor = sharedPrefs.get().edit();
+                    editor.clear();
+                    return commitOrThrow(editor);
+                },
+                backgroundExecutor);
+    }
+
+    @Override
+    public ListenableFuture<SamplingInfo> getStableSamplingInfo() {
+        return futureSerializer.submit(
+                () -> {
+                    long salt;
+                    long persistedTimestampMillis;
+
+                    boolean hasCreatedSalt = sharedPrefs.get().contains(SALT_KEY);
+                    if (hasCreatedSalt) {
+                        salt = sharedPrefs.get().getLong(SALT_KEY, 0);
+                        persistedTimestampMillis = sharedPrefs.get().getLong(SALT_TIMESTAMP_MILLIS_KEY, 0);
+                    } else {
+                        salt = random.nextLong();
+                        persistedTimestampMillis = timeSource.currentTimeMillis();
+
+                        SharedPreferences.Editor editor = sharedPrefs.get().edit();
+                        editor.putLong(SALT_KEY, salt);
+                        editor.putLong(SALT_TIMESTAMP_MILLIS_KEY, persistedTimestampMillis);
+                        commitOrThrow(editor);
+                    }
+
+                    Timestamp timestamp = fromMillis(persistedTimestampMillis);
+                    return SamplingInfo.newBuilder()
+                            .setStableLogSamplingSalt(salt)
+                            .setLogSamplingSaltSetTimestamp(timestamp)
+                            .build();
+                },
+                backgroundExecutor);
+    }
+
+    // Use UTC time zone here so we don't have to worry about time zone change or daylight savings.
+    private static final TimeZone UTC_TIMEZONE = TimeZone.getTimeZone("UTC");
+
+    // TODO(b/237533403): extract as shareable code with ProtoDataStoreLoggingState
+    private static long truncateTimestampToStartOfDay(long timestampMillis) {
+        // We use the regular java.util.Calendar classes here since neither Joda time nor java.time is
+        // supported across all client apps.
+        Calendar cal = new GregorianCalendar(UTC_TIMEZONE);
+        cal.setTimeInMillis(timestampMillis);
+        cal.set(Calendar.HOUR_OF_DAY, 0);
+        cal.set(Calendar.MINUTE, 0);
+        cal.set(Calendar.SECOND, 0);
+        cal.set(Calendar.MILLISECOND, 0);
+        return cal.getTimeInMillis();
+    }
+
+    /** Calls {@code editor.commit()} and returns void, or throws IOException if the commit failed. */
+    private static Void commitOrThrow(SharedPreferences.Editor editor) throws IOException {
+        if (!editor.commit()) {
+            throw new IOException("Failed to commit");
+        }
+        return null;
+    }
+
+    // TODO(b/243397277) Remove following methods.
+    public static Timestamp fromMillis(long milliseconds) {
+        return normalizedTimestamp(milliseconds / 1000L, (int)(milliseconds % 1000L * 1000000L));
+    }
+
+    private static Timestamp normalizedTimestamp(long seconds, int nanos) {
+        if ((long)nanos <= -1000000000L || (long)nanos >= 1000000000L) {
+            seconds += (long)nanos / 1000000000L;
+            nanos = (int)((long)nanos % 1000000000L);
+        }
+
+        if (nanos < 0) {
+            nanos = (int)((long)nanos + 1000000000L);
+            --seconds;
+        }
+
+        checkValid(seconds, nanos);
+        return Timestamp.newBuilder().setSeconds(seconds).setNanos(nanos).build();
+    }
+
+    private static void checkValid(long seconds, int nanos) {
+        if (!isValid(seconds, (long)nanos)) {
+            throw new IllegalArgumentException(String.format("Timestamp is not valid. See proto definition for valid values. Seconds (%s) must be in range [-62,135,596,800, +253,402,300,799].Nanos (%s) must be in range [0, +999,999,999].", seconds, nanos));
+        }
+    }
+
+    private static boolean isValid(long seconds, long nanos) {
+        if (seconds >= -62135596800L && seconds <= 253402300799L) {
+            return nanos >= 0L && nanos < 1000000000L;
+        } else {
+            return false;
+        }
+    }
+}
\ No newline at end of file
diff --git a/java/com/google/android/libraries/mobiledatadownload/internal/util/FileGroupsMetadataUtil.java b/java/com/google/android/libraries/mobiledatadownload/internal/util/FileGroupsMetadataUtil.java
index fda3b1e..7853bfa 100644
--- a/java/com/google/android/libraries/mobiledatadownload/internal/util/FileGroupsMetadataUtil.java
+++ b/java/com/google/android/libraries/mobiledatadownload/internal/util/FileGroupsMetadataUtil.java
@@ -94,7 +94,7 @@ public final class FileGroupsMetadataUtil {
   }
 
   // TODO(b/129702287): Move away from proto based serialization.
-  public static String getSerializedGroupKey(GroupKey groupKey, Context context) {
+  public static String getSerializedGroupKey(GroupKey groupKey) {
     byte[] byteValue = groupKey.toByteArray();
     return Base64.encodeToString(byteValue, Base64.NO_PADDING | Base64.NO_WRAP);
   }
diff --git a/java/com/google/android/libraries/mobiledatadownload/tracing/PropagatedExecutionSequencer.java b/java/com/google/android/libraries/mobiledatadownload/tracing/PropagatedExecutionSequencer.java
new file mode 100644
index 0000000..c2bfec5
--- /dev/null
+++ b/java/com/google/android/libraries/mobiledatadownload/tracing/PropagatedExecutionSequencer.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.libraries.mobiledatadownload.tracing;
+
+import com.google.common.util.concurrent.AsyncCallable;
+import com.google.common.util.concurrent.ExecutionSequencer;
+import com.google.common.util.concurrent.ListenableFuture;
+import java.util.concurrent.Callable;
+import java.util.concurrent.Executor;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+/** Wrapper around {@link ExecutionSequencer} with trace propagation. */
+public final class PropagatedExecutionSequencer {
+
+    private final ExecutionSequencer executionSequencer = ExecutionSequencer.create();
+
+    private PropagatedExecutionSequencer() {}
+
+    /** Creates a new instance. */
+    public static PropagatedExecutionSequencer create() {
+        return new PropagatedExecutionSequencer();
+    }
+
+    /** See {@link ExecutionSequencer#submit(Callable, Executor)}. */
+    public <T extends @Nullable Object> ListenableFuture<T> submit(
+            Callable<T> callable, Executor executor) {
+        return executionSequencer.submit(callable, executor);
+    }
+
+    /** See {@link ExecutionSequencer#submitAsync(AsyncCallable, Executor)}. */
+    public <T extends @Nullable Object> ListenableFuture<T> submitAsync(
+            AsyncCallable<T> callable, Executor executor) {
+        return executionSequencer.submitAsync(callable, executor);
+    }
+}
\ No newline at end of file
diff --git a/javatests/com/google/android/libraries/mobiledatadownload/internal/logging/FileGroupStatsLoggerTest.java b/javatests/com/google/android/libraries/mobiledatadownload/internal/logging/FileGroupStatsLoggerTest.java
new file mode 100644
index 0000000..ad7777a
--- /dev/null
+++ b/javatests/com/google/android/libraries/mobiledatadownload/internal/logging/FileGroupStatsLoggerTest.java
@@ -0,0 +1,339 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.libraries.mobiledatadownload.internal.logging;
+
+import static com.google.common.truth.Truth.assertThat;
+import static junit.framework.TestCase.assertTrue;
+import static org.junit.Assert.assertFalse;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.util.Pair;
+import com.google.android.libraries.mdi.download.MetadataProto.DataFile;
+import com.google.android.libraries.mdi.download.MetadataProto.DataFileGroupBookkeeping;
+import com.google.android.libraries.mdi.download.MetadataProto.DataFileGroupInternal;
+import com.google.android.libraries.mdi.download.MetadataProto.GroupKey;
+import com.google.android.libraries.mobiledatadownload.internal.FileGroupManager;
+import com.google.android.libraries.mobiledatadownload.internal.FileGroupManager.GroupDownloadStatus;
+import com.google.android.libraries.mobiledatadownload.internal.FileGroupsMetadata;
+import com.google.android.libraries.mobiledatadownload.internal.MddTestUtil;
+import com.google.android.libraries.mobiledatadownload.internal.util.FileGroupUtil;
+import com.google.common.util.concurrent.AsyncCallable;
+import com.google.common.util.concurrent.Futures;
+import com.google.common.util.concurrent.MoreExecutors;
+import com.google.mobiledatadownload.LogEnumsProto.MddFileGroupDownloadStatus;
+import com.google.mobiledatadownload.LogProto.DataDownloadFileGroupStats;
+import com.google.mobiledatadownload.LogProto.MddFileGroupStatus;
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Captor;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+import org.robolectric.RobolectricTestRunner;
+
+@RunWith(RobolectricTestRunner.class)
+public class FileGroupStatsLoggerTest {
+
+    private static final String TEST_GROUP = "test-group";
+    private static final String TEST_GROUP_2 = "test-group-2";
+
+    private static final String TEST_PACKAGE = "test-package";
+
+    // This one has account
+    private static final GroupKey TEST_KEY =
+            GroupKey.newBuilder()
+                    .setGroupName(TEST_GROUP)
+                    .setOwnerPackage(TEST_PACKAGE)
+                    .setAccount("some_account")
+                    .build();
+
+    // This one does not have account
+    private static final GroupKey TEST_KEY_2 =
+            GroupKey.newBuilder().setGroupName(TEST_GROUP_2).setOwnerPackage(TEST_PACKAGE).build();
+
+    @Mock FileGroupManager mockFileGroupManager;
+    @Mock FileGroupsMetadata mockFileGroupsMetadata;
+    @Mock EventLogger mockEventLogger;
+
+    private FileGroupStatsLogger fileGroupStatsLogger;
+
+    @Rule public final MockitoRule mocks = MockitoJUnit.rule();
+
+    @Captor
+    ArgumentCaptor<AsyncCallable<List<EventLogger.FileGroupStatusWithDetails>>>
+            fileGroupStatusAndDetailsListCaptor;
+
+    @Before
+    public void setUp() throws Exception {
+
+        fileGroupStatsLogger =
+                new FileGroupStatsLogger(
+                        mockFileGroupManager,
+                        mockFileGroupsMetadata,
+                        mockEventLogger,
+                        MoreExecutors.directExecutor());
+    }
+
+    @Test
+    public void fileGroupStatsLogging() throws Exception {
+        int daysSinceLastLog = 10;
+
+        List<Pair<GroupKey, DataFileGroupInternal>> groups = new ArrayList<>();
+
+        // Add a downloaded group with version number 10.
+        DataFileGroupInternal fileGroupDownloaded =
+                MddTestUtil.createDataFileGroupInternal(TEST_GROUP, 2).toBuilder()
+                        .setFileGroupVersionNumber(10)
+                        .setBuildId(10)
+                        .setVariantId("test-variant")
+                        .build();
+        fileGroupDownloaded =
+                FileGroupUtil.setGroupNewFilesReceivedTimestamp(fileGroupDownloaded, 5000);
+        fileGroupDownloaded = FileGroupUtil.setDownloadedTimestampInMillis(fileGroupDownloaded, 10000);
+
+        groups.add(Pair.create(TEST_KEY.toBuilder().setDownloaded(true).build(), fileGroupDownloaded));
+
+        // Add a pending download group for the same group name with version number 11.
+        DataFileGroupInternal fileGroupPending =
+                MddTestUtil.createDataFileGroupInternal(TEST_GROUP, 3).toBuilder()
+                        .setFileGroupVersionNumber(11)
+                        .setStaleLifetimeSecs(0)
+                        .setExpirationDateSecs(0)
+                        .setBookkeeping(DataFileGroupBookkeeping.newBuilder().setStaleExpirationDate(0).build())
+                        .setBuildId(11)
+                        .setVariantId("test-variant")
+                        .build();
+        fileGroupPending = FileGroupUtil.setGroupNewFilesReceivedTimestamp(fileGroupPending, 15000);
+        groups.add(Pair.create(TEST_KEY, fileGroupPending));
+        when(mockFileGroupManager.getFileGroupDownloadStatus(fileGroupPending))
+                .thenReturn(Futures.immediateFuture(GroupDownloadStatus.PENDING));
+
+        // Add a failed group to metadata with version 5.
+        DataFileGroupInternal fileGroupFailed =
+                MddTestUtil.createDataFileGroupInternal(TEST_GROUP_2, 3).toBuilder()
+                        .setFileGroupVersionNumber(5)
+                        .setStaleLifetimeSecs(0)
+                        .setExpirationDateSecs(0)
+                        .setBookkeeping(DataFileGroupBookkeeping.newBuilder().setStaleExpirationDate(0).build())
+                        .build();
+        fileGroupFailed = FileGroupUtil.setGroupNewFilesReceivedTimestamp(fileGroupFailed, 12000);
+        groups.add(Pair.create(TEST_KEY_2, fileGroupFailed));
+        when(mockFileGroupManager.getFileGroupDownloadStatus(fileGroupFailed))
+                .thenReturn(Futures.immediateFuture(GroupDownloadStatus.FAILED));
+
+        when(mockFileGroupsMetadata.getAllFreshGroups()).thenReturn(Futures.immediateFuture(groups));
+
+        when(mockEventLogger.logMddFileGroupStats(any())).thenReturn(Futures.immediateVoidFuture());
+        fileGroupStatsLogger.log(daysSinceLastLog).get();
+
+        verify(mockEventLogger, times(1))
+                .logMddFileGroupStats(fileGroupStatusAndDetailsListCaptor.capture());
+
+        List<EventLogger.FileGroupStatusWithDetails> allFileGroupStatusAndDetailsList =
+                fileGroupStatusAndDetailsListCaptor.getValue().call().get();
+        MddFileGroupStatus status1 = allFileGroupStatusAndDetailsList.get(0).fileGroupStatus();
+        MddFileGroupStatus status2 = allFileGroupStatusAndDetailsList.get(1).fileGroupStatus();
+        MddFileGroupStatus status3 = allFileGroupStatusAndDetailsList.get(2).fileGroupStatus();
+
+        DataDownloadFileGroupStats details1 =
+                allFileGroupStatusAndDetailsList.get(0).fileGroupDetails();
+        DataDownloadFileGroupStats details2 =
+                allFileGroupStatusAndDetailsList.get(1).fileGroupDetails();
+        DataDownloadFileGroupStats details3 =
+                allFileGroupStatusAndDetailsList.get(2).fileGroupDetails();
+
+        // Check that the downloaded group status is logged.
+        assertThat(details1.getFileGroupName()).isEqualTo(TEST_GROUP);
+        assertThat(details1.getOwnerPackage()).isEqualTo(TEST_PACKAGE);
+        assertThat(details1.getFileGroupVersionNumber()).isEqualTo(10);
+        assertThat(details1.getBuildId()).isEqualTo(10);
+        assertThat(details1.getVariantId()).isEqualTo("test-variant");
+        assertThat(details1.getFileCount()).isEqualTo(2);
+        assertThat(details1.getInlineFileCount()).isEqualTo(0);
+        assertTrue(details1.getHasAccount());
+        assertThat(status1.getFileGroupDownloadStatus())
+                .isEqualTo(MddFileGroupDownloadStatus.Code.COMPLETE);
+        assertThat(status1.getGroupAddedTimestampInSeconds()).isEqualTo(5);
+        assertThat(status1.getGroupDownloadedTimestampInSeconds()).isEqualTo(10);
+        assertThat(status1.getDaysSinceLastLog()).isEqualTo(daysSinceLastLog);
+
+        // Check that the pending group status is logged.
+        assertThat(details2.getFileGroupName()).isEqualTo(TEST_GROUP);
+        assertThat(details2.getFileGroupVersionNumber()).isEqualTo(11);
+        assertThat(details2.getBuildId()).isEqualTo(11);
+        assertThat(details2.getVariantId()).isEqualTo("test-variant");
+        assertThat(details2.getOwnerPackage()).isEqualTo(TEST_PACKAGE);
+        assertThat(details2.getFileCount()).isEqualTo(3);
+        assertThat(details2.getInlineFileCount()).isEqualTo(0);
+        assertTrue(details2.getHasAccount());
+        assertThat(status2.getFileGroupDownloadStatus())
+                .isEqualTo(MddFileGroupDownloadStatus.Code.PENDING);
+        assertThat(status2.getGroupAddedTimestampInSeconds()).isEqualTo(15);
+        assertThat(status2.getGroupDownloadedTimestampInSeconds()).isEqualTo(-1);
+        assertThat(status2.getDaysSinceLastLog()).isEqualTo(daysSinceLastLog);
+
+        // Check that the failed group status is logged.
+        assertThat(details3.getFileGroupName()).isEqualTo(TEST_GROUP_2);
+        assertThat(details3.getFileGroupVersionNumber()).isEqualTo(5);
+        assertThat(details3.getOwnerPackage()).isEqualTo(TEST_PACKAGE);
+        assertThat(details3.getFileCount()).isEqualTo(3);
+        assertThat(details3.getInlineFileCount()).isEqualTo(0);
+        assertFalse(details3.getHasAccount());
+        assertThat(status3.getFileGroupDownloadStatus())
+                .isEqualTo(MddFileGroupDownloadStatus.Code.FAILED);
+        assertThat(status3.getGroupAddedTimestampInSeconds()).isEqualTo(12);
+        assertThat(status3.getGroupDownloadedTimestampInSeconds()).isEqualTo(-1);
+        assertThat(status3.getDaysSinceLastLog()).isEqualTo(daysSinceLastLog);
+    }
+
+    @Test
+    public void fileGroupStatsLogging_withInlineFiles() throws Exception {
+        int daysSinceLastLog = 10;
+
+        List<Pair<GroupKey, DataFileGroupInternal>> groups = new ArrayList<>();
+
+        DataFile inlineFile1 =
+                DataFile.newBuilder()
+                        .setFileId("inline-file")
+                        .setUrlToDownload("inlinefile:sha1:checksum")
+                        .setChecksum("checksum")
+                        .setByteSize(10)
+                        .build();
+        DataFile inlineFile2 =
+                DataFile.newBuilder()
+                        .setFileId("inline-file-2")
+                        .setUrlToDownload("inlinefile:sha1:checksum2")
+                        .setChecksum("checksum2")
+                        .setByteSize(11)
+                        .build();
+
+        // Add a downloaded group with version number 10 and inline file
+        DataFileGroupInternal fileGroupDownloaded =
+                MddTestUtil.createDataFileGroupInternal(TEST_GROUP, 2).toBuilder()
+                        .setFileGroupVersionNumber(10)
+                        .setBuildId(10)
+                        .setVariantId("test-variant")
+                        .addFile(inlineFile1)
+                        .addFile(inlineFile2)
+                        .build();
+        fileGroupDownloaded =
+                FileGroupUtil.setGroupNewFilesReceivedTimestamp(fileGroupDownloaded, 5000);
+        fileGroupDownloaded = FileGroupUtil.setDownloadedTimestampInMillis(fileGroupDownloaded, 10000);
+
+        groups.add(Pair.create(TEST_KEY.toBuilder().setDownloaded(true).build(), fileGroupDownloaded));
+
+        // Add a pending download group for the same group name with version number 11 and inline file.
+        DataFileGroupInternal fileGroupPending =
+                MddTestUtil.createDataFileGroupInternal(TEST_GROUP, 3).toBuilder()
+                        .setFileGroupVersionNumber(11)
+                        .setStaleLifetimeSecs(0)
+                        .setExpirationDateSecs(0)
+                        .setBookkeeping(DataFileGroupBookkeeping.newBuilder().setStaleExpirationDate(0).build())
+                        .setBuildId(11)
+                        .setVariantId("test-variant")
+                        .addFile(inlineFile1)
+                        .build();
+        fileGroupPending = FileGroupUtil.setGroupNewFilesReceivedTimestamp(fileGroupPending, 15000);
+        groups.add(Pair.create(TEST_KEY, fileGroupPending));
+        when(mockFileGroupManager.getFileGroupDownloadStatus(fileGroupPending))
+                .thenReturn(Futures.immediateFuture(GroupDownloadStatus.PENDING));
+
+        // Add a failed group to metadata with version 5 with no inline files.
+        DataFileGroupInternal fileGroupFailed =
+                MddTestUtil.createDataFileGroupInternal(TEST_GROUP_2, 3).toBuilder()
+                        .setFileGroupVersionNumber(5)
+                        .setStaleLifetimeSecs(0)
+                        .setExpirationDateSecs(0)
+                        .setBookkeeping(DataFileGroupBookkeeping.newBuilder().setStaleExpirationDate(0).build())
+                        .build();
+        fileGroupFailed = FileGroupUtil.setGroupNewFilesReceivedTimestamp(fileGroupFailed, 12000);
+        groups.add(Pair.create(TEST_KEY_2, fileGroupFailed));
+        when(mockFileGroupManager.getFileGroupDownloadStatus(fileGroupFailed))
+                .thenReturn(Futures.immediateFuture(GroupDownloadStatus.FAILED));
+
+        when(mockFileGroupsMetadata.getAllFreshGroups()).thenReturn(Futures.immediateFuture(groups));
+        when(mockEventLogger.logMddFileGroupStats(any())).thenReturn(Futures.immediateVoidFuture());
+
+        fileGroupStatsLogger.log(daysSinceLastLog).get();
+
+        verify(mockEventLogger, times(1))
+                .logMddFileGroupStats(fileGroupStatusAndDetailsListCaptor.capture());
+
+        List<EventLogger.FileGroupStatusWithDetails> allFileGroupStatusAndDetailsList =
+                fileGroupStatusAndDetailsListCaptor.getValue().call().get();
+        MddFileGroupStatus status1 = allFileGroupStatusAndDetailsList.get(0).fileGroupStatus();
+        MddFileGroupStatus status2 = allFileGroupStatusAndDetailsList.get(1).fileGroupStatus();
+        MddFileGroupStatus status3 = allFileGroupStatusAndDetailsList.get(2).fileGroupStatus();
+
+        DataDownloadFileGroupStats details1 =
+                allFileGroupStatusAndDetailsList.get(0).fileGroupDetails();
+        DataDownloadFileGroupStats details2 =
+                allFileGroupStatusAndDetailsList.get(1).fileGroupDetails();
+        DataDownloadFileGroupStats details3 =
+                allFileGroupStatusAndDetailsList.get(2).fileGroupDetails();
+
+        // Check that the downloaded group status is logged.
+        assertThat(details1.getFileGroupName()).isEqualTo(TEST_GROUP);
+        assertThat(details1.getOwnerPackage()).isEqualTo(TEST_PACKAGE);
+        assertThat(details1.getFileGroupVersionNumber()).isEqualTo(10);
+        assertThat(details1.getBuildId()).isEqualTo(10);
+        assertThat(details1.getVariantId()).isEqualTo("test-variant");
+        assertThat(details1.getFileCount()).isEqualTo(4);
+        assertThat(details1.getInlineFileCount()).isEqualTo(2);
+        assertTrue(details1.getHasAccount());
+        assertThat(status1.getFileGroupDownloadStatus())
+                .isEqualTo(MddFileGroupDownloadStatus.Code.COMPLETE);
+        assertThat(status1.getGroupAddedTimestampInSeconds()).isEqualTo(5);
+        assertThat(status1.getGroupDownloadedTimestampInSeconds()).isEqualTo(10);
+        assertThat(status1.getDaysSinceLastLog()).isEqualTo(daysSinceLastLog);
+
+        // Check that the pending group status is logged.
+        assertThat(details2.getFileGroupName()).isEqualTo(TEST_GROUP);
+        assertThat(details2.getFileGroupVersionNumber()).isEqualTo(11);
+        assertThat(details2.getBuildId()).isEqualTo(11);
+        assertThat(details2.getVariantId()).isEqualTo("test-variant");
+        assertThat(details2.getOwnerPackage()).isEqualTo(TEST_PACKAGE);
+        assertThat(details2.getFileCount()).isEqualTo(4);
+        assertThat(details2.getInlineFileCount()).isEqualTo(1);
+        assertTrue(details2.getHasAccount());
+        assertThat(status2.getFileGroupDownloadStatus())
+                .isEqualTo(MddFileGroupDownloadStatus.Code.PENDING);
+        assertThat(status2.getGroupAddedTimestampInSeconds()).isEqualTo(15);
+        assertThat(status2.getGroupDownloadedTimestampInSeconds()).isEqualTo(-1);
+        assertThat(status2.getDaysSinceLastLog()).isEqualTo(daysSinceLastLog);
+
+        // Check that the failed group status is logged.
+        assertThat(details3.getFileGroupName()).isEqualTo(TEST_GROUP_2);
+        assertThat(details3.getFileGroupVersionNumber()).isEqualTo(5);
+        assertThat(details3.getOwnerPackage()).isEqualTo(TEST_PACKAGE);
+        assertThat(details3.getFileCount()).isEqualTo(3);
+        assertThat(details3.getInlineFileCount()).isEqualTo(0);
+        assertFalse(details3.getHasAccount());
+        assertThat(status3.getFileGroupDownloadStatus())
+                .isEqualTo(MddFileGroupDownloadStatus.Code.FAILED);
+        assertThat(status3.getGroupAddedTimestampInSeconds()).isEqualTo(12);
+        assertThat(status3.getGroupDownloadedTimestampInSeconds()).isEqualTo(-1);
+        assertThat(status3.getDaysSinceLastLog()).isEqualTo(daysSinceLastLog);
+    }
+}
\ No newline at end of file
diff --git a/javatests/com/google/android/libraries/mobiledatadownload/internal/logging/LogSamplerTest.java b/javatests/com/google/android/libraries/mobiledatadownload/internal/logging/LogSamplerTest.java
new file mode 100644
index 0000000..69c8186
--- /dev/null
+++ b/javatests/com/google/android/libraries/mobiledatadownload/internal/logging/LogSamplerTest.java
@@ -0,0 +1,233 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.libraries.mobiledatadownload.internal.logging;
+
+import static com.google.android.libraries.mobiledatadownload.internal.logging.SharedPreferencesLoggingState.SALT_KEY;
+import static com.google.common.base.Preconditions.checkState;
+import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assume.assumeTrue;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import androidx.test.core.app.ApplicationProvider;
+import com.google.android.libraries.mobiledatadownload.Flags;
+import com.google.android.libraries.mobiledatadownload.file.SynchronousFileStorage;
+import com.google.android.libraries.mobiledatadownload.file.backends.JavaFileBackend;
+import com.google.android.libraries.mobiledatadownload.testing.FakeTimeSource;
+import com.google.common.base.Optional;
+import com.google.common.util.concurrent.ListeningExecutorService;
+import com.google.common.util.concurrent.MoreExecutors;
+import com.google.mobiledatadownload.LogProto.StableSamplingInfo;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Random;
+import java.util.concurrent.Executors;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.ParameterizedRobolectricTestRunner;
+import org.robolectric.ParameterizedRobolectricTestRunner.Parameter;
+import org.robolectric.ParameterizedRobolectricTestRunner.Parameters;
+
+@RunWith(ParameterizedRobolectricTestRunner.class)
+public final class LogSamplerTest {
+    @Parameter(value = 0)
+    public boolean stableLoggingEnabled;
+
+    @Parameters(name = "stableLoggingEnabled = {0}")
+    public static List<Boolean> parameters() {
+        return Arrays.asList(true, false);
+    }
+
+    private LoggingStateStore loggingStateStore;
+    private SharedPreferences loggingStateSharedPrefs;
+    private static final ListeningExecutorService executorService =
+            MoreExecutors.listeningDecorator(Executors.newCachedThreadPool());
+    private LogSampler logSampler;
+
+    private static final FakeTimeSource timeSource = new FakeTimeSource();
+    private Context context;
+
+    // Seed for first long
+    private static final int LOGS_AT_1_PERCENT_SEED = 750; // -5772485602628857500
+
+    private static final int ONE_PERCENT_SAMPLE_INTERVAL = 100;
+    private static final int TEN_PERCENT_SAMPLE_INTERVAL = 10;
+    private static final int ONE_HUNDRED_PERCENT_SAMPLE_INTERVAL = 1;
+    private static final int NEVER_SAMPLE_INTERVAL = 0;
+
+    @Before
+    public void setUp() throws Exception {
+        context = ApplicationProvider.getApplicationContext();
+
+        SynchronousFileStorage fileStorage =
+                new SynchronousFileStorage(Arrays.asList(new JavaFileBackend()));
+
+        loggingStateSharedPrefs = context.getSharedPreferences("loggingStateSharedPrefs", 0);
+        loggingStateStore =
+                SharedPreferencesLoggingState.create(
+                        () -> loggingStateSharedPrefs, timeSource, executorService, new Random());
+
+        logSampler = constructLogSampler(0);
+    }
+
+    @Test
+    public void shouldLog_withInvalidSamplingRate_returnsAbsent() throws Exception {
+        int invalidSamplingRate = -1;
+        Optional<StableSamplingInfo> samplingInfo =
+                logSampler.shouldLog(invalidSamplingRate, Optional.of(loggingStateStore)).get();
+
+        assertThat(samplingInfo).isAbsent();
+    }
+
+    @Test
+    public void shouldLog_with0SamplingRate_returnsAbsent() throws Exception {
+        Optional<StableSamplingInfo> samplingInfo =
+                logSampler.shouldLog(NEVER_SAMPLE_INTERVAL, Optional.of(loggingStateStore)).get();
+
+        assertThat(samplingInfo).isAbsent();
+    }
+
+    @Test
+    public void shouldLog_stable_with1PercentGroup_logsAt1Percent() throws Exception {
+        assumeTrue(stableLoggingEnabled);
+        setStableSamplingRandomNumber(100); // 100 % 100 = 0
+
+        Optional<StableSamplingInfo> samplingInfo =
+                logSampler.shouldLog(ONE_PERCENT_SAMPLE_INTERVAL, Optional.of(loggingStateStore)).get();
+
+        assertThat(samplingInfo).isPresent();
+        assertThat(samplingInfo.get().getStableSamplingUsed()).isTrue();
+        assertThat(samplingInfo.get().getPartOfAlwaysLoggingGroup()).isTrue();
+        assertThat(samplingInfo.get().getInvalidSamplingRateUsed()).isFalse();
+    }
+
+    @Test
+    public void shouldLog_stable_with1PercentGroup_logsAt10Percent() throws Exception {
+        assumeTrue(stableLoggingEnabled);
+        setStableSamplingRandomNumber(100); // 100 % 100 = 0
+
+        Optional<StableSamplingInfo> samplingInfo =
+                logSampler.shouldLog(TEN_PERCENT_SAMPLE_INTERVAL, Optional.of(loggingStateStore)).get();
+
+        assertThat(samplingInfo).isPresent();
+        assertThat(samplingInfo.get().getStableSamplingUsed()).isTrue();
+        assertThat(samplingInfo.get().getPartOfAlwaysLoggingGroup()).isTrue();
+        assertThat(samplingInfo.get().getInvalidSamplingRateUsed()).isFalse();
+    }
+
+    @Test
+    public void shouldLog_stable_with10PercentGroup_doesntLogAt1Percent() throws Exception {
+        assumeTrue(stableLoggingEnabled);
+        setStableSamplingRandomNumber(10); // 10 % 100 = 10
+
+        Optional<StableSamplingInfo> samplingInfo =
+                logSampler.shouldLog(ONE_PERCENT_SAMPLE_INTERVAL, Optional.of(loggingStateStore)).get();
+
+        assertThat(samplingInfo).isAbsent();
+    }
+
+    @Test
+    public void shouldLog_stable_with10PercentGroup_logsAt10Percent() throws Exception {
+        assumeTrue(stableLoggingEnabled);
+        setStableSamplingRandomNumber(10); // 10 % 100 = 10
+
+        Optional<StableSamplingInfo> samplingInfo =
+                logSampler.shouldLog(TEN_PERCENT_SAMPLE_INTERVAL, Optional.of(loggingStateStore)).get();
+
+        assertThat(samplingInfo).isPresent();
+        assertThat(samplingInfo.get().getStableSamplingUsed()).isTrue();
+        assertThat(samplingInfo.get().getPartOfAlwaysLoggingGroup()).isFalse();
+        assertThat(samplingInfo.get().getInvalidSamplingRateUsed()).isFalse();
+    }
+
+    @Test
+    public void shouldLog_stable_withIncompatibleSamplingRate_isMarkedAsIncompatible()
+            throws Exception {
+        assumeTrue(stableLoggingEnabled);
+        setStableSamplingRandomNumber(77);
+
+        Optional<StableSamplingInfo> samplingInfo =
+                logSampler.shouldLog(77, Optional.of(loggingStateStore)).get();
+
+        assertThat(samplingInfo).isPresent();
+        assertThat(samplingInfo.get().getStableSamplingUsed()).isTrue();
+        assertThat(samplingInfo.get().getInvalidSamplingRateUsed()).isTrue();
+        assertThat(samplingInfo.get().getPartOfAlwaysLoggingGroup()).isFalse();
+    }
+
+    @Test
+    public void shouldLog_with100Percent_logsAt100Percent() throws Exception {
+        Optional<StableSamplingInfo> samplingInfo1 =
+                logSampler
+                        .shouldLog(ONE_HUNDRED_PERCENT_SAMPLE_INTERVAL, Optional.of(loggingStateStore))
+                        .get();
+        Optional<StableSamplingInfo> samplingInfo2 =
+                logSampler
+                        .shouldLog(ONE_HUNDRED_PERCENT_SAMPLE_INTERVAL, Optional.of(loggingStateStore))
+                        .get();
+
+        assertThat(samplingInfo1).isPresent();
+        assertThat(samplingInfo2).isPresent();
+        assertThat(samplingInfo1.get().getStableSamplingUsed()).isEqualTo(stableLoggingEnabled);
+        assertThat(samplingInfo2.get().getStableSamplingUsed()).isEqualTo(stableLoggingEnabled);
+    }
+
+    @Test
+    public void shouldLog_event_changesPerEvent() throws Exception {
+        assumeTrue(!stableLoggingEnabled);
+
+        LogSampler logSampler = constructLogSampler(LOGS_AT_1_PERCENT_SEED);
+        checkState(
+                logSampler
+                        .shouldLog(ONE_PERCENT_SAMPLE_INTERVAL, Optional.of(loggingStateStore))
+                        .get()
+                        .isPresent());
+
+        assertThat(
+                logSampler.shouldLog(ONE_PERCENT_SAMPLE_INTERVAL, Optional.of(loggingStateStore)).get())
+                .isAbsent();
+    }
+
+    @Test
+    public void shouldLog_stable_withoutLoggingStateStore_usesPerEvent() throws Exception {
+        assumeTrue(stableLoggingEnabled);
+
+        Optional<StableSamplingInfo> stableSamplingInfo =
+                logSampler.shouldLog(ONE_HUNDRED_PERCENT_SAMPLE_INTERVAL, Optional.absent()).get();
+
+        assertThat(stableSamplingInfo).isPresent();
+        assertThat(stableSamplingInfo.get().getStableSamplingUsed()).isFalse();
+    }
+
+    private LogSampler constructLogSampler(int seed) {
+        return new LogSampler(
+                new Flags() {
+                    @Override
+                    public boolean enableRngBasedDeviceStableSampling() {
+                        return stableLoggingEnabled;
+                    }
+                },
+                new Random(seed));
+    }
+
+    private void setStableSamplingRandomNumber(int randomNumber) throws Exception {
+        SharedPreferences.Editor editor = loggingStateSharedPrefs.edit();
+        editor.putLong(SALT_KEY, randomNumber);
+        assumeTrue(editor.commit());
+    }
+}
\ No newline at end of file
diff --git a/javatests/com/google/android/libraries/mobiledatadownload/internal/logging/MddEventLoggerTest.java b/javatests/com/google/android/libraries/mobiledatadownload/internal/logging/MddEventLoggerTest.java
new file mode 100644
index 0000000..d0bbb5c
--- /dev/null
+++ b/javatests/com/google/android/libraries/mobiledatadownload/internal/logging/MddEventLoggerTest.java
@@ -0,0 +1,186 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.libraries.mobiledatadownload.internal.logging;
+
+import static com.google.common.util.concurrent.Futures.immediateFuture;
+import static com.google.common.util.concurrent.MoreExecutors.directExecutor;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import androidx.test.core.app.ApplicationProvider;
+import com.google.android.libraries.mobiledatadownload.Logger;
+import com.google.android.libraries.mobiledatadownload.internal.logging.EventLogger.FileGroupStatusWithDetails;
+import com.google.android.libraries.mobiledatadownload.testing.FakeTimeSource;
+import com.google.android.libraries.mobiledatadownload.testing.TestFlags;
+import com.google.common.base.Optional;
+import com.google.common.collect.ImmutableList;
+import com.google.mobiledatadownload.LogEnumsProto.MddClientEvent;
+import com.google.mobiledatadownload.LogEnumsProto.MddFileGroupDownloadStatus;
+import com.google.mobiledatadownload.LogProto.AndroidClientInfo;
+import com.google.mobiledatadownload.LogProto.DataDownloadFileGroupStats;
+import com.google.mobiledatadownload.LogProto.MddDeviceInfo;
+import com.google.mobiledatadownload.LogProto.MddFileGroupStatus;
+import com.google.mobiledatadownload.LogProto.MddLogData;
+import com.google.mobiledatadownload.LogProto.StableSamplingInfo;
+import java.security.SecureRandom;
+import java.util.Random;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+import org.robolectric.RobolectricTestRunner;
+
+@RunWith(RobolectricTestRunner.class)
+public class MddEventLoggerTest {
+
+    @Rule public final MockitoRule mocks = MockitoJUnit.rule();
+
+    private static final int SOME_MODULE_VERSION = 42;
+    private static final int SAMPLING_ALWAYS = 1;
+    private static final int SAMPLING_NEVER = 0;
+
+    @Mock private Logger mockLogger;
+    private MddEventLogger mddEventLogger;
+
+    private final Context context = ApplicationProvider.getApplicationContext();
+    private final TestFlags flags = new TestFlags();
+
+    @Before
+    public void setUp() throws Exception {
+        SharedPreferences loggingStateSharedPrefs =
+                context.getSharedPreferences("loggingStateSharedPrefs", 0);
+        mddEventLogger =
+                new MddEventLogger(
+                        context,
+                        mockLogger,
+                        SOME_MODULE_VERSION,
+                        new LogSampler(flags, new SecureRandom()),
+                        flags);
+        mddEventLogger.setLoggingStateStore(
+                SharedPreferencesLoggingState.create(
+                        () -> loggingStateSharedPrefs, new FakeTimeSource(), directExecutor(), new Random(0)));
+    }
+
+    private MddLogData.Builder newLogDataBuilderWithClientInfo() {
+        return MddLogData.newBuilder()
+                .setAndroidClientInfo(
+                        AndroidClientInfo.newBuilder()
+                                .setModuleVersion(SOME_MODULE_VERSION)
+                                .setHostPackageName(context.getPackageName()));
+    }
+
+    @Test
+    public void testSampleInterval_zero_none() {
+        assertFalse(LogUtil.shouldSampleInterval(0));
+    }
+
+    @Test
+    public void testSampleInterval_negative_none() {
+        assertFalse(LogUtil.shouldSampleInterval(-1));
+    }
+
+    @Test
+    public void testSampleInterval_always() {
+        assertTrue(LogUtil.shouldSampleInterval(1));
+    }
+
+    @Test
+    public void testLogMddEvents_noLog() throws Exception {
+        overrideDefaultSampleInterval(SAMPLING_NEVER);
+
+        DataDownloadFileGroupStats fileGroupStats =
+                DataDownloadFileGroupStats.newBuilder()
+                        .setFileGroupName("fileGroup")
+                        .setFileGroupVersionNumber(1)
+                        .setBuildId(123)
+                        .setVariantId("testVariant")
+                        .build();
+        MddFileGroupStatus fileGroupStatus =
+                MddFileGroupStatus.newBuilder()
+                        .setFileGroupDownloadStatus(MddFileGroupDownloadStatus.Code.COMPLETE)
+                        .build();
+        FileGroupStatusWithDetails fileGroupStatusWithDetails =
+                FileGroupStatusWithDetails.create(fileGroupStatus, fileGroupStats);
+
+        mddEventLogger
+                .logMddFileGroupStats(() -> immediateFuture(ImmutableList.of(fileGroupStatusWithDetails)))
+                .get();
+
+        verifyNoInteractions(mockLogger);
+    }
+
+    @Test
+    public void testLogMddEvents() throws Exception {
+        overrideDefaultSampleInterval(SAMPLING_ALWAYS);
+
+        DataDownloadFileGroupStats fileGroupStats =
+                DataDownloadFileGroupStats.newBuilder()
+                        .setFileGroupName("fileGroup")
+                        .setFileGroupVersionNumber(1)
+                        .setBuildId(123)
+                        .setVariantId("testVariant")
+                        .build();
+        MddFileGroupStatus fileGroupStatus =
+                MddFileGroupStatus.newBuilder()
+                        .setFileGroupDownloadStatus(MddFileGroupDownloadStatus.Code.COMPLETE)
+                        .build();
+        FileGroupStatusWithDetails fileGroupStatusWithDetails =
+                FileGroupStatusWithDetails.create(fileGroupStatus, fileGroupStats);
+
+        MddLogData expectedData =
+                newLogDataBuilderWithClientInfo()
+                        .setSamplingInterval(SAMPLING_ALWAYS)
+                        .setDataDownloadFileGroupStats(fileGroupStats)
+                        .setMddFileGroupStatus(fileGroupStatus)
+                        .setDeviceInfo(MddDeviceInfo.newBuilder().setDeviceStorageLow(false))
+                        .setStableSamplingInfo(getStableSamplingInfo())
+                        .build();
+
+        mddEventLogger
+                .logMddFileGroupStats(() -> immediateFuture(ImmutableList.of(fileGroupStatusWithDetails)))
+                .get();
+
+        verify(mockLogger)
+                .log(eq(expectedData), eq(MddClientEvent.Code.DATA_DOWNLOAD_FILE_GROUP_STATUS_VALUE));
+    }
+
+    private void overrideDefaultSampleInterval(int sampleInterval) {
+        flags.mddDefaultSampleInterval = Optional.of(sampleInterval);
+        flags.groupStatsLoggingSampleInterval = Optional.of(sampleInterval);
+    }
+
+    private StableSamplingInfo getStableSamplingInfo() {
+        if (flags.enableRngBasedDeviceStableSampling()) {
+            return StableSamplingInfo.newBuilder()
+                    .setStableSamplingUsed(true)
+                    .setStableSamplingFirstEnabledTimestampMs(0)
+                    .setPartOfAlwaysLoggingGroup(false)
+                    .setInvalidSamplingRateUsed(false)
+                    .build();
+        }
+
+        return StableSamplingInfo.newBuilder().setStableSamplingUsed(false).build();
+    }
+}
\ No newline at end of file
diff --git a/mobile-data-download.iml b/mobile-data-download.iml
deleted file mode 100644
index afa4d1e..0000000
--- a/mobile-data-download.iml
+++ /dev/null
@@ -1,13 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<module type="JAVA_MODULE" version="4">
-  <component name="NewModuleRootManager" inherit-compiler-output="true">
-    <exclude-output />
-    <content url="file://$MODULE_DIR$">
-      <sourceFolder url="file://$MODULE_DIR$/android-annotation-stubs" isTestSource="false" packagePrefix="__PACKAGE__" />
-      <sourceFolder url="file://$MODULE_DIR$/java" isTestSource="false" />
-      <sourceFolder url="file://$MODULE_DIR$/javatests" isTestSource="false" />
-    </content>
-    <orderEntry type="inheritedJdk" />
-    <orderEntry type="sourceFolder" forTests="false" />
-  </component>
-</module>
\ No newline at end of file
diff --git a/proto/Android.bp b/proto/Android.bp
index 6c3e681..198768f 100644
--- a/proto/Android.bp
+++ b/proto/Android.bp
@@ -41,6 +41,6 @@ java_library {
     apex_available: [
         "//apex_available:platform",
         "com.android.adservices",
-	"com.android.ondevicepersonalization",
+	    "com.android.ondevicepersonalization",
     ],
 }
diff --git a/proto/atoms.proto b/proto/atoms.proto
new file mode 100644
index 0000000..293b466
--- /dev/null
+++ b/proto/atoms.proto
@@ -0,0 +1,56 @@
+syntax = "proto2";
+
+package mobiledatadownload.logs;
+
+option java_multiple_files = true;
+option java_package = "com.google.mobiledatadownload";
+option java_outer_classname = "AtomsProto";
+
+/**
+ * These protos are duplicates of the MobileDataDownload protos logged as
+ * MODE_BYTES in go/atoms.proto.
+ * TODO(b/243579271): remove this duplication
+ */
+/** Shared data among MobileDataDownload statistics. Not meant to be a top level
+ * atom proto.*/
+message MobileDataDownloadFileGroupStats {
+  // The name of the file group. This a string set server side used to retrieve
+  // the files. Does not contain PII.
+  optional string file_group_name = 1;
+  // Allows the clients to identify a file group based on a given set of
+  // properties. This string is set server side and does not contain PII.
+  optional string variant_id = 2;
+  // Identifier for the data file group created to identify the version of the
+  // file group.
+  optional int64 build_id = 3;
+  // The number of files in the file group.
+  optional int32 file_count = 4;
+  // Whether the file group has an account associated with it.
+  optional bool has_account = 5;
+  // Inverse of the sampling rate used to sample this event.
+  optional int32 sampling_interval = 6;
+  // Note: we do not have owner_package since that's already transmitted.
+}
+
+/**
+ * Container for MobileDataDownloadFileGroupStorageStats
+ */
+message MobileDataDownloadStorageStats {
+  repeated MobileDataDownloadFileGroupStorageStats
+      mobile_data_download_file_group_storage_stats = 1;
+}
+
+/**
+ * Storage stats for a single file group. This is logged as a nested field and
+ * is not meant to be logged as a top level proto.
+ */
+message MobileDataDownloadFileGroupStorageStats {
+  // The total number of bytes used by this file group
+  optional int64 total_bytes_used = 1;
+  // The total number of inline file bytes used by this file group
+  optional int64 total_inline_bytes_used = 2;
+  // The number of bytes used for the downloaded version of the file group
+  optional int64 downloaded_group_bytes_used = 3;
+  // Specifies which file group this storage is associated with
+  optional MobileDataDownloadFileGroupStats file_group_stats = 4;
+}
diff --git a/proto/log_enums.proto b/proto/log_enums.proto
new file mode 100644
index 0000000..a6d4d63
--- /dev/null
+++ b/proto/log_enums.proto
@@ -0,0 +1,50 @@
+syntax = "proto3";
+
+package mobiledatadownload.logs;
+
+option java_package = "com.google.mobiledatadownload";
+option java_outer_classname = "LogEnumsProto";
+
+// MDD client side events used for logging with MddLogData.
+//
+// Each feature gets a range of 1000 enums starting at X000. 1st enum specifies
+// if the feature is enabled. Subsequent 999 enums can be used to define events
+// within the feature. Unused enums in the range are left for future use for
+// the *same* feature.
+// If a feature ever exhausts it's quota of enums, it should be migrated to a
+// new range of contiguous 2000 enums by deprecating the existing enums.
+//
+// Enums should never be deleted or reused, but they can be renamed*. Old enums
+// should be left in their position with [deprecated=true] attribute.
+//
+// * For renaming enums, see <internal>
+message MddClientEvent {
+  enum Code {
+    // Do not use this default value.
+    EVENT_CODE_UNSPECIFIED = 0;
+
+    // Events for Mobile Data Download (<internal>) (1000-1999).
+    // Next enum for data download: 1114
+
+    // Log in a periodic tasks.
+    // Logged with DataDownloadFileGroupStats, MddFileGroupStatus.
+    DATA_DOWNLOAD_FILE_GROUP_STATUS = 1044;
+
+    reserved 1000 to 1043, 1045 to 1113;
+
+    reserved 2000 to 2999, 3000 to 3999, 4000 to 4099, 4100 to 4199,
+        5000 to 5999, 6000 to 6999, 7000 to 7999, 8000 to 8999, 9000 to 9999,
+        10000 to 10999, 11000 to 11999, 12000 to 12999, 13000, 13999,
+        14000 to 14999, 15000 to 15999, 16000 to 16999, 17000 to 17999,
+        18000 to 18999, 19000 to 19999;
+  }
+}
+
+message MddFileGroupDownloadStatus {
+  enum Code {
+    INVALID = 0;
+    COMPLETE = 1;
+    PENDING = 2;
+    FAILED = 3;
+  }
+}
\ No newline at end of file
diff --git a/proto/logs.proto b/proto/logs.proto
new file mode 100644
index 0000000..c4c2f6e
--- /dev/null
+++ b/proto/logs.proto
@@ -0,0 +1,203 @@
+// Logging protos for MobileDataDownload
+
+syntax = "proto2";
+
+package mobiledatadownload.logs;
+
+import "log_enums.proto";
+
+// option jspb_use_correct_proto2_semantics = false;  // <internal>
+option java_package = "com.google.mobiledatadownload";
+option java_outer_classname = "LogProto";
+
+// Info about the Android client that logged.
+// Next tag: 3
+message AndroidClientInfo {
+  // Version of the module we are currently running. aMDD will log its own
+  // version that it shares between GMSCore module and library.
+
+  optional int32 module_version = 1 [default = -1];
+
+  // Package name of the hosting application.
+  // It is to differentiate logs from GMS service and library.
+  optional string host_package_name = 2;
+}
+
+// Attributes of the device and/or MDD
+// Recommended to log this message with each MDD log defined below. This will
+// allow slicing MDD stats on the state of the device.
+//
+// TODO: Make Fields of this proto available as RASTA conditions for
+// experimentation.
+//
+// Next tag: 3
+message MddDeviceInfo {
+  // Indicates low storage space condition on the device.
+  // Currently in O-, it is the result of Android's ACTION_DEVICE_STORAGE_LOW
+  // intent when the storage state was logged.
+  // For O+, MDD will define its own threshold for low storage: b/77856395
+  optional bool device_storage_low = 1;
+
+  reserved 2;
+}
+
+// Metadata associated with each data download event specific to a file group.
+//
+// Next tag: 9
+message DataDownloadFileGroupStats {
+  // Name of the file group.
+  optional string file_group_name = 1;
+
+  // Client set version number used to identify the file group.
+  // Note that this does not uniquely identify the contents of the file group.
+  // It simply reflects a snapshot of client config changes.
+  // For example: say there's a file group 'language-detector-model' that
+  // downloads a different file per user locale.
+  // data_file_group {
+  //   file_group_name = 'language-detector-model'
+  //   file_group_version_number = 1
+  //   file {
+  //      url = 'en-model'
+  //   }
+  //  }
+  // data_file_group {
+  //   file_group_name = 'language-detector-model'
+  //   file_group_version_number = 1
+  //   file {
+  //      url = 'es-model'
+  //   }
+  //  }
+  // Note that even though the actual contents of the file group are different
+  // for each locale, the version is the same because this config was pushed
+  // at the same snapshot.
+  optional int32 file_group_version_number = 2;
+
+  // The package name of the group owner.
+  optional string owner_package = 3;
+
+  // The total number of files in the file group.
+  //
+  // NOTE: This count is only included for storage and file group stats logging
+  optional int32 file_count = 4;
+
+  // The number of inline files in the file group.
+  //
+  // NOTE: This count is only included for storage and file group stats logging
+  optional int32 inline_file_count = 8;
+
+  // Whether the file group has an account associated with it or not. This will
+  // allow us to slice metrics by having account or not. For more info see
+  // cs/symbol:mdi.download.internal.GroupKey.account
+  optional bool has_account = 5;
+
+  // The build id for the file group. Unique identifier for a file group config
+  // created when using MDD Ingress API.
+  // For more details see <internal>.
+  optional int64 build_id = 6;
+
+  // The VariantID of the DataFileGroup. This is set up server side via code
+  // review. For more details see <internal>.
+  // Examples: "en", "de-universal", etc.
+  optional string variant_id = 7;
+}
+
+// The status of a MDD file group. This data is logged periodically to get
+// a snapshot of the status of a file group on devices.
+// Next tag: 5
+message MddFileGroupStatus {
+  // Download status of the whole file group. This is an AND over the
+  // download status of each file within the file group.
+  optional MddFileGroupDownloadStatus.Code file_group_download_status = 1;
+
+  // Time since epoch when this file group was first added to mdd.
+  //
+  // Set to -1 if this time is unknown (for legacy groups).
+  //
+  // This matches the field "group_new_files_received_timestamp" in metadata
+  // <internal>
+  optional int64 group_added_timestamp_in_seconds = 2;
+
+  // Time since epoch when this file group was downloaded by mdd.
+  //
+  // Set to -1 if this time is unknown (for legacy groups) and non-downloaded
+  // groups
+  //
+  // This matches the field "group_downloaded_timestamp_in_millis" in metadata
+  // <internal>
+  optional int64 group_downloaded_timestamp_in_seconds = 3;
+
+  // Number of days since this status was last logged (number of days since
+  // daily maintenance was last run).
+  //
+  // Set to -1 if there is an invalid or unknown value.
+  //
+  // See <internal> for more info.
+  optional int32 days_since_last_log = 4;
+}
+
+// Various health reports.
+// Ideally, this should be defined as an empty message that allows extensions
+// and each inner proto should be defined as its extension.
+// TODO: Figure out if there are limitations in nano-proto that might
+// not allow this.
+//
+// Next tag: 74
+message MddLogData {
+  // MDD data download file group stats.
+  optional DataDownloadFileGroupStats data_download_file_group_stats = 10;
+
+  // Sampling interval used while logging this message. The default value 0 is
+  // not a valid value for messages using this filed since it a special value
+  // denoting that message should not be logged. Hence value of 0 means it was
+  // not filled in.
+  optional int64 sampling_interval = 21;
+
+  // Additional info necessary for stable sampling.
+  optional StableSamplingInfo stable_sampling_info = 72;
+
+  // Data download file group download status (logged periodically).
+  optional MddFileGroupStatus mdd_file_group_status = 32;
+
+  // Attributes of the device and/or MDD at the time we log other stats.
+  optional MddDeviceInfo device_info = 40;
+
+  // Android client info.
+  optional AndroidClientInfo android_client_info = 51;
+
+  reserved 1 to 9, 11 to 20, 22 to 31, 33 to 39, 41 to 50, 52 to 71, 73;
+}
+
+// Info on sampling method used for log events. Stable sampling means if a
+// device is selected to log, it will log all events. See <internal>
+// Next tag: 5
+message StableSamplingInfo {
+  // Whether a stable sampling method (as described in <internal>)
+  // was used.
+  optional bool stable_sampling_used = 1;
+
+  // When stable sampling was first enabled on the device. This will be useful
+  // when rolling out and processing logs over multiple days.
+  optional int64 stable_sampling_first_enabled_timestamp_ms = 2;
+
+  // Whether or not this device would log with the 1% cohort. Devices in the 1%
+  // cohort are *always* logging, and will always log without further code
+  // changes. When a device has this set to true, it's expected that the device
+  // is *always* logging and the sampling rate should not be changed to
+  // something that results in this device being excluded from the logging group
+  // (see invalid_sampling_rate_used).
+  //
+  // Most dashboards/metrics depending on linking together multiple events from
+  // the same device should filter to devices/events that have this set to true
+  // (with the caveat that we won't use all data from all devices reporting).
+  // This is useful when we need to change sampling rates, e.g. for an
+  // experiment.
+  optional bool part_of_always_logging_group = 3;
+
+  // If we are using stable sampling, we expect a sampling rate where  '100 %
+  // sample_interval == 0'. This ensures that devices logging at 1 percent
+  // sampling interval, will continue to log at other chosen sampling rates too.
+  // This should only be false if we've incorrectly configured our sampling
+  // rates (e.g. a sampling rate of 101 would mean that the 1 percent cohort
+  // devices would not log).
+  optional bool invalid_sampling_rate_used = 4;
+}
\ No newline at end of file