feat: Add ErrCredUnavailable sentinel error (#65)upstream/v0.2.2

4 files changed, 33 insertions, 3 deletions

diff --git a/client/client.go b/client/client.go
index 80b3d2b..0a2d4d7 100644
--- a/client/client.go
+++ b/client/client.go
@@ -22,6 +22,7 @@ import (
 	"crypto/rsa"
 	"crypto/x509"
 	"encoding/gob"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -119,6 +120,10 @@ func (k *Key) Sign(_ io.Reader, digest []byte, opts crypto.SignerOpts) (signed [
 	return
 }
 
+// ErrCredUnavailable is a sentinel error that indicates ECP Cred is unavailable,
+// possibly due to missing config or missing binary path.
+var ErrCredUnavailable = errors.New("Cred is unavailable")
+
 // Cred spawns a signer subprocess that listens on stdin/stdout to perform certificate
 // related operations, including signing messages with the private key.
 //
@@ -133,6 +138,9 @@ func Cred(configFilePath string) (*Key, error) {
 	}
 	enterpriseCertSignerPath, err := util.LoadSignerBinaryPath(configFilePath)
 	if err != nil {
+		if errors.Is(err, util.ErrConfigUnavailable) {
+			return nil, ErrCredUnavailable
+		}
 		return nil, err
 	}
 	k := &Key{
diff --git a/client/client_test.go b/client/client_test.go
index cbb7126..b0305b4 100644
--- a/client/client_test.go
+++ b/client/client_test.go
@@ -18,7 +18,6 @@ import (
 	"bytes"
 	"crypto"
 	"errors"
-	"os"
 	"testing"
 )
 
@@ -31,11 +30,18 @@ func TestClient_Cred_Success(t *testing.T) {
 
 func TestClient_Cred_ConfigMissing(t *testing.T) {
 	_, err := Cred("missing.json")
-	if got, want := err, os.ErrNotExist; !errors.Is(got, want) {
+	if got, want := err, ErrCredUnavailable; !errors.Is(got, want) {
 		t.Errorf("Cred: with missing config; got %v, want %v err", got, want)
 	}
 }
 
+func TestClient_Cred_PathMissing(t *testing.T) {
+	_, err := Cred("testdata/certificate_config_missing_path.json")
+	if got, want := err, ErrCredUnavailable; !errors.Is(got, want) {
+		t.Errorf("Cred: with missing ECP path; got %v, want %v err", got, want)
+	}
+}
+
 func TestClient_Public(t *testing.T) {
 	key, err := Cred("testdata/certificate_config.json")
 	if err != nil {
diff --git a/client/testdata/certificate_config_missing_path.json b/client/testdata/certificate_config_missing_path.json
new file mode 100644
index 0000000..327d54c
--- /dev/null
+++ b/client/testdata/certificate_config_missing_path.json
@@ -0,0 +1,9 @@
+{
+  "cert_configs": {
+    "test": {
+      "issuer": "Test Issuer"
+    }
+  },
+  "libs": {
+  }
+}
diff --git a/client/util/util.go b/client/util/util.go
index 0226a6a..a88dbd4 100644
--- a/client/util/util.go
+++ b/client/util/util.go
@@ -36,10 +36,17 @@ type Libs struct {
 	ECP string `json:"ecp"`
 }
 
+// ErrConfigUnavailable is a sentinel error that indicates ECP config is unavailable,
+// possibly due to entire config missing or missing binary path.
+var ErrConfigUnavailable = errors.New("Config is unavailable")
+
 // LoadSignerBinaryPath retrieves the path of the signer binary from the config file.
 func LoadSignerBinaryPath(configFilePath string) (path string, err error) {
 	jsonFile, err := os.Open(configFilePath)
 	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return "", ErrConfigUnavailable
+		}
 		return "", err
 	}
 
@@ -54,7 +61,7 @@ func LoadSignerBinaryPath(configFilePath string) (path string, err error) {
 	}
 	signerBinaryPath := config.Libs.ECP
 	if signerBinaryPath == "" {
-		return "", errors.New("signer binary path is missing")
+		return "", ErrConfigUnavailable
 	}
 	return signerBinaryPath, nil
 }