diff options
Diffstat (limited to 'src/layer/mod.rs')
| -rw-r--r-- | src/layer/mod.rs | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/src/layer/mod.rs b/src/layer/mod.rs index bdc1543..296de5e 100644 --- a/src/layer/mod.rs +++ b/src/layer/mod.rs @@ -468,6 +468,24 @@ //! function pointer. In addition, when more control is required, the [`Filter`] //! trait may also be implemented for user-defined types. //! +//! //! [`Option<Filter>`] also implements [`Filter`], which allows for an optional +//! filter. [`None`](Option::None) filters out _nothing_ (that is, allows +//! everything through). For example: +//! +//! ```rust +//! # use tracing_subscriber::{filter::filter_fn, Layer}; +//! # use tracing_core::{Metadata, subscriber::Subscriber}; +//! # struct MyLayer<S>(std::marker::PhantomData<S>); +//! # impl<S> MyLayer<S> { fn new() -> Self { Self(std::marker::PhantomData)} } +//! # impl<S: Subscriber> Layer<S> for MyLayer<S> {} +//! # fn my_filter(_: &str) -> impl Fn(&Metadata) -> bool { |_| true } +//! fn setup_tracing<S: Subscriber>(filter_config: Option<&str>) { +//! let layer = MyLayer::<S>::new() +//! .with_filter(filter_config.map(|config| filter_fn(my_filter(config)))); +//! //... +//! } +//! ``` +//! //! <pre class="compile_fail" style="white-space:normal;font:inherit;"> //! <strong>Warning</strong>: Currently, the <a href="../struct.Registry.html"> //! <code>Registry</code></a> type defined in this crate is the only root @@ -732,8 +750,8 @@ where /// [`WeakDispatch`]: tracing_core::dispatcher::WeakDispatch /// [upgraded]: tracing_core::dispatcher::WeakDispatch::upgrade /// [`Subscriber`]: tracing_core::Subscriber - fn on_register_dispatch(&self, collector: &Dispatch) { - let _ = collector; + fn on_register_dispatch(&self, subscriber: &Dispatch) { + let _ = subscriber; } /// Performs late initialization when attaching a `Layer` to a |