tokio-rs/tracing tracing-subscriber-0.2.21

tracing-subscriber 0.2.21

on GitHub

This release introduces the Filter trait, a new API for per-layer
filtering. This allows controlling which spans and events are
recorded by various layers individually, rather than globally.

In addition, it adds a new Targets filter, which provides a
lighter-weight version of the filtering provided by EnvFilter, as
well as other smaller API improvements and fixes.

Deprecated

• registry: SpanRef::parent_id, which cannot properly support
  per-layer filtering. Use .parent().map(SpanRef::id) instead.
  (#1523)

Fixed

• layer Context methods that are provided when the Subscriber
  implements LookupSpan no longer require the "registry" feature flag
  (#1525)
• layer fmt::Debug implementation for Layered no longer requires
  the S type parameter to implement Debug (#1528)

Added

• registry: Filter trait, Filtered type, Layer::with_filter
  method, and other APIs for per-layer filtering (#1523)
• filter: FilterFn and DynFilterFn types that implement global
  (Layer) and per-layer (Filter) filtering for closures and function
  pointers (#1523)
• filter: Targets filter, which implements a lighter-weight form
  of EnvFilter-like filtering (#1550)
• env-filter: Added support for filtering on floating-point values
  (#1507)
• layer: Layer::on_layer callback, called when layering the
  Layer onto a Subscriber (#1523)
• layer: Layer implementations for Box<L> and Arc<L> where L: Layer (#1536)
• layer: Layer implementations for Box<dyn Layer> and
  Arc<dyn Layer> (#1536)
• A number of small documentation fixes and improvements (#1553,
  #1544, #1539, #1524)

Special thanks to new contributors @jsgf and @maxburke for contributing
to this release!