tracing-subscriber 0.2.21

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!

tracing-core 0.1.20

This release adds support for f64 as one of the tracing-core
primitive field values, allowing floating-point values to be recorded as
typed values rather than with fmt::Debug. Additionally, it adds
NoSubscriber, a Subscriber implementation that does nothing.

Added

• subscriber: NoSubscriber, a no-op Subscriber implementation
  (#1549)
• field: Added Visit::record_f64 and support for recording
  floating-point values (#1507)

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

tracing-subscriber 0.2.14

0.2.14 (October 22, 2020)

Fixed

• registry: Fixed Registry::new allocating an excessively large amount of
  memory, most of which would never be used (#1064)

Changed

• registry: Improved new_span performance by reusing HashMap allocations
  for Extensions (#1064)
• registry: Significantly improved the performance of Registry::enter and
  Registry::exit (#1058)

tracing-core 0.1.17

Fixed

• Incorrect inlining of Event::dispatch and Event::child_of, which
  could result in dispatcher::get_default being inlined at the
  callsite (#994)

Added

• Copy implementations for Level and LevelFilter (#992)

Thanks to new contributors @jyn514 and @TaKO8Ki for contributing
to this release!

tracing-subscriber 0.2.9

Fixed

• fmt: Fixed compilation failure on MSRV when the chrono feature
  is disabled (#844)

Added

• fmt: Span lookup methods defined by layer::Context are now also
  provided by FmtContext (#834)

Tracing 0.1.17

Changed

• log: Moved verbose span enter/exit log records to
  "tracing::span::active" target, allowing them to be filtered
  separately (#833)
• log: All span lifecycle log records without fields now have the
  Trace log filter, to guard against log users enabling them by
  default with blanket level filtering (#833)

Fixed

• log/macros: Fixed missing implicit imports of the
  tracing::field::debug and tracing::field::display functions inside
  the macros when the "log" feature is enabled (#835)