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Diffstat (limited to 'vendor/tracing/src/level_filters.rs')
-rw-r--r-- | vendor/tracing/src/level_filters.rs | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/vendor/tracing/src/level_filters.rs b/vendor/tracing/src/level_filters.rs new file mode 100644 index 000000000..44f5e5f57 --- /dev/null +++ b/vendor/tracing/src/level_filters.rs @@ -0,0 +1,94 @@ +//! Trace verbosity level filtering. +//! +//! # Compile time filters +//! +//! Trace verbosity levels can be statically disabled at compile time via Cargo +//! features, similar to the [`log` crate]. Trace instrumentation at disabled +//! levels will be skipped and will not even be present in the resulting binary +//! unless the verbosity level is specified dynamically. This level is +//! configured separately for release and debug builds. The features are: +//! +//! * `max_level_off` +//! * `max_level_error` +//! * `max_level_warn` +//! * `max_level_info` +//! * `max_level_debug` +//! * `max_level_trace` +//! * `release_max_level_off` +//! * `release_max_level_error` +//! * `release_max_level_warn` +//! * `release_max_level_info` +//! * `release_max_level_debug` +//! * `release_max_level_trace` +//! +//! These features control the value of the `STATIC_MAX_LEVEL` constant. The +//! instrumentation macros macros check this value before recording an event or +//! constructing a span. By default, no levels are disabled. +//! +//! For example, a crate can disable trace level instrumentation in debug builds +//! and trace, debug, and info level instrumentation in release builds with the +//! following configuration: +//! +//! ```toml +//! [dependencies] +//! tracing = { version = "0.1", features = ["max_level_debug", "release_max_level_warn"] } +//! ``` +//! ## Notes +//! +//! Please note that `tracing`'s static max level features do *not* control the +//! [`log`] records that may be emitted when [`tracing`'s "log" feature flag][f] is +//! enabled. This is to allow `tracing` to be disabled entirely at compile time +//! while still emitting `log` records --- such as when a library using +//! `tracing` is used by an application using `log` that doesn't want to +//! generate any `tracing`-related code, but does want to collect `log` records. +//! +//! This means that if the "log" feature is in use, some code may be generated +//! for `log` records emitted by disabled `tracing` events. If this is not +//! desirable, `log` records may be disabled separately using [`log`'s static +//! max level features][`log` crate]. +//! +//! [`log`]: https://docs.rs/log/ +//! [`log` crate]: https://docs.rs/log/latest/log/#compile-time-filters +//! [f]: https://docs.rs/tracing/latest/tracing/#emitting-log-records +pub use tracing_core::{metadata::ParseLevelFilterError, LevelFilter}; + +/// The statically configured maximum trace level. +/// +/// See the [module-level documentation] for information on how to configure +/// this. +/// +/// This value is checked by the `event!` and `span!` macros. Code that +/// manually constructs events or spans via the `Event::record` function or +/// `Span` constructors should compare the level against this value to +/// determine if those spans or events are enabled. +/// +/// [module-level documentation]: super#compile-time-filters +pub const STATIC_MAX_LEVEL: LevelFilter = MAX_LEVEL; + +cfg_if::cfg_if! { + if #[cfg(all(not(debug_assertions), feature = "release_max_level_off"))] { + const MAX_LEVEL: LevelFilter = LevelFilter::OFF; + } else if #[cfg(all(not(debug_assertions), feature = "release_max_level_error"))] { + const MAX_LEVEL: LevelFilter = LevelFilter::ERROR; + } else if #[cfg(all(not(debug_assertions), feature = "release_max_level_warn"))] { + const MAX_LEVEL: LevelFilter = LevelFilter::WARN; + } else if #[cfg(all(not(debug_assertions), feature = "release_max_level_info"))] { + const MAX_LEVEL: LevelFilter = LevelFilter::INFO; + } else if #[cfg(all(not(debug_assertions), feature = "release_max_level_debug"))] { + const MAX_LEVEL: LevelFilter = LevelFilter::DEBUG; + } else if #[cfg(all(not(debug_assertions), feature = "release_max_level_trace"))] { + const MAX_LEVEL: LevelFilter = LevelFilter::TRACE; + } else if #[cfg(feature = "max_level_off")] { + const MAX_LEVEL: LevelFilter = LevelFilter::OFF; + } else if #[cfg(feature = "max_level_error")] { + const MAX_LEVEL: LevelFilter = LevelFilter::ERROR; + } else if #[cfg(feature = "max_level_warn")] { + const MAX_LEVEL: LevelFilter = LevelFilter::WARN; + } else if #[cfg(feature = "max_level_info")] { + const MAX_LEVEL: LevelFilter = LevelFilter::INFO; + } else if #[cfg(feature = "max_level_debug")] { + const MAX_LEVEL: LevelFilter = LevelFilter::DEBUG; + } else { + const MAX_LEVEL: LevelFilter = LevelFilter::TRACE; + } +} |