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+//! A `Layer` that enables or disables spans and events based on a set of
+//! filtering directives.
+
+// these are publicly re-exported, but the compiler doesn't realize
+// that for some reason.
+#[allow(unreachable_pub)]
+pub use self::{builder::Builder, directive::Directive, field::BadName as BadFieldName};
+mod builder;
+mod directive;
+mod field;
+
+use crate::{
+ filter::LevelFilter,
+ layer::{Context, Layer},
+ sync::RwLock,
+};
+use directive::ParseError;
+use std::{cell::RefCell, collections::HashMap, env, error::Error, fmt, str::FromStr};
+use thread_local::ThreadLocal;
+use tracing_core::{
+ callsite,
+ field::Field,
+ span,
+ subscriber::{Interest, Subscriber},
+ Metadata,
+};
+
+/// A [`Layer`] which filters spans and events based on a set of filter
+/// directives.
+///
+/// `EnvFilter` implements both the [`Layer`](#impl-Layer<S>) and [`Filter`] traits, so it may
+/// be used for both [global filtering][global] and [per-layer filtering][plf],
+/// respectively. See [the documentation on filtering with `Layer`s][filtering]
+/// for details.
+///
+/// The [`Targets`] type implements a similar form of filtering, but without the
+/// ability to dynamically enable events based on the current span context, and
+/// without filtering on field values. When these features are not required,
+/// [`Targets`] provides a lighter-weight alternative to [`EnvFilter`].
+///
+/// # Directives
+///
+/// A filter consists of one or more comma-separated directives which match on [`Span`]s and [`Event`]s.
+/// Each directive may have a corresponding maximum verbosity [`level`] which
+/// enables (e.g., _selects for_) spans and events that match. Like `log`,
+/// `tracing` considers less exclusive levels (like `trace` or `info`) to be more
+/// verbose than more exclusive levels (like `error` or `warn`).
+///
+/// The directive syntax is similar to that of [`env_logger`]'s. At a high level, the syntax for directives
+/// consists of several parts:
+///
+/// ```text
+/// target[span{field=value}]=level
+/// ```
+///
+/// Each component (`target`, `span`, `field`, `value`, and `level`) will be covered in turn.
+///
+/// - `target` matches the event or span's target. In general, this is the module path and/or crate name.
+/// Examples of targets `h2`, `tokio::net`, or `tide::server`. For more information on targets,
+/// please refer to [`Metadata`]'s documentation.
+/// - `span` matches on the span's name. If a `span` directive is provided alongside a `target`,
+/// the `span` directive will match on spans _within_ the `target`.
+/// - `field` matches on [fields] within spans. Field names can also be supplied without a `value`
+/// and will match on any [`Span`] or [`Event`] that has a field with that name.
+/// For example: `[span{field=\"value\"}]=debug`, `[{field}]=trace`.
+/// - `value` matches on the value of a span's field. If a value is a numeric literal or a bool,
+/// it will match _only_ on that value. Otherwise, this filter matches the
+/// [`std::fmt::Debug`] output from the value.
+/// - `level` sets a maximum verbosity level accepted by this directive.
+///
+/// When a field value directive (`[{<FIELD NAME>=<FIELD_VALUE>}]=...`) matches a
+/// value's [`std::fmt::Debug`] output (i.e., the field value in the directive
+/// is not a `bool`, `i64`, `u64`, or `f64` literal), the matched pattern may be
+/// interpreted as either a regular expression or as the precise expected
+/// output of the field's [`std::fmt::Debug`] implementation. By default, these
+/// filters are interpreted as regular expressions, but this can be disabled
+/// using the [`Builder::with_regex`] builder method to use precise matching
+/// instead.
+///
+/// When field value filters are interpreted as regular expressions, the
+/// [`regex-automata` crate's regular expression syntax][re-syntax] is
+/// supported.
+///
+/// **Note**: When filters are constructed from potentially untrusted inputs,
+/// [disabling regular expression matching](Builder::with_regex) is strongly
+/// recommended.
+///
+/// ## Usage Notes
+///
+/// - The portion of the directive which is included within the square brackets is `tracing`-specific.
+/// - Any portion of the directive can be omitted.
+/// - The sole exception are the `field` and `value` directives. If a `value` is provided,
+/// a `field` must _also_ be provided. However, the converse does not hold, as fields can
+/// be matched without a value.
+/// - If only a level is provided, it will set the maximum level for all `Span`s and `Event`s
+/// that are not enabled by other filters.
+/// - A directive without a level will enable anything that it matches. This is equivalent to `=trace`.
+/// - When a crate has a dash in its name, the default target for events will be the
+/// crate's module path as it appears in Rust. This means every dash will be replaced
+/// with an underscore.
+/// - A dash in a target will only appear when being specified explicitly:
+/// `tracing::info!(target: "target-name", ...);`
+///
+/// ## Example Syntax
+///
+/// - `tokio::net=info` will enable all spans or events that:
+/// - have the `tokio::net` target,
+/// - at the level `info` or above.
+/// - `warn,tokio::net=info` will enable all spans and events that:
+/// - are at the level `warn` or above, *or*
+/// - have the `tokio::net` target at the level `info` or above.
+/// - `my_crate[span_a]=trace` will enable all spans and events that:
+/// - are within the `span_a` span or named `span_a` _if_ `span_a` has the target `my_crate`,
+/// - at the level `trace` or above.
+/// - `[span_b{name=\"bob\"}]` will enable all spans or event that:
+/// - have _any_ target,
+/// - are inside a span named `span_b`,
+/// - which has a field named `name` with value `bob`,
+/// - at _any_ level.
+///
+/// # Examples
+///
+/// Parsing an `EnvFilter` from the [default environment
+/// variable](EnvFilter::from_default_env) (`RUST_LOG`):
+///
+/// ```
+/// use tracing_subscriber::{EnvFilter, fmt, prelude::*};
+///
+/// tracing_subscriber::registry()
+/// .with(fmt::layer())
+/// .with(EnvFilter::from_default_env())
+/// .init();
+/// ```
+///
+/// Parsing an `EnvFilter` [from a user-provided environment
+/// variable](EnvFilter::from_env):
+///
+/// ```
+/// use tracing_subscriber::{EnvFilter, fmt, prelude::*};
+///
+/// tracing_subscriber::registry()
+/// .with(fmt::layer())
+/// .with(EnvFilter::from_env("MYAPP_LOG"))
+/// .init();
+/// ```
+///
+/// Using `EnvFilter` as a [per-layer filter][plf] to filter only a single
+/// [`Layer`]:
+///
+/// ```
+/// use tracing_subscriber::{EnvFilter, fmt, prelude::*};
+///
+/// // Parse an `EnvFilter` configuration from the `RUST_LOG`
+/// // environment variable.
+/// let filter = EnvFilter::from_default_env();
+///
+/// // Apply the filter to this layer *only*.
+/// let filtered_layer = fmt::layer().with_filter(filter);
+///
+/// // Some other layer, whose output we don't want to filter.
+/// let unfiltered_layer = // ...
+/// # fmt::layer();
+///
+/// tracing_subscriber::registry()
+/// .with(filtered_layer)
+/// .with(unfiltered_layer)
+/// .init();
+/// ```
+/// # Constructing `EnvFilter`s
+///
+/// An `EnvFilter` is be constructed by parsing a string containing one or more
+/// directives. The [`EnvFilter::new`] constructor parses an `EnvFilter` from a
+/// string, ignoring any invalid directives, while [`EnvFilter::try_new`]
+/// returns an error if invalid directives are encountered. Similarly, the
+/// [`EnvFilter::from_env`] and [`EnvFilter::try_from_env`] constructors parse
+/// an `EnvFilter` from the value of the provided environment variable, with
+/// lossy and strict validation, respectively.
+///
+/// A [builder](EnvFilter::builder) interface is available to set additional
+/// configuration options prior to parsing an `EnvFilter`. See the [`Builder`
+/// type's documentation](Builder) for details on the options that can be
+/// configured using the builder.
+///
+/// [`Span`]: tracing_core::span
+/// [fields]: tracing_core::Field
+/// [`Event`]: tracing_core::Event
+/// [`level`]: tracing_core::Level
+/// [`Metadata`]: tracing_core::Metadata
+/// [`Targets`]: crate::filter::Targets
+/// [`env_logger`]: https://crates.io/crates/env_logger
+/// [`Filter`]: #impl-Filter<S>
+/// [global]: crate::layer#global-filtering
+/// [plf]: crate::layer#per-layer-filtering
+/// [filtering]: crate::layer#filtering-with-layers
+#[cfg_attr(docsrs, doc(cfg(all(feature = "env-filter", feature = "std"))))]
+#[derive(Debug)]
+pub struct EnvFilter {
+ statics: directive::Statics,
+ dynamics: directive::Dynamics,
+ has_dynamics: bool,
+ by_id: RwLock<HashMap<span::Id, directive::SpanMatcher>>,
+ by_cs: RwLock<HashMap<callsite::Identifier, directive::CallsiteMatcher>>,
+ scope: ThreadLocal<RefCell<Vec<LevelFilter>>>,
+ regex: bool,
+}
+
+type FieldMap<T> = HashMap<Field, T>;
+
+/// Indicates that an error occurred while parsing a `EnvFilter` from an
+/// environment variable.
+#[cfg_attr(docsrs, doc(cfg(all(feature = "env-filter", feature = "std"))))]
+#[derive(Debug)]
+pub struct FromEnvError {
+ kind: ErrorKind,
+}
+
+#[derive(Debug)]
+enum ErrorKind {
+ Parse(ParseError),
+ Env(env::VarError),
+}
+
+impl EnvFilter {
+ /// `RUST_LOG` is the default environment variable used by
+ /// [`EnvFilter::from_default_env`] and [`EnvFilter::try_from_default_env`].
+ ///
+ /// [`EnvFilter::from_default_env`]: EnvFilter::from_default_env()
+ /// [`EnvFilter::try_from_default_env`]: EnvFilter::try_from_default_env()
+ pub const DEFAULT_ENV: &'static str = "RUST_LOG";
+
+ // === constructors, etc ===
+
+ /// Returns a [builder] that can be used to configure a new [`EnvFilter`]
+ /// instance.
+ ///
+ /// The [`Builder`] type is used to set additional configurations, such as
+ /// [whether regular expressions are enabled](Builder::with_regex) or [the
+ /// default directive](Builder::with_default_directive) before parsing an
+ /// [`EnvFilter`] from a string or environment variable.
+ ///
+ /// [builder]: https://rust-unofficial.github.io/patterns/patterns/creational/builder.html
+ pub fn builder() -> Builder {
+ Builder::default()
+ }
+
+ /// Returns a new `EnvFilter` from the value of the `RUST_LOG` environment
+ /// variable, ignoring any invalid filter directives.
+ ///
+ /// If the environment variable is empty or not set, or if it contains only
+ /// invalid directives, a default directive enabling the [`ERROR`] level is
+ /// added.
+ ///
+ /// To set additional configuration options prior to parsing the filter, use
+ /// the [`Builder`] type instead.
+ ///
+ /// This function is equivalent to the following:
+ ///
+ /// ```rust
+ /// use tracing_subscriber::filter::{EnvFilter, LevelFilter};
+ ///
+ /// # fn docs() -> EnvFilter {
+ /// EnvFilter::builder()
+ /// .with_default_directive(LevelFilter::ERROR.into())
+ /// .from_env_lossy()
+ /// # }
+ /// ```
+ ///
+ /// [`ERROR`]: tracing::Level::ERROR
+ pub fn from_default_env() -> Self {
+ Self::builder()
+ .with_default_directive(LevelFilter::ERROR.into())
+ .from_env_lossy()
+ }
+
+ /// Returns a new `EnvFilter` from the value of the given environment
+ /// variable, ignoring any invalid filter directives.
+ ///
+ /// If the environment variable is empty or not set, or if it contains only
+ /// invalid directives, a default directive enabling the [`ERROR`] level is
+ /// added.
+ ///
+ /// To set additional configuration options prior to parsing the filter, use
+ /// the [`Builder`] type instead.
+ ///
+ /// This function is equivalent to the following:
+ ///
+ /// ```rust
+ /// use tracing_subscriber::filter::{EnvFilter, LevelFilter};
+ ///
+ /// # fn docs() -> EnvFilter {
+ /// # let env = "";
+ /// EnvFilter::builder()
+ /// .with_default_directive(LevelFilter::ERROR.into())
+ /// .with_env_var(env)
+ /// .from_env_lossy()
+ /// # }
+ /// ```
+ ///
+ /// [`ERROR`]: tracing::Level::ERROR
+ pub fn from_env<A: AsRef<str>>(env: A) -> Self {
+ Self::builder()
+ .with_default_directive(LevelFilter::ERROR.into())
+ .with_env_var(env.as_ref())
+ .from_env_lossy()
+ }
+
+ /// Returns a new `EnvFilter` from the directives in the given string,
+ /// ignoring any that are invalid.
+ ///
+ /// If the string is empty or contains only invalid directives, a default
+ /// directive enabling the [`ERROR`] level is added.
+ ///
+ /// To set additional configuration options prior to parsing the filter, use
+ /// the [`Builder`] type instead.
+ ///
+ /// This function is equivalent to the following:
+ ///
+ /// ```rust
+ /// use tracing_subscriber::filter::{EnvFilter, LevelFilter};
+ ///
+ /// # fn docs() -> EnvFilter {
+ /// # let directives = "";
+ /// EnvFilter::builder()
+ /// .with_default_directive(LevelFilter::ERROR.into())
+ /// .parse_lossy(directives)
+ /// # }
+ /// ```
+ ///
+ /// [`ERROR`]: tracing::Level::ERROR
+ pub fn new<S: AsRef<str>>(directives: S) -> Self {
+ Self::builder()
+ .with_default_directive(LevelFilter::ERROR.into())
+ .parse_lossy(directives)
+ }
+
+ /// Returns a new `EnvFilter` from the directives in the given string,
+ /// or an error if any are invalid.
+ ///
+ /// If the string is empty, a default directive enabling the [`ERROR`] level
+ /// is added.
+ ///
+ /// To set additional configuration options prior to parsing the filter, use
+ /// the [`Builder`] type instead.
+ ///
+ /// This function is equivalent to the following:
+ ///
+ /// ```rust
+ /// use tracing_subscriber::filter::{EnvFilter, LevelFilter};
+ ///
+ /// # fn docs() -> Result<EnvFilter, tracing_subscriber::filter::ParseError> {
+ /// # let directives = "";
+ /// EnvFilter::builder()
+ /// .with_default_directive(LevelFilter::ERROR.into())
+ /// .parse(directives)
+ /// # }
+ /// ```
+ ///
+ /// [`ERROR`]: tracing::Level::ERROR
+ pub fn try_new<S: AsRef<str>>(dirs: S) -> Result<Self, directive::ParseError> {
+ Self::builder().parse(dirs)
+ }
+
+ /// Returns a new `EnvFilter` from the value of the `RUST_LOG` environment
+ /// variable, or an error if the environment variable is unset or contains
+ /// any invalid filter directives.
+ ///
+ /// To set additional configuration options prior to parsing the filter, use
+ /// the [`Builder`] type instead.
+ ///
+ /// This function is equivalent to the following:
+ ///
+ /// ```rust
+ /// use tracing_subscriber::EnvFilter;
+ ///
+ /// # fn docs() -> Result<EnvFilter, tracing_subscriber::filter::FromEnvError> {
+ /// EnvFilter::builder().try_from_env()
+ /// # }
+ /// ```
+ pub fn try_from_default_env() -> Result<Self, FromEnvError> {
+ Self::builder().try_from_env()
+ }
+
+ /// Returns a new `EnvFilter` from the value of the given environment
+ /// variable, or an error if the environment variable is unset or contains
+ /// any invalid filter directives.
+ ///
+ /// To set additional configuration options prior to parsing the filter, use
+ /// the [`Builder`] type instead.
+ ///
+ /// This function is equivalent to the following:
+ ///
+ /// ```rust
+ /// use tracing_subscriber::EnvFilter;
+ ///
+ /// # fn docs() -> Result<EnvFilter, tracing_subscriber::filter::FromEnvError> {
+ /// # let env = "";
+ /// EnvFilter::builder().with_env_var(env).try_from_env()
+ /// # }
+ /// ```
+ pub fn try_from_env<A: AsRef<str>>(env: A) -> Result<Self, FromEnvError> {
+ Self::builder().with_env_var(env.as_ref()).try_from_env()
+ }
+
+ /// Add a filtering directive to this `EnvFilter`.
+ ///
+ /// The added directive will be used in addition to any previously set
+ /// directives, either added using this method or provided when the filter
+ /// is constructed.
+ ///
+ /// Filters may be created from [`LevelFilter`] or [`Level`], which will
+ /// enable all traces at or below a certain verbosity level, or
+ /// parsed from a string specifying a directive.
+ ///
+ /// If a filter directive is inserted that matches exactly the same spans
+ /// and events as a previous filter, but sets a different level for those
+ /// spans and events, the previous directive is overwritten.
+ ///
+ /// [`LevelFilter`]: super::LevelFilter
+ /// [`Level`]: tracing_core::Level
+ ///
+ /// # Examples
+ ///
+ /// From [`LevelFilter`]:
+ ///
+ /// ```rust
+ /// use tracing_subscriber::filter::{EnvFilter, LevelFilter};
+ /// let mut filter = EnvFilter::from_default_env()
+ /// .add_directive(LevelFilter::INFO.into());
+ /// ```
+ ///
+ /// Or from [`Level`]:
+ ///
+ /// ```rust
+ /// # use tracing_subscriber::filter::{EnvFilter, LevelFilter};
+ /// # use tracing::Level;
+ /// let mut filter = EnvFilter::from_default_env()
+ /// .add_directive(Level::INFO.into());
+ /// ```
+ ///
+ /// Parsed from a string:
+ ///
+ /// ```rust
+ /// use tracing_subscriber::filter::{EnvFilter, Directive};
+ ///
+ /// # fn try_mk_filter() -> Result<(), Box<dyn ::std::error::Error>> {
+ /// let mut filter = EnvFilter::try_from_default_env()?
+ /// .add_directive("my_crate::module=trace".parse()?)
+ /// .add_directive("my_crate::my_other_module::something=info".parse()?);
+ /// # Ok(())
+ /// # }
+ /// ```
+ /// In the above example, substitute `my_crate`, `module`, etc. with the
+ /// name your target crate/module is imported with. This might be
+ /// different from the package name in Cargo.toml (`-` is replaced by `_`).
+ /// Example, if the package name in your Cargo.toml is `MY-FANCY-LIB`, then
+ /// the corresponding Rust identifier would be `MY_FANCY_LIB`:
+ pub fn add_directive(mut self, mut directive: Directive) -> Self {
+ if !self.regex {
+ directive.deregexify();
+ }
+ if let Some(stat) = directive.to_static() {
+ self.statics.add(stat)
+ } else {
+ self.has_dynamics = true;
+ self.dynamics.add(directive);
+ }
+ self
+ }
+
+ // === filtering methods ===
+
+ /// Returns `true` if this `EnvFilter` would enable the provided `metadata`
+ /// in the current context.
+ ///
+ /// This is equivalent to calling the [`Layer::enabled`] or
+ /// [`Filter::enabled`] methods on `EnvFilter`'s implementations of those
+ /// traits, but it does not require the trait to be in scope.
+ pub fn enabled<S>(&self, metadata: &Metadata<'_>, _: Context<'_, S>) -> bool {
+ let level = metadata.level();
+
+ // is it possible for a dynamic filter directive to enable this event?
+ // if not, we can avoid the thread loca'l access + iterating over the
+ // spans in the current scope.
+ if self.has_dynamics && self.dynamics.max_level >= *level {
+ if metadata.is_span() {
+ // If the metadata is a span, see if we care about its callsite.
+ let enabled_by_cs = self
+ .by_cs
+ .read()
+ .ok()
+ .map(|by_cs| by_cs.contains_key(&metadata.callsite()))
+ .unwrap_or(false);
+ if enabled_by_cs {
+ return true;
+ }
+ }
+
+ let enabled_by_scope = {
+ let scope = self.scope.get_or_default().borrow();
+ for filter in &*scope {
+ if filter >= level {
+ return true;
+ }
+ }
+ false
+ };
+ if enabled_by_scope {
+ return true;
+ }
+ }
+
+ // is it possible for a static filter directive to enable this event?
+ if self.statics.max_level >= *level {
+ // Otherwise, fall back to checking if the callsite is
+ // statically enabled.
+ return self.statics.enabled(metadata);
+ }
+
+ false
+ }
+
+ /// Returns an optional hint of the highest [verbosity level][level] that
+ /// this `EnvFilter` will enable.
+ ///
+ /// This is equivalent to calling the [`Layer::max_level_hint`] or
+ /// [`Filter::max_level_hint`] methods on `EnvFilter`'s implementations of those
+ /// traits, but it does not require the trait to be in scope.
+ ///
+ /// [level]: tracing_core::metadata::Level
+ pub fn max_level_hint(&self) -> Option<LevelFilter> {
+ if self.dynamics.has_value_filters() {
+ // If we perform any filtering on span field *values*, we will
+ // enable *all* spans, because their field values are not known
+ // until recording.
+ return Some(LevelFilter::TRACE);
+ }
+ std::cmp::max(
+ self.statics.max_level.into(),
+ self.dynamics.max_level.into(),
+ )
+ }
+
+ /// Informs the filter that a new span was created.
+ ///
+ /// This is equivalent to calling the [`Layer::on_new_span`] or
+ /// [`Filter::on_new_span`] methods on `EnvFilter`'s implementations of those
+ /// traits, but it does not require the trait to be in scope.
+ pub fn on_new_span<S>(&self, attrs: &span::Attributes<'_>, id: &span::Id, _: Context<'_, S>) {
+ let by_cs = try_lock!(self.by_cs.read());
+ if let Some(cs) = by_cs.get(&attrs.metadata().callsite()) {
+ let span = cs.to_span_match(attrs);
+ try_lock!(self.by_id.write()).insert(id.clone(), span);
+ }
+ }
+
+ /// Informs the filter that the span with the provided `id` was entered.
+ ///
+ /// This is equivalent to calling the [`Layer::on_enter`] or
+ /// [`Filter::on_enter`] methods on `EnvFilter`'s implementations of those
+ /// traits, but it does not require the trait to be in scope.
+ pub fn on_enter<S>(&self, id: &span::Id, _: Context<'_, S>) {
+ // XXX: This is where _we_ could push IDs to the stack instead, and use
+ // that to allow changing the filter while a span is already entered.
+ // But that might be much less efficient...
+ if let Some(span) = try_lock!(self.by_id.read()).get(id) {
+ self.scope.get_or_default().borrow_mut().push(span.level());
+ }
+ }
+
+ /// Informs the filter that the span with the provided `id` was exited.
+ ///
+ /// This is equivalent to calling the [`Layer::on_exit`] or
+ /// [`Filter::on_exit`] methods on `EnvFilter`'s implementations of those
+ /// traits, but it does not require the trait to be in scope.
+ pub fn on_exit<S>(&self, id: &span::Id, _: Context<'_, S>) {
+ if self.cares_about_span(id) {
+ self.scope.get_or_default().borrow_mut().pop();
+ }
+ }
+
+ /// Informs the filter that the span with the provided `id` was closed.
+ ///
+ /// This is equivalent to calling the [`Layer::on_close`] or
+ /// [`Filter::on_close`] methods on `EnvFilter`'s implementations of those
+ /// traits, but it does not require the trait to be in scope.
+ pub fn on_close<S>(&self, id: span::Id, _: Context<'_, S>) {
+ // If we don't need to acquire a write lock, avoid doing so.
+ if !self.cares_about_span(&id) {
+ return;
+ }
+
+ let mut spans = try_lock!(self.by_id.write());
+ spans.remove(&id);
+ }
+
+ /// Informs the filter that the span with the provided `id` recorded the
+ /// provided field `values`.
+ ///
+ /// This is equivalent to calling the [`Layer::on_record`] or
+ /// [`Filter::on_record`] methods on `EnvFilter`'s implementations of those
+ /// traits, but it does not require the trait to be in scope
+ pub fn on_record<S>(&self, id: &span::Id, values: &span::Record<'_>, _: Context<'_, S>) {
+ if let Some(span) = try_lock!(self.by_id.read()).get(id) {
+ span.record_update(values);
+ }
+ }
+
+ fn cares_about_span(&self, span: &span::Id) -> bool {
+ let spans = try_lock!(self.by_id.read(), else return false);
+ spans.contains_key(span)
+ }
+
+ fn base_interest(&self) -> Interest {
+ if self.has_dynamics {
+ Interest::sometimes()
+ } else {
+ Interest::never()
+ }
+ }
+
+ fn register_callsite(&self, metadata: &'static Metadata<'static>) -> Interest {
+ if self.has_dynamics && metadata.is_span() {
+ // If this metadata describes a span, first, check if there is a
+ // dynamic filter that should be constructed for it. If so, it
+ // should always be enabled, since it influences filtering.
+ if let Some(matcher) = self.dynamics.matcher(metadata) {
+ let mut by_cs = try_lock!(self.by_cs.write(), else return self.base_interest());
+ by_cs.insert(metadata.callsite(), matcher);
+ return Interest::always();
+ }
+ }
+
+ // Otherwise, check if any of our static filters enable this metadata.
+ if self.statics.enabled(metadata) {
+ Interest::always()
+ } else {
+ self.base_interest()
+ }
+ }
+}
+
+impl<S: Subscriber> Layer<S> for EnvFilter {
+ #[inline]
+ fn register_callsite(&self, metadata: &'static Metadata<'static>) -> Interest {
+ EnvFilter::register_callsite(self, metadata)
+ }
+
+ #[inline]
+ fn max_level_hint(&self) -> Option<LevelFilter> {
+ EnvFilter::max_level_hint(self)
+ }
+
+ #[inline]
+ fn enabled(&self, metadata: &Metadata<'_>, ctx: Context<'_, S>) -> bool {
+ self.enabled(metadata, ctx)
+ }
+
+ #[inline]
+ fn on_new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, ctx: Context<'_, S>) {
+ self.on_new_span(attrs, id, ctx)
+ }
+
+ #[inline]
+ fn on_record(&self, id: &span::Id, values: &span::Record<'_>, ctx: Context<'_, S>) {
+ self.on_record(id, values, ctx);
+ }
+
+ #[inline]
+ fn on_enter(&self, id: &span::Id, ctx: Context<'_, S>) {
+ self.on_enter(id, ctx);
+ }
+
+ #[inline]
+ fn on_exit(&self, id: &span::Id, ctx: Context<'_, S>) {
+ self.on_exit(id, ctx);
+ }
+
+ #[inline]
+ fn on_close(&self, id: span::Id, ctx: Context<'_, S>) {
+ self.on_close(id, ctx);
+ }
+}
+
+feature! {
+ #![all(feature = "registry", feature = "std")]
+ use crate::layer::Filter;
+
+ impl<S> Filter<S> for EnvFilter {
+ #[inline]
+ fn enabled(&self, meta: &Metadata<'_>, ctx: &Context<'_, S>) -> bool {
+ self.enabled(meta, ctx.clone())
+ }
+
+ #[inline]
+ fn callsite_enabled(&self, meta: &'static Metadata<'static>) -> Interest {
+ self.register_callsite(meta)
+ }
+
+ #[inline]
+ fn max_level_hint(&self) -> Option<LevelFilter> {
+ EnvFilter::max_level_hint(self)
+ }
+
+ #[inline]
+ fn on_new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, ctx: Context<'_, S>) {
+ self.on_new_span(attrs, id, ctx)
+ }
+
+ #[inline]
+ fn on_record(&self, id: &span::Id, values: &span::Record<'_>, ctx: Context<'_, S>) {
+ self.on_record(id, values, ctx);
+ }
+
+ #[inline]
+ fn on_enter(&self, id: &span::Id, ctx: Context<'_, S>) {
+ self.on_enter(id, ctx);
+ }
+
+ #[inline]
+ fn on_exit(&self, id: &span::Id, ctx: Context<'_, S>) {
+ self.on_exit(id, ctx);
+ }
+
+ #[inline]
+ fn on_close(&self, id: span::Id, ctx: Context<'_, S>) {
+ self.on_close(id, ctx);
+ }
+ }
+}
+
+impl FromStr for EnvFilter {
+ type Err = directive::ParseError;
+
+ fn from_str(spec: &str) -> Result<Self, Self::Err> {
+ Self::try_new(spec)
+ }
+}
+
+impl<S> From<S> for EnvFilter
+where
+ S: AsRef<str>,
+{
+ fn from(s: S) -> Self {
+ Self::new(s)
+ }
+}
+
+impl Default for EnvFilter {
+ fn default() -> Self {
+ Builder::default().from_directives(std::iter::empty())
+ }
+}
+
+impl fmt::Display for EnvFilter {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ let mut statics = self.statics.iter();
+ let wrote_statics = if let Some(next) = statics.next() {
+ fmt::Display::fmt(next, f)?;
+ for directive in statics {
+ write!(f, ",{}", directive)?;
+ }
+ true
+ } else {
+ false
+ };
+
+ let mut dynamics = self.dynamics.iter();
+ if let Some(next) = dynamics.next() {
+ if wrote_statics {
+ f.write_str(",")?;
+ }
+ fmt::Display::fmt(next, f)?;
+ for directive in dynamics {
+ write!(f, ",{}", directive)?;
+ }
+ }
+ Ok(())
+ }
+}
+
+// ===== impl FromEnvError =====
+
+impl From<directive::ParseError> for FromEnvError {
+ fn from(p: directive::ParseError) -> Self {
+ Self {
+ kind: ErrorKind::Parse(p),
+ }
+ }
+}
+
+impl From<env::VarError> for FromEnvError {
+ fn from(v: env::VarError) -> Self {
+ Self {
+ kind: ErrorKind::Env(v),
+ }
+ }
+}
+
+impl fmt::Display for FromEnvError {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match self.kind {
+ ErrorKind::Parse(ref p) => p.fmt(f),
+ ErrorKind::Env(ref e) => e.fmt(f),
+ }
+ }
+}
+
+impl Error for FromEnvError {
+ fn source(&self) -> Option<&(dyn Error + 'static)> {
+ match self.kind {
+ ErrorKind::Parse(ref p) => Some(p),
+ ErrorKind::Env(ref e) => Some(e),
+ }
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+ use tracing_core::field::FieldSet;
+ use tracing_core::*;
+
+ struct NoSubscriber;
+ impl Subscriber for NoSubscriber {
+ #[inline]
+ fn register_callsite(&self, _: &'static Metadata<'static>) -> subscriber::Interest {
+ subscriber::Interest::always()
+ }
+ fn new_span(&self, _: &span::Attributes<'_>) -> span::Id {
+ span::Id::from_u64(0xDEAD)
+ }
+ fn event(&self, _event: &Event<'_>) {}
+ fn record(&self, _span: &span::Id, _values: &span::Record<'_>) {}
+ fn record_follows_from(&self, _span: &span::Id, _follows: &span::Id) {}
+
+ #[inline]
+ fn enabled(&self, _metadata: &Metadata<'_>) -> bool {
+ true
+ }
+ fn enter(&self, _span: &span::Id) {}
+ fn exit(&self, _span: &span::Id) {}
+ }
+
+ struct Cs;
+ impl Callsite for Cs {
+ fn set_interest(&self, _interest: Interest) {}
+ fn metadata(&self) -> &Metadata<'_> {
+ unimplemented!()
+ }
+ }
+
+ #[test]
+ fn callsite_enabled_no_span_directive() {
+ let filter = EnvFilter::new("app=debug").with_subscriber(NoSubscriber);
+ static META: &Metadata<'static> = &Metadata::new(
+ "mySpan",
+ "app",
+ Level::TRACE,
+ None,
+ None,
+ None,
+ FieldSet::new(&[], identify_callsite!(&Cs)),
+ Kind::SPAN,
+ );
+
+ let interest = filter.register_callsite(META);
+ assert!(interest.is_never());
+ }
+
+ #[test]
+ fn callsite_off() {
+ let filter = EnvFilter::new("app=off").with_subscriber(NoSubscriber);
+ static META: &Metadata<'static> = &Metadata::new(
+ "mySpan",
+ "app",
+ Level::ERROR,
+ None,
+ None,
+ None,
+ FieldSet::new(&[], identify_callsite!(&Cs)),
+ Kind::SPAN,
+ );
+
+ let interest = filter.register_callsite(META);
+ assert!(interest.is_never());
+ }
+
+ #[test]
+ fn callsite_enabled_includes_span_directive() {
+ let filter = EnvFilter::new("app[mySpan]=debug").with_subscriber(NoSubscriber);
+ static META: &Metadata<'static> = &Metadata::new(
+ "mySpan",
+ "app",
+ Level::TRACE,
+ None,
+ None,
+ None,
+ FieldSet::new(&[], identify_callsite!(&Cs)),
+ Kind::SPAN,
+ );
+
+ let interest = filter.register_callsite(META);
+ assert!(interest.is_always());
+ }
+
+ #[test]
+ fn callsite_enabled_includes_span_directive_field() {
+ let filter =
+ EnvFilter::new("app[mySpan{field=\"value\"}]=debug").with_subscriber(NoSubscriber);
+ static META: &Metadata<'static> = &Metadata::new(
+ "mySpan",
+ "app",
+ Level::TRACE,
+ None,
+ None,
+ None,
+ FieldSet::new(&["field"], identify_callsite!(&Cs)),
+ Kind::SPAN,
+ );
+
+ let interest = filter.register_callsite(META);
+ assert!(interest.is_always());
+ }
+
+ #[test]
+ fn callsite_enabled_includes_span_directive_multiple_fields() {
+ let filter = EnvFilter::new("app[mySpan{field=\"value\",field2=2}]=debug")
+ .with_subscriber(NoSubscriber);
+ static META: &Metadata<'static> = &Metadata::new(
+ "mySpan",
+ "app",
+ Level::TRACE,
+ None,
+ None,
+ None,
+ FieldSet::new(&["field"], identify_callsite!(&Cs)),
+ Kind::SPAN,
+ );
+
+ let interest = filter.register_callsite(META);
+ assert!(interest.is_never());
+ }
+
+ #[test]
+ fn roundtrip() {
+ let f1: EnvFilter =
+ "[span1{foo=1}]=error,[span2{bar=2 baz=false}],crate2[{quux=\"quuux\"}]=debug"
+ .parse()
+ .unwrap();
+ let f2: EnvFilter = format!("{}", f1).parse().unwrap();
+ assert_eq!(f1.statics, f2.statics);
+ assert_eq!(f1.dynamics, f2.dynamics);
+ }
+
+ #[test]
+ fn size_of_filters() {
+ fn print_sz(s: &str) {
+ let filter = s.parse::<EnvFilter>().expect("filter should parse");
+ println!(
+ "size_of_val({:?})\n -> {}B",
+ s,
+ std::mem::size_of_val(&filter)
+ );
+ }
+
+ print_sz("info");
+
+ print_sz("foo=debug");
+
+ print_sz(
+ "crate1::mod1=error,crate1::mod2=warn,crate1::mod2::mod3=info,\
+ crate2=debug,crate3=trace,crate3::mod2::mod1=off",
+ );
+
+ print_sz("[span1{foo=1}]=error,[span2{bar=2 baz=false}],crate2[{quux=\"quuux\"}]=debug");
+
+ print_sz(
+ "crate1::mod1=error,crate1::mod2=warn,crate1::mod2::mod3=info,\
+ crate2=debug,crate3=trace,crate3::mod2::mod1=off,[span1{foo=1}]=error,\
+ [span2{bar=2 baz=false}],crate2[{quux=\"quuux\"}]=debug",
+ );
+ }
+
+ #[test]
+ fn parse_empty_string() {
+ // There is no corresponding test for [`Builder::parse_lossy`] as failed
+ // parsing does not produce any observable side effects. If this test fails
+ // check that [`Builder::parse_lossy`] is behaving correctly as well.
+ assert!(EnvFilter::builder().parse("").is_ok());
+ }
+}