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Diffstat (limited to 'vendor/tracing-subscriber-0.3.3/src/filter/env/mod.rs')
| -rw-r--r-- | vendor/tracing-subscriber-0.3.3/src/filter/env/mod.rs | 738 |
1 files changed, 738 insertions, 0 deletions
diff --git a/vendor/tracing-subscriber-0.3.3/src/filter/env/mod.rs b/vendor/tracing-subscriber-0.3.3/src/filter/env/mod.rs new file mode 100644 index 000000000..81fe0e62d --- /dev/null +++ b/vendor/tracing-subscriber-0.3.3/src/filter/env/mod.rs @@ -0,0 +1,738 @@ +//! 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::{directive::Directive, field::BadName as BadFieldName}; +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 tracing_core::{ + callsite, + field::Field, + span, + subscriber::{Interest, Subscriber}, + Metadata, +}; + +/// A [`Layer`] which filters spans and events based on a set of filter +/// directives. +/// +/// # 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 acts as a regex on +/// the `std::fmt::Debug` output from the value. +/// - `level` sets a maximum verbosity level accepted by this directive. +/// +/// ## 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", ...);` +/// +/// ## Examples +/// +/// - `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. +/// +/// 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`]. +/// +/// [`Span`]: tracing_core::span +/// [fields]: tracing_core::Field +/// [`Event`]: tracing_core::Event +/// [`level`]: tracing_core::Level +/// [`Metadata`]: tracing_core::Metadata +/// [`Targets`]: crate::filter::Targets +#[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>>, +} + +thread_local! { + static SCOPE: RefCell<Vec<LevelFilter>> = RefCell::new(Vec::new()); +} + +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`]: #method.from_default_env + /// [`EnvFilter::try_from_default_env`]: #method.try_from_default_env + pub const DEFAULT_ENV: &'static str = "RUST_LOG"; + + /// Returns a new `EnvFilter` from the value of the `RUST_LOG` environment + /// variable, ignoring any invalid filter directives. + pub fn from_default_env() -> Self { + Self::from_env(Self::DEFAULT_ENV) + } + + /// Returns a new `EnvFilter` from the value of the given environment + /// variable, ignoring any invalid filter directives. + pub fn from_env<A: AsRef<str>>(env: A) -> Self { + env::var(env.as_ref()).map(Self::new).unwrap_or_default() + } + + /// Returns a new `EnvFilter` from the directives in the given string, + /// ignoring any that are invalid. + pub fn new<S: AsRef<str>>(dirs: S) -> Self { + let directives = dirs.as_ref().split(',').filter_map(|s| match s.parse() { + Ok(d) => Some(d), + Err(err) => { + eprintln!("ignoring `{}`: {}", s, err); + None + } + }); + Self::from_directives(directives) + } + + /// Returns a new `EnvFilter` from the directives in the given string, + /// or an error if any are invalid. + pub fn try_new<S: AsRef<str>>(dirs: S) -> Result<Self, directive::ParseError> { + let directives = dirs + .as_ref() + .split(',') + .map(|s| s.parse()) + .collect::<Result<Vec<_>, _>>()?; + Ok(Self::from_directives(directives)) + } + + /// Returns a new `EnvFilter` from the value of the `RUST_LOG` environment + /// variable, or an error if the environment variable contains any invalid + /// filter directives. + pub fn try_from_default_env() -> Result<Self, FromEnvError> { + Self::try_from_env(Self::DEFAULT_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. + pub fn try_from_env<A: AsRef<str>>(env: A) -> Result<Self, FromEnvError> { + env::var(env.as_ref())?.parse().map_err(Into::into) + } + + /// 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`]: ../filter/struct.LevelFilter.html + /// [`Level`]: https://docs.rs/tracing-core/latest/tracing_core/struct.Level.html + /// + /// # 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(()) + /// # } + /// ``` + pub fn add_directive(mut self, directive: Directive) -> Self { + if let Some(stat) = directive.to_static() { + self.statics.add(stat) + } else { + self.has_dynamics = true; + self.dynamics.add(directive); + } + self + } + + fn from_directives(directives: impl IntoIterator<Item = Directive>) -> Self { + use tracing::level_filters::STATIC_MAX_LEVEL; + use tracing::Level; + + let directives: Vec<_> = directives.into_iter().collect(); + + let disabled: Vec<_> = directives + .iter() + .filter(|directive| directive.level > STATIC_MAX_LEVEL) + .collect(); + + if !disabled.is_empty() { + #[cfg(feature = "ansi_term")] + use ansi_term::{Color, Style}; + // NOTE: We can't use a configured `MakeWriter` because the EnvFilter + // has no knowledge of any underlying subscriber or subscriber, which + // may or may not use a `MakeWriter`. + let warn = |msg: &str| { + #[cfg(not(feature = "ansi_term"))] + let msg = format!("warning: {}", msg); + #[cfg(feature = "ansi_term")] + let msg = { + let bold = Style::new().bold(); + let mut warning = Color::Yellow.paint("warning"); + warning.style_ref_mut().is_bold = true; + format!("{}{} {}", warning, bold.paint(":"), bold.paint(msg)) + }; + eprintln!("{}", msg); + }; + let ctx_prefixed = |prefix: &str, msg: &str| { + #[cfg(not(feature = "ansi_term"))] + let msg = format!("note: {}", msg); + #[cfg(feature = "ansi_term")] + let msg = { + let mut equal = Color::Fixed(21).paint("="); // dark blue + equal.style_ref_mut().is_bold = true; + format!(" {} {} {}", equal, Style::new().bold().paint(prefix), msg) + }; + eprintln!("{}", msg); + }; + let ctx_help = |msg| ctx_prefixed("help:", msg); + let ctx_note = |msg| ctx_prefixed("note:", msg); + let ctx = |msg: &str| { + #[cfg(not(feature = "ansi_term"))] + let msg = format!("note: {}", msg); + #[cfg(feature = "ansi_term")] + let msg = { + let mut pipe = Color::Fixed(21).paint("|"); + pipe.style_ref_mut().is_bold = true; + format!(" {} {}", pipe, msg) + }; + eprintln!("{}", msg); + }; + warn("some trace filter directives would enable traces that are disabled statically"); + for directive in disabled { + let target = if let Some(target) = &directive.target { + format!("the `{}` target", target) + } else { + "all targets".into() + }; + let level = directive + .level + .into_level() + .expect("=off would not have enabled any filters"); + ctx(&format!( + "`{}` would enable the {} level for {}", + directive, level, target + )); + } + ctx_note(&format!("the static max level is `{}`", STATIC_MAX_LEVEL)); + let help_msg = || { + let (feature, filter) = match STATIC_MAX_LEVEL.into_level() { + Some(Level::TRACE) => unreachable!( + "if the max level is trace, no static filtering features are enabled" + ), + Some(Level::DEBUG) => ("max_level_debug", Level::TRACE), + Some(Level::INFO) => ("max_level_info", Level::DEBUG), + Some(Level::WARN) => ("max_level_warn", Level::INFO), + Some(Level::ERROR) => ("max_level_error", Level::WARN), + None => return ("max_level_off", String::new()), + }; + (feature, format!("{} ", filter)) + }; + let (feature, earlier_level) = help_msg(); + ctx_help(&format!( + "to enable {}logging, remove the `{}` feature", + earlier_level, feature + )); + } + + let (dynamics, mut statics) = Directive::make_tables(directives); + let has_dynamics = !dynamics.is_empty(); + + if statics.is_empty() && !has_dynamics { + statics.add(directive::StaticDirective::default()); + } + + Self { + statics, + dynamics, + has_dynamics, + by_id: RwLock::new(HashMap::new()), + by_cs: RwLock::new(HashMap::new()), + } + } + + 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() + } + } +} + +impl<S: Subscriber> Layer<S> for EnvFilter { + 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() + } + } + + 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(), + ) + } + + fn enabled(&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 local 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 = SCOPE.with(|scope| { + for filter in scope.borrow().iter() { + 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 + } + + fn on_new_span(&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); + } + } + + fn on_record(&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 on_enter(&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) { + SCOPE.with(|scope| scope.borrow_mut().push(span.level())); + } + } + + fn on_exit(&self, id: &span::Id, _: Context<'_, S>) { + if self.cares_about_span(id) { + SCOPE.with(|scope| scope.borrow_mut().pop()); + } + } + + fn on_close(&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); + } +} + +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 { + Self::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", + ); + } +} |