Export logs only if the level/logger/target is enabled. (#1147)

Author: lalitb

opentelemetry-api/Cargo.toml

@@ -31,3 +31,4 @@ trace = ["pin-project-lite"]
 metrics = []
 testing = ["trace"]
 logs = []
+logs_level_enabled = ["logs"]

opentelemetry-api/src/global/logs.rs

@@ -52,6 +52,11 @@ impl Logger for BoxedLogger {
     fn emit(&self, record: crate::logs::LogRecord) {
         self.0.emit(record)
     }
+
+    #[cfg(feature = "logs_level_enabled")]
+    fn event_enabled(&self, level: crate::logs::Severity, target: &str) -> bool {
+        self.0.event_enabled(level, target)
+    }
 }
 
 #[derive(Clone)]

opentelemetry-api/src/logs/logger.rs

@@ -2,14 +2,22 @@ use std::{borrow::Cow, sync::Arc};
 
 use crate::{logs::LogRecord, InstrumentationLibrary, KeyValue};
 
+#[cfg(feature = "logs_level_enabled")]
+use super::Severity;
+
 /// The interface for emitting [`LogRecord`]s.
+
 pub trait Logger {
     /// Emit a [`LogRecord`]. If there is active current thread's [`Context`],
     ///  the logger will set the record's [`TraceContext`] to the active trace context,
     ///
     /// [`Context`]: crate::Context
     /// [`TraceContext`]: crate::logs::TraceContext
     fn emit(&self, record: LogRecord);
+
+    #[cfg(feature = "logs_level_enabled")]
+    /// Check if the given log level is enabled.
+    fn event_enabled(&self, level: Severity, target: &str) -> bool;
 }
 
 /// Interfaces that can create [`Logger`] instances.

opentelemetry-api/src/logs/noop.rs

@@ -40,4 +40,8 @@ pub struct NoopLogger(());
 
 impl Logger for NoopLogger {
     fn emit(&self, _record: LogRecord) {}
+    #[cfg(feature = "logs_level_enabled")]
+    fn event_enabled(&self, _level: super::Severity, _target: &str) -> bool {
+        true
+    }
 }

opentelemetry-appender-log/Cargo.toml

@@ -13,3 +13,7 @@ edition = "2021"
 [dependencies]
 opentelemetry_api = { version = "0.19", path = "../opentelemetry-api", features = ["logs"]}
 log = {version = "0.4.17", features = ["kv_unstable", "std"]}
+
+[features]
+logs_level_enabled = ["opentelemetry_api/logs_level_enabled"]
+default = ["logs_level_enabled"]

opentelemetry-appender-log/src/lib.rs

@@ -17,7 +17,12 @@ where
     L: Logger + Send + Sync,
 {
     fn enabled(&self, _metadata: &Metadata) -> bool {
-        // TODO: This should be dynamic instead of the current hardcoded value.
+        #[cfg(feature = "logs_level_enabled")]
+        return self.logger.event_enabled(
+            map_severity_to_otel_severity(_metadata.level()),
+            _metadata.target(),
+        );
+        #[cfg(not(feature = "logs_level_enabled"))]
         true
     }
 

opentelemetry-appender-tracing/Cargo.toml

@@ -19,4 +19,9 @@ tracing-subscriber = { version = "0.3.0", default-features = false, features = [
 once_cell = "1.13.0"
 
 [dev-dependencies]
-opentelemetry-stdout = { path = "../opentelemetry-stdout", features = ["logs"] }
+opentelemetry-stdout = { path = "../opentelemetry-stdout", features = ["logs"] }
+
+[features]
+logs_level_enabled = ["opentelemetry_api/logs_level_enabled", "opentelemetry_sdk/logs_level_enabled"]
+default = ["logs_level_enabled"]
+

opentelemetry-appender-tracing/src/layer.rs

@@ -106,6 +106,17 @@ where
         event.record(&mut visitor);
         self.logger.emit(log_record);
     }
+
+    #[cfg(feature = "logs_level_enabled")]
+    fn event_enabled(
+        &self,
+        _event: &tracing_core::Event<'_>,
+        _ctx: tracing_subscriber::layer::Context<'_, S>,
+    ) -> bool {
+        let severity = map_severity_to_otel_severity(_event.metadata().level().as_str());
+        self.logger
+            .event_enabled(severity, _event.metadata().target())
+    }
 }
 
 fn map_severity_to_otel_severity(level: &str) -> Severity {

opentelemetry-sdk/Cargo.toml

@@ -45,6 +45,7 @@ default = ["trace"]
 trace = ["opentelemetry_api/trace", "crossbeam-channel", "rand", "async-trait", "percent-encoding"]
 jaeger_remote_sampler = ["trace", "opentelemetry-http", "http", "serde", "serde_json", "url"]
 logs = ["opentelemetry_api/logs", "crossbeam-channel", "async-trait", "serde_json"]
+logs_level_enabled = ["logs", "opentelemetry_api/logs_level_enabled"]
 metrics = ["opentelemetry_api/metrics", "regex", "async-trait"]
 testing = ["opentelemetry_api/testing", "trace", "metrics", "logs", "rt-async-std", "rt-tokio", "rt-tokio-current-thread", "tokio/macros", "tokio/rt-multi-thread"]
 rt-tokio = ["tokio", "tokio-stream"]

opentelemetry-sdk/src/export/logs/mod.rs

@@ -1,6 +1,8 @@
 //! Log exporters
 use crate::Resource;
 use async_trait::async_trait;
+#[cfg(feature = "logs_level_enabled")]
+use opentelemetry_api::logs::Severity;
 use opentelemetry_api::{
     logs::{LogError, LogRecord, LogResult},
     InstrumentationLibrary,
@@ -14,6 +16,11 @@ pub trait LogExporter: Send + Debug {
     async fn export(&mut self, batch: Vec<LogData>) -> LogResult<()>;
     /// Shuts down the expoter.
     fn shutdown(&mut self) {}
+    #[cfg(feature = "logs_level_enabled")]
+    /// Chek if logs are enabled.
+    fn event_enabled(&self, _level: Severity, _target: &str, _name: &str) -> bool {
+        true
+    }
 }
 
 /// `LogData` associates a [`LogRecord`] with a [`Resource`] and