feat(logs): make logger shutdown &self

opentelemetry-appender-tracing/benches/logs.rs

@@ -62,7 +62,7 @@ impl LogProcessor for NoopProcessor {
         Ok(())
     }
 
-    fn shutdown(&mut self) -> LogResult<()> {
+    fn shutdown(&self) -> LogResult<()> {
         Ok(())
     }
 

opentelemetry-sdk/CHANGELOG.md

@@ -13,6 +13,11 @@
   `ProcessResourceDetector` resource detectors, use the
   [`opentelemetry-resource-detector`](https://crates.io/crates/opentelemetry-resource-detectors) instead.
 - Baggage propagation error will be reported to global error handler [#1640](https://github.com/open-telemetry/opentelemetry-rust/pull/1640)
+- Improves `shutdown` behavior of `LoggerProvider` and `LogProcessor` [#1643](https://github.com/open-telemetry/opentelemetry-rust/pull/1643).
+  - `shutdown` can be called by any clone of the `LoggerProvider` without the need of waiting on all `Logger` drops. Thus, `try_shutdown` has been removed. 
+  - `shutdown` methods in `LoggerProvider` and `LogProcessor` now takes a immutable reference
+  - After `shutdown`, `LoggerProvider` will return noop `Logger`
+  - After `shutdown`, `LogProcessor` will not process any new logs
 
 ## v0.22.1
 

opentelemetry-sdk/Cargo.toml

@@ -29,6 +29,7 @@ url = { workspace = true, optional = true }
 tokio = { workspace = true, features = ["rt", "time"], optional = true }
 tokio-stream = { workspace = true, optional = true }
 http = { workspace = true, optional = true }
+lazy_static = "1.4.0"
 
 [package.metadata.docs.rs]
 all-features = true

opentelemetry-sdk/src/logs/log_emitter.rs

@@ -13,12 +13,25 @@ use opentelemetry::{
 #[cfg(feature = "logs_level_enabled")]
 use opentelemetry::logs::Severity;
 
+use std::sync::atomic::AtomicBool;
 use std::{borrow::Cow, sync::Arc};
 
+use once_cell::sync::Lazy;
+
+// a no nop logger provider used as placeholder when the provider is shutdown
+static NOOP_LOGGER_PROVIDER: Lazy<LoggerProvider> = Lazy::new(|| LoggerProvider {
+    inner: Arc::new(LoggerProviderInner {
+        processors: Vec::new(),
+        config: Config::default(),
+    }),
+    is_shutdown: Arc::new(AtomicBool::new(true)),
+});
+
 #[derive(Debug, Clone)]
 /// Creator for `Logger` instances.
 pub struct LoggerProvider {
     inner: Arc<LoggerProviderInner>,
+    is_shutdown: Arc<AtomicBool>,
 }
 
 /// Default logger name if empty string is provided.
@@ -59,6 +72,10 @@ impl opentelemetry::logs::LoggerProvider for LoggerProvider {
     }
 
     fn library_logger(&self, library: Arc<InstrumentationLibrary>) -> Self::Logger {
+        // If the provider is shutdown, new logger will refer a no-op logger provider.
+        if self.is_shutdown.load(std::sync::atomic::Ordering::Relaxed) {
+            return Logger::new(library, NOOP_LOGGER_PROVIDER.clone());
+        }
         Logger::new(library, self.clone())
     }
 }
@@ -87,22 +104,18 @@ impl LoggerProvider {
             .collect()
     }
 
-    /// Shuts down this `LoggerProvider`, panicking on failure.
-    pub fn shutdown(&mut self) -> Vec<LogResult<()>> {
-        self.try_shutdown()
-            .expect("cannot shutdown LoggerProvider when child Loggers are still active")
-    }
-
-    /// Attempts to shutdown this `LoggerProvider`, succeeding only when
-    /// all cloned `LoggerProvider` values have been dropped.
-    pub fn try_shutdown(&mut self) -> Option<Vec<LogResult<()>>> {
-        Arc::get_mut(&mut self.inner).map(|inner| {
-            inner
-                .processors
-                .iter_mut()
-                .map(|processor| processor.shutdown())
-                .collect()
-        })
+    /// Shuts down this `LoggerProvider`
+    pub fn shutdown(&self) -> Vec<LogResult<()>> {
+        // mark itself as already shutdown
+        self.is_shutdown
+            .store(true, std::sync::atomic::Ordering::Relaxed);
+        // propagate the shutdown signal to processors
+        // it's up to the processor to properly block new logs after shutdown
+        self.inner
+            .processors
+            .iter()
+            .map(|processor| processor.shutdown())
+            .collect()
     }
 }
 
@@ -168,6 +181,7 @@ impl Builder {
                 processors: self.processors,
                 config: self.config,
             }),
+            is_shutdown: Arc::new(AtomicBool::new(false)),
         }
     }
 }
@@ -253,11 +267,63 @@ mod tests {
 
     use super::*;
     use opentelemetry::global::{logger, set_logger_provider, shutdown_logger_provider};
-    use opentelemetry::logs::Logger;
+    use opentelemetry::logs::{Logger, LoggerProvider as _};
     use opentelemetry::{Key, KeyValue, Value};
-    use std::sync::Mutex;
+    use std::fmt::{Debug, Formatter};
+    use std::sync::atomic::AtomicU64;
+    use std::sync::{Arc, Mutex};
     use std::thread;
 
+    struct ShutdownTestLogProcessor {
+        is_shutdown: Arc<Mutex<bool>>,
+        counter: Arc<AtomicU64>,
+    }
+
+    impl Debug for ShutdownTestLogProcessor {
+        fn fmt(&self, _f: &mut Formatter<'_>) -> std::fmt::Result {
+            todo!()
+        }
+    }
+
+    impl ShutdownTestLogProcessor {
+        pub(crate) fn new(counter: Arc<AtomicU64>) -> Self {
+            ShutdownTestLogProcessor {
+                is_shutdown: Arc::new(Mutex::new(false)),
+                counter,
+            }
+        }
+    }
+
+    impl LogProcessor for ShutdownTestLogProcessor {
+        fn emit(&self, _data: LogData) {
+            self.is_shutdown
+                .lock()
+                .map(|is_shutdown| {
+                    if !*is_shutdown {
+                        self.counter
+                            .fetch_add(1, std::sync::atomic::Ordering::SeqCst);
+                    }
+                })
+                .expect("lock poisoned");
+        }
+
+        fn force_flush(&self) -> LogResult<()> {
+            Ok(())
+        }
+
+        fn shutdown(&self) -> LogResult<()> {
+            self.is_shutdown
+                .lock()
+                .map(|mut is_shutdown| *is_shutdown = true)
+                .expect("lock poisoned");
+            Ok(())
+        }
+
+        #[cfg(feature = "logs_level_enabled")]
+        fn event_enabled(&self, _level: Severity, _target: &str, _name: &str) -> bool {
+            true
+        }
+    }
     #[test]
     fn test_logger_provider_default_resource() {
         let assert_resource = |provider: &super::LoggerProvider,
@@ -386,6 +452,30 @@ mod tests {
 
     #[test]
     fn shutdown_test() {
+        let counter = Arc::new(AtomicU64::new(0));
+        let logger_provider = LoggerProvider::builder()
+            .with_log_processor(ShutdownTestLogProcessor::new(counter.clone()))
+            .build();
+
+        let logger1 = logger_provider.logger("test-logger1");
+        let logger2 = logger_provider.logger("test-logger2");
+        logger1.emit(LogRecord::default());
+        logger2.emit(LogRecord::default());
+
+        let logger3 = logger_provider.logger("test-logger3");
+        let handle = thread::spawn(move || {
+            logger3.emit(LogRecord::default());
+        });
+        handle.join().expect("thread panicked");
+
+        let _ = logger_provider.shutdown();
+        logger1.emit(LogRecord::default());
+
+        assert_eq!(counter.load(std::sync::atomic::Ordering::SeqCst), 3);
+    }
+
+    #[test]
+    fn global_shutdown_test() {
         // cargo test shutdown_test --features=logs
 
         // Arrange
@@ -493,7 +583,7 @@ mod tests {
             Ok(())
         }
 
-        fn shutdown(&mut self) -> LogResult<()> {
+        fn shutdown(&self) -> LogResult<()> {
             *self.shutdown_called.lock().unwrap() = true;
             Ok(())
         }

opentelemetry-sdk/src/logs/log_processor.rs

@@ -13,6 +13,7 @@ use opentelemetry::{
     global,
     logs::{LogError, LogResult},
 };
+use std::sync::atomic::AtomicBool;
 use std::{cmp::min, env, sync::Mutex};
 use std::{
     fmt::{self, Debug, Formatter},
@@ -46,7 +47,9 @@ pub trait LogProcessor: Send + Sync + Debug {
     /// Force the logs lying in the cache to be exported.
     fn force_flush(&self) -> LogResult<()>;
     /// Shuts down the processor.
-    fn shutdown(&mut self) -> LogResult<()>;
+    /// After shutdown returns the log processor should stop processing any logs.
+    /// It's up to the implementation on when to drop the LogProcessor.
+    fn shutdown(&self) -> LogResult<()>;
     #[cfg(feature = "logs_level_enabled")]
     /// Check if logging is enabled
     fn event_enabled(&self, level: Severity, target: &str, name: &str) -> bool;
@@ -59,18 +62,25 @@ pub trait LogProcessor: Send + Sync + Debug {
 #[derive(Debug)]
 pub struct SimpleLogProcessor {
     exporter: Mutex<Box<dyn LogExporter>>,
+    is_shutdown: AtomicBool,
 }
 
 impl SimpleLogProcessor {
     pub(crate) fn new(exporter: Box<dyn LogExporter>) -> Self {
         SimpleLogProcessor {
             exporter: Mutex::new(exporter),
+            is_shutdown: AtomicBool::new(false),
         }
     }
 }
 
 impl LogProcessor for SimpleLogProcessor {
     fn emit(&self, data: LogData) {
+        // noop after shutdown
+        if self.is_shutdown.load(std::sync::atomic::Ordering::Relaxed) {
+            return;
+        }
+
         let result = self
             .exporter
             .lock()
@@ -85,7 +95,9 @@ impl LogProcessor for SimpleLogProcessor {
         Ok(())
     }
 
-    fn shutdown(&mut self) -> LogResult<()> {
+    fn shutdown(&self) -> LogResult<()> {
+        self.is_shutdown
+            .store(true, std::sync::atomic::Ordering::Relaxed);
         if let Ok(mut exporter) = self.exporter.lock() {
             exporter.shutdown();
             Ok(())
@@ -141,7 +153,7 @@ impl<R: RuntimeChannel> LogProcessor for BatchLogProcessor<R> {
             .and_then(std::convert::identity)
     }
 
-    fn shutdown(&mut self) -> LogResult<()> {
+    fn shutdown(&self) -> LogResult<()> {
         let (res_sender, res_receiver) = oneshot::channel();
         self.message_sender
             .try_send(BatchMessage::Shutdown(res_sender))
@@ -458,6 +470,9 @@ mod tests {
         BatchLogProcessor, OTEL_BLRP_EXPORT_TIMEOUT, OTEL_BLRP_MAX_EXPORT_BATCH_SIZE,
         OTEL_BLRP_MAX_QUEUE_SIZE, OTEL_BLRP_SCHEDULE_DELAY,
     };
+    use crate::export::logs::LogData;
+    use crate::logs::{LogProcessor, SimpleLogProcessor};
+    use crate::testing::logs::InMemoryLogsExporterBuilder;
     use crate::{
         logs::{
             log_processor::{
@@ -620,4 +635,61 @@ mod tests {
         assert_eq!(actual.max_export_timeout, Duration::from_millis(3));
         assert_eq!(actual.max_queue_size, 4);
     }
+
+    #[tokio::test(flavor = "multi_thread")]
+    async fn test_batch_shutdown() {
+        // assert we will receive an error
+        // setup
+        let exporter = InMemoryLogsExporterBuilder::default()
+            .keep_records_on_shutdown()
+            .build();
+        let processor = BatchLogProcessor::new(
+            Box::new(exporter.clone()),
+            BatchConfig::default(),
+            runtime::Tokio,
+        );
+        processor.emit(LogData {
+            record: Default::default(),
+            resource: Default::default(),
+            instrumentation: Default::default(),
+        });
+        processor.force_flush().unwrap();
+        processor.shutdown().unwrap();
+        // todo: expect to see errors here. How should we assert this?
+        processor.emit(LogData {
+            record: Default::default(),
+            resource: Default::default(),
+            instrumentation: Default::default(),
+        });
+        assert_eq!(1, exporter.get_emitted_logs().unwrap().len())
+    }
+
+    #[test]
+    fn test_simple_shutdown() {
+        let exporter = InMemoryLogsExporterBuilder::default()
+            .keep_records_on_shutdown()
+            .build();
+        let processor = SimpleLogProcessor::new(Box::new(exporter.clone()));
+
+        processor.emit(LogData {
+            record: Default::default(),
+            resource: Default::default(),
+            instrumentation: Default::default(),
+        });
+
+        processor.shutdown().unwrap();
+
+        let is_shutdown = processor
+            .is_shutdown
+            .load(std::sync::atomic::Ordering::Relaxed);
+        assert!(is_shutdown);
+
+        processor.emit(LogData {
+            record: Default::default(),
+            resource: Default::default(),
+            instrumentation: Default::default(),
+        });
+
+        assert_eq!(1, exporter.get_emitted_logs().unwrap().len())
+    }
 }