test: Add test to show how to add baggage to logrecords via processor

opentelemetry-sdk/src/logs/mod.rs

@@ -35,10 +35,11 @@
 mod tests {
     use super::*;
     use crate::Resource;
+    use opentelemetry::baggage::BaggageExt;
     use opentelemetry::logs::LogRecord;
     use opentelemetry::logs::{Logger, LoggerProvider, Severity};
-    use opentelemetry::InstrumentationScope;
     use opentelemetry::{logs::AnyValue, Key, KeyValue};
+    use opentelemetry::{Context, InstrumentationScope};
     use std::borrow::Borrow;
     use std::collections::HashMap;
 
@@ -150,4 +151,63 @@
             .attributes()
             .eq(&[KeyValue::new("test_k", "test_v")]));
     }
+
+    #[derive(Debug)]
+    struct EnrichWithBaggageProcessor;
+    impl LogProcessor for EnrichWithBaggageProcessor {
+        fn emit(&self, data: &mut SdkLogRecord, _instrumentation: &InstrumentationScope) {
+            Context::map_current(|cx| {
+                for (kk, vv) in cx.baggage().iter() {
+                    data.add_attribute(kk.clone(), vv.0.clone());
+                }
+            });
+        }
+
+        fn force_flush(&self) -> crate::error::OTelSdkResult {
+            Ok(())
+        }
+
+        fn shutdown(&self) -> crate::error::OTelSdkResult {
+            Ok(())
+        }
+    }
+    #[test]
+    fn log_and_baggage() {
+        // Arrange
+        let exporter: InMemoryLogExporter = InMemoryLogExporter::default();
+        let logger_provider = SdkLoggerProvider::builder()
+            .with_log_processor(EnrichWithBaggageProcessor)
+            .with_log_processor(SimpleLogProcessor::new(exporter.clone()))
+            .build();
+
+        // Act
+        let logger = logger_provider.logger("test-logger");
+        let context_with_baggage =
+            Context::current_with_baggage(vec![KeyValue::new("key-from-bag", "value-from-bag")]);
+        let _cx_guard = context_with_baggage.attach();
+        let mut log_record = logger.create_log_record();
+        log_record.add_attribute("key", "value");
+        logger.emit(log_record);
+
+        // Assert
+        let exported_logs = exporter
+            .get_emitted_logs()
+            .expect("Logs are expected to be exported.");
+        assert_eq!(exported_logs.len(), 1);
+        let log = exported_logs
+            .first()
+            .expect("Atleast one log is expected to be present.");
+        assert_eq!(log.instrumentation.name(), "test-logger");
+        assert_eq!(log.record.attributes_len(), 2);
+
+        // Assert that the log record contains the baggage attribute
+        // and the attribute added to the log record.
+        assert!(log
+            .record
+            .attributes_contains(&Key::new("key"), &AnyValue::String("value".into())));
+        assert!(log.record.attributes_contains(
+            &Key::new("key-from-bag"),
+            &AnyValue::String("value-from-bag".into())
+        ));
+    }
 }

opentelemetry/src/baggage.rs

@@ -13,6 +13,10 @@
 //! Baggage can be sent between systems using a baggage propagator in
 //! accordance with the [W3C Baggage] specification.
 //!
+//! Note: Baggage is not automatically added to any telemetry. Users have to
+//! explicitly add baggage entries to telemetry items.
+//!
+//!
 //! [W3C Baggage]: https://w3c.github.io/baggage
 use crate::{Context, Key, KeyValue, StringValue};
 use std::collections::hash_map::Entry;
@@ -75,10 +79,10 @@ impl Baggage {
     /// ```
     /// use opentelemetry::{baggage::Baggage, StringValue};
     ///
-    /// let mut cc = Baggage::new();
-    /// let _ = cc.insert("my-name", "my-value");
+    /// let mut baggage = Baggage::new();
+    /// let _ = baggage.insert("my-name", "my-value");
     ///
-    /// assert_eq!(cc.get("my-name"), Some(&StringValue::from("my-value")))
+    /// assert_eq!(baggage.get("my-name"), Some(&StringValue::from("my-value")))
     /// ```
     pub fn get<K: AsRef<str>>(&self, key: K) -> Option<&StringValue> {
         self.inner.get(key.as_ref()).map(|(value, _metadata)| value)
@@ -90,11 +94,11 @@ impl Baggage {
     /// ```
     /// use opentelemetry::{baggage::{Baggage, BaggageMetadata}, StringValue};
     ///
-    /// let mut cc = Baggage::new();
-    /// let _ = cc.insert("my-name", "my-value");
+    /// let mut baggage = Baggage::new();
+    /// let _ = baggage.insert("my-name", "my-value");
     ///
     /// // By default, the metadata is empty
-    /// assert_eq!(cc.get_with_metadata("my-name"), Some(&(StringValue::from("my-value"), BaggageMetadata::from(""))))
+    /// assert_eq!(baggage.get_with_metadata("my-name"), Some(&(StringValue::from("my-value"), BaggageMetadata::from(""))))
     /// ```
     pub fn get_with_metadata<K: AsRef<str>>(
         &self,
@@ -113,10 +117,10 @@ impl Baggage {
     /// ```
     /// use opentelemetry::{baggage::Baggage, StringValue};
     ///
-    /// let mut cc = Baggage::new();
-    /// let _ = cc.insert("my-name", "my-value");
+    /// let mut baggage = Baggage::new();
+    /// let _ = baggage.insert("my-name", "my-value");
     ///
-    /// assert_eq!(cc.get("my-name"), Some(&StringValue::from("my-value")))
+    /// assert_eq!(baggage.get("my-name"), Some(&StringValue::from("my-value")))
     /// ```
     pub fn insert<K, V>(&mut self, key: K, value: V) -> Option<StringValue>
     where
@@ -127,7 +131,7 @@ impl Baggage {
             .map(|pair| pair.0)
     }
 
-    /// Inserts a name/value pair into the baggage.
+    /// Inserts a name/value(+metadata) pair into the baggage.
     ///
     /// Same with `insert`, if the name was not present, [`None`] will be returned.
     /// If the name is present, the old value and metadata will be returned.
@@ -139,10 +143,10 @@ impl Baggage {
     /// ```
     /// use opentelemetry::{baggage::{Baggage, BaggageMetadata}, StringValue};
     ///
-    /// let mut cc = Baggage::new();
-    /// let _ = cc.insert_with_metadata("my-name", "my-value", "test");
+    /// let mut baggage = Baggage::new();
+    /// let _ = baggage.insert_with_metadata("my-name", "my-value", "test");
     ///
-    /// assert_eq!(cc.get_with_metadata("my-name"), Some(&(StringValue::from("my-value"), BaggageMetadata::from("test"))))
+    /// assert_eq!(baggage.get_with_metadata("my-name"), Some(&(StringValue::from("my-value"), BaggageMetadata::from("test"))))
     /// ```
     pub fn insert_with_metadata<K, V, S>(
         &mut self,