Add a set_trace_context method to LogRecord trait (#2129)

opentelemetry-sdk/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## vNext
 
+- Implement `LogRecord::set_trace_context` for `LogRecord`. Respect any trace context set on a `LogRecord` when emitting through a `Logger`. 
+
 ## v0.26.0
 Released 2024-Sep-30
 

opentelemetry-sdk/src/logs/log_emitter.rs

@@ -256,14 +256,17 @@ impl opentelemetry::logs::Logger for Logger {
     fn emit(&self, mut record: Self::LogRecord) {
         let provider = self.provider();
         let processors = provider.log_processors();
-        let trace_context = Context::map_current(|cx| {
-            cx.has_active_span()
-                .then(|| TraceContext::from(cx.span().span_context()))
-        });
 
         //let mut log_record = record;
-        if let Some(ref trace_context) = trace_context {
-            record.trace_context = Some(trace_context.clone());
+        if record.trace_context.is_none() {
+            let trace_context = Context::map_current(|cx| {
+                cx.has_active_span()
+                    .then(|| TraceContext::from(cx.span().span_context()))
+            });
+
+            if let Some(ref trace_context) = trace_context {
+                record.trace_context = Some(trace_context.clone());
+            }
         }
         if record.observed_timestamp.is_none() {
             record.observed_timestamp = Some(SystemTime::now());
@@ -293,13 +296,18 @@ impl opentelemetry::logs::Logger for Logger {
 
 #[cfg(test)]
 mod tests {
-    use crate::resource::{
-        SERVICE_NAME, TELEMETRY_SDK_LANGUAGE, TELEMETRY_SDK_NAME, TELEMETRY_SDK_VERSION,
+    use crate::{
+        resource::{
+            SERVICE_NAME, TELEMETRY_SDK_LANGUAGE, TELEMETRY_SDK_NAME, TELEMETRY_SDK_VERSION,
+        },
+        testing::logs::InMemoryLogsExporter,
+        trace::TracerProvider,
+        Resource,
     };
-    use crate::Resource;
 
     use super::*;
-    use opentelemetry::logs::{Logger, LoggerProvider as _};
+    use opentelemetry::logs::{AnyValue, LogRecord as _, Logger as _, LoggerProvider as _};
+    use opentelemetry::trace::{SpanId, TraceId, Tracer as _, TracerProvider as _};
     use opentelemetry::{Key, KeyValue, Value};
     use std::fmt::{Debug, Formatter};
     use std::sync::atomic::AtomicU64;
@@ -461,6 +469,72 @@ mod tests {
         assert_eq!(no_service_name.resource().len(), 0);
     }
 
+    #[test]
+    fn trace_context_test() {
+        let exporter = InMemoryLogsExporter::default();
+
+        let logger_provider = LoggerProvider::builder()
+            .with_simple_exporter(exporter.clone())
+            .build();
+
+        let logger = logger_provider.logger("test-logger");
+
+        let tracer_provider = TracerProvider::builder().build();
+
+        let tracer = tracer_provider.tracer("test-tracer");
+
+        tracer.in_span("test-span", |cx| {
+            let ambient_ctxt = cx.span().span_context().clone();
+            let explicit_ctxt = TraceContext {
+                trace_id: TraceId::from_u128(13),
+                span_id: SpanId::from_u64(14),
+                trace_flags: None,
+            };
+
+            let mut ambient_ctxt_record = logger.create_log_record();
+            ambient_ctxt_record.set_body(AnyValue::String("ambient".into()));
+
+            let mut explicit_ctxt_record = logger.create_log_record();
+            explicit_ctxt_record.set_body(AnyValue::String("explicit".into()));
+            explicit_ctxt_record.set_trace_context(
+                explicit_ctxt.trace_id,
+                explicit_ctxt.span_id,
+                explicit_ctxt.trace_flags,
+            );
+
+            logger.emit(ambient_ctxt_record);
+            logger.emit(explicit_ctxt_record);
+
+            let emitted = exporter.get_emitted_logs().unwrap();
+
+            assert_eq!(
+                Some(AnyValue::String("ambient".into())),
+                emitted[0].record.body
+            );
+            assert_eq!(
+                ambient_ctxt.trace_id(),
+                emitted[0].record.trace_context.as_ref().unwrap().trace_id
+            );
+            assert_eq!(
+                ambient_ctxt.span_id(),
+                emitted[0].record.trace_context.as_ref().unwrap().span_id
+            );
+
+            assert_eq!(
+                Some(AnyValue::String("explicit".into())),
+                emitted[1].record.body
+            );
+            assert_eq!(
+                explicit_ctxt.trace_id,
+                emitted[1].record.trace_context.as_ref().unwrap().trace_id
+            );
+            assert_eq!(
+                explicit_ctxt.span_id,
+                emitted[1].record.trace_context.as_ref().unwrap().span_id
+            );
+        });
+    }
+
     #[test]
     fn shutdown_test() {
         let counter = Arc::new(AtomicU64::new(0));

opentelemetry-sdk/src/logs/record.rs

@@ -102,6 +102,19 @@ impl opentelemetry::logs::LogRecord for LogRecord {
     {
         self.attributes.push(Some((key.into(), value.into())));
     }
+
+    fn set_trace_context(
+        &mut self,
+        trace_id: TraceId,
+        span_id: SpanId,
+        trace_flags: Option<TraceFlags>,
+    ) {
+        self.trace_context = Some(TraceContext {
+            trace_id,
+            span_id,
+            trace_flags,
+        });
+    }
 }
 
 impl LogRecord {

opentelemetry/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## vNext
 
+- Add `LogRecord::set_trace_context`; an optional method conditional on the `trace` feature for setting trace context on a log record.
+
 ## v0.26.0
 Released 2024-Sep-30
 

opentelemetry/src/logs/record.rs

@@ -1,4 +1,8 @@
 use crate::{Key, StringValue};
+
+#[cfg(feature = "trace")]
+use crate::trace::{SpanId, TraceFlags, TraceId};
+
 use std::{borrow::Cow, collections::HashMap, time::SystemTime};
 
 /// SDK implemented trait for managing log records
@@ -41,6 +45,19 @@ pub trait LogRecord {
     where
         K: Into<Key>,
         V: Into<AnyValue>;
+
+    /// Sets the trace context of the log.
+    #[cfg(feature = "trace")]
+    fn set_trace_context(
+        &mut self,
+        trace_id: TraceId,
+        span_id: SpanId,
+        trace_flags: Option<TraceFlags>,
+    ) {
+        let _ = trace_id;
+        let _ = span_id;
+        let _ = trace_flags;
+    }
 }
 
 /// Value types for representing arbitrary values in a log record.