Insert tracing event name into LogRecord::event_name instead of attributes (#1928)

Co-authored-by: Cijo Thomas <cithomas@microsoft.com>

Author: lalitb

opentelemetry-appender-tracing/CHANGELOG.md

@@ -5,6 +5,9 @@
 - [1869](https://github.com/open-telemetry/opentelemetry-rust/pull/1869) Utilize the `LogRecord::set_target()` method to pass the tracing target to the SDK.
   Exporters might use the target to override the instrumentation scope, which previously contained "opentelemetry-appender-tracing".
 
+- **Breaking** [1928](https://github.com/open-telemetry/opentelemetry-rust/pull/1928) Insert tracing event name into LogRecord::event_name instead of attributes.
+   - If using a custom exporter, then they must serialize this field directly from LogRecord::event_name instead of iterating over the attributes. OTLP Exporter is modified to handle this.
+
 ## v0.4.0
 
 - Removed unwanted dependency on opentelemetry-sdk.

opentelemetry-appender-tracing/src/layer.rs

@@ -3,7 +3,9 @@ use opentelemetry::{
     Key,
 };
 use std::borrow::Cow;
-use tracing_core::{Level, Metadata};
+use tracing_core::Level;
+#[cfg(feature = "experimental_metadata_attributes")]
+use tracing_core::Metadata;
 #[cfg(feature = "experimental_metadata_attributes")]
 use tracing_log::NormalizeEvent;
 use tracing_subscriber::Layer;
@@ -39,13 +41,6 @@ impl<'a, LR: LogRecord> EventVisitor<'a, LR> {
     fn new(log_record: &'a mut LR) -> Self {
         EventVisitor { log_record }
     }
-    fn visit_metadata(&mut self, meta: &Metadata) {
-        self.log_record
-            .add_attribute(Key::new("name"), AnyValue::from(meta.name()));
-
-        #[cfg(feature = "experimental_metadata_attributes")]
-        self.visit_experimental_metadata(meta);
-    }
 
     #[cfg(feature = "experimental_metadata_attributes")]
     fn visit_experimental_metadata(&mut self, meta: &Metadata) {
@@ -170,15 +165,17 @@ where
 
         //let mut log_record: LogRecord = LogRecord::default();
         let mut log_record = self.logger.create_log_record();
+        log_record.set_target(meta.target().to_string());
+        log_record.set_event_name(meta.name());
         log_record.set_severity_number(severity_of_level(meta.level()));
         log_record.set_severity_text(meta.level().to_string().into());
-        log_record.set_target(meta.target().to_string());
-
         let mut visitor = EventVisitor::new(&mut log_record);
-        visitor.visit_metadata(meta);
+        #[cfg(feature = "experimental_metadata_attributes")]
+        visitor.visit_experimental_metadata(meta);
         // Visit fields.
         event.record(&mut visitor);
 
+        //emit record
         self.logger.emit(log_record);
     }
 
@@ -261,10 +258,9 @@ mod tests {
             .clone()
             .expect("Attributes are expected");
         #[cfg(not(feature = "experimental_metadata_attributes"))]
-        assert_eq!(attributes.len(), 4);
+        assert_eq!(attributes.len(), 3);
         #[cfg(feature = "experimental_metadata_attributes")]
-        assert_eq!(attributes.len(), 9);
-        assert!(attributes.contains(&(Key::new("name"), "my-event-name".into())));
+        assert_eq!(attributes.len(), 8);
         assert!(attributes.contains(&(Key::new("event_id"), 20.into())));
         assert!(attributes.contains(&(Key::new("user_name"), "otel".into())));
         assert!(attributes.contains(&(Key::new("user_email"), "otel@opentelemetry.io".into())));
@@ -358,10 +354,9 @@ mod tests {
             .clone()
             .expect("Attributes are expected");
         #[cfg(not(feature = "experimental_metadata_attributes"))]
-        assert_eq!(attributes.len(), 4);
+        assert_eq!(attributes.len(), 3);
         #[cfg(feature = "experimental_metadata_attributes")]
-        assert_eq!(attributes.len(), 9);
-        assert!(attributes.contains(&(Key::new("name"), "my-event-name".into())));
+        assert_eq!(attributes.len(), 8);
         assert!(attributes.contains(&(Key::new("event_id"), 20.into())));
         assert!(attributes.contains(&(Key::new("user_name"), "otel".into())));
         assert!(attributes.contains(&(Key::new("user_email"), "otel@opentelemetry.io".into())));
@@ -419,6 +414,7 @@ mod tests {
         assert!(log.record.trace_context.is_none());
 
         // Validate attributes
+        #[cfg(feature = "experimental_metadata_attributes")]
         let attributes: Vec<(Key, AnyValue)> = log
             .record
             .attributes
@@ -427,9 +423,7 @@ mod tests {
 
         // Attributes can be polluted when we don't use this feature.
         #[cfg(feature = "experimental_metadata_attributes")]
-        assert_eq!(attributes.len(), 6);
-
-        assert!(attributes.contains(&(Key::new("name"), "log event".into())));
+        assert_eq!(attributes.len(), 5);
 
         #[cfg(feature = "experimental_metadata_attributes")]
         {
@@ -516,6 +510,7 @@ mod tests {
         );
 
         // validate attributes.
+        #[cfg(feature = "experimental_metadata_attributes")]
         let attributes: Vec<(Key, AnyValue)> = log
             .record
             .attributes
@@ -524,9 +519,7 @@ mod tests {
 
         // Attributes can be polluted when we don't use this feature.
         #[cfg(feature = "experimental_metadata_attributes")]
-        assert_eq!(attributes.len(), 6);
-
-        assert!(attributes.contains(&(Key::new("name"), "log event".into())));
+        assert_eq!(attributes.len(), 5);
 
         #[cfg(feature = "experimental_metadata_attributes")]
         {

opentelemetry-proto/src/transform/logs.rs

@@ -92,11 +92,22 @@ pub mod tonic {
                 severity_number: severity_number.into(),
                 severity_text: log_record.severity_text.map(Into::into).unwrap_or_default(),
                 body: log_record.body.map(Into::into),
-                attributes: log_record
-                    .attributes
-                    .map(Attributes::from_iter)
-                    .unwrap_or_default()
-                    .0,
+                attributes: {
+                    let mut attributes = log_record
+                        .attributes
+                        .map(Attributes::from_iter)
+                        .unwrap_or_default()
+                        .0;
+                    if let Some(event_name) = log_record.event_name.as_ref() {
+                        attributes.push(KeyValue {
+                            key: "name".into(),
+                            value: Some(AnyValue {
+                                value: Some(Value::StringValue(event_name.to_string())),
+                            }),
+                        })
+                    }
+                    attributes
+                },
                 dropped_attributes_count: 0,
                 flags: trace_context
                     .map(|ctx| {

opentelemetry-stdout/src/logs/transform.rs

@@ -131,16 +131,26 @@ impl From<opentelemetry_sdk::export::logs::LogData> for LogRecord {
                 .severity_number
                 .map(|u| u as u32)
                 .unwrap_or_default(),
-            attributes: value
-                .record
-                .attributes
-                .map(|attrs| {
-                    attrs
-                        .into_iter()
-                        .map(|(key, value)| (key, value).into())
-                        .collect()
-                })
-                .unwrap_or_default(),
+            attributes: {
+                let mut attributes = value
+                    .record
+                    .attributes
+                    .unwrap_or_default()
+                    .into_iter()
+                    .map(|(key, value)| (key, value).into())
+                    .collect::<Vec<_>>();
+
+                if let Some(event_name) = &value.record.event_name {
+                    attributes.push(
+                        (
+                            opentelemetry::Key::from("name"),
+                            opentelemetry::Value::String(event_name.clone().into()),
+                        )
+                            .into(),
+                    )
+                }
+                attributes
+            },
             dropped_attributes_count: 0,
             severity_text: value.record.severity_text,
             body: value.record.body.map(|a| a.into()),