feat: [Logs user_events exporter] default event_name to log, and flatten ext_dt, ext_cloud (#253)

Co-authored-by: Cijo Thomas <[email protected]>

Author: lalitb

opentelemetry-user-events-logs/CHANGELOG.md

@@ -5,6 +5,10 @@
 - Enhanced validation for the provider name in `with_user_event_exporter(provider_name)`:
   - Empty provider names are now disallowed.
 
+- Event header name is changed to use "Log" instead of "LogRecord.EventName". 
+- `ext_dt` and `ext_cloud` structs are flattened.
+  are flattened.
+
 ## v0.12.0
 
 - Added support for Populating Cloud RoleName, RoleInstance from Resource's

opentelemetry-user-events-logs/src/lib.rs

@@ -164,7 +164,7 @@ mod tests {
                 // Sample output from perf-decode
                 {
         "./perf.data": [
-          { "n": "myprovider:my-event-name", "__csver__": 1024, "PartA": { "time": "2025-03-07T16:31:28.279214367+00:00" }, "PartC": { "user_name": "otel user", "user_email": "[email protected]" }, "PartB": { "_typeName": "Log", "severityNumber": 2, "severityText": "ERROR", "eventId": 20, "name": "my-event-name" }, "meta": { "time": 81252.403220286, "cpu": 4, "pid": 21084, "tid": 21085, "level": 2, "keyword": "0x1" } } ]
+          { "n": "myprovider:Log", "__csver__": 1024, "PartA": { "time": "2025-03-07T16:31:28.279214367+00:00", "ext_cloud_role": "myrolename"  }, "PartC": { "user_name": "otel user", "user_email": "[email protected]" }, "PartB": { "_typeName": "Log", "severityNumber": 2, "severityText": "ERROR", "eventId": 20, "name": "my-event-name" }, "meta": { "time": 81252.403220286, "cpu": 4, "pid": 21084, "tid": 21085, "level": 2, "keyword": "0x1" } } ]
         }
                  */
 
@@ -185,26 +185,26 @@ mod tests {
             .iter()
             .find(|e| {
                 if let Some(name) = e.get("n") {
-                    name.as_str().unwrap_or("") == "myprovider:my-event-name"
+                    name.as_str().unwrap_or("") == "myprovider:Log"
                 } else {
                     false
                 }
             })
-            .expect("Event 'myprovider:my-event-name' not found");
+            .expect("Event 'myprovider:Log' not found");
 
         // Validate event structure and fields
-        assert_eq!(event["n"].as_str().unwrap(), "myprovider:my-event-name");
+        assert_eq!(event["n"].as_str().unwrap(), "myprovider:Log");
         assert_eq!(event["__csver__"].as_i64().unwrap(), 1024);
 
         // Validate PartA
         let part_a = &event["PartA"];
         // Only check if the time field exists, not the actual value
         assert!(part_a.get("time").is_some(), "PartA.time is missing");
 
-        let part_a_ext_cloud = part_a.get("ext_cloud").expect("PartA.ext_cloud is missing");
-
-        // Validate role
-        assert_eq!(part_a_ext_cloud["role"].as_str().unwrap(), "myrolename");
+        let role = part_a
+            .get("ext_cloud_role")
+            .expect("PartA.ext_cloud_role is missing");
+        assert_eq!(role.as_str().unwrap(), "myrolename");
 
         // Validate PartB
         let part_b = &event["PartB"];

opentelemetry-user-events-logs/src/logs/exporter.rs

@@ -197,7 +197,7 @@ impl UserEventsExporter {
                     .event_name()
                     .filter(|s| !s.trim().is_empty())
                     .unwrap_or("Log");                
-                eb.reset(event_name, 0);
+                eb.reset("Log", 0);
 
                 eb.add_value("__csver__", 1024, FieldFormat::UnsignedInt, 0); // 0x400 in hex
 
@@ -219,34 +219,29 @@ impl UserEventsExporter {
                 eb.add_str("time", time, FieldFormat::Default, 0);
 
                 if let Some(trace_context) = log_record.trace_context() {
-                    cs_a_count += 1; // for ext_dt
-                    // TODO: Flattened structure might be faster
-                    eb.add_struct("ext_dt", 2, 0);
-                    eb.add_str("traceId", trace_context.trace_id.to_string(), FieldFormat::Default, 0);
-                    eb.add_str("spanId", trace_context.span_id.to_string(), FieldFormat::Default, 0);
+                    cs_a_count += 2; // for ext_dt_traceId and ext_dt_spanId
+                    eb.add_str(
+                        "ext_dt_traceId",
+                        trace_context.trace_id.to_string(),
+                        FieldFormat::Default,
+                        0,
+                    );
+                    eb.add_str(
+                        "ext_dt_spanId",
+                        trace_context.span_id.to_string(),
+                        FieldFormat::Default,
+                        0,
+                    );
                 }
 
-                let mut cloud_ext_count = 0;
-                if self.cloud_role.is_some()
-                {
-                    cloud_ext_count += 1;
-                }
-                if self.cloud_role_instance.is_some()
-                {
-                    cloud_ext_count += 1;
+                if let Some(cloud_role) = &self.cloud_role {
+                    cs_a_count += 1;
+                    eb.add_str("ext_cloud_role", cloud_role, FieldFormat::Default, 0);
                 }
 
-                if cloud_ext_count > 0 {
-                    cs_a_count += 1; // for ext_cloud
-                    eb.add_struct("ext_cloud", cloud_ext_count, 0);
-
-                    if let Some(cloud_role) = &self.cloud_role {
-                        eb.add_str("role", cloud_role, FieldFormat::Default, 0);
-                    }
-
-                    if let Some(cloud_role_instance) = &self.cloud_role_instance {
-                        eb.add_str("roleInstance", cloud_role_instance, FieldFormat::Default, 0);
-                    }
+                if let Some(cloud_role_instance) = &self.cloud_role_instance {
+                    cs_a_count += 1;
+                    eb.add_str("ext_cloud_roleInstance", cloud_role_instance, FieldFormat::Default, 0);
                 }
 
                 eb.set_struct_field_count(cs_a_bookmark, cs_a_count);