opentelemetry-appender-log: Add code attributes to logs (#2193)

Author: tobz1000

opentelemetry-appender-log/CHANGELOG.md

@@ -3,6 +3,7 @@
 ## vNext
 
 - Bump MSRV to 1.70 [#2179](https://github.com/open-telemetry/opentelemetry-rust/pull/2179)
+- [2193](https://github.com/open-telemetry/opentelemetry-rust/pull/2193) `opentelemetry-appender-log`: Output experimental code attributes 
 
 ## v0.26.0
 Released 2024-Sep-30

opentelemetry-appender-log/Cargo.toml

@@ -11,17 +11,26 @@ rust-version = "1.70"
 edition = "2021"
 
 [dependencies]
-opentelemetry = { version = "0.26", path = "../opentelemetry", features = ["logs"]}
-log = { workspace = true, features = ["kv", "std"]}
+opentelemetry = { version = "0.26", path = "../opentelemetry", features = [
+  "logs",
+] }
+log = { workspace = true, features = ["kv", "std"] }
 serde = { workspace = true, optional = true, features = ["std"] }
+opentelemetry-semantic-conventions = { path = "../opentelemetry-semantic-conventions", optional = true, features = [
+  "semconv_experimental",
+] }
 
 [features]
 logs_level_enabled = ["opentelemetry/logs_level_enabled"]
 with-serde = ["log/kv_serde", "serde"]
+experimental_metadata_attributes = ["dep:opentelemetry-semantic-conventions"]
 
 [dev-dependencies]
-opentelemetry_sdk = { path = "../opentelemetry-sdk", features = [ "testing", "logs_level_enabled" ] }
-opentelemetry-stdout = { path = "../opentelemetry-stdout", features = ["logs"]}
+opentelemetry_sdk = { path = "../opentelemetry-sdk", features = [
+  "testing",
+  "logs_level_enabled",
+] }
+opentelemetry-stdout = { path = "../opentelemetry-stdout", features = ["logs"] }
 log = { workspace = true, features = ["kv_serde"] }
 tokio = { workspace = true }
 serde = { workspace = true, features = ["std", "derive"] }

opentelemetry-appender-log/src/lib.rs

@@ -99,6 +99,8 @@ use opentelemetry::{
     logs::{AnyValue, LogRecord, Logger, LoggerProvider, Severity},
     Key,
 };
+#[cfg(feature = "experimental_metadata_attributes")]
+use opentelemetry_semantic_conventions::trace::{CODE_FILEPATH, CODE_LINENO, CODE_NAMESPACE};
 use std::borrow::Cow;
 
 pub struct OpenTelemetryLogBridge<P, L>
@@ -130,6 +132,28 @@ where
             log_record.set_severity_number(severity_of_level(record.level()));
             log_record.set_severity_text(record.level().as_str());
             log_record.set_body(AnyValue::from(record.args().to_string()));
+
+            #[cfg(feature = "experimental_metadata_attributes")]
+            {
+                if let Some(filepath) = record.file() {
+                    log_record.add_attribute(
+                        Key::new(CODE_FILEPATH),
+                        AnyValue::from(filepath.to_string()),
+                    );
+                }
+
+                if let Some(line_no) = record.line() {
+                    log_record.add_attribute(Key::new(CODE_LINENO), AnyValue::from(line_no));
+                }
+
+                if let Some(module) = record.module_path() {
+                    log_record.add_attribute(
+                        Key::new(CODE_NAMESPACE),
+                        AnyValue::from(module.to_string()),
+                    );
+                }
+            }
+
             log_record.add_attributes(log_attributes(record.key_values()));
             log_record.set_target(record.metadata().target().to_string());
 
@@ -1127,6 +1151,54 @@ mod tests {
         }
     }
 
+    #[cfg(feature = "experimental_metadata_attributes")]
+    #[test]
+    fn logbridge_code_attributes() {
+        use opentelemetry_semantic_conventions::trace::{
+            CODE_FILEPATH, CODE_LINENO, CODE_NAMESPACE,
+        };
+
+        let exporter = InMemoryLogsExporter::default();
+
+        let logger_provider = LoggerProvider::builder()
+            .with_simple_exporter(exporter.clone())
+            .build();
+
+        let otel_log_appender = OpenTelemetryLogBridge::new(&logger_provider);
+
+        otel_log_appender.log(
+            &log::RecordBuilder::new()
+                .level(log::Level::Warn)
+                .args(format_args!("WARN"))
+                .file(Some("src/main.rs"))
+                .module_path(Some("service"))
+                .line(Some(101))
+                .build(),
+        );
+
+        let logs = exporter.get_emitted_logs().unwrap();
+
+        let get = |needle: &str| -> Option<AnyValue> {
+            logs[0].record.attributes_iter().find_map(|(k, v)| {
+                if k.as_str() == needle {
+                    Some(v.clone())
+                } else {
+                    None
+                }
+            })
+        };
+
+        assert_eq!(
+            Some(AnyValue::String(StringValue::from("src/main.rs"))),
+            get(CODE_FILEPATH)
+        );
+        assert_eq!(
+            Some(AnyValue::String(StringValue::from("service"))),
+            get(CODE_NAMESPACE)
+        );
+        assert_eq!(Some(AnyValue::Int(101)), get(CODE_LINENO));
+    }
+
     #[test]
     fn test_flush() {
         let exporter = InMemoryLogsExporter::default();