Propagate span_id & trace_id in logs records when converting trace events

examples/tracing-grpc/Cargo.toml

@@ -14,15 +14,15 @@ name = "grpc-client"
 path = "src/client.rs"
 
 [dependencies]
-opentelemetry = { version = "0.20" }
-opentelemetry_sdk = { version = "0.20", features = ["rt-tokio"] }
-opentelemetry-jaeger = { version = "0.19", features = ["rt-tokio"] }
+opentelemetry = { version = "0.21" }
+opentelemetry_sdk = { version = "0.21", features = ["rt-tokio"] }
+opentelemetry-jaeger = { version = "0.20", features = ["rt-tokio"] }
 prost = "0.11"
 tokio = { version = "1.28", features = ["full"] }
 tonic = "0.9.2"
 tracing = "0.1"
 tracing-futures = "0.2"
-tracing-opentelemetry = "0.20"
+tracing-opentelemetry = "0.22"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 
 [build-dependencies]

opentelemetry-appender-tracing/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## vNext
 
+- Support trace correlation by setting the trace_id and span_id on the log records
+
 ## v0.2.0
 
 ### Changed

opentelemetry-appender-tracing/Cargo.toml

@@ -13,15 +13,17 @@ rust-version = "1.65"
 [dependencies]
 opentelemetry = { version = "0.21", path = "../opentelemetry", features = ["logs"] }
 opentelemetry_sdk = { version = "0.21", path = "../opentelemetry-sdk", features = ["logs"] }
-tracing = {version = "0.1", default-features = false, features = ["std"]}
+tracing = { version = "0.1", default-features = false, features = ["std"] }
+tracing-opentelemetry = { version = "0.22", optional = true }
 tracing-core = "0.1.31"
 tracing-subscriber = { version = "0.3.0", default-features = false, features = ["registry", "std"] }
 once_cell = "1.13.0"
 
 [dev-dependencies]
-opentelemetry-stdout = { path = "../opentelemetry-stdout", features = ["logs"] }
+opentelemetry-stdout = { version = "0.2", path = "../opentelemetry-stdout", features = ["logs"] }
 
 [features]
 logs_level_enabled = ["opentelemetry/logs_level_enabled", "opentelemetry_sdk/logs_level_enabled"]
+tracing = ["tracing-opentelemetry"]
 default = ["logs_level_enabled"]
-testing = ["opentelemetry_sdk/testing"]
+testing = ["opentelemetry_sdk/testing"]

opentelemetry-appender-tracing/examples/basic.rs

@@ -6,7 +6,7 @@ use opentelemetry_sdk::{
     logs::{Config, LoggerProvider},
     Resource,
 };
-use tracing::error;
+use tracing::{error, info, info_span};
 use tracing_subscriber::prelude::*;
 
 fn main() {
@@ -23,6 +23,10 @@ fn main() {
     let layer = layer::OpenTelemetryTracingBridge::new(&provider);
     tracing_subscriber::registry().with(layer).init();
 
+    info_span!("my-span").in_scope(|| {
+        info!(target: "my-system", "an info log");
+    });
+
     error!(name: "my-event-name", target: "my-system", event_id = 20, user_name = "otel", user_email = "[email protected]");
     drop(provider);
 }

opentelemetry-appender-tracing/src/layer.rs

@@ -1,7 +1,7 @@
 use opentelemetry::logs::{LogRecord, Logger, LoggerProvider, Severity};
 use std::borrow::Cow;
-use tracing_core::Level;
-use tracing_subscriber::Layer;
+use tracing_core::{Level, Subscriber};
+use tracing_subscriber::{registry::LookupSpan, Layer};
 
 const INSTRUMENTATION_LIBRARY_NAME: &str = "opentelemetry-appender-tracing";
 
@@ -90,7 +90,7 @@
 
 impl<S, P, L> Layer<S> for OpenTelemetryTracingBridge<P, L>
 where
-    S: tracing::Subscriber,
+    S: Subscriber + for<'a> LookupSpan<'a>,
     P: LoggerProvider<Logger = L> + Send + Sync + 'static,
     L: Logger + Send + Sync + 'static,
 {
@@ -104,6 +104,10 @@
         log_record.severity_number = Some(severity_of_level(meta.level()));
         log_record.severity_text = Some(meta.level().to_string().into());
 
+        // Extract the trace_id & span_id from the opentelemetry extension.
+        #[cfg(feature = "tracing")]
+        set_trace_context(&mut log_record, &_ctx);
+
         // add the `name` metadata to attributes
         // TBD - Propose this to be part of log_record metadata.
         let vec = vec![("name", meta.name())];
@@ -131,6 +135,31 @@
     }
 }
 
+#[cfg(feature = "tracing")]
+fn set_trace_context<S>(log_record: &mut LogRecord, ctx: &tracing_subscriber::layer::Context<'_, S>)
+where
+    S: Subscriber + for<'a> LookupSpan<'a>,
+{
+    use opentelemetry::{
+        logs::TraceContext,
+        trace::{SpanContext, TraceFlags, TraceState},
+    };
+
+    if let Some((trace_id, span_id)) = ctx.lookup_current().and_then(|span| {
+        span.extensions()
+            .get::<tracing_opentelemetry::OtelData>()
+            .and_then(|ext| ext.builder.trace_id.zip(ext.builder.span_id))
+    }) {
+        log_record.trace_context = Some(TraceContext::from(&SpanContext::new(
+            trace_id,
+            span_id,
+            TraceFlags::default(),
+            false,
+            TraceState::default(),
+        )));
+    }
+}
+
 const fn severity_of_level(level: &Level) -> Severity {
     match *level {
         Level::TRACE => Severity::Trace,