Test implementation of optional tracing span

Author: rimutaka

lambda-runtime-api-client/src/tracing.rs

@@ -23,7 +23,7 @@ const DEFAULT_LOG_LEVEL: &str = "INFO";
 /// if they're configured for your function.
 ///
 /// This subscriber sets the logging level based on environment variables:
-///     - if `AWS_LAMBDA_LOG_LEVEL` is set, it takes predecence over any other environment variables.
+///     - if `AWS_LAMBDA_LOG_LEVEL` is set, it takes precedence over any other environment variables.
 ///     - if `AWS_LAMBDA_LOG_LEVEL` is not set, check if `RUST_LOG` is set.
 ///     - if none of those two variables are set, use `INFO` as the logging level.
 ///
@@ -44,7 +44,7 @@ pub fn init_default_subscriber() {
                 .from_env_lossy(),
         );
 
-    if log_format.eq_ignore_ascii_case("json") {
+    if log_format.to_lowercase().contains("json") {
         collector.json().init()
     } else {
         collector.init()

lambda-runtime/src/layers/trace.rs

@@ -14,6 +14,14 @@ impl TracingLayer {
     pub fn new() -> Self {
         Self::default()
     }
+
+    /// Returns true if the tracing span provided by this service should be included in the log output.
+    /// The span is enabled by default, 
+    /// but can be disabled by adding `no-span` to the `AWS_LAMBDA_LOG_FORMAT` environment variable.
+    /// E.g. AWS_LAMBDA_LOG_FORMAT=no-span or =json,no-span.
+    pub fn is_enabled() -> bool {
+        !matches! (std::env::var("AWS_LAMBDA_LOG_FORMAT") , Ok(v) if v.to_lowercase().contains("no-span"))
+    }
 }
 
 impl<S> Layer<S> for TracingLayer {

lambda-runtime/src/lib.rs

@@ -120,6 +120,11 @@ where
     D: Into<bytes::Bytes> + Send,
     E: Into<Error> + Send + Debug,
 {
-    let runtime = Runtime::new(handler).layer(layers::TracingLayer::new());
-    runtime.run().await
+    if layers::TracingLayer::is_enabled() {
+        let runtime = Runtime::new(handler).layer(layers::TracingLayer::new());
+        runtime.run().await
+    } else {
+        let runtime = Runtime::new(handler);
+        runtime.run().await
+    }
 }