opentelemetry: rename Layer to Subscriber. Related PR: #1015

examples/examples/opentelemetry-remote-context.rs

@@ -25,7 +25,7 @@ fn build_example_carrier() -> HashMap<String, String> {
 fn main() {
     // Set a format for propagating context. This MUST be provided, as the default is a no-op.
     global::set_text_map_propagator(TraceContextPropagator::new());
-    let subscriber = Registry::default().with(tracing_opentelemetry::layer());
+    let subscriber = Registry::default().with(tracing_opentelemetry::subscriber());
 
     tracing::collect::with_default(subscriber, || {
         // Extract context from request headers

examples/examples/opentelemetry.rs

@@ -18,7 +18,7 @@ fn main() -> Result<(), Box<dyn Error + Send + Sync + 'static>> {
     let (tracer, _uninstall) = opentelemetry_jaeger::new_pipeline()
         .with_service_name("report_example")
         .install()?;
-    let opentelemetry = tracing_opentelemetry::layer().with_tracer(tracer);
+    let opentelemetry = tracing_opentelemetry::subscriber().with_tracer(tracer);
     tracing_subscriber::registry()
         .with(opentelemetry)
         .try_init()?;

tracing-opentelemetry/src/lib.rs

@@ -57,7 +57,7 @@
 //! let (tracer, _uninstall) = stdout::new_pipeline().install();
 //!
 //! // Create a tracing layer with the configured tracer
-//! let telemetry = tracing_opentelemetry::layer().with_tracer(tracer);
+//! let telemetry = tracing_opentelemetry::subscriber().with_tracer(tracer);
 //!
 //! // Use the tracing subscriber `Registry`, or any other subscriber
 //! // that impls `LookupSpan`
@@ -96,13 +96,13 @@
     issue_tracker_base_url = "https://github.com/tokio-rs/tracing/issues/"
 )]
 
-/// Implementation of the trace::Subscriber as a source of OpenTelemetry data.
-mod layer;
 /// Span extension which enables OpenTelemetry context management.
 mod span_ext;
+/// Implementation of the trace::Subscriber as a source of OpenTelemetry data.
+mod subscriber;
 /// Protocols for OpenTelemetry Tracers that are compatible with Tracing
 mod tracer;
 
-pub use layer::{layer, OpenTelemetryLayer};
 pub use span_ext::OpenTelemetrySpanExt;
+pub use subscriber::{subscriber, OpenTelemetrySubscriber};
 pub use tracer::PreSampledTracer;

tracing-opentelemetry/src/span_ext.rs

@@ -1,4 +1,4 @@
-use crate::layer::WithContext;
+use crate::subscriber::WithContext;
 use opentelemetry::Context;
 
 /// Utility functions to allow tracing [`Span`]s to accept and return

tracing-opentelemetry/src/layer.rs → tracing-opentelemetry/src/subscriber.rs

@@ -15,28 +15,28 @@ use tracing_subscriber::Subscribe;
 static SPAN_NAME_FIELD: &str = "otel.name";
 static SPAN_KIND_FIELD: &str = "otel.kind";
 
-/// An [OpenTelemetry] propagation layer for use in a project that uses
+/// An [OpenTelemetry] propagation subscriber for use in a project that uses
 /// [tracing].
 ///
 /// [OpenTelemetry]: https://opentelemetry.io
 /// [tracing]: https://github.com/tokio-rs/tracing
-pub struct OpenTelemetryLayer<S, T> {
+pub struct OpenTelemetrySubscriber<S, T> {
     tracer: T,
     tracked_inactivity: bool,
     get_context: WithContext,
     _registry: marker::PhantomData<S>,
 }
 
-impl<S> Default for OpenTelemetryLayer<S, otel::NoopTracer>
+impl<S> Default for OpenTelemetrySubscriber<S, otel::NoopTracer>
 where
     S: Collect + for<'span> LookupSpan<'span>,
 {
     fn default() -> Self {
-        OpenTelemetryLayer::new(otel::NoopTracer::new())
+        OpenTelemetrySubscriber::new(otel::NoopTracer::new())
     }
 }
 
-/// Construct a layer to track spans via [OpenTelemetry].
+/// Construct a subscriber to track spans via [OpenTelemetry].
 ///
 /// [OpenTelemetry]: https://opentelemetry.io
 ///
@@ -48,14 +48,14 @@ where
 ///
 /// // Use the tracing subscriber `Registry`, or any other subscriber
 /// // that impls `LookupSpan`
-/// let subscriber = Registry::default().with(tracing_opentelemetry::layer());
+/// let subscriber = Registry::default().with(tracing_opentelemetry::subscriber());
 /// # drop(subscriber);
 /// ```
-pub fn layer<S>() -> OpenTelemetryLayer<S, otel::NoopTracer>
+pub fn subscriber<S>() -> OpenTelemetrySubscriber<S, otel::NoopTracer>
 where
     S: Collect + for<'span> LookupSpan<'span>,
 {
-    OpenTelemetryLayer::default()
+    OpenTelemetrySubscriber::default()
 }
 
 // this function "remembers" the types of the subscriber so that we
@@ -234,12 +234,12 @@ impl<'a> field::Visit for SpanAttributeVisitor<'a> {
     }
 }
 
-impl<S, T> OpenTelemetryLayer<S, T>
+impl<S, T> OpenTelemetrySubscriber<S, T>
 where
     S: Collect + for<'span> LookupSpan<'span>,
     T: otel::Tracer + PreSampledTracer + 'static,
 {
-    /// Set the [`Tracer`] that this layer will use to produce and track
+    /// Set the [`Tracer`] that this subscriber will use to produce and track
     /// OpenTelemetry [`Span`]s.
     ///
     /// [`Tracer`]: opentelemetry::trace::Tracer
@@ -248,7 +248,7 @@ where
     /// # Examples
     ///
     /// ```no_run
-    /// use tracing_opentelemetry::OpenTelemetryLayer;
+    /// use tracing_opentelemetry::OpenTelemetrySubscriber;
     /// use tracing_subscriber::subscribe::CollectExt;
     /// use tracing_subscriber::Registry;
     ///
@@ -257,24 +257,24 @@ where
     ///     .with_service_name("trace_demo")
     ///     .install().expect("Error initializing Jaeger exporter");
     ///
-    /// // Create a layer with the configured tracer
-    /// let otel_layer = OpenTelemetryLayer::new(tracer);
+    /// // Create a subscriber with the configured tracer
+    /// let otel_subscriber = OpenTelemetrySubscriber::new(tracer);
     ///
     /// // Use the tracing subscriber `Registry`, or any other subscriber
     /// // that impls `LookupSpan`
-    /// let subscriber = Registry::default().with(otel_layer);
+    /// let subscriber = Registry::default().with(otel_subscriber);
     /// # drop(subscriber);
     /// ```
     pub fn new(tracer: T) -> Self {
-        OpenTelemetryLayer {
+        OpenTelemetrySubscriber {
             tracer,
             tracked_inactivity: true,
             get_context: WithContext(Self::get_context),
             _registry: marker::PhantomData,
         }
     }
 
-    /// Set the [`Tracer`] that this layer will use to produce and track
+    /// Set the [`Tracer`] that this subscriber will use to produce and track
     /// OpenTelemetry [`Span`]s.
     ///
     /// [`Tracer`]: opentelemetry::trace::Tracer
@@ -291,22 +291,22 @@ where
     ///     .with_service_name("trace_demo")
     ///     .install().expect("Error initializing Jaeger exporter");
     ///
-    /// // Create a layer with the configured tracer
-    /// let otel_layer = tracing_opentelemetry::layer().with_tracer(tracer);
+    /// // Create a subscriber with the configured tracer
+    /// let otel_subscriber = tracing_opentelemetry::subscriber().with_tracer(tracer);
     ///
     /// // Use the tracing subscriber `Registry`, or any other subscriber
     /// // that impls `LookupSpan`
-    /// let subscriber = Registry::default().with(otel_layer);
+    /// let subscriber = Registry::default().with(otel_subscriber);
     /// # drop(subscriber);
     /// ```
-    pub fn with_tracer<Tracer>(self, tracer: Tracer) -> OpenTelemetryLayer<S, Tracer>
+    pub fn with_tracer<Tracer>(self, tracer: Tracer) -> OpenTelemetrySubscriber<S, Tracer>
     where
         Tracer: otel::Tracer + PreSampledTracer + 'static,
     {
-        OpenTelemetryLayer {
+        OpenTelemetrySubscriber {
             tracer,
             tracked_inactivity: self.tracked_inactivity,
-            get_context: WithContext(OpenTelemetryLayer::<S, Tracer>::get_context),
+            get_context: WithContext(OpenTelemetrySubscriber::<S, Tracer>::get_context),
             _registry: self._registry,
         }
     }
@@ -364,18 +364,18 @@ where
         let span = subscriber
             .span(id)
             .expect("registry should have a span for the current ID");
-        let layer = dispatch
-            .downcast_ref::<OpenTelemetryLayer<S, T>>()
-            .expect("layer should downcast to expected type; this is a bug!");
+        let subscriber = dispatch
+            .downcast_ref::<OpenTelemetrySubscriber<S, T>>()
+            .expect("subscriber should downcast to expected type; this is a bug!");
 
         let mut extensions = span.extensions_mut();
         if let Some(builder) = extensions.get_mut::<otel::SpanBuilder>() {
-            f(builder, &layer.tracer);
+            f(builder, &subscriber.tracer);
         }
     }
 }
 
-impl<S, T> Subscribe<S> for OpenTelemetryLayer<S, T>
+impl<S, T> Subscribe<S> for OpenTelemetrySubscriber<S, T>
 where
     S: Collect + for<'span> LookupSpan<'span>,
     T: otel::Tracer + PreSampledTracer + 'static,
@@ -642,7 +642,8 @@ mod tests {
     fn dynamic_span_names() {
         let dynamic_name = "GET http://example.com".to_string();
         let tracer = TestTracer(Arc::new(Mutex::new(None)));
-        let subscriber = tracing_subscriber::registry().with(layer().with_tracer(tracer.clone()));
+        let subscriber =
+            tracing_subscriber::registry().with(subscriber().with_tracer(tracer.clone()));
 
         tracing::collect::with_default(subscriber, || {
             tracing::debug_span!("static_name", otel.name = dynamic_name.as_str());
@@ -655,7 +656,8 @@ mod tests {
     #[test]
     fn span_kind() {
         let tracer = TestTracer(Arc::new(Mutex::new(None)));
-        let subscriber = tracing_subscriber::registry().with(layer().with_tracer(tracer.clone()));
+        let subscriber =
+            tracing_subscriber::registry().with(subscriber().with_tracer(tracer.clone()));
 
         tracing::collect::with_default(subscriber, || {
             tracing::debug_span!("request", otel.kind = %SpanKind::Server);
@@ -668,7 +670,8 @@ mod tests {
     #[test]
     fn trace_id_from_existing_context() {
         let tracer = TestTracer(Arc::new(Mutex::new(None)));
-        let subscriber = tracing_subscriber::registry().with(layer().with_tracer(tracer.clone()));
+        let subscriber =
+            tracing_subscriber::registry().with(subscriber().with_tracer(tracer.clone()));
         let trace_id = otel::TraceId::from_u128(42);
         let existing_cx = OtelContext::current_with_span(TestSpan(otel::SpanContext::new(
             trace_id,
@@ -702,7 +705,7 @@ mod tests {
     fn includes_timings() {
         let tracer = TestTracer(Arc::new(Mutex::new(None)));
         let subscriber = tracing_subscriber::registry().with(
-            layer()
+            subscriber()
                 .with_tracer(tracer.clone())
                 .with_tracked_inactivity(true),
         );

tracing-opentelemetry/tests/trace_state_propagation.rs

@@ -12,7 +12,7 @@ use opentelemetry::{
 use std::collections::{HashMap, HashSet};
 use std::sync::{Arc, Mutex};
 use tracing::Collect;
-use tracing_opentelemetry::{layer, OpenTelemetrySpanExt};
+use tracing_opentelemetry::{subscriber, OpenTelemetrySpanExt};
 use tracing_subscriber::prelude::*;
 
 #[test]
@@ -113,7 +113,7 @@ fn test_tracer() -> (Tracer, TracerProvider, TestExporter, impl Collect) {
         .with_simple_exporter(exporter.clone())
         .build();
     let tracer = provider.get_tracer("test", None);
-    let subscriber = tracing_subscriber::registry().with(layer().with_tracer(tracer.clone()));
+    let subscriber = tracing_subscriber::registry().with(subscriber().with_tracer(tracer.clone()));
 
     (tracer, provider, exporter, subscriber)
 }