fix: context not propagated if request_span is disabled (#39)

.github/workflows/ci.yml

@@ -16,6 +16,7 @@ jobs:
           - opentelemetry_0_14
           - opentelemetry_0_15
           - opentelemetry_0_16
+          - opentelemetry_0_17
     steps:
       - name: Checkout repository
         uses: actions/checkout@v2
@@ -59,6 +60,7 @@ jobs:
           - opentelemetry_0_14
           - opentelemetry_0_15
           - opentelemetry_0_16
+          - opentelemetry_0_17
     steps:
       - name: Checkout repository
         uses: actions/checkout@v2
@@ -85,6 +87,7 @@ jobs:
           - opentelemetry_0_14
           - opentelemetry_0_15
           - opentelemetry_0_16
+          - opentelemetry_0_17
     steps:
       - name: Checkout repository
         uses: actions/checkout@v2

reqwest-tracing/Cargo.toml

@@ -41,3 +41,5 @@ tracing-opentelemetry_0_17_pkg = { package = "tracing-opentelemetry",version = "
 [dev-dependencies]
 wiremock = "0.5"
 tokio = { version = "1", features = ["macros"] }
+tracing_subscriber_0_2 = { package = "tracing-subscriber", version = "0.2" }
+tracing_subscriber_0_3 = { package = "tracing-subscriber", version = "0.3" }

reqwest-tracing/src/middleware.rs

@@ -2,6 +2,7 @@ use reqwest::header::{HeaderMap, HeaderValue};
 use reqwest::{Request, Response, StatusCode as RequestStatusCode};
 use reqwest_middleware::{Error, Middleware, Next, Result};
 use task_local_extensions::Extensions;
+use tracing::Instrument;
 
 /// Middleware for tracing requests using the current Opentelemetry Context.
 pub struct TracingMiddleware;
@@ -38,6 +39,7 @@ impl Middleware for TracingMiddleware {
             )
         };
 
+        async {
             // Adds tracing headers to the given request to propagate the OpenTelemetry context to downstream revivers of the request.
             // Spans added by downstream consumers will be part of the same trace.
             #[cfg(any(
@@ -47,7 +49,7 @@ impl Middleware for TracingMiddleware {
                 feature = "opentelemetry_0_16",
                 feature = "opentelemetry_0_17",
             ))]
-        let req = crate::otel::inject_opentelemetry_context_into_request(&request_span, req);
+            let req = crate::otel::inject_opentelemetry_context_into_request(req);
 
             // Run the request
             let outcome = next.run(req, extensions).await;
@@ -83,11 +85,14 @@ impl Middleware for TracingMiddleware {
             }
             outcome
         }
+        .instrument(request_span.clone())
+        .await
+    }
 }
 
 fn get_header_value(key: &str, headers: &HeaderMap) -> String {
     let header_default = &HeaderValue::from_static("");
-    format!("{:?}", headers.get(key).unwrap_or(header_default)).replace("\"", "")
+    format!("{:?}", headers.get(key).unwrap_or(header_default)).replace('"', "")
 }
 
 /// HTTP Mapping <https://github.com/open-telemetry/opentelemetry-specification/blob/c4b7f4307de79009c97b3a98563e91fee39b7ba3/work_in_progress/opencensus/HTTP.md#status>

reqwest-tracing/src/otel.rs

@@ -38,9 +38,8 @@ use opentelemetry::propagation::Injector;
 use tracing_opentelemetry::OpenTelemetrySpanExt;
 
 /// Injects the given OpenTelemetry Context into a reqwest::Request headers to allow propagation downstream.
-pub fn inject_opentelemetry_context_into_request(span: &Span, request: Request) -> Request {
-    let context = span.context();
-    let mut request = request;
+pub fn inject_opentelemetry_context_into_request(mut request: Request) -> Request {
+    let context = Span::current().context();
 
     global::get_text_map_propagator(|injector| {
         injector.inject_context(&context, &mut RequestCarrier::new(&mut request))
@@ -72,3 +71,64 @@ impl<'a> Injector for RequestCarrier<'a> {
         self.request.headers_mut().insert(header_name, header_value);
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::TracingMiddleware;
+    use opentelemetry::sdk::propagation::TraceContextPropagator;
+    use reqwest_middleware::ClientBuilder;
+    use tracing::{info_span, Instrument, Level};
+    #[cfg(any(
+        feature = "opentelemetry_0_13",
+        feature = "opentelemetry_0_14",
+        feature = "opentelemetry_0_15"
+    ))]
+    use tracing_subscriber_0_2::{filter, layer::SubscriberExt, Registry};
+    #[cfg(not(any(
+        feature = "opentelemetry_0_13",
+        feature = "opentelemetry_0_14",
+        feature = "opentelemetry_0_15"
+    )))]
+    use tracing_subscriber_0_3::{filter, layer::SubscriberExt, Registry};
+    use wiremock::{matchers::any, Mock, MockServer, ResponseTemplate};
+
+    #[tokio::test]
+    async fn tracing_middleware_propagates_otel_data_even_when_the_span_is_disabled() {
+        let tracer = opentelemetry::sdk::export::trace::stdout::new_pipeline()
+            .with_writer(std::io::sink())
+            .install_simple();
+        let telemetry = tracing_opentelemetry::layer().with_tracer(tracer);
+        let subscriber = Registry::default()
+            .with(filter::Targets::new().with_target("reqwest_tracing::otel::test", Level::DEBUG))
+            .with(telemetry);
+        tracing::subscriber::set_global_default(subscriber).unwrap();
+        global::set_text_map_propagator(TraceContextPropagator::new());
+
+        // Mock server - sends all request headers back in the response
+        let server = MockServer::start().await;
+        Mock::given(any())
+            .respond_with(|req: &wiremock::Request| {
+                req.headers
+                    .iter()
+                    .fold(ResponseTemplate::new(200), |resp, (k, v)| {
+                        resp.append_header(k.clone(), v.clone())
+                    })
+            })
+            .mount(&server)
+            .await;
+
+        let client = ClientBuilder::new(reqwest::Client::new())
+            .with(TracingMiddleware)
+            .build();
+
+        let resp = client
+            .get(server.uri())
+            .send()
+            .instrument(info_span!("some_span"))
+            .await
+            .unwrap();
+
+        assert!(resp.headers().contains_key("traceparent"));
+    }
+}