Retrieve opentelemetry parent span from headers

limitador-server/src/envoy_rls/server.rs

@@ -1,8 +1,13 @@
+use opentelemetry::global;
+use opentelemetry::propagation::Extractor;
 use std::cmp::Ordering;
 use std::collections::HashMap;
 use std::sync::Arc;
 
+use tonic::codegen::http::HeaderMap;
 use tonic::{transport, transport::Server, Request, Response, Status};
+use tracing::Span;
+use tracing_opentelemetry::OpenTelemetrySpanExt;
 
 use limitador::counter::Counter;
 
@@ -48,8 +53,13 @@ impl RateLimitService for MyRateLimiter {
         debug!("Request received: {:?}", request);
 
         let mut values: HashMap<String, String> = HashMap::new();
-        let req = request.into_inner();
+        let (metadata, _ext, req) = request.into_parts();
         let namespace = req.domain;
+        let rl_headers = RateLimitRequestHeaders::new(metadata.into_headers());
+        let parent_context =
+            global::get_text_map_propagator(|propagator| propagator.extract(&rl_headers));
+        let span = Span::current();
+        span.set_parent(parent_context);
 
         if namespace.is_empty() {
             return Ok(Response::new(RateLimitResponse {
@@ -195,6 +205,27 @@ pub fn to_response_header(
     headers
 }
 
+struct RateLimitRequestHeaders {
+    inner: HeaderMap,
+}
+impl RateLimitRequestHeaders {
+    pub fn new(inner: HeaderMap) -> Self {
+        Self { inner }
+    }
+}
+impl Extractor for RateLimitRequestHeaders {
+    fn get(&self, key: &str) -> Option<&str> {
+        match self.inner.get(key) {
+            Some(v) => v.to_str().ok(),
+            None => None,
+        }
+    }
+
+    fn keys(&self) -> Vec<&str> {
+        self.inner.keys().map(|k| k.as_str()).collect()
+    }
+}
+
 mod rls_proto {
     pub(crate) const RLS_DESCRIPTOR_SET: &[u8] = tonic::include_file_descriptor_set!("rls");
 }

limitador-server/src/main.rs

@@ -32,8 +32,9 @@ use limitador::{
 };
 use notify::event::{ModifyKind, RenameMode};
 use notify::{Error, Event, EventKind, RecommendedWatcher, RecursiveMode, Watcher};
-use opentelemetry::KeyValue;
+use opentelemetry::{global, KeyValue};
 use opentelemetry_otlp::WithExportConfig;
+use opentelemetry_sdk::propagation::TraceContextPropagator;
 use opentelemetry_sdk::{trace, Resource};
 use std::env::VarError;
 use std::fmt::Display;
@@ -304,6 +305,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         };
 
         if !config.tracing_endpoint.is_empty() {
+            global::set_text_map_propagator(TraceContextPropagator::new());
             let tracer = opentelemetry_otlp::new_pipeline()
                 .tracing()
                 .with_exporter(
@@ -312,7 +314,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
                         .with_endpoint(config.tracing_endpoint.clone()),
                 )
                 .with_trace_config(trace::config().with_resource(Resource::new(vec![
-                    KeyValue::new("service.name", "limitador-server"),
+                    KeyValue::new("service.name", "limitador"),
                 ])))
                 .install_batch(opentelemetry_sdk::runtime::Tokio)?;
             let telemetry_layer = tracing_opentelemetry::layer().with_tracer(tracer);