3 files changed, 31 insertions, 0 deletions
diff --git a/lib/warden-middleware/Cargo.toml b/lib/warden-middleware/Cargo.toml
index 97c2c88..c68bc69 100644
--- a/lib/warden-middleware/Cargo.toml
+++ b/lib/warden-middleware/Cargo.toml
@@ -12,8 +12,10 @@ publish = false
 axum.workspace = true
 metrics.workspace = true
 metrics-exporter-prometheus.workspace = true
+tonic.workspace = true
 tower-http = { workspace = true, features = [
     "request-id",
     "trace",
 ] }
 tracing.workspace = true
+warden-stack = { workspace = true, features = ["opentelemetry-tonic"] }
diff --git a/lib/warden-middleware/src/grpc.rs b/lib/warden-middleware/src/grpc.rs
new file mode 100644
index 0000000..f239ddb
--- /dev/null
+++ b/lib/warden-middleware/src/grpc.rs
@@ -0,0 +1,28 @@
+pub mod interceptor {
+    use tonic::{
+        Status,
+        service::{Interceptor, interceptor::InterceptedService},
+        transport::Channel,
+    };
+    use tracing::Span;
+    use warden_stack::{
+        opentelemetry::global, tracing::telemetry::tonic::injector,
+        tracing_opentelemetry::OpenTelemetrySpanExt,
+    };
+
+    pub type Intercepted = InterceptedService<Channel, MyInterceptor>;
+
+    #[derive(Clone, Copy)]
+    pub struct MyInterceptor;
+
+    impl Interceptor for MyInterceptor {
+        fn call(&mut self, mut request: tonic::Request<()>) -> Result<tonic::Request<()>, Status> {
+            let cx = Span::current().context();
+            global::get_text_map_propagator(|propagator| {
+                propagator.inject_context(&cx, &mut injector::MetadataMap(request.metadata_mut()))
+            });
+
+            Ok(request)
+        }
+    }
+}
diff --git a/lib/warden-middleware/src/lib.rs b/lib/warden-middleware/src/lib.rs
index 6e3a0f4..2fb8df8 100644
--- a/lib/warden-middleware/src/lib.rs
+++ b/lib/warden-middleware/src/lib.rs
@@ -1,3 +1,4 @@
+pub mod grpc;
 mod metrics;
 mod trace_layer;