From 4f6a98332e28974a50914c95c7b812dac6561647 Mon Sep 17 00:00:00 2001
From: Zac Lou <97340247+ZacLou@users.noreply.github.com>
Date: Fri, 28 Aug 2026 08:00:12 +0800
Subject: [PATCH 1/3] feat: add request ID middleware to API (#27)

---
 crates/api/src/middleware.rs | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/crates/api/src/middleware.rs b/crates/api/src/middleware.rs
index 382733f..bc5e756 100644
--- a/crates/api/src/middleware.rs
+++ b/crates/api/src/middleware.rs
@@ -1,4 +1,5 @@
 // API key authentication middleware for admin routes.
+// + Request ID middleware for trace propagation across services.
 use axum::{
     body::Body,
     extract::State,
@@ -11,6 +12,31 @@ use serde_json::json;
 
 use crate::state::AppState;
 
+
+// Request ID middleware: reads X-Request-Id header or generates a UUIDv4,
+// injects it into response headers, and attaches it to the tracing span.
+pub async fn request_id(
+    req: Request<Body>,
+    next: Next,
+) -> Response {
+    let request_id = req
+        .headers()
+        .get("x-request-id")
+        .and_then(|v| v.to_str().ok())
+        .map(str::to_string)
+        .unwrap_or_else(|| uuid::Uuid::new_v4().to_string());
+
+    tracing::Span::current().record("request_id", &request_id);
+
+    let mut response = next.run(req).await;
+    response.headers_mut().insert(
+        "x-request-id",
+        request_id.parse().unwrap(),
+    );
+    response
+}
+
+
 pub async fn require_admin_key(
     State(state): State<AppState>,
     req: Request<Body>,

From 279f3a79fed02da1bd57141b45c871a61c53c4da Mon Sep 17 00:00:00 2001
From: Zac Lou <97340247+ZacLou@users.noreply.github.com>
Date: Fri, 28 Aug 2026 08:00:14 +0800
Subject: [PATCH 2/3] feat: wire request ID middleware into API router (#27)


From efd588d437792fdcf8d6b5bea4bedb0efc32f2b1 Mon Sep 17 00:00:00 2001
From: Zac Lou <97340247+ZacLou@users.noreply.github.com>
Date: Fri, 28 Aug 2026 08:00:17 +0800
Subject: [PATCH 3/3] feat: add request ID middleware to gateway (#27)

---
 crates/gateway/src/routes.rs | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/crates/gateway/src/routes.rs b/crates/gateway/src/routes.rs
index 861394a..d67d749 100644
--- a/crates/gateway/src/routes.rs
+++ b/crates/gateway/src/routes.rs
@@ -20,11 +20,37 @@ use crate::attestation::{
 use crate::state::AppState;
 use crate::webhook::{parse_merge_event, verify_github_signature};
 
+// Request ID middleware for trace propagation across services.
+async fn request_id(req: Request<Body>, next: Next) -> Response {
+    use axum::body::Body;
+    use axum::http::Request;
+    use axum::middleware::Next;
+    use axum::response::Response;
+
+    let request_id = req
+        .headers()
+        .get("x-request-id")
+        .and_then(|v| v.to_str().ok())
+        .map(str::to_string)
+        .unwrap_or_else(|| uuid::Uuid::new_v4().to_string());
+
+    tracing::Span::current().record("request_id", &request_id);
+
+    let mut response = next.run(req).await;
+    response.headers_mut().insert(
+        "x-request-id",
+        request_id.parse().unwrap(),
+    );
+    response
+}
+
+
 pub fn router(state: AppState) -> Router {
     Router::new()
         .route("/health", get(health))
         .route("/ready", get(ready))
         .route("/webhooks/github", post(github_webhook))
+        .layer(axum::middleware::from_fn(request_id))
         .with_state(state)
 }