api: propagate request ids through admin test runs

apps/admin-api/src/request_context.rs

@@ -0,0 +1,64 @@
+use axum::{
+    extract::Request,
+    http::{HeaderMap, HeaderName, HeaderValue},
+    middleware::Next,
+    response::Response,
+};
+use uuid::Uuid;
+
+pub const REQUEST_ID_HEADER: HeaderName = HeaderName::from_static("x-request-id");
+const MAX_REQUEST_ID_LEN: usize = 128;
+
+#[derive(Clone, Debug)]
+pub struct RequestContext {
+    pub request_id: String,
+}
+
+pub async fn apply_request_context(mut request: Request, next: Next) -> Response {
+    let context = RequestContext {
+        request_id: resolve_request_id(request.headers()),
+    };
+    request.extensions_mut().insert(context.clone());
+
+    let mut response = next.run(request).await;
+    if let Ok(value) = HeaderValue::from_str(&context.request_id) {
+        response.headers_mut().insert(REQUEST_ID_HEADER, value);
+    }
+    response
+}
+
+fn resolve_request_id(headers: &HeaderMap) -> String {
+    headers
+        .get(&REQUEST_ID_HEADER)
+        .and_then(|value| value.to_str().ok())
+        .map(str::trim)
+        .filter(|value| is_valid_request_id(value))
+        .map(ToOwned::to_owned)
+        .unwrap_or_else(|| Uuid::now_v7().to_string())
+}
+
+fn is_valid_request_id(value: &str) -> bool {
+    !value.is_empty()
+        && value.len() <= MAX_REQUEST_ID_LEN
+        && value
+            .bytes()
+            .all(|byte| matches!(byte, 0x21..=0x7e) && byte != b',' && byte != b';')
+}
+
+#[cfg(test)]
+mod tests {
+    use super::is_valid_request_id;
+
+    #[test]
+    fn accepts_visible_ascii_request_ids() {
+        assert!(is_valid_request_id("req_test_123"));
+        assert!(is_valid_request_id("trace-123/abc"));
+    }
+
+    #[test]
+    fn rejects_empty_or_control_request_ids() {
+        assert!(!is_valid_request_id(""));
+        assert!(!is_valid_request_id("bad value"));
+        assert!(!is_valid_request_id("bad\nvalue"));
+    }
+}