atrg_core/
request_id.rs

1//! Request ID middleware — assigns a unique ID to each request.
2
3use axum::extract::Request;
4use axum::http::{HeaderName, HeaderValue};
5use axum::middleware::Next;
6
7static REQUEST_ID_HEADER: HeaderName = HeaderName::from_static("x-request-id");
8
9/// Middleware that reads or generates a request ID and attaches it to the response.
10pub async fn request_id_middleware(mut req: Request, next: Next) -> axum::response::Response {
11    // Use existing header or generate a new one
12    let request_id = req
13        .headers()
14        .get(&REQUEST_ID_HEADER)
15        .and_then(|v| v.to_str().ok())
16        .map(|s| s.to_string())
17        .unwrap_or_else(generate_request_id);
18
19    // Add to request extensions for handler access
20    req.extensions_mut().insert(RequestId(request_id.clone()));
21
22    let mut response = next.run(req).await;
23
24    // Echo back in response
25    if let Ok(val) = HeaderValue::from_str(&request_id) {
26        response
27            .headers_mut()
28            .insert(REQUEST_ID_HEADER.clone(), val);
29    }
30
31    response
32}
33
34/// A request ID extracted from the middleware.
35#[derive(Debug, Clone)]
36pub struct RequestId(pub String);
37
38fn generate_request_id() -> String {
39    use rand::Rng;
40    let mut bytes = [0u8; 16];
41    rand::thread_rng().fill(&mut bytes);
42    hex::encode(bytes)
43}
44
45#[cfg(test)]
46mod tests {
47    use super::*;
48
49    #[test]
50    fn generate_request_id_is_32_hex_chars() {
51        let id = generate_request_id();
52        assert_eq!(id.len(), 32);
53        assert!(id.chars().all(|c| c.is_ascii_hexdigit()));
54    }
55
56    #[test]
57    fn generate_request_id_is_unique() {
58        let a = generate_request_id();
59        let b = generate_request_id();
60        assert_ne!(a, b);
61    }
62}
atrg_core/request_id.rs

atrg_core/
request_id.rs
