Function extract_from_headers

nodedb/src/control/trace_context.rs:28–47

Extract a `TraceId` from HTTP request headers. Priority order: 1. W3C `traceparent` (full 16-byte trace ID extracted from the 32-hex field). 2. `X-Trace-ID` (32 hex chars interpreted as 16 bytes). 3. Generate a fresh ID.

(headers: &axum::http::HeaderMap)

/// 2. `X-Trace-ID` (32 hex chars interpreted as 16 bytes).
/// 3. Generate a fresh ID.
pub fn extract_from_headers(headers: &axum::http::HeaderMap) -> TraceId {
    // 1. W3C traceparent: "00-<32hex>-<16hex>-<2hex>"
    if let Some(val) = headers.get("traceparent")
        && let Ok(s) = val.to_str()
        && let Some((tid, _sid, _flags)) = TraceId::from_traceparent(s)
    {
        return tid;
    }

    // 2. X-Trace-ID: 32 lowercase hex chars.
    if let Some(val) = headers.get("x-trace-id")
        && let Ok(s) = val.to_str()
        && let Ok(tid) = s.parse::<TraceId>()
    {
        return tid;
    }

    // 3. No trace ID supplied — generate one.
    TraceId::generate()
}

/// Extract a `TraceId` from a pgwire startup parameter map.
///