Using HTTP_X_REQUEST_ID in middleware/request_id.go

[zenazn]

Using HTTP_X_REQUEST_ID in middleware/request_id.go

[peterhellberg]

Example log line from the Heroku router.

2014-06-25T12:16:59.479578+00:00 heroku[router]: at=info method=GET path="/" host=stat-api-stage.herokuapp.com request_id=854f6200-bf13-4781-bf6b-ac2c16332f7a fwd="193.14.163.194" dyno=web.1 connect=1ms service=2ms status=200 bytes=159

[zenazn]

Presumably they're actually passing an X-Request-Id header? If so, you can just Abandon Goji's default request ID generator and Insert a middleware in its place that slurps it out of a header.

[peterhellberg]

Yes, as it turned out, you can do something like this:

// XRequestID replaces the Goji RequestID middleware
// by using the X-Request-ID header set by Heroku (and others)
func XRequestID(c *web.C, h http.Handler) http.Handler {
    fn := func(w http.ResponseWriter, r *http.Request) {
        if c.Env == nil {
            c.Env = make(map[string]interface{})
        }

        c.Env["reqID"] = r.Header.Get("X-Request-ID")

        h.ServeHTTP(w, r)
    }

    return http.HandlerFunc(fn)
}

and then just:

goji.Abandon(middleware.RequestID)
goji.Insert(XRequestID, middleware.Logger)