Metrics

Using the default labels, registers the following metrics:

• request_active{path, method} (up-down-counter)
• request_total{path, method, status} (counter)
• request_duration{path, method, status, phase} (histogram)

Status is by default the status code class (1xx, 2xx, etc.), and phase can be either headers or body - request duration is measured separately up to the point where the headers are determined, and then once again when the whole response body is complete.