Caddy route metrics

A simple Caddy HTTP middleware that records request duration metrics per route and exposes them to Prometheus.

Installation

Build Caddy with this plugin using xcaddy:

xcaddy build \
  --with github.com/onliner/caddy-route-metrics

Usage

Enable route_metrics inside your Caddyfile.
By default, the header name is X-Route-Pattern.

{
  metrics
  admin localhost:2019
}

example.com {
  route_metrics {
    header X-Route-Pattern
  }

  handle_path /ok* {
    header {
      X-Route-Pattern "/users/{id}"
    }
    respond "ok"
  }

  handle_path /miss* {
    respond "miss"
  }
}

Configuration options

The directive route_metrics supports the following option:

• header <name> (optional)
  The HTTP header name from which to read the route pattern. This header must be set on the response by your application or middleware.
  Defaults to X-Route-Pattern.

Metrics

The middleware records one Prometheus histogram for request duration:

Metric name	Type	Labels
caddy_route_request_duration_seconds	Histogram	method, route

Details

• method — the HTTP method (e.g. GET, POST).
• route — the route pattern taken from the configured header (e.g. /users/{id}).

Notes

• If the header is not present in the response, the request is skipped and no metric is recorded.