caddy/modules/metrics/adminmetrics.go

74 lines
2.1 KiB
Go

// Copyright 2020 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package metrics
import (
"errors"
"net/http"
"github.com/prometheus/client_golang/prometheus"
"github.com/caddyserver/caddy/v2"
)
func init() {
caddy.RegisterModule(AdminMetrics{})
}
// AdminMetrics is a module that serves a metrics endpoint so that any gathered
// metrics can be exposed for scraping. This module is not configurable, and
// is permanently mounted to the admin API endpoint at "/metrics".
// See the Metrics module for a configurable endpoint that is usable if the
// Admin API is disabled.
type AdminMetrics struct {
registry *prometheus.Registry
metricsHandler http.Handler
}
// CaddyModule returns the Caddy module information.
func (AdminMetrics) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
ID: "admin.api.metrics",
New: func() caddy.Module { return new(AdminMetrics) },
}
}
// Provision -
func (m *AdminMetrics) Provision(ctx caddy.Context) error {
m.registry = ctx.GetMetricsRegistry()
if m.registry == nil {
return errors.New("no metrics registry found")
}
m.metricsHandler = createMetricsHandler(nil, false, m.registry)
return nil
}
// Routes returns a route for the /metrics endpoint.
func (m *AdminMetrics) Routes() []caddy.AdminRoute {
return []caddy.AdminRoute{{Pattern: "/metrics", Handler: caddy.AdminHandlerFunc(m.serveHTTP)}}
}
func (m *AdminMetrics) serveHTTP(w http.ResponseWriter, r *http.Request) error {
m.metricsHandler.ServeHTTP(w, r)
return nil
}
// Interface guards
var (
_ caddy.Provisioner = (*AdminMetrics)(nil)
_ caddy.AdminRouter = (*AdminMetrics)(nil)
)