caddy/modules/metrics/metrics.go
Matthew Holt e43b6d8178 core: Variadic Context.Logger(); soft deprecation
Ideally I'd just remove the parameter to caddy.Context.Logger(), but
this would break most Caddy plugins.

Instead, I'm making it variadic and marking it as partially deprecated.
In the future, I might completely remove the parameter once most
plugins have updated.
2022-09-16 16:55:36 -06:00

124 lines
3.5 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 (
"net/http"
"github.com/caddyserver/caddy/v2"
"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
"github.com/caddyserver/caddy/v2/caddyconfig/httpcaddyfile"
"github.com/caddyserver/caddy/v2/modules/caddyhttp"
"go.uber.org/zap"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
)
func init() {
caddy.RegisterModule(Metrics{})
httpcaddyfile.RegisterHandlerDirective("metrics", parseCaddyfile)
}
// Metrics is a module that serves a /metrics endpoint so that any gathered
// metrics can be exposed for scraping. This module is configurable by end-users
// unlike AdminMetrics.
type Metrics struct {
metricsHandler http.Handler
// Disable OpenMetrics negotiation, enabled by default. May be necessary if
// the produced metrics cannot be parsed by the service scraping metrics.
DisableOpenMetrics bool `json:"disable_openmetrics,omitempty"`
}
// CaddyModule returns the Caddy module information.
func (Metrics) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
ID: "http.handlers.metrics",
New: func() caddy.Module { return new(Metrics) },
}
}
type zapLogger struct {
zl *zap.Logger
}
func (l *zapLogger) Println(v ...any) {
l.zl.Sugar().Error(v...)
}
// Provision sets up m.
func (m *Metrics) Provision(ctx caddy.Context) error {
log := ctx.Logger()
m.metricsHandler = createMetricsHandler(&zapLogger{log}, !m.DisableOpenMetrics)
return nil
}
func parseCaddyfile(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error) {
var m Metrics
err := m.UnmarshalCaddyfile(h.Dispenser)
return m, err
}
// UnmarshalCaddyfile sets up the handler from Caddyfile tokens. Syntax:
//
// metrics [<matcher>] {
// disable_openmetrics
// }
func (m *Metrics) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
for d.Next() {
args := d.RemainingArgs()
if len(args) > 0 {
return d.ArgErr()
}
for d.NextBlock(0) {
switch d.Val() {
case "disable_openmetrics":
m.DisableOpenMetrics = true
default:
return d.Errf("unrecognized subdirective %q", d.Val())
}
}
}
return nil
}
func (m Metrics) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
m.metricsHandler.ServeHTTP(w, r)
return nil
}
// Interface guards
var (
_ caddy.Provisioner = (*Metrics)(nil)
_ caddyhttp.MiddlewareHandler = (*Metrics)(nil)
_ caddyfile.Unmarshaler = (*Metrics)(nil)
)
func createMetricsHandler(logger promhttp.Logger, enableOpenMetrics bool) http.Handler {
return promhttp.InstrumentMetricHandler(prometheus.DefaultRegisterer,
promhttp.HandlerFor(prometheus.DefaultGatherer, promhttp.HandlerOpts{
// will only log errors if logger is non-nil
ErrorLog: logger,
// Allow OpenMetrics format to be negotiated - largely compatible,
// except quantile/le label values always have a decimal.
EnableOpenMetrics: enableOpenMetrics,
}),
)
}