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ebc278ec98
* metrics: allow disabling OpenMetrics negotiation Signed-off-by: Dave Henderson <dhenderson@gmail.com> * fixup! metrics: allow disabling OpenMetrics negotiation
124 lines
3.5 KiB
Go
124 lines
3.5 KiB
Go
// Copyright 2020 Matthew Holt and The Caddy Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package metrics
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import (
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"net/http"
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"github.com/caddyserver/caddy/v2"
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"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
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"github.com/caddyserver/caddy/v2/caddyconfig/httpcaddyfile"
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"github.com/caddyserver/caddy/v2/modules/caddyhttp"
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"go.uber.org/zap"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/promhttp"
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)
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func init() {
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caddy.RegisterModule(Metrics{})
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httpcaddyfile.RegisterHandlerDirective("metrics", parseCaddyfile)
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}
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// Metrics is a module that serves a /metrics endpoint so that any gathered
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// metrics can be exposed for scraping. This module is configurable by end-users
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// unlike AdminMetrics.
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type Metrics struct {
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metricsHandler http.Handler
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// Disable OpenMetrics negotiation, enabled by default. May be necessary if
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// the produced metrics cannot be parsed by the service scraping metrics.
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DisableOpenMetrics bool `json:"disable_openmetrics,omitempty"`
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}
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// CaddyModule returns the Caddy module information.
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func (Metrics) CaddyModule() caddy.ModuleInfo {
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return caddy.ModuleInfo{
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ID: "http.handlers.metrics",
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New: func() caddy.Module { return new(Metrics) },
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}
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}
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type zapLogger struct {
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zl *zap.Logger
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}
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func (l *zapLogger) Println(v ...interface{}) {
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l.zl.Sugar().Error(v...)
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}
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// Provision sets up m.
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func (m *Metrics) Provision(ctx caddy.Context) error {
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log := ctx.Logger(m)
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m.metricsHandler = createMetricsHandler(&zapLogger{log}, !m.DisableOpenMetrics)
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return nil
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}
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func parseCaddyfile(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error) {
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var m Metrics
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err := m.UnmarshalCaddyfile(h.Dispenser)
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return m, err
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}
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// UnmarshalCaddyfile sets up the handler from Caddyfile tokens. Syntax:
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//
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// metrics [<matcher>] {
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// disable_openmetrics
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// }
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//
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func (m *Metrics) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
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for d.Next() {
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args := d.RemainingArgs()
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if len(args) > 0 {
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return d.ArgErr()
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}
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for d.NextBlock(0) {
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switch d.Val() {
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case "disable_openmetrics":
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m.DisableOpenMetrics = true
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default:
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return d.Errf("unrecognized subdirective %q", d.Val())
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}
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}
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}
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return nil
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}
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func (m Metrics) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
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m.metricsHandler.ServeHTTP(w, r)
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return nil
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}
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// Interface guards
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var (
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_ caddy.Provisioner = (*Metrics)(nil)
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_ caddyhttp.MiddlewareHandler = (*Metrics)(nil)
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_ caddyfile.Unmarshaler = (*Metrics)(nil)
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)
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func createMetricsHandler(logger promhttp.Logger, enableOpenMetrics bool) http.Handler {
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return promhttp.InstrumentMetricHandler(prometheus.DefaultRegisterer,
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promhttp.HandlerFor(prometheus.DefaultGatherer, promhttp.HandlerOpts{
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// will only log errors if logger is non-nil
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ErrorLog: logger,
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// Allow OpenMetrics format to be negotiated - largely compatible,
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// except quantile/le label values always have a decimal.
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EnableOpenMetrics: enableOpenMetrics,
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}),
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)
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}
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