103 lines
2.5 KiB
Go
103 lines
2.5 KiB
Go
// Copyright 2016 The Chihaya Authors. All rights reserved.
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// Use of this source code is governed by the BSD 2-Clause license,
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// which can be found in the LICENSE file.
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// Package prometheus implements a chihaya Server for serving metrics to
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// Prometheus.
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package prometheus
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import (
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"errors"
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"log"
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"net"
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"net/http"
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"time"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/tylerb/graceful"
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"gopkg.in/yaml.v2"
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"github.com/chihaya/chihaya"
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"github.com/chihaya/chihaya/server"
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"github.com/chihaya/chihaya/tracker"
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)
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func init() {
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server.Register("prometheus", constructor)
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}
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func constructor(srvcfg *chihaya.ServerConfig, tkr *tracker.Tracker) (server.Server, error) {
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cfg, err := NewServerConfig(srvcfg)
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if err != nil {
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return nil, errors.New("prometheus: invalid config: " + err.Error())
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}
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return &Server{
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cfg: cfg,
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}, nil
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}
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// ServerConfig represents the configuration options for a
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// PrometheusServer.
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type ServerConfig struct {
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Addr string `yaml:"addr"`
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ShutdownTimeout time.Duration `yaml:"shutdown_timeout"`
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ReadTimeout time.Duration `yaml:"read_timeout"`
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WriteTimeout time.Duration `yaml:"write_timeout"`
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}
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// NewServerConfig marshals a chihaya.ServerConfig and unmarshals it
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// into a more specific prometheus ServerConfig.
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func NewServerConfig(srvcfg *chihaya.ServerConfig) (*ServerConfig, error) {
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bytes, err := yaml.Marshal(srvcfg.Config)
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if err != nil {
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return nil, err
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}
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var cfg ServerConfig
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err = yaml.Unmarshal(bytes, &cfg)
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if err != nil {
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return nil, err
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}
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return &cfg, nil
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}
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// Server implements a chihaya Server for serving metrics to Prometheus.
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type Server struct {
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cfg *ServerConfig
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grace *graceful.Server
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}
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var _ server.Server = &Server{}
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// Start starts the prometheus server and blocks until it exits.
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//
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// It panics if the server exits unexpectedly.
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func (s *Server) Start() {
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s.grace = &graceful.Server{
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Server: &http.Server{
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Addr: s.cfg.Addr,
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Handler: prometheus.Handler(),
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ReadTimeout: s.cfg.ReadTimeout,
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WriteTimeout: s.cfg.WriteTimeout,
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},
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Timeout: s.cfg.ShutdownTimeout,
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NoSignalHandling: true,
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}
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if err := s.grace.ListenAndServe(); err != nil {
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if opErr, ok := err.(*net.OpError); !ok || (ok && opErr.Op != "accept") {
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log.Printf("Failed to gracefully run Prometheus server: %s", err.Error())
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panic(err)
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}
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}
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log.Println("Prometheus server shut down cleanly")
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}
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// Stop stops the prometheus server and blocks until it exits.
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func (s *Server) Stop() {
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s.grace.Stop(s.cfg.ShutdownTimeout)
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<-s.grace.StopChan()
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}
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