prometheus/main.go

// Copyright 2013 Prometheus Team
// 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 main

import (
	"flag"
	"os"
	"os/signal"
	"sync"
	"syscall"
	"time"

	"github.com/golang/glog"
	"github.com/prometheus/client_golang/extraction"

	clientmodel "github.com/prometheus/client_golang/model"
	registry "github.com/prometheus/client_golang/prometheus"

	"github.com/prometheus/prometheus/config"
	"github.com/prometheus/prometheus/notification"
	"github.com/prometheus/prometheus/retrieval"
	"github.com/prometheus/prometheus/rules/manager"
	"github.com/prometheus/prometheus/storage/local"
	"github.com/prometheus/prometheus/storage/remote"
	"github.com/prometheus/prometheus/storage/remote/opentsdb"
	"github.com/prometheus/prometheus/web"
	"github.com/prometheus/prometheus/web/api"
)

const deletionBatchSize = 100

// Commandline flags.
var (
	configFile         = flag.String("configFile", "prometheus.conf", "Prometheus configuration file name.")
	metricsStoragePath = flag.String("metricsStoragePath", "/tmp/metrics", "Base path for metrics storage.")

	alertmanagerUrl = flag.String("alertmanager.url", "", "The URL of the alert manager to send notifications to.")

	remoteTSDBUrl     = flag.String("storage.remote.url", "", "The URL of the OpenTSDB instance to send samples to.")
	remoteTSDBTimeout = flag.Duration("storage.remote.timeout", 30*time.Second, "The timeout to use when sending samples to OpenTSDB.")

	samplesQueueCapacity = flag.Int("storage.queue.samplesCapacity", 4096, "The size of the unwritten samples queue.")

	memoryEvictionInterval = flag.Duration("storage.memory.evictionInterval", 15*time.Minute, "The period at which old data is evicted from memory.")
	memoryRetentionPeriod  = flag.Duration("storage.memory.retentionPeriod", time.Hour, "The period of time to retain in memory during evictions.")

	storagePurgeInterval   = flag.Duration("storage.purgeInterval", time.Hour, "The period at which old data is deleted completely from storage.")
	storageRetentionPeriod = flag.Duration("storage.retentionPeriod", 15*24*time.Hour, "The period of time to retain in storage.")

	checkpointInterval = flag.Duration("storage.checkpointInterval", 5*time.Minute, "The period at which the in-memory index of time series is checkpointed.")

	notificationQueueCapacity = flag.Int("alertmanager.notificationQueueCapacity", 100, "The size of the queue for pending alert manager notifications.")

	printVersion = flag.Bool("version", false, "print version information")
)

type prometheus struct {
	unwrittenSamples chan *extraction.Result

	ruleManager         manager.RuleManager
	targetManager       retrieval.TargetManager
	notificationHandler *notification.NotificationHandler
	storage             local.Storage
	remoteTSDBQueue     *remote.TSDBQueueManager

	webService *web.WebService

	closeOnce sync.Once
}

// NewPrometheus creates a new prometheus object based on flag values.
// Call Serve() to start serving and Close() for clean shutdown.
func NewPrometheus() *prometheus {
	conf, err := config.LoadFromFile(*configFile)
	if err != nil {
		glog.Fatalf("Error loading configuration from %s: %v", *configFile, err)
	}

	unwrittenSamples := make(chan *extraction.Result, *samplesQueueCapacity)

	ingester := &retrieval.MergeLabelsIngester{
		Labels:          conf.GlobalLabels(),
		CollisionPrefix: clientmodel.ExporterLabelPrefix,
		Ingester:        retrieval.ChannelIngester(unwrittenSamples),
	}
	targetManager := retrieval.NewTargetManager(ingester)
	targetManager.AddTargetsFromConfig(conf)

	notificationHandler := notification.NewNotificationHandler(*alertmanagerUrl, *notificationQueueCapacity)
	registry.MustRegister(notificationHandler)

	o := &local.MemorySeriesStorageOptions{
		MemoryEvictionInterval:     *memoryEvictionInterval,
		MemoryRetentionPeriod:      *memoryRetentionPeriod,
		PersistenceStoragePath:     *metricsStoragePath,
		PersistencePurgeInterval:   *storagePurgeInterval,
		PersistenceRetentionPeriod: *storageRetentionPeriod,
		CheckpointInterval:         *checkpointInterval,
	}
	memStorage, err := local.NewMemorySeriesStorage(o)
	if err != nil {
		glog.Fatal("Error opening memory series storage: ", err)
	}
	registry.MustRegister(memStorage)

	ruleManager := manager.NewRuleManager(&manager.RuleManagerOptions{
		Results:             unwrittenSamples,
		NotificationHandler: notificationHandler,
		EvaluationInterval:  conf.EvaluationInterval(),
		Storage:             memStorage,
		PrometheusUrl:       web.MustBuildServerUrl(),
	})
	if err := ruleManager.AddRulesFromConfig(conf); err != nil {
		glog.Fatal("Error loading rule files: ", err)
	}

	var remoteTSDBQueue *remote.TSDBQueueManager
	if *remoteTSDBUrl == "" {
		glog.Warningf("No TSDB URL provided; not sending any samples to long-term storage")
	} else {
		openTSDB := opentsdb.NewClient(*remoteTSDBUrl, *remoteTSDBTimeout)
		remoteTSDBQueue = remote.NewTSDBQueueManager(openTSDB, 512)
		registry.MustRegister(remoteTSDBQueue)
	}

	flags := map[string]string{}
	flag.VisitAll(func(f *flag.Flag) {
		flags[f.Name] = f.Value.String()
	})
	prometheusStatus := &web.PrometheusStatusHandler{
		BuildInfo:   BuildInfo,
		Config:      conf.String(),
		RuleManager: ruleManager,
		TargetPools: targetManager.Pools(),
		Flags:       flags,
		Birth:       time.Now(),
	}

	alertsHandler := &web.AlertsHandler{
		RuleManager: ruleManager,
	}

	consolesHandler := &web.ConsolesHandler{
		Storage: memStorage,
	}

	metricsService := &api.MetricsService{
		Config:        &conf,
		TargetManager: targetManager,
		Storage:       memStorage,
	}

	webService := &web.WebService{
		StatusHandler:   prometheusStatus,
		MetricsHandler:  metricsService,
		ConsolesHandler: consolesHandler,
		AlertsHandler:   alertsHandler,
	}

	p := &prometheus{
		unwrittenSamples: unwrittenSamples,

		ruleManager:         ruleManager,
		targetManager:       targetManager,
		notificationHandler: notificationHandler,
		storage:             memStorage,
		remoteTSDBQueue:     remoteTSDBQueue,

		webService: webService,
	}
	webService.QuitDelegate = p.Close
	return p
}

// Serve starts the Prometheus server. It returns after the server has been shut
// down. The method installs an interrupt handler, allowing to trigger a
// shutdown by sending SIGTERM to the process.
func (p *prometheus) Serve() {
	if p.remoteTSDBQueue != nil {
		go p.remoteTSDBQueue.Run()
	}
	go p.ruleManager.Run()
	go p.notificationHandler.Run()
	go p.interruptHandler()

	p.storage.Start()

	go func() {
		err := p.webService.ServeForever()
		if err != nil {
			glog.Fatal(err)
		}
	}()

	for block := range p.unwrittenSamples {
		if block.Err == nil && len(block.Samples) > 0 {
			p.storage.AppendSamples(block.Samples)
			if p.remoteTSDBQueue != nil {
				p.remoteTSDBQueue.Queue(block.Samples)
			}
		}
	}

	// The following shut-down operations have to happen after
	// unwrittenSamples is drained. So do not move them into close().
	if err := p.storage.Stop(); err != nil {
		glog.Error("Error stopping local storage: ", err)
	}
	glog.Info("Local Storage: Done")

	if p.remoteTSDBQueue != nil {
		p.remoteTSDBQueue.Stop()
		glog.Info("Remote Storage: Done")
	}

	p.notificationHandler.Stop()
	glog.Info("Sundry Queues: Done")
	glog.Info("See you next time!")
}

// Close cleanly shuts down the Prometheus server.
func (p *prometheus) Close() {
	p.closeOnce.Do(p.close)
}

func (p *prometheus) interruptHandler() {
	notifier := make(chan os.Signal)
	signal.Notify(notifier, os.Interrupt, syscall.SIGTERM)
	<-notifier

	glog.Warning("Received SIGTERM, exiting gracefully...")
	p.Close()
}

func (p *prometheus) close() {
	glog.Info("Shutdown has been requested; subsytems are closing:")
	p.targetManager.Stop()
	glog.Info("Remote Target Manager: Done")
	p.ruleManager.Stop()
	glog.Info("Rule Executor: Done")

	close(p.unwrittenSamples)
	// Note: Before closing the remaining subsystems (storage, ...), we have
	// to wait until p.unwrittenSamples is actually drained. Therefore,
	// remaining shut-downs happen in Serve().
}

func main() {
	flag.Parse()
	versionInfoTmpl.Execute(os.Stdout, BuildInfo)

	if *printVersion {
		os.Exit(0)
	}

	NewPrometheus().Serve()
}