energylink/pkg/cmd/grafana-server/main.go

package main

import (
	"context"
	"flag"
	"fmt"
	"io/ioutil"
	"os"
	"os/signal"
	"path/filepath"
	"runtime"
	"strconv"
	"syscall"
	"time"

	"golang.org/x/sync/errgroup"

	"github.com/grafana/grafana/pkg/log"
	"github.com/grafana/grafana/pkg/login"
	"github.com/grafana/grafana/pkg/metrics"
	"github.com/grafana/grafana/pkg/plugins"
	"github.com/grafana/grafana/pkg/services/cleanup"
	"github.com/grafana/grafana/pkg/services/eventpublisher"
	"github.com/grafana/grafana/pkg/services/notifications"
	"github.com/grafana/grafana/pkg/services/search"
	"github.com/grafana/grafana/pkg/services/sqlstore"
	"github.com/grafana/grafana/pkg/setting"
	"github.com/grafana/grafana/pkg/social"

	"github.com/grafana/grafana/pkg/services/alerting"
	_ "github.com/grafana/grafana/pkg/services/alerting/conditions"
	_ "github.com/grafana/grafana/pkg/services/alerting/notifiers"
	_ "github.com/grafana/grafana/pkg/tsdb/graphite"
	_ "github.com/grafana/grafana/pkg/tsdb/prometheus"
	_ "github.com/grafana/grafana/pkg/tsdb/testdata"
)

var version = "3.1.0"
var commit = "NA"
var buildstamp string
var build_date string

var configFile = flag.String("config", "", "path to config file")
var homePath = flag.String("homepath", "", "path to grafana install/home path, defaults to working directory")
var pidFile = flag.String("pidfile", "", "path to pid file")
var exitChan = make(chan int)

func init() {
	runtime.GOMAXPROCS(runtime.NumCPU())
}

func main() {
	v := flag.Bool("v", false, "prints current version and exits")
	flag.Parse()
	if *v {
		fmt.Printf("Version %s (commit: %s)\n", version, commit)
		os.Exit(0)
	}

	buildstampInt64, _ := strconv.ParseInt(buildstamp, 10, 64)
	if buildstampInt64 == 0 {
		buildstampInt64 = time.Now().Unix()
	}

	setting.BuildVersion = version
	setting.BuildCommit = commit
	setting.BuildStamp = buildstampInt64

	appContext, shutdownFn := context.WithCancel(context.Background())
	grafanaGroup, appContext := errgroup.WithContext(appContext)

	go listenToSystemSignals(shutdownFn, grafanaGroup)

	flag.Parse()
	writePIDFile()

	initRuntime()
	initSql()
	metrics.Init()
	search.Init()
	login.Init()
	social.NewOAuthService()
	eventpublisher.Init()
	plugins.Init()

	// init alerting
	if setting.AlertingEnabled {
		engine := alerting.NewEngine()
		grafanaGroup.Go(func() error { return engine.Run(appContext) })
	}

	// cleanup service
	cleanUpService := cleanup.NewCleanUpService()
	grafanaGroup.Go(func() error { return cleanUpService.Run(appContext) })

	if err := notifications.Init(); err != nil {
		log.Fatal(3, "Notification service failed to initialize", err)
	}

	exitCode := StartServer()

	grafanaGroup.Wait()
	exitChan <- exitCode
}

func initRuntime() {
	err := setting.NewConfigContext(&setting.CommandLineArgs{
		Config:   *configFile,
		HomePath: *homePath,
		Args:     flag.Args(),
	})

	if err != nil {
		log.Fatal(3, err.Error())
	}

	logger := log.New("main")
	logger.Info("Starting Grafana", "version", version, "commit", commit, "compiled", time.Unix(setting.BuildStamp, 0))

	setting.LogConfigurationInfo()
}

func initSql() {
	sqlstore.NewEngine()
	sqlstore.EnsureAdminUser()
}

func writePIDFile() {
	if *pidFile == "" {
		return
	}

	// Ensure the required directory structure exists.
	err := os.MkdirAll(filepath.Dir(*pidFile), 0700)
	if err != nil {
		log.Fatal(3, "Failed to verify pid directory", err)
	}

	// Retrieve the PID and write it.
	pid := strconv.Itoa(os.Getpid())
	if err := ioutil.WriteFile(*pidFile, []byte(pid), 0644); err != nil {
		log.Fatal(3, "Failed to write pidfile", err)
	}
}

func listenToSystemSignals(cancel context.CancelFunc, grafanaGroup *errgroup.Group) {
	signalChan := make(chan os.Signal, 1)
	code := 0

	signal.Notify(signalChan, os.Interrupt, os.Kill, syscall.SIGTERM)

	select {
	case sig := <-signalChan:
		log.Info2("Received system signal. Shutting down", "signal", sig)
	case code = <-exitChan:
		switch code {
		case 0:
			log.Info("Shutting down")
		default:
			log.Warn("Shutting down")
		}
	}

	cancel()
	grafanaGroup.Wait()
	log.Close()
	os.Exit(code)
}