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197 lines
4.1 KiB
Go
197 lines
4.1 KiB
Go
package main // import "github.com/v2tec/watchtower"
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import (
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"fmt"
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"os"
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"os/signal"
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"syscall"
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"time"
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"strconv"
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log "github.com/Sirupsen/logrus"
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"github.com/robfig/cron"
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"github.com/urfave/cli"
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"github.com/v2tec/watchtower/actions"
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"github.com/v2tec/watchtower/container"
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)
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var (
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client container.Client
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scheduleSpec string
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cleanup bool
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noRestart bool
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)
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func init() {
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log.SetLevel(log.InfoLevel)
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}
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func main() {
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app := cli.NewApp()
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app.Name = "watchtower"
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app.Usage = "Automatically update running Docker containers"
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app.Before = before
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app.Action = start
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app.Flags = []cli.Flag{
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cli.StringFlag{
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Name: "host, H",
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Usage: "daemon socket to connect to",
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Value: "unix:///var/run/docker.sock",
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EnvVar: "DOCKER_HOST",
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},
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cli.IntFlag{
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Name: "interval, i",
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Usage: "poll interval (in seconds)",
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Value: 300,
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EnvVar: "WATCHTOWER_POLL_INTERVAL",
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},
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cli.StringFlag{
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Name: "schedule, s",
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Usage: "the cron expression which defines when to update",
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EnvVar: "WATCHTOWER_SCHEDULE",
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},
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cli.BoolFlag{
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Name: "no-pull",
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Usage: "do not pull new images",
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EnvVar: "WATCHTOWER_NO_PULL",
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},
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cli.BoolFlag{
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Name: "no-restart",
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Usage: "do not restart containers",
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EnvVar: "WATCHTOWER_NO_RESTART",
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},
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cli.BoolFlag{
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Name: "cleanup",
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Usage: "remove old images after updating",
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EnvVar: "WATCHTOWER_CLEANUP",
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},
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cli.BoolFlag{
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Name: "tlsverify",
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Usage: "use TLS and verify the remote",
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EnvVar: "DOCKER_TLS_VERIFY",
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},
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cli.BoolFlag{
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Name: "debug",
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Usage: "enable debug mode with verbose logging",
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},
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cli.StringFlag{
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Name: "apiversion",
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Usage: "the version of the docker api",
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EnvVar: "DOCKER_API_VERSION",
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},
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}
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if err := app.Run(os.Args); err != nil {
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log.Fatal(err)
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}
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}
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func before(c *cli.Context) error {
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if c.GlobalBool("debug") {
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log.SetLevel(log.DebugLevel)
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}
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pollingSet := c.IsSet("interval")
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cronSet := c.IsSet("schedule")
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if pollingSet && cronSet {
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log.Fatal("Only schedule or interval can be defined, not both.")
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} else if cronSet {
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scheduleSpec = c.String("schedule")
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} else {
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scheduleSpec = "@every " + strconv.Itoa(c.Int("interval")) + "s"
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}
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cleanup = c.GlobalBool("cleanup")
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noRestart = c.GlobalBool("no-restart")
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// configure environment vars for client
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err := envConfig(c)
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if err != nil {
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return err
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}
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client = container.NewClient(!c.GlobalBool("no-pull"))
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return nil
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}
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func start(c *cli.Context) error {
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names := c.Args()
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if err := actions.CheckPrereqs(client, cleanup); err != nil {
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log.Fatal(err)
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}
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tryLockSem := make(chan bool, 1)
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tryLockSem <- true
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cron := cron.New()
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err := cron.AddFunc(
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scheduleSpec,
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func() {
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select {
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case v := <-tryLockSem:
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defer func() { tryLockSem <- v }()
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if err := actions.Update(client, names, cleanup, noRestart); err != nil {
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fmt.Println(err)
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}
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default:
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log.Debug("Skipped another update already running.")
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}
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nextRuns := cron.Entries()
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if len(nextRuns) > 0 {
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log.Debug("Scheduled next run: " + nextRuns[0].Next.String())
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}
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})
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if err != nil {
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return err
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}
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log.Info("First run: " + cron.Entries()[0].Schedule.Next(time.Now()).String())
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cron.Start()
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// Graceful shut-down on SIGINT/SIGTERM
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interrupt := make(chan os.Signal, 1)
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signal.Notify(interrupt, os.Interrupt)
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signal.Notify(interrupt, syscall.SIGTERM)
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<-interrupt
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cron.Stop()
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log.Info("Waiting for running update to be finished...")
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<-tryLockSem
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os.Exit(1)
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return nil
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}
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func setEnvOptStr(env string, opt string) error {
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if opt != "" && opt != os.Getenv(env) {
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err := os.Setenv(env, opt)
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if err != nil {
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return err
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}
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}
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return nil
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}
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func setEnvOptBool(env string, opt bool) error {
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if opt == true {
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return setEnvOptStr(env, "1")
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}
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return nil
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}
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// envConfig translates the command-line options into environment variables
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// that will initialize the api client
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func envConfig(c *cli.Context) error {
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var err error
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err = setEnvOptStr("DOCKER_HOST", c.GlobalString("host"))
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err = setEnvOptBool("DOCKER_TLS_VERIFY", c.GlobalBool("tlsverify"))
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err = setEnvOptStr("DOCKER_API_VERSION", c.GlobalString("apiversion"))
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return err
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}
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