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watchtower/main.go

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package main // import "github.com/v2tec/watchtower"
import (
"os"
"os/signal"
"syscall"
"time"
"strconv"
"github.com/robfig/cron"
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log "github.com/sirupsen/logrus"
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"github.com/urfave/cli"
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"github.com/v2tec/watchtower/actions"
"github.com/v2tec/watchtower/container"
"github.com/v2tec/watchtower/notifications"
)
// DockerAPIMinVersion is the version of the docker API, which is minimally required by
// watchtower. Currently we require at least API 1.24 and therefore Docker 1.12 or later.
const DockerAPIMinVersion string = "1.24"
var version = "master"
var commit = "unknown"
var date = "unknown"
var (
client container.Client
scheduleSpec string
cleanup bool
noRestart bool
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enableLabel bool
notifier *notifications.Notifier
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timeout time.Duration
)
func init() {
log.SetLevel(log.InfoLevel)
}
func main() {
app := cli.NewApp()
app.Name = "watchtower"
app.Version = version + " - " + commit + " - " + date
app.Usage = "Automatically update running Docker containers"
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app.Before = before
app.Action = start
app.Flags = []cli.Flag{
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cli.StringFlag{
Name: "host, H",
Usage: "daemon socket to connect to",
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Value: "unix:///var/run/docker.sock",
EnvVar: "DOCKER_HOST",
},
cli.IntFlag{
Name: "interval, i",
Usage: "poll interval (in seconds)",
Value: 300,
EnvVar: "WATCHTOWER_POLL_INTERVAL",
},
cli.StringFlag{
Name: "schedule, s",
Usage: "the cron expression which defines when to update",
EnvVar: "WATCHTOWER_SCHEDULE",
},
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cli.BoolFlag{
Name: "no-pull",
Usage: "do not pull new images",
EnvVar: "WATCHTOWER_NO_PULL",
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},
cli.BoolFlag{
Name: "no-restart",
Usage: "do not restart containers",
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EnvVar: "WATCHTOWER_NO_RESTART",
},
cli.BoolFlag{
Name: "cleanup",
Usage: "remove old images after updating",
EnvVar: "WATCHTOWER_CLEANUP",
},
cli.BoolFlag{
Name: "tlsverify",
Usage: "use TLS and verify the remote",
EnvVar: "DOCKER_TLS_VERIFY",
},
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cli.DurationFlag{
Name: "stop-timeout",
Usage: "timeout before container is forcefully stopped",
Value: time.Second * 10,
EnvVar: "WATCHTOWER_TIMEOUT",
},
cli.BoolFlag{
Name: "label-enable",
Usage: "watch containers where the com.centurylinklabs.watchtower.enable label is true",
EnvVar: "WATCHTOWER_LABEL_ENABLE",
},
cli.BoolFlag{
Name: "debug",
Usage: "enable debug mode with verbose logging",
},
cli.StringSliceFlag{
Name: "notifications",
Value: &cli.StringSlice{},
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Usage: "notification types to send (valid: email, slack)",
EnvVar: "WATCHTOWER_NOTIFICATIONS",
},
cli.StringFlag{
Name: "notifications-level",
Usage: "The log level used for sending notifications. Possible values: \"panic\", \"fatal\", \"error\", \"warn\", \"info\" or \"debug\"",
EnvVar: "WATCHTOWER_NOTIFICATIONS_LEVEL",
Value: "info",
},
cli.StringFlag{
Name: "notification-email-from",
Usage: "Address to send notification e-mails from",
EnvVar: "WATCHTOWER_NOTIFICATION_EMAIL_FROM",
},
cli.StringFlag{
Name: "notification-email-to",
Usage: "Address to send notification e-mails to",
EnvVar: "WATCHTOWER_NOTIFICATION_EMAIL_TO",
},
cli.StringFlag{
Name: "notification-email-server",
Usage: "SMTP server to send notification e-mails through",
EnvVar: "WATCHTOWER_NOTIFICATION_EMAIL_SERVER",
},
cli.IntFlag{
Name: "notification-email-server-port",
Usage: "SMTP server port to send notification e-mails through",
Value: 25,
EnvVar: "WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PORT",
},
cli.BoolFlag{
Name: "notification-email-server-tls-skip-verify",
Usage: "Controls whether watchtower verifies the SMTP server's certificate chain and host name. " +
"If set, TLS accepts any certificate " +
"presented by the server and any host name in that certificate. " +
"In this mode, TLS is susceptible to man-in-the-middle attacks. " +
"This should be used only for testing.",
EnvVar: "WATCHTOWER_NOTIFICATION_EMAIL_SERVER_TLS_SKIP_VERIFY",
},
cli.StringFlag{
Name: "notification-email-server-user",
Usage: "SMTP server user for sending notifications",
EnvVar: "WATCHTOWER_NOTIFICATION_EMAIL_SERVER_USER",
},
cli.StringFlag{
Name: "notification-email-server-password",
Usage: "SMTP server password for sending notifications",
EnvVar: "WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD",
},
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cli.StringFlag{
Name: "notification-slack-hook-url",
Usage: "The Slack Hook URL to send notifications to",
EnvVar: "WATCHTOWER_NOTIFICATION_SLACK_HOOK_URL",
},
cli.StringFlag{
Name: "notification-slack-identifier",
Usage: "A string which will be used to identify the messages coming from this watchtower instance. Default if omitted is \"watchtower\"",
EnvVar: "WATCHTOWER_NOTIFICATION_SLACK_IDENTIFIER",
Value: "watchtower",
},
}
if err := app.Run(os.Args); err != nil {
log.Fatal(err)
}
}
func before(c *cli.Context) error {
if c.GlobalBool("debug") {
log.SetLevel(log.DebugLevel)
}
pollingSet := c.IsSet("interval")
cronSet := c.IsSet("schedule")
if pollingSet && cronSet {
log.Fatal("Only schedule or interval can be defined, not both.")
} else if cronSet {
scheduleSpec = c.String("schedule")
} else {
scheduleSpec = "@every " + strconv.Itoa(c.Int("interval")) + "s"
}
cleanup = c.GlobalBool("cleanup")
noRestart = c.GlobalBool("no-restart")
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timeout = c.GlobalDuration("stop-timeout")
if timeout < 0 {
log.Fatal("Please specify a positive value for timeout value.")
}
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enableLabel = c.GlobalBool("label-enable")
// configure environment vars for client
err := envConfig(c)
if err != nil {
return err
}
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client = container.NewClient(!c.GlobalBool("no-pull"))
notifier = notifications.NewNotifier(c)
return nil
}
func start(c *cli.Context) error {
names := c.Args()
if err := actions.CheckPrereqs(client, cleanup); err != nil {
log.Fatal(err)
}
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filter := container.BuildFilter(names, enableLabel)
tryLockSem := make(chan bool, 1)
tryLockSem <- true
cron := cron.New()
err := cron.AddFunc(
scheduleSpec,
func() {
select {
case v := <-tryLockSem:
defer func() { tryLockSem <- v }()
notifier.StartNotification()
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if err := actions.Update(client, filter, cleanup, noRestart, timeout); err != nil {
log.Println(err)
}
notifier.SendNotification()
default:
log.Debug("Skipped another update already running.")
}
nextRuns := cron.Entries()
if len(nextRuns) > 0 {
log.Debug("Scheduled next run: " + nextRuns[0].Next.String())
}
})
if err != nil {
return err
}
log.Info("First run: " + cron.Entries()[0].Schedule.Next(time.Now()).String())
cron.Start()
// Graceful shut-down on SIGINT/SIGTERM
interrupt := make(chan os.Signal, 1)
signal.Notify(interrupt, os.Interrupt)
signal.Notify(interrupt, syscall.SIGTERM)
<-interrupt
cron.Stop()
log.Info("Waiting for running update to be finished...")
<-tryLockSem
os.Exit(1)
return nil
}
func setEnvOptStr(env string, opt string) error {
if opt != "" && opt != os.Getenv(env) {
err := os.Setenv(env, opt)
if err != nil {
return err
}
}
return nil
}
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func setEnvOptBool(env string, opt bool) error {
if opt == true {
return setEnvOptStr(env, "1")
}
return nil
}
// envConfig translates the command-line options into environment variables
// that will initialize the api client
func envConfig(c *cli.Context) error {
var err error
err = setEnvOptStr("DOCKER_HOST", c.GlobalString("host"))
err = setEnvOptBool("DOCKER_TLS_VERIFY", c.GlobalBool("tlsverify"))
err = setEnvOptStr("DOCKER_API_VERSION", DockerAPIMinVersion)
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return err
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}