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watchtower/main.go

81 lines
1.5 KiB
Go

package main // import "github.com/CenturyLinkLabs/watchtower"
import (
"fmt"
"os"
"os/signal"
"sync"
"syscall"
"time"
"github.com/CenturyLinkLabs/watchtower/actions"
"github.com/CenturyLinkLabs/watchtower/container"
"github.com/codegangsta/cli"
)
var (
wg sync.WaitGroup
)
func main() {
app := cli.NewApp()
app.Name = "watchtower"
app.Usage = "Automatically update running Docker containers"
app.Before = before
app.Action = start
app.Flags = []cli.Flag{
cli.StringFlag{
Name: "host, H",
Value: "unix:///var/run/docker.sock",
Usage: "Docker daemon socket to connect to",
EnvVar: "DOCKER_HOST",
},
cli.IntFlag{
Name: "interval, i",
Value: 300,
Usage: "poll interval (in seconds)",
},
}
handleSignals()
app.Run(os.Args)
}
func handleSignals() {
// Graceful shut-down on SIGINT/SIGTERM
c := make(chan os.Signal, 1)
signal.Notify(c, os.Interrupt)
signal.Notify(c, syscall.SIGTERM)
go func() {
<-c
wg.Wait()
os.Exit(1)
}()
}
func before(c *cli.Context) error {
client := newContainerClient(c)
return actions.CheckPrereqs(client)
}
func start(c *cli.Context) {
client := newContainerClient(c)
secs := time.Duration(c.Int("interval")) * time.Second
for {
wg.Add(1)
if err := actions.Update(client); err != nil {
fmt.Println(err)
}
wg.Done()
time.Sleep(secs)
}
}
func newContainerClient(c *cli.Context) container.Client {
dockerHost := c.GlobalString("host")
return container.NewClient(dockerHost)
}