améliorations

.gitignore

@@ -12,3 +12,4 @@
 *.out
 
 .idea/
+/main

Dockerfile

@@ -0,0 +1,19 @@
+#
+# Alpine image to get some needed data
+#
+FROM alpine:latest as alpine
+RUN apk add --no-cache \
+    ca-certificates \
+    tzdata
+
+#
+# Image
+#
+FROM scratch
+
+# copy files from other containers
+COPY --from=alpine /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/ca-certificates.crt
+COPY --from=alpine /usr/share/zoneinfo /usr/share/zoneinfo
+
+COPY main /
+ENTRYPOINT ["/main"]

main.go

@@ -3,73 +3,200 @@ package main
 import (
 	"encoding/json"
 	"fmt"
+	"github.com/robfig/cron"
+	log "github.com/sirupsen/logrus"
+	"github.com/urfave/cli"
 	"gopkg.in/src-d/go-git.v4"
 	"gopkg.in/src-d/go-git.v4/plumbing/object"
 	githttp "gopkg.in/src-d/go-git.v4/plumbing/transport/http"
 	"io/ioutil"
 	"net/http"
 	"os"
+	"os/signal"
 	"path"
 	"regexp"
+	"strconv"
 	"strings"
+	"syscall"
 	"time"
 )
 
 type Configuration struct {
 	RepositoryUrl string `json:"url"`
-	Username string `json:"name"`
+	Username      string `json:"name"`
-	Email string `json:"email"`
+	Email         string `json:"email"`
-	GitLogin string `json:"login"`
+	GitLogin      string `json:"login"`
-	GitPassword string `json:"password"`
+	GitPassword   string `json:"password"`
 }
 
-var configPath string
+var (
+	configPath   string
+	scheduleSpec string
+)
+
+var version = "master"
+var commit = "unknown"
+var date = "unknown"
 
 func main() {
 
+	app := cli.NewApp()
+	app.Name = "watchtower"
+	app.Version = version + " - " + commit + " - " + date
+	app.Usage = "Automatically update running Docker containers"
+	app.Before = before
+	app.Action = start
+	app.Flags = []cli.Flag{
+
+		cli.StringFlag{
+			Name:   "config, C",
+			Usage:  "path to config file",
+			Value:  "/config/conf.json",
+			EnvVar: "CONFIG_PATH",
+		},
+		cli.IntFlag{
+			Name:   "interval, i",
+			Usage:  "poll interval (in seconds)",
+			Value:  300,
+			EnvVar: "DNSUPDATER_POLL_INTERVAL",
+		},
+		cli.StringFlag{
+			Name:   "schedule, s",
+			Usage:  "the cron expression which defines when to update",
+			EnvVar: "DNSUPDATER_SCHEDULE",
+		},
+	}
+
+	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"
+	}
+	return nil
+}
+
+func start(c *cli.Context) error {
+	tryLockSem := make(chan bool, 1)
+	tryLockSem <- true
+
+	cron := cron.New()
+	err := cron.AddFunc(
+		scheduleSpec,
+		func() {
+			select {
+			case v := <-tryLockSem:
+				defer func() { tryLockSem <- v }()
+				if err := update(c); err != nil {
+					log.Println(err)
+
+				}
+			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 update(c *cli.Context) error {
 	Info("Running dnsupdater...")
 
-	configPath = os.Args[1]
+	configPath = c.String("config")
 
-	if confPathExists, _ := exists(configPath); !confPathExists{
+	if confPathExists, _ := exists(configPath); !confPathExists {
 		configPath = "./data";
 	}
 
-	file, _ := os.Open(path.Join(configPath,"conf.json"))
+	file, _ := os.Open(path.Join(configPath, "conf.json"))
 	defer file.Close()
 	decoder := json.NewDecoder(file)
 	configuration := Configuration{}
 	err := decoder.Decode(&configuration)
 
-	err = os.RemoveAll(path.Join(configPath,"data"))
+	err = os.RemoveAll(path.Join(configPath, "data"))
-	CheckIfError(err)
+	if err != nil {
+		return err
+	}
 
-	_, err = git.PlainClone(path.Join(configPath,"data"), false, &git.CloneOptions{
+	_, err = git.PlainClone(path.Join(configPath, "data"), false, &git.CloneOptions{
 		URL:      configuration.RepositoryUrl,
 		Progress: os.Stdout,
 	})
-	CheckIfError(err)
+	if err != nil {
+		return err
+	}
 
-	currentIp := GetCurrentIp()
+	currentIp, err := GetCurrentIp()
-	newIp := GetOutboundIP()
+	if err != nil {
+		return err
+	}
+	newIp, err := GetOutboundIP()
+	if err != nil {
+		return err
+	}
 
 	if currentIp == newIp {
 		Info("Ip has not changed %s", currentIp)
-		os.Exit(0)
+		return nil
 	}
 
 	Info("Ip has changed %s -> %s", currentIp, newIp)
 	SetCurrentIp(currentIp, newIp)
 
-	repo, err := git.PlainOpen(path.Join(configPath,"data"))
+	repo, err := git.PlainOpen(path.Join(configPath, "data"))
-	CheckIfError(err)
+	if err != nil {
+		return err
+	}
 	w, err := repo.Worktree()
-	CheckIfError(err)
+	if err != nil {
+		return err
+	}
 	_, err = w.Add("templates/home_a.lua")
-	CheckIfError(err)
+	if err != nil {
+		return err
+	}
 
 	status, err := w.Status()
-	CheckIfError(err)
+	if err != nil {
+		return err
+	}
 
 	fmt.Println(status)
 	_, err = w.Commit(fmt.Sprintf("Changement d'IP maison : %s -> %s", currentIp, newIp), &git.CommitOptions{
@@ -79,7 +206,9 @@ func main() {
 			When:  time.Now().Local(),
 		},
 	})
-	CheckIfError(err)
+	if err != nil {
+		return err
+	}
 
 	err = repo.Push(&git.PushOptions{
 		Auth: &githttp.BasicAuth{
@@ -87,47 +216,51 @@ func main() {
 			Password: configuration.GitPassword,
 		},
 	})
-	CheckIfError(err)
+	if err != nil {
-
+		return err
+	}
+	return nil
 }
 
-func GetCurrentIp() string {
+func GetCurrentIp() (string, error) {
-	b, err := ioutil.ReadFile(path.Join(configPath,"data/templates/home_a.lua"))
+	b, err := ioutil.ReadFile(path.Join(configPath, "data/templates/home_a.lua"))
-	CheckIfError(err)
+	if err != nil {
+		return "", err
+	}
 
 	re := regexp.MustCompile("\"(.*?)\"")
 	match := re.FindStringSubmatch(string(b))
-	return match[1]
+	return match[1], nil
 }
 
-func SetCurrentIp(oldip string, newip string) {
+func SetCurrentIp(oldip string, newip string) error {
-	b, err := ioutil.ReadFile(path.Join(configPath,"data/templates/home_a.lua"))
+	b, err := ioutil.ReadFile(path.Join(configPath, "data/templates/home_a.lua"))
-	CheckIfError(err)
+	if err != nil {
+		return err
+	}
 
 	s := string(b)
 	s = strings.Replace(s, oldip, newip, 1)
-	ioutil.WriteFile(path.Join(configPath,"data/templates/home_a.lua"), []byte(s), 0644)
+	ioutil.WriteFile(path.Join(configPath, "data/templates/home_a.lua"), []byte(s), 0644)
+	return nil
 }
 
-func CheckIfError(err error) {
+func GetOutboundIP() (string, error) {
-	if err == nil {
-		return
-	}
-
-	fmt.Printf("\x1b[31;1m%s\x1b[0m\n", fmt.Sprintf("error: %s", err))
-	os.Exit(1)
-}
-
-func GetOutboundIP() string {
 	url := "https://diagnostic.opendns.com/myip"
 	req, err := http.NewRequest("GET", url, nil)
-	CheckIfError(err)
+	if err != nil {
+		return "", err
+	}
 	res, err := http.DefaultClient.Do(req)
-	CheckIfError(err)
+	if err != nil {
+		return "", err
+	}
 	defer res.Body.Close()
 	body, err := ioutil.ReadAll(res.Body)
-	CheckIfError(err)
+	if err != nil {
-	return string(body)
+		return "", err
+	}
+	return string(body), nil
 }
 
 func exists(path string) (bool, error) {