Update checker

cmd/main.go

@@ -19,8 +19,9 @@ var (
 )
 
 var (
-	configPath  = flag.String("config", "config.json", "Config file")
+	configPath         = flag.String("config", "config.json", "Config file")
-	showVersion = flag.Bool("version", false, "Show version")
+	showVersion        = flag.Bool("version", false, "Show version")
+	disableUpdateCheck = flag.Bool("no-check", false, "Disable update check")
 )
 
 func init() {
@@ -47,7 +48,10 @@ func init() {
 	} else {
 		logrus.SetFormatter(&nested.Formatter{
 			FieldsOrder: []string{
-				"config", "file", "mode", "addr", "src", "dst", "session", "action", "error",
+				"version", "url",
+				"config", "file", "mode",
+				"addr", "src", "dst", "session", "action",
+				"error",
 			},
 			TimestampFormat: tsFormat,
 		})
@@ -64,6 +68,9 @@ func main() {
 		fmt.Printf("%-10s%s\n", "Date:", appDate)
 		return
 	}
+	if !*disableUpdateCheck {
+		go checkUpdate()
+	}
 	cb, err := ioutil.ReadFile(*configPath)
 	if err != nil {
 		logrus.WithFields(logrus.Fields{

cmd/update.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"encoding/json"
+	"github.com/sirupsen/logrus"
+	"io/ioutil"
+	"net/http"
+	"time"
+)
+
+const githubAPIURL = "https://api.github.com/repos/HyNetwork/hysteria/releases/latest"
+
+type releaseInfo struct {
+	URL         string `json:"html_url"`
+	TagName     string `json:"tag_name"`
+	CreatedAt   string `json:"created_at"`
+	PublishedAt string `json:"published_at"`
+}
+
+func checkUpdate() {
+	info, err := fetchLatestRelease()
+	if err != nil {
+		logrus.WithFields(logrus.Fields{
+			"error": err,
+		}).Warn("Failed to check for updates")
+	} else if info.TagName != appVersion {
+		logrus.WithFields(logrus.Fields{
+			"version": info.TagName,
+			"url":     info.URL,
+		}).Info("New version available")
+	}
+}
+
+func fetchLatestRelease() (*releaseInfo, error) {
+	hc := &http.Client{
+		Timeout: time.Second * 20,
+	}
+	resp, err := hc.Get(githubAPIURL)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+	var info releaseInfo
+	err = json.Unmarshal(body, &info)
+	return &info, err
+}