embed: overwrite advertise URLs only when IP is 0.0.0.0

Fix etcd-io#7009.

embed/config.go

@@ -55,22 +55,9 @@ var (
 	DefaultInitialAdvertisePeerURLs = "http://localhost:2380"
 	DefaultAdvertiseClientURLs      = "http://localhost:2379"
 
-	defaultHostname   string = "localhost"
-	defaultHostStatus error
+	defaultHostname string = "localhost"
 )
 
-func init() {
-	ip, err := netutil.GetDefaultHost()
-	if err != nil {
-		defaultHostStatus = err
-		return
-	}
-	// found default host, advertise on it
-	DefaultInitialAdvertisePeerURLs = "http://" + ip + ":2380"
-	DefaultAdvertiseClientURLs = "http://" + ip + ":2379"
-	defaultHostname = ip
-}
-
 // Config holds the arguments for configuring an etcd server.
 type Config struct {
 	// member
@@ -346,14 +333,27 @@ func (cfg Config) ElectionTicks() int { return int(cfg.ElectionMs / cfg.TickMs)
 
 // IsDefaultHost returns the default hostname, if used, and the error, if any,
 // from getting the machine's default host.
-func (cfg Config) IsDefaultHost() (string, error) {
-	if len(cfg.APUrls) == 1 && cfg.APUrls[0].String() == DefaultInitialAdvertisePeerURLs {
-		return defaultHostname, defaultHostStatus
+func (cfg *Config) IsDefaultHost() (string, error) {
+	h, herr := netutil.GetDefaultHost()
+	if len(cfg.APUrls) == 1 {
+		ip, port, err := net.SplitHostPort(cfg.APUrls[0].Host)
+		if err != nil {
+			return "", err
+		}
+		if ip == "0.0.0.0" {
+			cfg.APUrls[0] = url.URL{Scheme: cfg.APUrls[0].Scheme, Host: fmt.Sprintf("%s:%s", h, port)}
+		}
 	}
-	if len(cfg.ACUrls) == 1 && cfg.ACUrls[0].String() == DefaultAdvertiseClientURLs {
-		return defaultHostname, defaultHostStatus
+	if len(cfg.ACUrls) == 1 {
+		ip, port, err := net.SplitHostPort(cfg.ACUrls[0].Host)
+		if err != nil {
+			return "", err
+		}
+		if ip == "0.0.0.0" {
+			cfg.ACUrls[0] = url.URL{Scheme: cfg.ACUrls[0].Scheme, Host: fmt.Sprintf("%s:%s", h, port)}
+		}
 	}
-	return "", defaultHostStatus
+	return h, herr
 }
 
 // checkBindURLs returns an error if any URL uses a domain name.