add config-check flag for pd-server (tikv#1695)

Signed-off-by: cwen0 <cwenyin0@gmail.com>

cmd/pd-server/main.go

@@ -53,6 +53,12 @@ func main() {
 	default:
 		log.Fatal("parse cmd flags error", zap.Error(err))
 	}
+
+	if cfg.ConfigCheck {
+		server.PrintConfigCheckMsg(cfg)
+		exit(0)
+	}
+
 	// New zap logger
 	err = cfg.SetupLogger()
 	if err == nil {

server/config.go

@@ -44,6 +44,8 @@ type Config struct {
 
 	Version bool `json:"-"`
 
+	ConfigCheck bool `json:"-"`
+
 	ClientUrls          string `toml:"client-urls" json:"client-urls"`
 	PeerUrls            string `toml:"peer-urls" json:"peer-urls"`
 	AdvertiseClientUrls string `toml:"advertise-client-urls" json:"advertise-client-urls"`
@@ -145,6 +147,7 @@ func NewConfig() *Config {
 	fs.BoolVar(&cfg.Version, "V", false, "print version information and exit")
 	fs.BoolVar(&cfg.Version, "version", false, "print version information and exit")
 	fs.StringVar(&cfg.configFile, "config", "", "Config file")
+	fs.BoolVar(&cfg.ConfigCheck, "config-check", false, "check config file validity and exit")
 
 	fs.StringVar(&cfg.Name, "name", "", "human-readable name for this pd member")
 

server/util.go

@@ -71,6 +71,18 @@ func PrintPDInfo() {
 	fmt.Println("UTC Build Time: ", PDBuildTS)
 }
 
+// PrintConfigCheckMsg prints the message about configuration checks.
+func PrintConfigCheckMsg(cfg *config.Config) {
+	if len(cfg.WarningMsgs) == 0 {
+		fmt.Println("config check successful")
+		return
+	}
+
+	for _, msg := range cfg.WarningMsgs {
+		fmt.Println(msg)
+	}
+}
+
 // CheckPDVersion checks if PD needs to be upgraded.
 func CheckPDVersion(opt *scheduleOption) {
 	pdVersion := MinSupportedVersion(Base)