*: fix wrong timezone when env TZ is not set (#512)

cdc/server.go

@@ -44,7 +44,7 @@ var defaultServerOptions = options{
 	pdEndpoints: "http://127.0.0.1:2379",
 	statusHost:  "127.0.0.1",
 	statusPort:  defaultStatusPort,
-	timezone:    time.Local,
+	timezone:    nil,
 	gcTTL:       DefaultCDCGCSafePointTTL,
 }
 

cdc/sink/mysql.go

@@ -267,7 +267,6 @@ var defaultParams = params{
 }
 
 func configureSinkURI(dsnCfg *dmysql.Config, tz *time.Location) (string, error) {
-	dsnCfg.Loc = tz
 	if dsnCfg.Params == nil {
 		dsnCfg.Params = make(map[string]string, 1)
 	}

cmd/server.go

@@ -7,7 +7,6 @@ import (
 	"strconv"
 	"strings"
 	"syscall"
-	"time"
 
 	"github.com/pingcap/errors"
 	"github.com/pingcap/log"
@@ -54,15 +53,18 @@ func runEServer(cmd *cobra.Command, args []string) error {
 		return errors.Annotatef(err, "invalid status address: %s", statusAddr)
 	}
 
-	var opts []cdc.ServerOption
-	opts = append(opts, cdc.PDEndpoints(serverPdAddr), cdc.StatusHost(addrs[0]), cdc.StatusPort(int(statusPort)), cdc.GCTTL(gcTTL))
-	if strings.ToLower(timezone) != "system" {
-		tz, err := time.LoadLocation(timezone)
-		if err != nil {
-			return errors.Annotate(err, "can not load timezone")
-		}
-		opts = append(opts, cdc.Timezone(tz))
+	tz, err := util.GetTimezone(timezone)
+	if err != nil {
+		return errors.Annotate(err, "can not load timezone")
 	}
+
+	opts := []cdc.ServerOption{
+		cdc.PDEndpoints(serverPdAddr),
+		cdc.StatusHost(addrs[0]),
+		cdc.StatusPort(int(statusPort)),
+		cdc.GCTTL(gcTTL),
+		cdc.Timezone(tz)}
+
 	server, err := cdc.NewServer(opts...)
 	if err != nil {
 		return errors.Annotate(err, "new server")

pkg/util/tz.go

@@ -0,0 +1,34 @@
+package util
+
+import (
+	"os"
+	"path"
+	"strings"
+	"time"
+)
+
+// GetTimezone returns the timezone specified by the name
+func GetTimezone(name string) (*time.Location, error) {
+	switch strings.ToLower(name) {
+	case "", "system", "local":
+		return GetLocalTimezone()
+	default:
+		return time.LoadLocation(name)
+	}
+}
+
+// GetLocalTimezone returns the timezone in local system
+func GetLocalTimezone() (*time.Location, error) {
+	if time.Local.String() != "Local" {
+		return time.Local, nil
+	}
+	str, err := os.Readlink("/etc/localtime")
+	if err != nil {
+		return nil, err
+	}
+	// the linked path of `/etc/localtime`
+	// MacOS: /var/db/timezone/zoneinfo/Asia/Shanghai
+	// Linux: /etc/usr/share/zoneinfo/Asia/Shanghai
+	tzName := path.Join(path.Base(path.Dir(str)), path.Base(str))
+	return time.LoadLocation(tzName)
+}