github.com/pingcap/ticdc@v0.0.0-20220526033649-485a10ef2652/pkg/util/tz.go (about)

     1  // Copyright 2020 PingCAP, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package util
    15  
    16  import (
    17  	"os"
    18  	"path/filepath"
    19  	"strings"
    20  	"time"
    21  
    22  	cerror "github.com/pingcap/ticdc/pkg/errors"
    23  )
    24  
    25  // GetTimezone returns the timezone specified by the name
    26  func GetTimezone(name string) (tz *time.Location, err error) {
    27  	switch strings.ToLower(name) {
    28  	case "", "system", "local":
    29  		tz, err = GetLocalTimezone()
    30  		err = cerror.WrapError(cerror.ErrLoadTimezone, err)
    31  	default:
    32  		tz, err = time.LoadLocation(name)
    33  		err = cerror.WrapError(cerror.ErrLoadTimezone, err)
    34  	}
    35  	return
    36  }
    37  
    38  func getTimezoneFromZonefile(zonefile string) (tz *time.Location, err error) {
    39  	// the linked path of `/etc/localtime` sample:
    40  	// MacOS: /var/db/timezone/zoneinfo/Asia/Shanghai
    41  	// Linux: /usr/share/zoneinfo/Asia/Shanghai
    42  	region := filepath.Base(filepath.Dir(zonefile))
    43  	zone := filepath.Base(zonefile)
    44  	var tzName string
    45  	if region == "zoneinfo" {
    46  		tzName = zone
    47  	} else {
    48  		tzName = filepath.Join(region, zone)
    49  	}
    50  	tz, err = time.LoadLocation(tzName)
    51  	err = cerror.WrapError(cerror.ErrLoadTimezone, err)
    52  	return
    53  }
    54  
    55  // GetLocalTimezone returns the timezone in local system
    56  func GetLocalTimezone() (*time.Location, error) {
    57  	if time.Local.String() != "Local" {
    58  		return time.Local, nil
    59  	}
    60  	str, err := os.Readlink("/etc/localtime")
    61  	if err != nil {
    62  		return nil, cerror.WrapError(cerror.ErrLoadTimezone, err)
    63  	}
    64  	return getTimezoneFromZonefile(str)
    65  }