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81 lines
2.1 KiB
81 lines
2.1 KiB
// Copyright 2015 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package util
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import (
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"encoding/json"
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"path"
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"github.com/juju/errors"
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"github.com/ngaut/go-zookeeper/zk"
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"github.com/ngaut/zkhelper"
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)
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func getLeader(data []byte) (string, error) {
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m := struct {
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Addr string `json:"Addr"`
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}{}
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err := json.Unmarshal(data, &m)
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if err != nil {
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return "", errors.Trace(err)
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}
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return m.Addr, nil
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}
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// getLeaderPath gets the leader path in zookeeper.
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func getLeaderPath(rootPath string) string {
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return path.Join(rootPath, "leader")
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}
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// func checkLeaderExists(conn zkhelper.Conn) error {
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// // the leader node is not ephemeral, so we may meet no any tso server but leader node
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// // has the data for last closed tso server.
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// // TODO: check children in /candidates, if no child, we will treat it as no leader too.
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// return nil
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// }
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// GetLeaderAddr gets the leader tso address in zookeeper for outer use.
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func GetLeader(conn zkhelper.Conn, rootPath string) (string, error) {
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data, _, err := conn.Get(getLeaderPath(rootPath))
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if err != nil {
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return "", errors.Trace(err)
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}
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// if err != checkLeaderExists(conn); err != nil {
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// return "", errors.Trace(err)
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// }
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return getLeader(data)
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}
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// GetWatchLeader gets the leader tso address in zookeeper and returns a watcher for leader change.
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func GetWatchLeader(conn zkhelper.Conn, rootPath string) (string, <-chan zk.Event, error) {
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data, _, watcher, err := conn.GetW(getLeaderPath(rootPath))
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if err != nil {
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return "", nil, errors.Trace(err)
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}
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addr, err := getLeader(data)
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if err != nil {
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return "", nil, errors.Trace(err)
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}
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// if err != checkLeaderExists(conn); err != nil {
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// return "", errors.Trace(err)
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// }
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return addr, watcher, nil
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}
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