/
server_leader.go
148 lines (127 loc) · 3.83 KB
/
server_leader.go
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// Copyright 2016 DeepFabric, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
package pdserver
import (
"sync/atomic"
"time"
"github.com/fagongzi/log"
"github.com/deepfabric/elasticell/pkg/pb/pdpb"
)
var (
loopInterval = 200 * time.Millisecond
)
func (s *Server) startLeaderLoop() {
s.leaderSignature = s.marshalLeader()
for {
if s.isClosed() {
log.Infof("leader-loop: server is closed, return leader loop")
return
}
leader, err := s.store.GetCurrentLeader()
if err != nil {
if !s.callStop {
log.Errorf("leader-loop: get current leader failure, errors:\n %+v",
err)
time.Sleep(loopInterval)
continue
} else {
return
}
}
if leader != nil {
if s.isMatchLeader(leader) {
// oh, we are already leader, we may meet something wrong
// in previous campaignLeader. we can resign and campaign again.
log.Warnf("leader-loop: leader is matched, resign and campaign again, leader=<%v>",
leader)
if err = s.store.ResignLeader(s.leaderSignature); err != nil {
log.Warnf("leader-loop: resign leader failure, leader=<%v>, errors:\n %+v",
leader,
err)
time.Sleep(loopInterval)
continue
}
} else {
log.Infof("leader-loop: we are not leader, watch the leader, leader=<%v>",
leader)
s.resetLeaderRPCProxy(leader)
s.notifier.removedAllWatcher()
s.notifyElectionComplete()
s.store.WatchLeader()
log.Infof("leader-loop: leader changed, try to campaign leader, leader=<%v>", leader)
}
}
log.Debugf("leader-loop: begin to campaign leader, name=<%s>",
s.cfg.Name)
if err = s.store.CampaignLeader(s.leaderSignature, s.cfg.DurationLeaderLease, s.enableLeader, s.disableLeader); err != nil {
if !s.callStop {
log.Errorf("leader-loop: campaign leader failure, errors:\n %+v", err)
}
}
}
}
func (s *Server) enableLeader() {
// now, we are leader
atomic.StoreInt64(&s.isLeaderValue, 1)
log.Infof("leader-loop: PD cluster leader is ready, leader=<%s>", s.cfg.Name)
// if we start cell cluster failure, exit pd.
// Than other pd will become leader and try to start cell cluster
err := s.cluster.start()
if err != nil {
log.Fatalf("leader-loop: start cell cluster failure, errors:\n %+v", err)
return
}
// load watchers
err = s.store.LoadWatchers(s.GetClusterID(), 256, s.notifier.addWatcher)
if err != nil {
log.Fatalf("leader-loop: load watchers failure, errors:\n %+v", err)
return
}
s.notifyElectionComplete()
}
func (s *Server) disableLeader() {
// now we are not leader
atomic.StoreInt64(&s.isLeaderValue, 0)
}
func (s *Server) isMatchLeader(leader *pdpb.Leader) bool {
return leader != nil &&
s.cfg.AddrRPC == leader.GetAddr() &&
s.id == leader.GetID()
}
// IsLeader returns whether server is leader or not.
func (s *Server) IsLeader() bool {
return atomic.LoadInt64(&s.isLeaderValue) == 1
}
// GetLeader returns current leader pd for API
func (s *Server) GetLeader() (*pdpb.Leader, error) {
return s.store.GetCurrentLeader()
}
func (s *Server) marshalLeader() string {
leader := &pdpb.Leader{
Addr: s.cfg.AddrRPC,
EtcdClientAddr: s.cfg.URLsClient,
ID: s.id,
Name: s.cfg.Name,
}
return marshal(leader)
}
func marshal(leader *pdpb.Leader) string {
data, err := leader.Marshal()
if err != nil {
// can't fail, so panic here.
log.Fatalf("bootstrap: marshal leader failure, leader=<%v> errors:\n %+v",
leader,
err)
}
return string(data)
}