election: provide methods to read and write campaignTimes instead of export

pkg/election/leadership.go

@@ -33,6 +33,7 @@ import (
 )
 
 const (
+	defaultCampaignTimesSlot   = 10
 	watchLoopUnhealthyTimeout  = 60 * time.Second
 	campaignTimesRecordTimeout = 5 * time.Minute
 )
@@ -65,9 +66,9 @@ type Leadership struct {
 	keepAliveCtx            context.Context
 	keepAliveCancelFunc     context.CancelFunc
 	keepAliveCancelFuncLock syncutil.Mutex
-	// CampaignTimes is used to record the campaign times of the leader within `campaignTimesRecordTimeout`.
+	// campaignTimes is used to record the campaign times of the leader within `campaignTimesRecordTimeout`.
 	// It is ordered by time to prevent the leader from campaigning too frequently.
-	CampaignTimes []time.Time
+	campaignTimes []time.Time
 }
 
 // NewLeadership creates a new Leadership.
@@ -76,7 +77,7 @@ func NewLeadership(client *clientv3.Client, leaderKey, purpose string) *Leadersh
 		purpose:       purpose,
 		client:        client,
 		leaderKey:     leaderKey,
-		CampaignTimes: make([]time.Time, 0, 10),
+		campaignTimes: make([]time.Time, 0, defaultCampaignTimesSlot),
 	}
 	return leadership
 }
@@ -111,18 +112,37 @@ func (ls *Leadership) GetLeaderKey() string {
 	return ls.leaderKey
 }
 
+// GetCampaignTimesNum is used to get the campaign times of the leader within `campaignTimesRecordTimeout`.
+func (ls *Leadership) GetCampaignTimesNum() int {
+	if ls == nil {
+		return 0
+	}
+	return len(ls.campaignTimes)
+}
+
+// ResetCampaignTimes is used to reset the campaign times of the leader.
+func (ls *Leadership) ResetCampaignTimes() {
+	if ls == nil {
+		return
+	}
+	ls.campaignTimes = make([]time.Time, 0, defaultCampaignTimesSlot)
+}
+
 // addCampaignTimes is used to add the campaign times of the leader.
 func (ls *Leadership) addCampaignTimes() {
-	for i := len(ls.CampaignTimes) - 1; i >= 0; i-- {
-		if time.Since(ls.CampaignTimes[i]) > campaignTimesRecordTimeout {
+	if ls == nil {
+		return
+	}
+	for i := len(ls.campaignTimes) - 1; i >= 0; i-- {
+		if time.Since(ls.campaignTimes[i]) > campaignTimesRecordTimeout {
 			// remove the time which is more than `campaignTimesRecordTimeout`
 			// array is sorted by time
-			ls.CampaignTimes = ls.CampaignTimes[i:]
+			ls.campaignTimes = ls.campaignTimes[i:]
 			break
 		}
 	}
 
-	ls.CampaignTimes = append(ls.CampaignTimes, time.Now())
+	ls.campaignTimes = append(ls.campaignTimes, time.Now())
 }
 
 // Campaign is used to campaign the leader with given lease and returns a leadership

pkg/member/member.go

@@ -185,11 +185,10 @@ func (m *EmbeddedEtcdMember) CampaignLeader(ctx context.Context, leaseTimeout in
 	failpoint.Inject("skipCampaignLeaderCheck", func() {
 		failpoint.Return(m.leadership.Campaign(leaseTimeout, m.MemberValue()))
 	})
-	if len(m.leadership.CampaignTimes) >= campaignLeaderFrequencyTimes {
+	if m.leadership.GetCampaignTimesNum() >= campaignLeaderFrequencyTimes {
 		log.Warn("campaign times is too frequent, resign and campaign again",
 			zap.String("leader-name", m.Name()), zap.String("leader-key", m.GetLeaderPath()))
-		// remove all campaign times
-		m.leadership.CampaignTimes = nil
+		m.leadership.ResetCampaignTimes()
 		return m.ResignEtcdLeader(ctx, m.Name(), "")
 	}
 	return m.leadership.Campaign(leaseTimeout, m.MemberValue())

tests/server/member/member_test.go

@@ -341,8 +341,7 @@ func TestCampaignLeaderFrequently(t *testing.T) {
 		cluster.GetLeaderServer().ResetPDLeader()
 		cluster.WaitLeader()
 	}
-	// leader should be changed when campaign leader frequently
-	cluster.WaitLeader()
+	// PD leader should be different from before because etcd leader changed.
 	re.NotEmpty(cluster.GetLeader())
 	re.NotEqual(leader, cluster.GetLeader())
 }