-
Notifications
You must be signed in to change notification settings - Fork 719
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Browse files
Browse the repository at this point in the history
* server: use leader lease to determine tso service validity#1676 Signed-off-by: nolouch <nolouch@gmail.com>
- Loading branch information
Showing
6 changed files
with
195 additions
and
41 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,140 @@ | ||
| // Copyright 2019 PingCAP, 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 server | ||
|
|
||
| import ( | ||
| "context" | ||
| "sync/atomic" | ||
| "time" | ||
|
|
||
| "github.com/pingcap/log" | ||
| "github.com/pkg/errors" | ||
| "go.etcd.io/etcd/clientv3" | ||
| "go.uber.org/zap" | ||
| ) | ||
|
|
||
| // LeaderLease is used for renewing leadership of PD server. | ||
| type LeaderLease struct { | ||
| client *clientv3.Client | ||
| lease clientv3.Lease | ||
| ID clientv3.LeaseID | ||
| leaseTimeout time.Duration | ||
|
|
||
| expireTime atomic.Value | ||
| } | ||
|
|
||
| // NewLeaderLease creates a lease. | ||
| func NewLeaderLease(client *clientv3.Client) *LeaderLease { | ||
| return &LeaderLease{ | ||
| client: client, | ||
| lease: clientv3.NewLease(client), | ||
| } | ||
| } | ||
|
|
||
| // Grant uses `lease.Grant` to initialize the lease and expireTime. | ||
| func (l *LeaderLease) Grant(leaseTimeout int64) error { | ||
| start := time.Now() | ||
| ctx, cancel := context.WithTimeout(l.client.Ctx(), requestTimeout) | ||
| leaseResp, err := l.lease.Grant(ctx, leaseTimeout) | ||
| cancel() | ||
| if err != nil { | ||
| return errors.WithStack(err) | ||
| } | ||
| if cost := time.Since(start); cost > slowRequestTime { | ||
| log.Warn("lease grants too slow", zap.Duration("cost", cost)) | ||
| } | ||
| l.ID = leaseResp.ID | ||
| l.leaseTimeout = time.Duration(leaseTimeout) * time.Second | ||
| l.expireTime.Store(start.Add(time.Duration(leaseResp.TTL) * time.Second)) | ||
| return nil | ||
| } | ||
|
|
||
| const revokeLeaseTimeout = time.Second | ||
|
|
||
| // Close releases the lease. | ||
| func (l *LeaderLease) Close() error { | ||
| // Reset expire time. | ||
| l.expireTime.Store(time.Time{}) | ||
| // Try to revoke lease to make subsequent elections faster. | ||
| ctx, cancel := context.WithTimeout(l.client.Ctx(), revokeLeaseTimeout) | ||
| defer cancel() | ||
| l.lease.Revoke(ctx, l.ID) | ||
| return l.lease.Close() | ||
| } | ||
|
|
||
| // IsExpired checks if the lease is expired. If it returns true, current PD | ||
| // server should step down and try to re-elect again. | ||
| func (l *LeaderLease) IsExpired() bool { | ||
| return time.Now().After(l.expireTime.Load().(time.Time)) | ||
| } | ||
|
|
||
| // KeepAlive auto renews the lease and update expireTime. | ||
| func (l *LeaderLease) KeepAlive(ctx context.Context) { | ||
| ctx, cancel := context.WithCancel(ctx) | ||
| defer cancel() | ||
| timeCh := l.keepAliveWorker(ctx, l.leaseTimeout/3) | ||
|
|
||
| var maxExpire time.Time | ||
| for { | ||
| select { | ||
| case t := <-timeCh: | ||
| if t.After(maxExpire) { | ||
| maxExpire = t | ||
| l.expireTime.Store(t) | ||
| } | ||
| case <-time.After(l.leaseTimeout): | ||
| return | ||
| case <-ctx.Done(): | ||
| return | ||
| } | ||
| } | ||
| } | ||
|
|
||
| // Periodically call `lease.KeepAliveOnce` and post back latest received expire time into the channel. | ||
| func (l *LeaderLease) keepAliveWorker(ctx context.Context, interval time.Duration) <-chan time.Time { | ||
| ch := make(chan time.Time) | ||
|
|
||
| go func() { | ||
| ticker := time.NewTicker(interval) | ||
| defer ticker.Stop() | ||
|
|
||
| for { | ||
| go func() { | ||
| start := time.Now() | ||
| ctx1, cancel := context.WithTimeout(ctx, time.Duration(l.leaseTimeout)) | ||
| defer cancel() | ||
| res, err := l.lease.KeepAliveOnce(ctx1, l.ID) | ||
| if err != nil { | ||
| log.Warn("leader lease keep alive failed", zap.Error(err)) | ||
| return | ||
| } | ||
| if res.TTL > 0 { | ||
| expire := start.Add(time.Duration(res.TTL) * time.Second) | ||
| select { | ||
| case ch <- expire: | ||
| case <-ctx1.Done(): | ||
| } | ||
| } | ||
| }() | ||
|
|
||
| select { | ||
| case <-ctx.Done(): | ||
| return | ||
| case <-ticker.C: | ||
| } | ||
| } | ||
| }() | ||
|
|
||
| return ch | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters