Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

plugin: fix bug that watch loop will refresh frequently when channel closed (#49275) #49288

Merged
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions plugin/BUILD.bazel
Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,7 @@ go_test(
"//testkit",
"//testkit/testsetup",
"@com_github_stretchr_testify//require",
"@io_etcd_go_etcd_client_v3//:client",
"@org_uber_go_goleak//:goleak",
],
)
28 changes: 24 additions & 4 deletions plugin/plugin.go
Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@ import (
gplugin "plugin"
"strconv"
"sync/atomic"
"time"
"unsafe"

"github.com/pingcap/errors"
Expand Down Expand Up @@ -272,14 +273,33 @@ func (w *flushWatcher) refreshPluginState() error {
}
return nil
}

func (w *flushWatcher) watchLoop() {
watchChan := w.etcd.Watch(w.ctx, w.path)
const reWatchInterval = time.Second * 5
logutil.BgLogger().Info("plugin flushWatcher loop started", zap.String("plugin", w.manifest.Name))
for w.ctx.Err() == nil {
ch := w.etcd.Watch(w.ctx, w.path)
if exit := w.watchLoopWithChan(ch); exit {
break
}

logutil.BgLogger().Info(
"plugin flushWatcher old chan closed, restart loop later",
zap.String("plugin", w.manifest.Name),
zap.Duration("after", reWatchInterval))
time.Sleep(reWatchInterval)
}
}

func (w *flushWatcher) watchLoopWithChan(ch clientv3.WatchChan) (exit bool) {
for {
select {
case <-w.ctx.Done():
return
case <-watchChan:
return true
case _, ok := <-ch:
if !ok {
return false
}
logutil.BgLogger().Info("plugin flushWatcher detected event to reload plugin config", zap.String("plugin", w.manifest.Name))
_ = w.refreshPluginState()
}
}
Expand Down
43 changes: 43 additions & 0 deletions plugin/plugin_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -18,10 +18,13 @@ import (
"context"
"io"
"strconv"
"sync/atomic"
"testing"
"time"

"github.com/pingcap/tidb/sessionctx/variable"
"github.com/stretchr/testify/require"
clientv3 "go.etcd.io/etcd/client/v3"
)

func TestLoadPluginSuccess(t *testing.T) {
Expand Down Expand Up @@ -242,3 +245,43 @@ func TestPluginsClone(t *testing.T) {
require.Equal(t, uint16(1), cps.versions["whitelist"])
require.Len(t, cps.dyingPlugins, 1)
}

func TestPluginWatcherLoop(t *testing.T) {
// exit when ctx done
ctx, cancel := context.WithCancel(context.Background())
watcher := &flushWatcher{
ctx: ctx,
manifest: &Manifest{
Name: "test",
},
}
ch := make(chan clientv3.WatchResponse)
var cancelled atomic.Bool
go func() {
time.Sleep(10 * time.Millisecond)
cancelled.Store(true)
cancel()
}()
exit := watcher.watchLoopWithChan(ch)
require.True(t, exit)
require.True(t, cancelled.Load())

// exit when ch closed
watcher = &flushWatcher{
ctx: context.Background(),
manifest: &Manifest{
Name: "test",
},
}

var closed atomic.Bool
ch = make(chan clientv3.WatchResponse)
go func() {
time.Sleep(10 * time.Millisecond)
closed.Store(true)
close(ch)
}()
exit = watcher.watchLoopWithChan(ch)
require.False(t, exit)
require.True(t, cancelled.Load())
}