polardbxoperator/pkg/binlogtool/binlog/async.go

116 lines
2.2 KiB
Go

/*
Copyright 2022 Alibaba Group Holding Limited.
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,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package binlog
import (
"context"
"errors"
"io"
"sync"
"sync/atomic"
"github.com/alibaba/polardbx-operator/pkg/binlogtool/binlog/event"
)
type asyncLogEventScanCloser struct {
s LogEventScanner
close uint32
ch chan struct {
EventOffset
event.LogEvent
error
}
wg sync.WaitGroup
}
func (s *asyncLogEventScanCloser) asyncScanAndClose(ctx context.Context) {
defer func() {
close(s.ch)
if closer, ok := s.s.(io.Closer); ok {
_ = closer.Close()
}
}()
for {
select {
case <-ctx.Done():
s.ch <- struct {
EventOffset
event.LogEvent
error
}{EventOffset{}, nil, ctx.Err()}
return
default:
}
if atomic.LoadUint32(&s.close) > 0 {
s.ch <- struct {
EventOffset
event.LogEvent
error
}{EventOffset{}, nil, errors.New("scanner closed")}
return
}
off, ev, err := s.s.Next()
t := struct {
EventOffset
event.LogEvent
error
}{off, ev, err}
s.ch <- t
if err != nil {
return
}
}
}
func (s *asyncLogEventScanCloser) start(ctx context.Context) {
s.wg.Add(1)
go func() {
defer s.wg.Done()
s.asyncScanAndClose(ctx)
}()
}
func (s *asyncLogEventScanCloser) Next() (EventOffset, event.LogEvent, error) {
t := <-s.ch
return t.EventOffset, t.LogEvent, t.error
}
func (s *asyncLogEventScanCloser) Close() error {
atomic.StoreUint32(&s.close, 1)
s.wg.Wait()
return nil
}
func NewAsyncLogEventScanCloser(ctx context.Context, s LogEventScanner, bufSize int) LogEventScanCloser {
as := &asyncLogEventScanCloser{
s: s,
ch: make(chan struct {
EventOffset
event.LogEvent
error
}, bufSize),
}
as.start(ctx)
return as
}