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96 lines
1.9 KiB
Go

package replication
import (
"context"
"io"
"os"
"path"
"time"
"github.com/pingcap/errors"
. "github.com/starainrt/go-mysql/mysql"
)
// StartBackup: Like mysqlbinlog remote raw backup
// Backup remote binlog from position (filename, offset) and write in backupDir
func (b *BinlogSyncer) StartBackup(backupDir string, p Position, timeout time.Duration) error {
if timeout == 0 {
// a very long timeout here
timeout = 30 * 3600 * 24 * time.Second
}
// Force use raw mode
b.parser.SetRawMode(true)
if err := os.MkdirAll(backupDir, 0755); err != nil {
return errors.Trace(err)
}
s, err := b.StartSync(p)
if err != nil {
return errors.Trace(err)
}
var filename string
var offset uint32
var f *os.File
defer func() {
if f != nil {
f.Close()
}
}()
for {
ctx, cancel := context.WithTimeout(context.Background(), timeout)
e, err := s.GetEvent(ctx)
cancel()
if err == context.DeadlineExceeded {
return nil
}
if err != nil {
return errors.Trace(err)
}
offset = e.Header.LogPos
if e.Header.EventType == ROTATE_EVENT {
rotateEvent := e.Event.(*RotateEvent)
filename = string(rotateEvent.NextLogName)
if e.Header.Timestamp == 0 || offset == 0 {
// fake rotate event
continue
}
} else if e.Header.EventType == FORMAT_DESCRIPTION_EVENT {
// FormateDescriptionEvent is the first event in binlog, we will close old one and create a new
if f != nil {
f.Close()
}
if len(filename) == 0 {
return errors.Errorf("empty binlog filename for FormateDescriptionEvent")
}
f, err = os.OpenFile(path.Join(backupDir, filename), os.O_CREATE|os.O_WRONLY, 0644)
if err != nil {
return errors.Trace(err)
}
// write binlog header fe'bin'
if _, err = f.Write(BinLogFileHeader); err != nil {
return errors.Trace(err)
}
}
if n, err := f.Write(e.RawData); err != nil {
return errors.Trace(err)
} else if n != len(e.RawData) {
return errors.Trace(io.ErrShortWrite)
}
}
}