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110 lines
2.6 KiB
Go

package binlog
import (
"encoding/binary"
"fmt"
"io"
"os"
)
func innerDumpBinlogFromPos(srcFilePath string, startPos uint, dumpEmptyBinlog bool, targetFilePath string) error {
tracef("dump binlog from pos : srcFilePath=%v, startPos=%v, targetFilePath=%v", srcFilePath, startPos, targetFilePath)
srcFile, err := os.Open(srcFilePath)
if nil != err {
return err
}
defer srcFile.Close()
stat, err := srcFile.Stat()
if nil != err {
return err
}
srcFileSize := uint(stat.Size())
if dumpEmptyBinlog {
startPos = srcFileSize
}
if startPos > srcFileSize {
return fmt.Errorf("startPos (%v) >= binlog file size (%v)", startPos, srcFileSize)
}
emptyFile := startPos == srcFileSize
headerBs := make([]byte, 19)
headerEndPos := uint(4)
for {
if _, err := srcFile.Seek(int64(headerEndPos), 0); nil != err {
if "EOF" == err.Error() {
break
}
return err
}
if _, err := io.ReadFull(srcFile, headerBs); nil != err {
if "EOF" == err.Error() {
break
}
return err
}
eventType := int(headerBs[4])
length := binary.LittleEndian.Uint32(headerBs[9:13])
if FORMAT_DESCRIPTION_EVENT != eventType && ROTATE_EVENT != eventType && PREVIOUS_GTIDS_LOG_EVENT != eventType {
break
}
headerEndPos += uint(length)
}
if headerEndPos >= srcFileSize {
emptyFile = true
} else if startPos < headerEndPos {
return fmt.Errorf("dump binlog from startPos (%v) failed, pos < headerEndPos (%v) ", startPos, headerEndPos)
}
if target, err := os.Create(targetFilePath); nil != err {
return err
} else {
defer target.Close()
if _, err := srcFile.Seek(0, 0); nil != err {
os.Remove(targetFilePath)
return err
}
if _, err := io.CopyN(target, srcFile, int64(headerEndPos)); nil != err {
os.Remove(targetFilePath)
return err
}
if !emptyFile {
if _, err := srcFile.Seek(int64(startPos), 0); nil != err {
os.Remove(targetFilePath)
return err
}
if _, err := io.Copy(target, srcFile); nil != err {
os.Remove(targetFilePath)
return err
}
}
}
return nil
}
func DumpBinlogFromPos(srcFilePath string, startPos uint, targetFilePath string) error {
return innerDumpBinlogFromPos(srcFilePath, startPos, false, targetFilePath)
}
func DumpUnexecutedBinlogByGtid(srcFilePath string, executedGtidDesc string, targetFilePath string, includeEventBeforeFirst bool) error {
pos, err := GetUnexecutedBinlogPosByGtid(srcFilePath, executedGtidDesc, includeEventBeforeFirst)
if nil != err {
if "EOF" == err.Error() {
return innerDumpBinlogFromPos(srcFilePath, 0, true, targetFilePath)
} else {
return err
}
}
return innerDumpBinlogFromPos(srcFilePath, pos, false, targetFilePath)
}