/
ao_increment.go
157 lines (127 loc) · 3.93 KB
/
ao_increment.go
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package greenplum
import (
"bytes"
"fmt"
"io"
"os"
"github.com/apecloud/dataprotection-wal-g/internal/ioextensions"
"github.com/apecloud/dataprotection-wal-g/internal/limiters"
"github.com/apecloud/dataprotection-wal-g/internal/walparser/parsingutil"
"github.com/apecloud/dataprotection-wal-g/utility"
"github.com/pkg/errors"
"github.com/wal-g/tracelog"
)
const SignatureMagicNumber byte = 0x56
const sizeofInt32 = 4
type UnexpectedTarDataError struct {
error
}
func newUnexpectedTarDataError() UnexpectedTarDataError {
return UnexpectedTarDataError{errors.New("Expected end of Tar")}
}
func (err UnexpectedTarDataError) Error() string {
return fmt.Sprintf(tracelog.GetErrorFormatter(), err.error)
}
// IncrementFileHeader contains "wi" at the head which stands for "wal-g increment"
// format version "1", signature magic number
var IncrementFileHeader = []byte{'w', 'i', '1', SignatureMagicNumber}
type UnknownIncrementFileHeaderError struct {
error
}
func newUnknownIncrementFileHeaderError() UnknownIncrementFileHeaderError {
return UnknownIncrementFileHeaderError{errors.New("Unknown increment file header")}
}
func (err UnknownIncrementFileHeaderError) Error() string {
return fmt.Sprintf(tracelog.GetErrorFormatter(), err.error)
}
type InvalidIncrementFileHeaderError struct {
error
}
func newInvalidIncrementFileHeaderError(header []byte) InvalidIncrementFileHeaderError {
return InvalidIncrementFileHeaderError{fmt.Errorf("invalid increment file header: %v", header)}
}
func (err InvalidIncrementFileHeaderError) Error() string {
return fmt.Sprintf(tracelog.GetErrorFormatter(), err.error)
}
func ReadIncrementFileHeader(reader io.Reader) error {
header := make([]byte, sizeofInt32)
_, err := io.ReadFull(reader, header)
if err != nil {
return err
}
for i := range []int{0, 1, 3} {
if header[i] != IncrementFileHeader[i] {
return newInvalidIncrementFileHeaderError(header)
}
}
if header[2] != IncrementFileHeader[2] {
return newUnknownIncrementFileHeaderError()
}
return nil
}
func ApplyFileIncrement(fileName string, increment io.Reader, fsync bool) error {
tracelog.DebugLogger.Printf("Incrementing AO/AOCS segment %s\n", fileName)
err := ReadIncrementFileHeader(increment)
if err != nil {
return err
}
var eof uint64
var offset uint64
err = parsingutil.ParseMultipleFieldsFromReader([]parsingutil.FieldToParse{
{Field: &eof, Name: "eof"},
{Field: &offset, Name: "offset"},
}, increment)
if err != nil {
return err
}
if eof <= offset {
return fmt.Errorf("%s: parsed eof %d is smaller than offset %d", fileName, eof, offset)
}
openFlags := os.O_RDWR
file, err := os.OpenFile(fileName, openFlags, 0666)
if err != nil {
if os.IsNotExist(err) {
return errors.Wrap(err, "incremented file should always exist")
}
return errors.Wrap(err, "can't open file to increment")
}
defer utility.LoggedClose(file, "")
defer utility.LoggedSync(file, "", fsync)
err = file.Truncate(int64(eof))
if err != nil {
return err
}
_, err = file.Seek(int64(offset), io.SeekStart)
if err != nil {
return err
}
_, err = io.CopyN(file, increment, int64(eof-offset))
if err != nil {
return err
}
all, _ := increment.Read(make([]byte, 1))
if all > 0 {
return newUnexpectedTarDataError()
}
return nil
}
func NewIncrementalPageReader(file io.ReadSeekCloser, eof, offset int64) (io.ReadCloser, error) {
if eof <= offset {
return nil, fmt.Errorf("file eof %d is less or equal than offset %d", eof, offset)
}
var headerBuffer bytes.Buffer
headerBuffer.Write(IncrementFileHeader)
headerBuffer.Write(utility.ToBytes(uint64(eof)))
headerBuffer.Write(utility.ToBytes(uint64(offset)))
if _, err := file.Seek(offset, io.SeekStart); err != nil {
utility.LoggedClose(file, "")
return nil, err
}
return &ioextensions.ReadCascadeCloser{
Reader: &io.LimitedReader{
R: io.MultiReader(&headerBuffer, limiters.NewDiskLimitReader(file)),
N: int64(headerBuffer.Len()) + eof - offset,
},
Closer: file,
}, nil
}