milvus/internal/storage/binlog_reader.go
smellthemoon 2a1356985d
enhance: support null in go payload (#32296)
#31728

---------

Signed-off-by: lixinguo <xinguo.li@zilliz.com>
Co-authored-by: lixinguo <xinguo.li@zilliz.com>
2024-06-19 17:08:00 +08:00

130 lines
3.5 KiB
Go

// Licensed to the LF AI & Data foundation under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you 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 storage
import (
"bytes"
"encoding/binary"
"fmt"
"io"
"github.com/cockroachdb/errors"
"github.com/milvus-io/milvus/pkg/common"
)
// BinlogReader is an object to read binlog file. Binlog file's format can be
// found in design docs.
type BinlogReader struct {
magicNumber int32
descriptorEvent
buffer *bytes.Buffer
eventReader *EventReader
isClose bool
}
// NextEventReader iters all events reader to read the binlog file.
func (reader *BinlogReader) NextEventReader() (*EventReader, error) {
if reader.isClose {
return nil, errors.New("bin log reader is closed")
}
if reader.buffer.Len() <= 0 {
return nil, nil
}
// close the previous reader
if reader.eventReader != nil {
reader.eventReader.Close()
}
var err error
reader.eventReader, err = newEventReader(reader.descriptorEvent.PayloadDataType, reader.buffer, reader.descriptorEvent.Nullable)
if err != nil {
return nil, err
}
return reader.eventReader, nil
}
func (reader *BinlogReader) readMagicNumber() (int32, error) {
var err error
reader.magicNumber, err = readMagicNumber(reader.buffer)
return reader.magicNumber, err
}
func (reader *BinlogReader) readDescriptorEvent() (*descriptorEvent, error) {
event, err := ReadDescriptorEvent(reader.buffer)
if err != nil {
return nil, err
}
reader.descriptorEvent = *event
return &reader.descriptorEvent, nil
}
func readMagicNumber(buffer io.Reader) (int32, error) {
var magicNumber int32
if err := binary.Read(buffer, common.Endian, &magicNumber); err != nil {
return -1, err
}
if magicNumber != MagicNumber {
return -1, fmt.Errorf("parse magic number failed, expected: %d, actual: %d", MagicNumber, magicNumber)
}
return magicNumber, nil
}
// ReadDescriptorEvent reads a descriptorEvent from buffer
func ReadDescriptorEvent(buffer io.Reader) (*descriptorEvent, error) {
header, err := readDescriptorEventHeader(buffer)
if err != nil {
return nil, err
}
data, err := readDescriptorEventData(buffer)
if err != nil {
return nil, err
}
return &descriptorEvent{
descriptorEventHeader: *header,
descriptorEventData: *data,
}, nil
}
// Close closes the BinlogReader object.
// It mainly calls the Close method of the internal events, reclaims resources, and marks itself as closed.
func (reader *BinlogReader) Close() {
if reader.isClose {
return
}
if reader.eventReader != nil {
reader.eventReader.Close()
}
reader.isClose = true
}
// NewBinlogReader creates binlogReader to read binlog file.
func NewBinlogReader(data []byte) (*BinlogReader, error) {
reader := &BinlogReader{
buffer: bytes.NewBuffer(data),
isClose: false,
}
if _, err := reader.readMagicNumber(); err != nil {
return nil, err
}
if _, err := reader.readDescriptorEvent(); err != nil {
return nil, err
}
return reader, nil
}