93 lines
2.3 KiB
Go
93 lines
2.3 KiB
Go
package parser
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import (
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"errors"
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"github.com/localhots/pretty"
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)
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var (
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// ErrInvalidHeader is returned when event header cannot be parsed.
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ErrInvalidHeader = errors.New("Header is invalid")
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)
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// EventHeader represents binlog event header.
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type EventHeader struct {
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Timestamp uint32
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Type EventType
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ServerID uint32
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EventLen uint32
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NextOffset uint32
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Flags uint16
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ExtraHeaders []byte
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eventBody []byte
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}
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// Spec: https://dev.mysql.com/doc/internals/en/event-header-fields.html
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func (r *Reader) parseHeader(data []byte) (*EventHeader, error) {
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headerLen := r.headerLen()
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if len(data) < headerLen {
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return nil, ErrInvalidHeader
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}
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// pretty.Println(headerLen, data)
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buf := newReadBuffer(data)
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h := &EventHeader{
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Timestamp: buf.readUint32(),
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Type: EventType(buf.readUint8()),
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ServerID: buf.readUint32(),
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EventLen: buf.readUint32(),
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}
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if r.format.Version == 0 || r.format.Version >= 3 {
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h.NextOffset = buf.readUint32()
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h.Flags = buf.readUint16()
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}
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if r.format.Version >= 4 {
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h.ExtraHeaders = buf.readStringVarLen(headerLen - 19)
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}
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h.eventBody = buf.cur()
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if h.NextOffset > 0 {
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r.state.Offset = uint64(h.NextOffset)
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}
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csa := r.format.ServerDetails.ChecksumAlgorithm
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if h.Type != FormatDescriptionEvent && csa == ChecksumAlgorithmCRC32 {
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h.eventBody = h.eventBody[:len(h.eventBody)-4]
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}
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// pretty.Println(h)
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switch h.Type {
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case FormatDescriptionEvent:
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r.format = decodeFormatDescription(h.eventBody)
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pretty.Println(h.Type.String(), r.format)
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case RotateEvent:
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r.state = r.decodeRotateEvent(h.eventBody)
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pretty.Println(h.Type.String(), r.state)
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case TableMapEvent:
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tm := r.decodeTableMap(h.eventBody)
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r.tableMap[tm.TableID] = tm
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// pretty.Println(h.Type.String(), tm)
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case WriteRowsEventV0, WriteRowsEventV1, WriteRowsEventV2,
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UpdateRowsEventV0, UpdateRowsEventV1, UpdateRowsEventV2,
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DeleteRowsEventV0, DeleteRowsEventV1, DeleteRowsEventV2:
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r.decodeRowsEvent(h.eventBody, h.Type)
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case XIDEvent, GTIDEvent:
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// TODO: Add support for these too
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case QueryEvent:
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// TODO: Handle schema changes
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}
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return h, nil
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}
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func (r *Reader) headerLen() int {
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const defaultHeaderLength = 19
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if r.format.EventHeaderLength > 0 {
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return int(r.format.EventHeaderLength)
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}
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return defaultHeaderLength
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}
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