Give RowsEvent a method to inspect the underlying event type. (#1016)

* Give `RowsEvent` methods to inspect the underlying event type.

It's currently impossible to figure out what kind of operation led to a
`RowsEvent`; multiple results indicate an `UPDATE`, but there's no way to
differentiate an `INSERT` from a `DELETE`.

* Rework individual methods for `INSERT`/`UPDATE`/`DELETE` into a single public RowsEvent type.

* Nit: clarify difference between private an public `RowsEvent` types.

* List event type information on dumps for `RowsEvent`.

* Verify `RowsEvent` type handling within `TransactionPayloadEvent` decoded event tests.

Author: proton-lisandro-pin

replication/row_event.go

@@ -905,6 +905,7 @@ type RowsEvent struct {
 	// for mariadb *_COMPRESSED_EVENT_V1
 	compressed bool
 
+	// raw event type associated with a RowsEvent
 	eventType EventType
 
 	Table *TableMapEvent
@@ -950,6 +951,29 @@ type RowsEvent struct {
 	ignoreJSONDecodeErr     bool
 }
 
+// EnumRowsEventType is an abridged type describing the operation which triggered the given RowsEvent.
+type EnumRowsEventType byte
+
+const (
+	EnumRowsEventTypeUnknown = EnumRowsEventType(iota)
+	EnumRowsEventTypeInsert
+	EnumRowsEventTypeUpdate
+	EnumRowsEventTypeDelete
+)
+
+func (t EnumRowsEventType) String() string {
+	switch t {
+	case EnumRowsEventTypeInsert:
+		return "insert"
+	case EnumRowsEventTypeUpdate:
+		return "update"
+	case EnumRowsEventTypeDelete:
+		return "delete"
+	default:
+		return fmt.Sprintf("unknown (%d)", t)
+	}
+}
+
 // EnumRowImageType is allowed types for every row in mysql binlog.
 // See https://github.com/mysql/mysql-server/blob/1bfe02bdad6604d54913c62614bde57a055c8332/sql/rpl_record.h#L39
 // enum class enum_row_image_type { WRITE_AI, UPDATE_BI, UPDATE_AI, DELETE_BI };
@@ -1120,6 +1144,19 @@ func (e *RowsEvent) Decode(data []byte) error {
 	return e.DecodeData(pos, data)
 }
 
+func (e *RowsEvent) Type() EnumRowsEventType {
+	switch e.eventType {
+	case WRITE_ROWS_EVENTv0, WRITE_ROWS_EVENTv1, WRITE_ROWS_EVENTv2, MARIADB_WRITE_ROWS_COMPRESSED_EVENT_V1:
+		return EnumRowsEventTypeInsert
+	case UPDATE_ROWS_EVENTv0, UPDATE_ROWS_EVENTv1, UPDATE_ROWS_EVENTv2, MARIADB_UPDATE_ROWS_COMPRESSED_EVENT_V1:
+		return EnumRowsEventTypeUpdate
+	case DELETE_ROWS_EVENTv0, DELETE_ROWS_EVENTv1, DELETE_ROWS_EVENTv2, MARIADB_DELETE_ROWS_COMPRESSED_EVENT_V1:
+		return EnumRowsEventTypeDelete
+	default:
+		return EnumRowsEventTypeUnknown
+	}
+}
+
 func isBitSet(bitmap []byte, i int) bool {
 	return bitmap[i>>3]&(1<<(uint(i)&7)) > 0
 }
@@ -1817,6 +1854,7 @@ func (e *RowsEvent) Dump(w io.Writer) {
 	fmt.Fprintf(w, "Flags: %d\n", e.Flags)
 	fmt.Fprintf(w, "Column count: %d\n", e.ColumnCount)
 	fmt.Fprintf(w, "NDB data: %s\n", e.NdbData)
+	fmt.Fprintf(w, "Event type: %s (%s)", e.Type(), e.eventType)
 
 	fmt.Fprintf(w, "Values:\n")
 	for _, rows := range e.Rows {

replication/row_event_test.go

@@ -1176,6 +1176,37 @@ func TestRowsDataExtraData(t *testing.T) {
 	}
 }
 
+func TestRowsEventType(t *testing.T) {
+	testcases := []struct {
+		eventType EventType
+		want      EnumRowsEventType
+	}{
+		{WRITE_ROWS_EVENTv0, EnumRowsEventTypeInsert},
+		{WRITE_ROWS_EVENTv1, EnumRowsEventTypeInsert},
+		{WRITE_ROWS_EVENTv2, EnumRowsEventTypeInsert},
+		{MARIADB_WRITE_ROWS_COMPRESSED_EVENT_V1, EnumRowsEventTypeInsert},
+		{UPDATE_ROWS_EVENTv0, EnumRowsEventTypeUpdate},
+		{UPDATE_ROWS_EVENTv1, EnumRowsEventTypeUpdate},
+		{UPDATE_ROWS_EVENTv2, EnumRowsEventTypeUpdate},
+		{MARIADB_UPDATE_ROWS_COMPRESSED_EVENT_V1, EnumRowsEventTypeUpdate},
+		{DELETE_ROWS_EVENTv0, EnumRowsEventTypeDelete},
+		{DELETE_ROWS_EVENTv1, EnumRowsEventTypeDelete},
+		{DELETE_ROWS_EVENTv2, EnumRowsEventTypeDelete},
+		{MARIADB_DELETE_ROWS_COMPRESSED_EVENT_V1, EnumRowsEventTypeDelete},
+
+		// Whoops, these are not rows events at all
+		{EXEC_LOAD_EVENT, EnumRowsEventTypeUnknown},
+		{HEARTBEAT_EVENT, EnumRowsEventTypeUnknown},
+	}
+
+	for _, tc := range testcases {
+		rev := new(RowsEvent)
+		rev.eventType = tc.eventType
+
+		require.Equal(t, tc.want, rev.Type())
+	}
+}
+
 func TestTableMapHelperMaps(t *testing.T) {
 	/*
 		CREATE TABLE `_types` (

replication/transaction_payload_event_test.go

@@ -69,6 +69,8 @@ func TestTransactionPayloadEventDecode(t *testing.T) {
 	}
 	err := e.decodePayload()
 	require.NoError(t, err)
+
+	// Check raw events
 	require.Len(t, e.Events, 8)
 	require.Equal(t, QUERY_EVENT, e.Events[0].Header.EventType)
 	require.Equal(t, TABLE_MAP_EVENT, e.Events[1].Header.EventType)
@@ -78,4 +80,17 @@ func TestTransactionPayloadEventDecode(t *testing.T) {
 	require.Equal(t, TABLE_MAP_EVENT, e.Events[5].Header.EventType)
 	require.Equal(t, DELETE_ROWS_EVENTv2, e.Events[6].Header.EventType)
 	require.Equal(t, XID_EVENT, e.Events[7].Header.EventType)
+
+	// Check insert/update/delete rows events casting
+	ievent, ok := e.Events[2].Event.(*RowsEvent)
+	require.True(t, ok)
+	require.Equal(t, ievent.Type(), EnumRowsEventTypeInsert)
+
+	uevent, ok := e.Events[4].Event.(*RowsEvent)
+	require.True(t, ok)
+	require.Equal(t, uevent.Type(), EnumRowsEventTypeUpdate)
+
+	devent, ok := e.Events[6].Event.(*RowsEvent)
+	require.True(t, ok)
+	require.Equal(t, devent.Type(), EnumRowsEventTypeDelete)
 }