Golang ServiceContext.IsRunning方法代码示例

func (rci *RowcacheInvalidator) run(ctx *sync2.ServiceContext) error {
	for {
		evs := binlog.NewEventStreamer(rci.dbname, rci.mysqld, rci.Position(), rci.processEvent)
		// We wrap this code in a func so we can catch all panics.
		// If an error is returned, we log it, wait 1 second, and retry.
		// This loop can only be stopped by calling Close.
		err := func() (inner error) {
			defer func() {
				if x := recover(); x != nil {
					inner = fmt.Errorf("%v: uncaught panic:\n%s", x, tb.Stack(4))
				}
			}()
			return evs.Stream(ctx)
		}()
		if err == nil || !ctx.IsRunning() {
			break
		}
		if IsConnErr(err) {
			rci.checker.CheckMySQL()
		}
		log.Errorf("binlog.ServeUpdateStream returned err '%v', retrying in 1 second.", err.Error())
		rci.qe.queryServiceStats.InternalErrors.Add("Invalidation", 1)
		time.Sleep(1 * time.Second)
	}
	log.Infof("Rowcache invalidator stopped")
	return nil
}

// nextStatement returns the next statement encountered in the binlog stream. If there are
// positional comments, it updates the binlogFileStreamer state. It also ignores events that
// are not material. If it returns nil, it's the end of stream. If err is also nil, then
// it was due to a normal termination.
func (bls *binlogFileStreamer) nextStatement(ctx *sync2.ServiceContext, bufReader *bufio.Reader) (stmt []byte, err error) {
eventLoop:
	for {
		// Stop processing if we're shutting down
		if !ctx.IsRunning() {
			return nil, io.EOF
		}
		event, err := bls.readEvent(bufReader)
		if err != nil {
			if err == io.EOF {
				return nil, nil
			}
			return nil, err
		}
		values := posRE.FindSubmatch(event)
		if values != nil {
			bls.blPos.ServerId = mustParseInt64(values[1])
			bls.file.Set(mustParseInt64(values[2]))

			// Make the fake Google GTID format we invented.
			gtid := string(values[1]) + "-" + string(values[3])
			bls.blPos.GTID = myproto.MustParseGTID(blsMysqlFlavor, gtid)
			continue
		}
		values = rotateRE.FindSubmatch(event)
		if values != nil {
			err = bls.file.Rotate(path.Join(bls.dir, string(values[1])), mustParseInt64(values[2]))
			if err != nil {
				return nil, err
			}
			return nil, nil
		}
		if bytes.HasPrefix(event, eolfPrefix) {
			return nil, nil
		}
		values = delimRE.FindSubmatch(event)
		if values != nil {
			bls.delim = values[1]
			continue
		}
		for _, ignorePrefix := range ignorePrefixes {
			if bytes.HasPrefix(event, ignorePrefix) {
				continue eventLoop
			}
		}
		return event, nil
	}
}

func (f *fileInfo) WaitForChange(ctx *sync2.ServiceContext) error {
	for {
		// Stop waiting if we're shutting down
		if !ctx.IsRunning() {
			return io.EOF
		}
		time.Sleep(100 * time.Millisecond)
		fi, err := f.handle.Stat()
		if err != nil {
			return fmt.Errorf("stat error: %v", err)
		}
		if fi.Size() != f.lastPos {
			return nil
		}
	}
}

// parseEvents processes the raw binlog dump stream from the server, one event
// at a time, and groups them into transactions. It is called from within the
// service function launched by Stream().
//
// If the sendTransaction func returns io.EOF, parseEvents returns ErrClientEOF.
// If the events channel is closed, parseEvents returns ErrServerEOF.
func (bls *BinlogStreamer) parseEvents(ctx *sync2.ServiceContext, events <-chan proto.BinlogEvent) (myproto.ReplicationPosition, error) {
	var statements []proto.Statement
	var format proto.BinlogFormat
	var gtid myproto.GTID
	var pos = bls.startPos
	var autocommit = true
	var err error

	// A begin can be triggered either by a BEGIN query, or by a GTID_EVENT.
	begin := func() {
		if statements != nil {
			// If this happened, it would be a legitimate error.
			log.Errorf("BEGIN in binlog stream while still in another transaction; dropping %d statements: %v", len(statements), statements)
			binlogStreamerErrors.Add("ParseEvents", 1)
		}
		statements = make([]proto.Statement, 0, 10)
		autocommit = false
	}
	// A commit can be triggered either by a COMMIT query, or by an XID_EVENT.
	// Statements that aren't wrapped in BEGIN/COMMIT are committed immediately.
	commit := func(timestamp uint32) error {
		trans := &proto.BinlogTransaction{
			Statements:    statements,
			Timestamp:     int64(timestamp),
			TransactionID: myproto.EncodeGTID(gtid),
		}
		if err = bls.sendTransaction(trans); err != nil {
			if err == io.EOF {
				return ErrClientEOF
			}
			return fmt.Errorf("send reply error: %v", err)
		}
		statements = nil
		autocommit = true
		return nil
	}

	// Parse events.
	for ctx.IsRunning() {
		var ev proto.BinlogEvent
		var ok bool

		select {
		case ev, ok = <-events:
			if !ok {
				// events channel has been closed, which means the connection died.
				log.Infof("reached end of binlog event stream")
				return pos, ErrServerEOF
			}
		case <-ctx.ShuttingDown:
			log.Infof("stopping early due to BinlogStreamer service shutdown")
			return pos, nil
		}

		// Validate the buffer before reading fields from it.
		if !ev.IsValid() {
			return pos, fmt.Errorf("can't parse binlog event, invalid data: %#v", ev)
		}

		// We need to keep checking for FORMAT_DESCRIPTION_EVENT even after we've
		// seen one, because another one might come along (e.g. on log rotate due to
		// binlog settings change) that changes the format.
		if ev.IsFormatDescription() {
			format, err = ev.Format()
			if err != nil {
				return pos, fmt.Errorf("can't parse FORMAT_DESCRIPTION_EVENT: %v, event data: %#v", err, ev)
			}
			continue
		}

		// We can't parse anything until we get a FORMAT_DESCRIPTION_EVENT that
		// tells us the size of the event header.
		if format.IsZero() {
			// The only thing that should come before the FORMAT_DESCRIPTION_EVENT
			// is a fake ROTATE_EVENT, which the master sends to tell us the name
			// of the current log file.
			if ev.IsRotate() {
				continue
			}
			return pos, fmt.Errorf("got a real event before FORMAT_DESCRIPTION_EVENT: %#v", ev)
		}

		// Strip the checksum, if any. We don't actually verify the checksum, so discard it.
		ev, _, err = ev.StripChecksum(format)
		if err != nil {
			return pos, fmt.Errorf("can't strip checksum from binlog event: %v, event data: %#v", err, ev)
		}

		// Update the GTID if the event has one. The actual event type could be
		// something special like GTID_EVENT (MariaDB, MySQL 5.6), or it could be
		// an arbitrary event with a GTID in the header (Google MySQL).
		if ev.HasGTID(format) {
			gtid, err = ev.GTID(format)
			if err != nil {
//.........这里部分代码省略.........