grpc-go 요청handleRawConn 원본 읽기

grpc(go)handleRawConn 원본 읽기 요청

방법

newHTTP2Transport

serveStreams

grpc(go) 요청 해석handleRawConn 원본 읽기

메서드

코드를 먼저 붙여주세요.

// handleRawConn forks a goroutine to handle a just-accepted connection that
// has not had any I/O performed on it yet.
func (s *Server) handleRawConn(rawConn net.Conn) {
	if s.quit.HasFired() {
		rawConn.Close()
		return
	}
	rawConn.SetDeadline(time.Now().Add(s.opts.connectionTimeout))
	conn, authInfo, err := s.useTransportAuthenticator(rawConn)
	if err != nil {
		// ErrConnDispatched means that the connection was dispatched away from
		// gRPC; those connections should be left open.
		if err != credentials.ErrConnDispatched {
			s.mu.Lock()
			s.errorf("ServerHandshake(%q) failed: %v", rawConn.RemoteAddr(), err)
			s.mu.Unlock()
			channelz.Warningf(s.channelzID, "grpc: Server.Serve failed to complete security handshake from %q: %v", rawConn.RemoteAddr(), err)
			rawConn.Close()
		}
		rawConn.SetDeadline(time.Time{})
		return
	}

	// Finish handshaking (HTTP2)
	st := s.newHTTP2Transport(conn, authInfo)
	if st == nil {
		return
	}

	rawConn.SetDeadline(time.Time{})
	if !s.addConn(st) {
		return
	}
	go func() {
		s.serveStreams(st)
		s.removeConn(st)
	}()
}

여기는 주로 세 가지 일을 했다. (1) 검사 요청(앞에 인증서가 설치되어 있다면)과 만료 시간 설정 등 일부 매개 변수(2)http2 요청을 분석하여 하나의transport를 얻는다.ServerTransport(3) ServerTransport를 통해 요청 처리
우리 는 상관하지 않고, 안 에서 무슨 처리 를 했는지 보았다

newHTTP2Transport

// newHTTP2Transport sets up a http/2 transport (using the
// gRPC http2 server transport in transport/http2_server.go).
func (s *Server) newHTTP2Transport(c net.Conn, authInfo credentials.AuthInfo) transport.ServerTransport {
	config := &transport.ServerConfig{
		MaxStreams:            s.opts.maxConcurrentStreams,
		AuthInfo:              authInfo,
		InTapHandle:           s.opts.inTapHandle,
		StatsHandler:          s.opts.statsHandler,
		KeepaliveParams:       s.opts.keepaliveParams,
		KeepalivePolicy:       s.opts.keepalivePolicy,
		InitialWindowSize:     s.opts.initialWindowSize,
		InitialConnWindowSize: s.opts.initialConnWindowSize,
		WriteBufferSize:       s.opts.writeBufferSize,
		ReadBufferSize:        s.opts.readBufferSize,
		ChannelzParentID:      s.channelzID,
		MaxHeaderListSize:     s.opts.maxHeaderListSize,
		HeaderTableSize:       s.opts.headerTableSize,
	}
	st, err := transport.NewServerTransport("http2", c, config)
	if err != nil {
		s.mu.Lock()
		s.errorf("NewServerTransport(%q) failed: %v", c.RemoteAddr(), err)
		s.mu.Unlock()
		c.Close()
		channelz.Warning(s.channelzID, "grpc: Server.Serve failed to create ServerTransport: ", err)
		return nil
	}

	return st
}

grpc가 시작되기 전에, 우리는 서버를 생성하여 일련의 옵션을 설정합니다. http2의 config, 예를 들어readBufferSize (기본 4m) 를 설정하고, New ServerTransport를 통해 서버Transport를 가져오는 데 사용할 부분을 꺼냅니다.

// NewServerTransport creates a ServerTransport with conn or non-nil error
// if it fails.
func NewServerTransport(protocol string, conn net.Conn, config *ServerConfig) (ServerTransport, error) {
	return newHTTP2Server(conn, config)
}

// newHTTP2Server constructs a ServerTransport based on HTTP2. ConnectionError is
// returned if something goes wrong.
func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err error) {
	writeBufSize := config.WriteBufferSize
	readBufSize := config.ReadBufferSize
	maxHeaderListSize := defaultServerMaxHeaderListSize
	if config.MaxHeaderListSize != nil {
		maxHeaderListSize = *config.MaxHeaderListSize
	}
	framer := newFramer(conn, writeBufSize, readBufSize, maxHeaderListSize)
	// Send initial settings as connection preface to client.
	//                 
	isettings := []http2.Setting{{
		ID:  http2.SettingMaxFrameSize,
		Val: http2MaxFrameLen,
	}}
	// TODO(zhaoq): Have a better way to signal "no limit" because 0 is
	// permitted in the HTTP2 spec.
	maxStreams := config.MaxStreams
	if maxStreams == 0 {
		maxStreams = math.MaxUint32
	} else {
		isettings = append(isettings, http2.Setting{
			ID:  http2.SettingMaxConcurrentStreams,
			Val: maxStreams,
		})
	}
	dynamicWindow := true
	iwz := int32(initialWindowSize)
	if config.InitialWindowSize >= defaultWindowSize {
		iwz = config.InitialWindowSize
		dynamicWindow = false
	}
	icwz := int32(initialWindowSize)
	if config.InitialConnWindowSize >= defaultWindowSize {
		icwz = config.InitialConnWindowSize
		dynamicWindow = false
	}
	if iwz != defaultWindowSize {
		isettings = append(isettings, http2.Setting{
			ID:  http2.SettingInitialWindowSize,
			Val: uint32(iwz)})
	}
	if config.MaxHeaderListSize != nil {
		isettings = append(isettings, http2.Setting{
			ID:  http2.SettingMaxHeaderListSize,
			Val: *config.MaxHeaderListSize,
		})
	}
	if config.HeaderTableSize != nil {
		isettings = append(isettings, http2.Setting{
			ID:  http2.SettingHeaderTableSize,
			Val: *config.HeaderTableSize,
		})
	}
	if err := framer.fr.WriteSettings(isettings...); err != nil {
		return nil, connectionErrorf(false, err, "transport: %v", err)
	}
	// Adjust the connection flow control window if needed.
	if delta := uint32(icwz - defaultWindowSize); delta > 0 {
		if err := framer.fr.WriteWindowUpdate(0, delta); err != nil {
			return nil, connectionErrorf(false, err, "transport: %v", err)
		}
	}
	kp := config.KeepaliveParams
	if kp.MaxConnectionIdle == 0 {
		kp.MaxConnectionIdle = defaultMaxConnectionIdle
	}
	if kp.MaxConnectionAge == 0 {
		kp.MaxConnectionAge = defaultMaxConnectionAge
	}
	// Add a jitter to MaxConnectionAge.
	kp.MaxConnectionAge += getJitter(kp.MaxConnectionAge)
	if kp.MaxConnectionAgeGrace == 0 {
		kp.MaxConnectionAgeGrace = defaultMaxConnectionAgeGrace
	}
	if kp.Time == 0 {
		kp.Time = defaultServerKeepaliveTime
	}
	if kp.Timeout == 0 {
		kp.Timeout = defaultServerKeepaliveTimeout
	}
	kep := config.KeepalivePolicy
	if kep.MinTime == 0 {
		kep.MinTime = defaultKeepalivePolicyMinTime
	}
	done := make(chan struct{})
	t := &http2Server{
		ctx:               context.Background(),
		done:              done,
		conn:              conn,
		remoteAddr:        conn.RemoteAddr(),
		localAddr:         conn.LocalAddr(),
		authInfo:          config.AuthInfo,
		framer:            framer,
		readerDone:        make(chan struct{}),
		writerDone:        make(chan struct{}),
		maxStreams:        maxStreams,
		inTapHandle:       config.InTapHandle,
		fc:                &trInFlow{limit: uint32(icwz)},
		state:             reachable,
		activeStreams:     make(map[uint32]*Stream),
		stats:             config.StatsHandler,
		kp:                kp,
		idle:              time.Now(),
		kep:               kep,
		initialWindowSize: iwz,
		czData:            new(channelzData),
		bufferPool:        newBufferPool(),
	}
	t.controlBuf = newControlBuffer(t.done)
	if dynamicWindow {
		t.bdpEst = &bdpEstimator{
			bdp:               initialWindowSize,
			updateFlowControl: t.updateFlowControl,
		}
	}
	if t.stats != nil {
		t.ctx = t.stats.TagConn(t.ctx, &stats.ConnTagInfo{
			RemoteAddr: t.remoteAddr,
			LocalAddr:  t.localAddr,
		})
		connBegin := &stats.ConnBegin{}
		t.stats.HandleConn(t.ctx, connBegin)
	}
	if channelz.IsOn() {
		t.channelzID = channelz.RegisterNormalSocket(t, config.ChannelzParentID, fmt.Sprintf("%s -> %s", t.remoteAddr, t.localAddr))
	}

	t.connectionID = atomic.AddUint64(&serverConnectionCounter, 1)

	t.framer.writer.Flush()

	defer func() {
		if err != nil {
			t.Close()
		}
	}()

	// Check the validity of client preface.
	preface := make([]byte, len(clientPreface))
	if _, err := io.ReadFull(t.conn, preface); err != nil {
		return nil, connectionErrorf(false, err, "transport: http2Server.HandleStreams failed to receive the preface from client: %v", err)
	}
	if !bytes.Equal(preface, clientPreface) {
		return nil, connectionErrorf(false, nil, "transport: http2Server.HandleStreams received bogus greeting from client: %q", preface)
	}

	frame, err := t.framer.fr.ReadFrame()
	if err == io.EOF || err == io.ErrUnexpectedEOF {
		return nil, err
	}
	if err != nil {
		return nil, connectionErrorf(false, err, "transport: http2Server.HandleStreams failed to read initial settings frame: %v", err)
	}
	atomic.StoreInt64(&t.lastRead, time.Now().UnixNano())
	sf, ok := frame.(*http2.SettingsFrame)
	if !ok {
		return nil, connectionErrorf(false, nil, "transport: http2Server.HandleStreams saw invalid preface type %T from client", frame)
	}
	t.handleSettings(sf)

	go func() {
		t.loopy = newLoopyWriter(serverSide, t.framer, t.controlBuf, t.bdpEst)
		t.loopy.ssGoAwayHandler = t.outgoingGoAwayHandler
		if err := t.loopy.run(); err != nil {
			errorf("transport: loopyWriter.run returning. Err: %v", err)
		}
		t.conn.Close()
		close(t.writerDone)
	}()
	go t.keepalive()
	return t, nil
}

사실 이 코드는 기본적으로http2 프로토콜의 실행 과정을 따른다.아래의 http2 프로토콜 규범을 참고할 수 있습니다 http2 프로토콜 규범

serveStreams

serveStreams 코드는 다음과 같습니다.

func (s *Server) serveStreams(st transport.ServerTransport) {
	defer st.Close()
	var wg sync.WaitGroup
	st.HandleStreams(func(stream *transport.Stream) {
		wg.Add(1)
		go func() {
			defer wg.Done()
			s.handleStream(st, stream, s.traceInfo(st, stream))
		}()
	}, func(ctx context.Context, method string) context.Context {
		if !EnableTracing {
			return ctx
		}
		tr := trace.New("grpc.Recv."+methodFamily(method), method)
		return trace.NewContext(ctx, tr)
	})
	wg.Wait()
}

HandleStreams는 주로 서로 다른 프레임을 가져와 처리합니다

// HandleStreams receives incoming streams using the given handler. This is
// typically run in a separate goroutine.
// traceCtx attaches trace to ctx and returns the new context.
func (t *http2Server) HandleStreams(handle func(*Stream), traceCtx func(context.Context, string) context.Context) {
	defer close(t.readerDone)
	for {
		t.controlBuf.throttle()
		frame, err := t.framer.fr.ReadFrame()
		atomic.StoreInt64(&t.lastRead, time.Now().UnixNano())
		if err != nil {
			if se, ok := err.(http2.StreamError); ok {
				warningf("transport: http2Server.HandleStreams encountered http2.StreamError: %v", se)
				t.mu.Lock()
				s := t.activeStreams[se.StreamID]
				t.mu.Unlock()
				if s != nil {
					t.closeStream(s, true, se.Code, false)
				} else {
					t.controlBuf.put(&cleanupStream{
						streamID: se.StreamID,
						rst:      true,
						rstCode:  se.Code,
						onWrite:  func() {},
					})
				}
				continue
			}
			if err == io.EOF || err == io.ErrUnexpectedEOF {
				t.Close()
				return
			}
			warningf("transport: http2Server.HandleStreams failed to read frame: %v", err)
			t.Close()
			return
		}
		switch frame := frame.(type) {
		case *http2.MetaHeadersFrame:
			if t.operateHeaders(frame, handle, traceCtx) {
				t.Close()
				break
			}
		case *http2.DataFrame:
			t.handleData(frame)
		case *http2.RSTStreamFrame:
			t.handleRSTStream(frame)
		case *http2.SettingsFrame:
			t.handleSettings(frame)
		case *http2.PingFrame:
			t.handlePing(frame)
		case *http2.WindowUpdateFrame:
			t.handleWindowUpdate(frame)
		case *http2.GoAwayFrame:
			// TODO: Handle GoAway from the client appropriately.
		default:
			errorf("transport: http2Server.HandleStreams found unhandled frame type %v.", frame)
		}
	}
}

다시 한 번 s.handle Stream(st,stream,s.trace Info(st,stream))를 살펴보자. 이것은 비교적 중요한 것이다.

func (s *Server) handleStream(t transport.ServerTransport, stream *transport.Stream, trInfo *traceInfo) {
	sm := stream.Method()
	if sm != "" && sm[0] == '/' {
		sm = sm[1:]
	}
	pos := strings.LastIndex(sm, "/")
	if pos == -1 {
		if trInfo != nil {
			trInfo.tr.LazyLog(&fmtStringer{"Malformed method name %q", []interface{}{sm}}, true)
			trInfo.tr.SetError()
		}
		errDesc := fmt.Sprintf("malformed method name: %q", stream.Method())
		if err := t.WriteStatus(stream, status.New(codes.ResourceExhausted, errDesc)); err != nil {
			if trInfo != nil {
				trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
				trInfo.tr.SetError()
			}
			channelz.Warningf(s.channelzID, "grpc: Server.handleStream failed to write status: %v", err)
		}
		if trInfo != nil {
			trInfo.tr.Finish()
		}
		return
	}
	service := sm[:pos]
	method := sm[pos+1:]

	srv, knownService := s.m[service]
	if knownService {
		if md, ok := srv.md[method]; ok {
			s.processUnaryRPC(t, stream, srv, md, trInfo)
			return
		}
		if sd, ok := srv.sd[method]; ok {
			s.processStreamingRPC(t, stream, srv, sd, trInfo)
			return
		}
	}
	// Unknown service, or known server unknown method.
	if unknownDesc := s.opts.unknownStreamDesc; unknownDesc != nil {
		s.processStreamingRPC(t, stream, nil, unknownDesc, trInfo)
		return
	}
	var errDesc string
	if !knownService {
		errDesc = fmt.Sprintf("unknown service %v", service)
	} else {
		errDesc = fmt.Sprintf("unknown method %v for service %v", method, service)
	}
	if trInfo != nil {
		trInfo.tr.LazyPrintf("%s", errDesc)
		trInfo.tr.SetError()
	}
	if err := t.WriteStatus(stream, status.New(codes.Unimplemented, errDesc)); err != nil {
		if trInfo != nil {
			trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
			trInfo.tr.SetError()
		}
		channelz.Warningf(s.channelzID, "grpc: Server.handleStream failed to write status: %v", err)
	}
	if trInfo != nil {
		trInfo.tr.Finish()
	}
}

그 중

if knownService {
		if md, ok := srv.md[method]; ok {
			s.processUnaryRPC(t, stream, srv, md, trInfo)
			return
		}
		if sd, ok := srv.sd[method]; ok {
			s.processStreamingRPC(t, stream, srv, sd, trInfo)
			return
		}
	}

서비스 이름과 방법명을 통해 서비스의 호출을 완성하였다