grpc(go)请求解析 handleRawConn 源码阅读
grpc-go 请求解析 handleRawConn 源码阅读
- grpc(go)请求解析 handleRawConn 源码阅读
- 方法
- newHTTP2Transport
- serveStreams
grpc(go)请求解析 handleRawConn 源码阅读
方法
先将代码贴上
// 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)
}()
}
这里主要做了三件事：
（1）校验请求（如果前面有设置证书）和设置过期时间等一些参数
（2）将http2请求解析，获取到一个transport.ServerTransport
（3）通过ServerTransport将请求做一些处理
我们不管（1），从（2）里面看看做了什么处理
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
}
在grpc启动前，我们会生成一个server，配置了一系列的options，这里将取出部分，用于设置http2的config，如readBufferSize（默认4m），然后通过NewServerTransport获取serverTransport返回。
// 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.
//将初始设置作为连接前言发送到客户端
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
}
其实这段代码基本是遵循http2的协议的执行过程。可以参考下面的http2协议规范
http2协议规范
serveStreams
serveStreams的代码如下
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()
}
HandleStreams主要获取不同的帧，做了不同的处理
// 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)
}
}
}
再回来看一下s.handleStream(st, stream, s.traceInfo(st, stream)),这个是比较重要的
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()
}
}
其中
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
}
}
通过服务名和方法名完成了服务的调用