Golang Context.Deadline方法代码示例

// NewClientStream creates a new Stream for the client side. This is called
// by generated code.
func NewClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (ClientStream, error) {
	var (
		t   transport.ClientTransport
		err error
	)
	t, err = cc.dopts.picker.Pick(ctx)
	if err != nil {
		return nil, toRPCErr(err)
	}
	// TODO(zhaoq): CallOption is omitted. Add support when it is needed.
	callHdr := &transport.CallHdr{
		Host:   cc.authority,
		Method: method,
	}
	cs := &clientStream{
		desc:    desc,
		codec:   cc.dopts.codec,
		tracing: EnableTracing,
	}
	if cs.tracing {
		cs.trInfo.tr = trace.New("grpc.Sent."+methodFamily(method), method)
		cs.trInfo.firstLine.client = true
		if deadline, ok := ctx.Deadline(); ok {
			cs.trInfo.firstLine.deadline = deadline.Sub(time.Now())
		}
		cs.trInfo.tr.LazyLog(&cs.trInfo.firstLine, false)
		ctx = trace.NewContext(ctx, cs.trInfo.tr)
	}
	s, err := t.NewStream(ctx, callHdr)
	if err != nil {
		return nil, toRPCErr(err)
	}
	cs.t = t
	cs.s = s
	cs.p = &parser{s: s}
	// Listen on ctx.Done() to detect cancellation when there is no pending
	// I/O operations on this stream.
	go func() {
		<-s.Context().Done()
		cs.closeTransportStream(transport.ContextErr(s.Context().Err()))
	}()
	return cs, nil
}

// Invoke is called by the generated code. It sends the RPC request on the
// wire and returns after response is received.
func Invoke(ctx context.Context, method string, args, reply interface{}, cc *ClientConn, opts ...CallOption) (err error) {
	var c callInfo
	for _, o := range opts {
		if err := o.before(&c); err != nil {
			return toRPCErr(err)
		}
	}
	defer func() {
		for _, o := range opts {
			o.after(&c)
		}
	}()
	if EnableTracing {
		c.traceInfo.tr = trace.New("grpc.Sent."+methodFamily(method), method)
		defer c.traceInfo.tr.Finish()
		c.traceInfo.firstLine.client = true
		if deadline, ok := ctx.Deadline(); ok {
			c.traceInfo.firstLine.deadline = deadline.Sub(time.Now())
		}
		c.traceInfo.tr.LazyLog(&c.traceInfo.firstLine, false)
		// TODO(dsymonds): Arrange for c.traceInfo.firstLine.remoteAddr to be set.
		defer func() {
			if err != nil {
				c.traceInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
				c.traceInfo.tr.SetError()
			}
		}()
	}
	topts := &transport.Options{
		Last:  true,
		Delay: false,
	}
	var (
		lastErr error // record the error that happened
	)
	for {
		var (
			err    error
			t      transport.ClientTransport
			stream *transport.Stream
		)
		// TODO(zhaoq): Need a formal spec of retry strategy for non-failfast rpcs.
		if lastErr != nil && c.failFast {
			return toRPCErr(lastErr)
		}
		callHdr := &transport.CallHdr{
			Host:   cc.authority,
			Method: method,
		}
		t, err = cc.dopts.picker.Pick(ctx)
		if err != nil {
			if lastErr != nil {
				// This was a retry; return the error from the last attempt.
				return toRPCErr(lastErr)
			}
			return toRPCErr(err)
		}
		if c.traceInfo.tr != nil {
			c.traceInfo.tr.LazyLog(&payload{sent: true, msg: args}, true)
		}
		stream, err = sendRequest(ctx, cc.dopts.codec, callHdr, t, args, topts)
		if err != nil {
			if _, ok := err.(transport.ConnectionError); ok {
				lastErr = err
				continue
			}
			if lastErr != nil {
				return toRPCErr(lastErr)
			}
			return toRPCErr(err)
		}
		// Receive the response
		lastErr = recvResponse(cc.dopts.codec, t, &c, stream, reply)
		if _, ok := lastErr.(transport.ConnectionError); ok {
			continue
		}
		if c.traceInfo.tr != nil {
			c.traceInfo.tr.LazyLog(&payload{sent: false, msg: reply}, true)
		}
		t.CloseStream(stream, lastErr)
		if lastErr != nil {
			return toRPCErr(lastErr)
		}
		return Errorf(stream.StatusCode(), stream.StatusDesc())
	}
}

// NewStream creates a stream and register it into the transport as "active"
// streams.
func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Stream, err error) {
	// Record the timeout value on the context.
	var timeout time.Duration
	if dl, ok := ctx.Deadline(); ok {
		timeout = dl.Sub(time.Now())
		if timeout <= 0 {
			return nil, ContextErr(context.DeadlineExceeded)
		}
	}
	// Attach Auth info if there is any.
	if t.authInfo != nil {
		ctx = credentials.NewContext(ctx, t.authInfo)
	}
	authData := make(map[string]string)
	for _, c := range t.authCreds {
		// Construct URI required to get auth request metadata.
		var port string
		if pos := strings.LastIndex(t.target, ":"); pos != -1 {
			// Omit port if it is the default one.
			if t.target[pos+1:] != "443" {
				port = ":" + t.target[pos+1:]
			}
		}
		pos := strings.LastIndex(callHdr.Method, "/")
		if pos == -1 {
			return nil, StreamErrorf(codes.InvalidArgument, "transport: malformed method name: %q", callHdr.Method)
		}
		audience := "https://" + callHdr.Host + port + callHdr.Method[:pos]
		data, err := c.GetRequestMetadata(ctx, audience)
		if err != nil {
			return nil, StreamErrorf(codes.InvalidArgument, "transport: %v", err)
		}
		for k, v := range data {
			authData[k] = v
		}
	}
	t.mu.Lock()
	if t.state != reachable {
		t.mu.Unlock()
		return nil, ErrConnClosing
	}
	checkStreamsQuota := t.streamsQuota != nil
	t.mu.Unlock()
	if checkStreamsQuota {
		sq, err := wait(ctx, t.shutdownChan, t.streamsQuota.acquire())
		if err != nil {
			return nil, err
		}
		// Returns the quota balance back.
		if sq > 1 {
			t.streamsQuota.add(sq - 1)
		}
	}
	if _, err := wait(ctx, t.shutdownChan, t.writableChan); err != nil {
		// t.streamsQuota will be updated when t.CloseStream is invoked.
		return nil, err
	}
	t.mu.Lock()
	if t.state != reachable {
		t.mu.Unlock()
		return nil, ErrConnClosing
	}
	s := t.newStream(ctx, callHdr)
	t.activeStreams[s.id] = s

	// This stream is not counted when applySetings(...) initialize t.streamsQuota.
	// Reset t.streamsQuota to the right value.
	var reset bool
	if !checkStreamsQuota && t.streamsQuota != nil {
		reset = true
	}
	t.mu.Unlock()
	if reset {
		t.streamsQuota.reset(-1)
	}

	// HPACK encodes various headers. Note that once WriteField(...) is
	// called, the corresponding headers/continuation frame has to be sent
	// because hpack.Encoder is stateful.
	t.hBuf.Reset()
	t.hEnc.WriteField(hpack.HeaderField{Name: ":method", Value: "POST"})
	t.hEnc.WriteField(hpack.HeaderField{Name: ":scheme", Value: t.scheme})
	t.hEnc.WriteField(hpack.HeaderField{Name: ":path", Value: callHdr.Method})
	t.hEnc.WriteField(hpack.HeaderField{Name: ":authority", Value: callHdr.Host})
	t.hEnc.WriteField(hpack.HeaderField{Name: "content-type", Value: "application/grpc"})
	t.hEnc.WriteField(hpack.HeaderField{Name: "user-agent", Value: t.userAgent})
	t.hEnc.WriteField(hpack.HeaderField{Name: "te", Value: "trailers"})

	if timeout > 0 {
		t.hEnc.WriteField(hpack.HeaderField{Name: "grpc-timeout", Value: timeoutEncode(timeout)})
	}
	for k, v := range authData {
		t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: v})
	}
	var (
		hasMD      bool
		endHeaders bool
	)
//.........这里部分代码省略.........