398 lines
11 KiB
Go
398 lines
11 KiB
Go
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/*
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* Copyright 2016, Google Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following disclaimer
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* in the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Google Inc. nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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// This file is the implementation of a gRPC server using HTTP/2 which
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// uses the standard Go http2 Server implementation (via the
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// http.Handler interface), rather than speaking low-level HTTP/2
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// frames itself. It is the implementation of *grpc.Server.ServeHTTP.
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package transport
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import (
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"errors"
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"fmt"
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"io"
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"net"
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"net/http"
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"strings"
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"sync"
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"time"
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"golang.org/x/net/context"
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"golang.org/x/net/http2"
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"google.golang.org/grpc/codes"
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"google.golang.org/grpc/credentials"
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"google.golang.org/grpc/metadata"
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"google.golang.org/grpc/peer"
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)
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// NewServerHandlerTransport returns a ServerTransport handling gRPC
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// from inside an http.Handler. It requires that the http Server
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// supports HTTP/2.
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func NewServerHandlerTransport(w http.ResponseWriter, r *http.Request) (ServerTransport, error) {
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if r.ProtoMajor != 2 {
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return nil, errors.New("gRPC requires HTTP/2")
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}
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if r.Method != "POST" {
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return nil, errors.New("invalid gRPC request method")
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}
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if !validContentType(r.Header.Get("Content-Type")) {
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return nil, errors.New("invalid gRPC request content-type")
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}
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if _, ok := w.(http.Flusher); !ok {
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return nil, errors.New("gRPC requires a ResponseWriter supporting http.Flusher")
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}
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if _, ok := w.(http.CloseNotifier); !ok {
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return nil, errors.New("gRPC requires a ResponseWriter supporting http.CloseNotifier")
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}
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st := &serverHandlerTransport{
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rw: w,
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req: r,
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closedCh: make(chan struct{}),
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writes: make(chan func()),
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}
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if v := r.Header.Get("grpc-timeout"); v != "" {
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to, err := decodeTimeout(v)
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if err != nil {
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return nil, streamErrorf(codes.Internal, "malformed time-out: %v", err)
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}
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st.timeoutSet = true
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st.timeout = to
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}
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var metakv []string
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if r.Host != "" {
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metakv = append(metakv, ":authority", r.Host)
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}
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for k, vv := range r.Header {
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k = strings.ToLower(k)
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if isReservedHeader(k) && !isWhitelistedPseudoHeader(k) {
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continue
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}
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for _, v := range vv {
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if k == "user-agent" {
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// user-agent is special. Copying logic of http_util.go.
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if i := strings.LastIndex(v, " "); i == -1 {
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// There is no application user agent string being set
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continue
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} else {
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v = v[:i]
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}
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}
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metakv = append(metakv, k, v)
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}
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}
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st.headerMD = metadata.Pairs(metakv...)
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return st, nil
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}
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// serverHandlerTransport is an implementation of ServerTransport
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// which replies to exactly one gRPC request (exactly one HTTP request),
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// using the net/http.Handler interface. This http.Handler is guaranteed
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// at this point to be speaking over HTTP/2, so it's able to speak valid
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// gRPC.
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type serverHandlerTransport struct {
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rw http.ResponseWriter
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req *http.Request
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timeoutSet bool
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timeout time.Duration
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didCommonHeaders bool
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headerMD metadata.MD
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closeOnce sync.Once
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closedCh chan struct{} // closed on Close
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// writes is a channel of code to run serialized in the
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// ServeHTTP (HandleStreams) goroutine. The channel is closed
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// when WriteStatus is called.
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writes chan func()
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}
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func (ht *serverHandlerTransport) Close() error {
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ht.closeOnce.Do(ht.closeCloseChanOnce)
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return nil
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}
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func (ht *serverHandlerTransport) closeCloseChanOnce() { close(ht.closedCh) }
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func (ht *serverHandlerTransport) RemoteAddr() net.Addr { return strAddr(ht.req.RemoteAddr) }
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// strAddr is a net.Addr backed by either a TCP "ip:port" string, or
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// the empty string if unknown.
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type strAddr string
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func (a strAddr) Network() string {
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if a != "" {
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// Per the documentation on net/http.Request.RemoteAddr, if this is
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// set, it's set to the IP:port of the peer (hence, TCP):
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// https://golang.org/pkg/net/http/#Request
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//
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// If we want to support Unix sockets later, we can
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// add our own grpc-specific convention within the
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// grpc codebase to set RemoteAddr to a different
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// format, or probably better: we can attach it to the
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// context and use that from serverHandlerTransport.RemoteAddr.
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return "tcp"
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}
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return ""
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}
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func (a strAddr) String() string { return string(a) }
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// do runs fn in the ServeHTTP goroutine.
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func (ht *serverHandlerTransport) do(fn func()) error {
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select {
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case ht.writes <- fn:
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return nil
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case <-ht.closedCh:
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return ErrConnClosing
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}
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}
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func (ht *serverHandlerTransport) WriteStatus(s *Stream, statusCode codes.Code, statusDesc string) error {
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err := ht.do(func() {
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ht.writeCommonHeaders(s)
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// And flush, in case no header or body has been sent yet.
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// This forces a separation of headers and trailers if this is the
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// first call (for example, in end2end tests's TestNoService).
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ht.rw.(http.Flusher).Flush()
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h := ht.rw.Header()
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h.Set("Grpc-Status", fmt.Sprintf("%d", statusCode))
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if statusDesc != "" {
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h.Set("Grpc-Message", encodeGrpcMessage(statusDesc))
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}
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if md := s.Trailer(); len(md) > 0 {
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for k, vv := range md {
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// Clients don't tolerate reading restricted headers after some non restricted ones were sent.
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if isReservedHeader(k) {
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continue
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}
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for _, v := range vv {
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// http2 ResponseWriter mechanism to
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// send undeclared Trailers after the
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// headers have possibly been written.
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h.Add(http2.TrailerPrefix+k, v)
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}
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}
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}
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})
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close(ht.writes)
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return err
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}
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// writeCommonHeaders sets common headers on the first write
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// call (Write, WriteHeader, or WriteStatus).
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func (ht *serverHandlerTransport) writeCommonHeaders(s *Stream) {
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if ht.didCommonHeaders {
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return
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}
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ht.didCommonHeaders = true
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h := ht.rw.Header()
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h["Date"] = nil // suppress Date to make tests happy; TODO: restore
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h.Set("Content-Type", "application/grpc")
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// Predeclare trailers we'll set later in WriteStatus (after the body).
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// This is a SHOULD in the HTTP RFC, and the way you add (known)
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// Trailers per the net/http.ResponseWriter contract.
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// See https://golang.org/pkg/net/http/#ResponseWriter
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// and https://golang.org/pkg/net/http/#example_ResponseWriter_trailers
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h.Add("Trailer", "Grpc-Status")
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h.Add("Trailer", "Grpc-Message")
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if s.sendCompress != "" {
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h.Set("Grpc-Encoding", s.sendCompress)
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}
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}
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func (ht *serverHandlerTransport) Write(s *Stream, data []byte, opts *Options) error {
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return ht.do(func() {
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ht.writeCommonHeaders(s)
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ht.rw.Write(data)
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if !opts.Delay {
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ht.rw.(http.Flusher).Flush()
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}
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})
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}
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func (ht *serverHandlerTransport) WriteHeader(s *Stream, md metadata.MD) error {
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return ht.do(func() {
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ht.writeCommonHeaders(s)
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h := ht.rw.Header()
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for k, vv := range md {
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// Clients don't tolerate reading restricted headers after some non restricted ones were sent.
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if isReservedHeader(k) {
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continue
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}
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for _, v := range vv {
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h.Add(k, v)
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}
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}
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ht.rw.WriteHeader(200)
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ht.rw.(http.Flusher).Flush()
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})
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}
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func (ht *serverHandlerTransport) HandleStreams(startStream func(*Stream), traceCtx func(context.Context, string) context.Context) {
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// With this transport type there will be exactly 1 stream: this HTTP request.
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var ctx context.Context
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var cancel context.CancelFunc
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if ht.timeoutSet {
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ctx, cancel = context.WithTimeout(context.Background(), ht.timeout)
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} else {
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ctx, cancel = context.WithCancel(context.Background())
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}
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// requestOver is closed when either the request's context is done
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// or the status has been written via WriteStatus.
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requestOver := make(chan struct{})
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// clientGone receives a single value if peer is gone, either
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// because the underlying connection is dead or because the
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// peer sends an http2 RST_STREAM.
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clientGone := ht.rw.(http.CloseNotifier).CloseNotify()
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go func() {
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select {
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case <-requestOver:
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return
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case <-ht.closedCh:
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case <-clientGone:
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}
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cancel()
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}()
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req := ht.req
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s := &Stream{
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id: 0, // irrelevant
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windowHandler: func(int) {}, // nothing
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cancel: cancel,
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buf: newRecvBuffer(),
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st: ht,
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method: req.URL.Path,
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recvCompress: req.Header.Get("grpc-encoding"),
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}
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pr := &peer.Peer{
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Addr: ht.RemoteAddr(),
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}
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if req.TLS != nil {
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pr.AuthInfo = credentials.TLSInfo{State: *req.TLS}
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}
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ctx = metadata.NewContext(ctx, ht.headerMD)
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ctx = peer.NewContext(ctx, pr)
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s.ctx = newContextWithStream(ctx, s)
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s.dec = &recvBufferReader{ctx: s.ctx, recv: s.buf}
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// readerDone is closed when the Body.Read-ing goroutine exits.
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readerDone := make(chan struct{})
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go func() {
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defer close(readerDone)
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// TODO: minimize garbage, optimize recvBuffer code/ownership
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const readSize = 8196
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for buf := make([]byte, readSize); ; {
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n, err := req.Body.Read(buf)
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if n > 0 {
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s.buf.put(&recvMsg{data: buf[:n:n]})
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buf = buf[n:]
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}
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if err != nil {
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s.buf.put(&recvMsg{err: mapRecvMsgError(err)})
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return
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}
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if len(buf) == 0 {
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buf = make([]byte, readSize)
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}
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}
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}()
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// startStream is provided by the *grpc.Server's serveStreams.
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// It starts a goroutine serving s and exits immediately.
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// The goroutine that is started is the one that then calls
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// into ht, calling WriteHeader, Write, WriteStatus, Close, etc.
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startStream(s)
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ht.runStream()
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close(requestOver)
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// Wait for reading goroutine to finish.
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req.Body.Close()
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<-readerDone
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}
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func (ht *serverHandlerTransport) runStream() {
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for {
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select {
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case fn, ok := <-ht.writes:
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if !ok {
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return
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}
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fn()
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case <-ht.closedCh:
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return
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}
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}
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}
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func (ht *serverHandlerTransport) Drain() {
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panic("Drain() is not implemented")
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}
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// mapRecvMsgError returns the non-nil err into the appropriate
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// error value as expected by callers of *grpc.parser.recvMsg.
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// In particular, in can only be:
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// * io.EOF
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// * io.ErrUnexpectedEOF
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// * of type transport.ConnectionError
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// * of type transport.StreamError
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func mapRecvMsgError(err error) error {
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if err == io.EOF || err == io.ErrUnexpectedEOF {
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return err
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}
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if se, ok := err.(http2.StreamError); ok {
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if code, ok := http2ErrConvTab[se.Code]; ok {
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return StreamError{
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Code: code,
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Desc: se.Error(),
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}
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}
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}
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return connectionErrorf(true, err, err.Error())
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}
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