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dex/vendor/google.golang.org/grpc/server.go
2016-07-31 23:26:27 -07:00

835 lines
24 KiB
Go

/*
*
* Copyright 2014, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
package grpc
import (
"bytes"
"errors"
"fmt"
"io"
"net"
"net/http"
"reflect"
"runtime"
"strings"
"sync"
"time"
"golang.org/x/net/context"
"golang.org/x/net/http2"
"golang.org/x/net/trace"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/credentials"
"google.golang.org/grpc/grpclog"
"google.golang.org/grpc/internal"
"google.golang.org/grpc/metadata"
"google.golang.org/grpc/transport"
)
type methodHandler func(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor UnaryServerInterceptor) (interface{}, error)
// MethodDesc represents an RPC service's method specification.
type MethodDesc struct {
MethodName string
Handler methodHandler
}
// ServiceDesc represents an RPC service's specification.
type ServiceDesc struct {
ServiceName string
// The pointer to the service interface. Used to check whether the user
// provided implementation satisfies the interface requirements.
HandlerType interface{}
Methods []MethodDesc
Streams []StreamDesc
Metadata interface{}
}
// service consists of the information of the server serving this service and
// the methods in this service.
type service struct {
server interface{} // the server for service methods
md map[string]*MethodDesc
sd map[string]*StreamDesc
mdata interface{}
}
// Server is a gRPC server to serve RPC requests.
type Server struct {
opts options
mu sync.Mutex // guards following
lis map[net.Listener]bool
conns map[io.Closer]bool
m map[string]*service // service name -> service info
events trace.EventLog
}
type options struct {
creds credentials.TransportCredentials
codec Codec
cp Compressor
dc Decompressor
unaryInt UnaryServerInterceptor
streamInt StreamServerInterceptor
maxConcurrentStreams uint32
useHandlerImpl bool // use http.Handler-based server
}
// A ServerOption sets options.
type ServerOption func(*options)
// CustomCodec returns a ServerOption that sets a codec for message marshaling and unmarshaling.
func CustomCodec(codec Codec) ServerOption {
return func(o *options) {
o.codec = codec
}
}
// RPCCompressor returns a ServerOption that sets a compressor for outbound message.
func RPCCompressor(cp Compressor) ServerOption {
return func(o *options) {
o.cp = cp
}
}
// RPCDecompressor returns a ServerOption that sets a decompressor for inbound message.
func RPCDecompressor(dc Decompressor) ServerOption {
return func(o *options) {
o.dc = dc
}
}
// MaxConcurrentStreams returns a ServerOption that will apply a limit on the number
// of concurrent streams to each ServerTransport.
func MaxConcurrentStreams(n uint32) ServerOption {
return func(o *options) {
o.maxConcurrentStreams = n
}
}
// Creds returns a ServerOption that sets credentials for server connections.
func Creds(c credentials.TransportCredentials) ServerOption {
return func(o *options) {
o.creds = c
}
}
// UnaryInterceptor returns a ServerOption that sets the UnaryServerInterceptor for the
// server. Only one unary interceptor can be installed. The construction of multiple
// interceptors (e.g., chaining) can be implemented at the caller.
func UnaryInterceptor(i UnaryServerInterceptor) ServerOption {
return func(o *options) {
if o.unaryInt != nil {
panic("The unary server interceptor has been set.")
}
o.unaryInt = i
}
}
// StreamInterceptor returns a ServerOption that sets the StreamServerInterceptor for the
// server. Only one stream interceptor can be installed.
func StreamInterceptor(i StreamServerInterceptor) ServerOption {
return func(o *options) {
if o.streamInt != nil {
panic("The stream server interceptor has been set.")
}
o.streamInt = i
}
}
// NewServer creates a gRPC server which has no service registered and has not
// started to accept requests yet.
func NewServer(opt ...ServerOption) *Server {
var opts options
for _, o := range opt {
o(&opts)
}
if opts.codec == nil {
// Set the default codec.
opts.codec = protoCodec{}
}
s := &Server{
lis: make(map[net.Listener]bool),
opts: opts,
conns: make(map[io.Closer]bool),
m: make(map[string]*service),
}
if EnableTracing {
_, file, line, _ := runtime.Caller(1)
s.events = trace.NewEventLog("grpc.Server", fmt.Sprintf("%s:%d", file, line))
}
return s
}
// printf records an event in s's event log, unless s has been stopped.
// REQUIRES s.mu is held.
func (s *Server) printf(format string, a ...interface{}) {
if s.events != nil {
s.events.Printf(format, a...)
}
}
// errorf records an error in s's event log, unless s has been stopped.
// REQUIRES s.mu is held.
func (s *Server) errorf(format string, a ...interface{}) {
if s.events != nil {
s.events.Errorf(format, a...)
}
}
// RegisterService register a service and its implementation to the gRPC
// server. Called from the IDL generated code. This must be called before
// invoking Serve.
func (s *Server) RegisterService(sd *ServiceDesc, ss interface{}) {
ht := reflect.TypeOf(sd.HandlerType).Elem()
st := reflect.TypeOf(ss)
if !st.Implements(ht) {
grpclog.Fatalf("grpc: Server.RegisterService found the handler of type %v that does not satisfy %v", st, ht)
}
s.register(sd, ss)
}
func (s *Server) register(sd *ServiceDesc, ss interface{}) {
s.mu.Lock()
defer s.mu.Unlock()
s.printf("RegisterService(%q)", sd.ServiceName)
if _, ok := s.m[sd.ServiceName]; ok {
grpclog.Fatalf("grpc: Server.RegisterService found duplicate service registration for %q", sd.ServiceName)
}
srv := &service{
server: ss,
md: make(map[string]*MethodDesc),
sd: make(map[string]*StreamDesc),
mdata: sd.Metadata,
}
for i := range sd.Methods {
d := &sd.Methods[i]
srv.md[d.MethodName] = d
}
for i := range sd.Streams {
d := &sd.Streams[i]
srv.sd[d.StreamName] = d
}
s.m[sd.ServiceName] = srv
}
// MethodInfo contains information about an RPC.
type MethodInfo struct {
// Name is the method name only, without the service name or package name.
Name string
// IsClientStream indicates whether the RPC is a client streaming RPC.
IsClientStream bool
// IsServerStream indicates whether the RPC is a server streaming RPC.
IsServerStream bool
}
// ServiceInfo contains unary RPC method info, streaming RPC methid info and metadata for a service.
type ServiceInfo struct {
Methods []MethodInfo
// Metadata is the metadata specified in ServiceDesc when registering service.
Metadata interface{}
}
// GetServiceInfo returns a map from service names to ServiceInfo.
// Service names include the package names, in the form of <package>.<service>.
func (s *Server) GetServiceInfo() map[string]*ServiceInfo {
ret := make(map[string]*ServiceInfo)
for n, srv := range s.m {
methods := make([]MethodInfo, 0, len(srv.md)+len(srv.sd))
for m := range srv.md {
methods = append(methods, MethodInfo{
Name: m,
IsClientStream: false,
IsServerStream: false,
})
}
for m, d := range srv.sd {
methods = append(methods, MethodInfo{
Name: m,
IsClientStream: d.ClientStreams,
IsServerStream: d.ServerStreams,
})
}
ret[n] = &ServiceInfo{
Methods: methods,
Metadata: srv.mdata,
}
}
return ret
}
var (
// ErrServerStopped indicates that the operation is now illegal because of
// the server being stopped.
ErrServerStopped = errors.New("grpc: the server has been stopped")
)
func (s *Server) useTransportAuthenticator(rawConn net.Conn) (net.Conn, credentials.AuthInfo, error) {
if s.opts.creds == nil {
return rawConn, nil, nil
}
return s.opts.creds.ServerHandshake(rawConn)
}
// Serve accepts incoming connections on the listener lis, creating a new
// ServerTransport and service goroutine for each. The service goroutines
// read gRPC requests and then call the registered handlers to reply to them.
// Service returns when lis.Accept fails. lis will be closed when
// this method returns.
func (s *Server) Serve(lis net.Listener) error {
s.mu.Lock()
s.printf("serving")
if s.lis == nil {
s.mu.Unlock()
lis.Close()
return ErrServerStopped
}
s.lis[lis] = true
s.mu.Unlock()
defer func() {
lis.Close()
s.mu.Lock()
delete(s.lis, lis)
s.mu.Unlock()
}()
for {
rawConn, err := lis.Accept()
if err != nil {
s.mu.Lock()
s.printf("done serving; Accept = %v", err)
s.mu.Unlock()
return err
}
// Start a new goroutine to deal with rawConn
// so we don't stall this Accept loop goroutine.
go s.handleRawConn(rawConn)
}
}
// handleRawConn is run in its own goroutine and handles a just-accepted
// connection that has not had any I/O performed on it yet.
func (s *Server) handleRawConn(rawConn net.Conn) {
conn, authInfo, err := s.useTransportAuthenticator(rawConn)
if err != nil {
s.mu.Lock()
s.errorf("ServerHandshake(%q) failed: %v", rawConn.RemoteAddr(), err)
s.mu.Unlock()
grpclog.Printf("grpc: Server.Serve failed to complete security handshake from %q: %v", rawConn.RemoteAddr(), err)
rawConn.Close()
return
}
s.mu.Lock()
if s.conns == nil {
s.mu.Unlock()
conn.Close()
return
}
s.mu.Unlock()
if s.opts.useHandlerImpl {
s.serveUsingHandler(conn)
} else {
s.serveNewHTTP2Transport(conn, authInfo)
}
}
// serveNewHTTP2Transport sets up a new http/2 transport (using the
// gRPC http2 server transport in transport/http2_server.go) and
// serves streams on it.
// This is run in its own goroutine (it does network I/O in
// transport.NewServerTransport).
func (s *Server) serveNewHTTP2Transport(c net.Conn, authInfo credentials.AuthInfo) {
st, err := transport.NewServerTransport("http2", c, s.opts.maxConcurrentStreams, authInfo)
if err != nil {
s.mu.Lock()
s.errorf("NewServerTransport(%q) failed: %v", c.RemoteAddr(), err)
s.mu.Unlock()
c.Close()
grpclog.Println("grpc: Server.Serve failed to create ServerTransport: ", err)
return
}
if !s.addConn(st) {
st.Close()
return
}
s.serveStreams(st)
}
func (s *Server) serveStreams(st transport.ServerTransport) {
defer s.removeConn(st)
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))
}()
})
wg.Wait()
}
var _ http.Handler = (*Server)(nil)
// serveUsingHandler is called from handleRawConn when s is configured
// to handle requests via the http.Handler interface. It sets up a
// net/http.Server to handle the just-accepted conn. The http.Server
// is configured to route all incoming requests (all HTTP/2 streams)
// to ServeHTTP, which creates a new ServerTransport for each stream.
// serveUsingHandler blocks until conn closes.
//
// This codepath is only used when Server.TestingUseHandlerImpl has
// been configured. This lets the end2end tests exercise the ServeHTTP
// method as one of the environment types.
//
// conn is the *tls.Conn that's already been authenticated.
func (s *Server) serveUsingHandler(conn net.Conn) {
if !s.addConn(conn) {
conn.Close()
return
}
defer s.removeConn(conn)
h2s := &http2.Server{
MaxConcurrentStreams: s.opts.maxConcurrentStreams,
}
h2s.ServeConn(conn, &http2.ServeConnOpts{
Handler: s,
})
}
func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
st, err := transport.NewServerHandlerTransport(w, r)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
if !s.addConn(st) {
st.Close()
return
}
defer s.removeConn(st)
s.serveStreams(st)
}
// traceInfo returns a traceInfo and associates it with stream, if tracing is enabled.
// If tracing is not enabled, it returns nil.
func (s *Server) traceInfo(st transport.ServerTransport, stream *transport.Stream) (trInfo *traceInfo) {
if !EnableTracing {
return nil
}
trInfo = &traceInfo{
tr: trace.New("grpc.Recv."+methodFamily(stream.Method()), stream.Method()),
}
trInfo.firstLine.client = false
trInfo.firstLine.remoteAddr = st.RemoteAddr()
stream.TraceContext(trInfo.tr)
if dl, ok := stream.Context().Deadline(); ok {
trInfo.firstLine.deadline = dl.Sub(time.Now())
}
return trInfo
}
func (s *Server) addConn(c io.Closer) bool {
s.mu.Lock()
defer s.mu.Unlock()
if s.conns == nil {
return false
}
s.conns[c] = true
return true
}
func (s *Server) removeConn(c io.Closer) {
s.mu.Lock()
defer s.mu.Unlock()
if s.conns != nil {
delete(s.conns, c)
}
}
func (s *Server) sendResponse(t transport.ServerTransport, stream *transport.Stream, msg interface{}, cp Compressor, opts *transport.Options) error {
var cbuf *bytes.Buffer
if cp != nil {
cbuf = new(bytes.Buffer)
}
p, err := encode(s.opts.codec, msg, cp, cbuf)
if err != nil {
// This typically indicates a fatal issue (e.g., memory
// corruption or hardware faults) the application program
// cannot handle.
//
// TODO(zhaoq): There exist other options also such as only closing the
// faulty stream locally and remotely (Other streams can keep going). Find
// the optimal option.
grpclog.Fatalf("grpc: Server failed to encode response %v", err)
}
return t.Write(stream, p, opts)
}
func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.Stream, srv *service, md *MethodDesc, trInfo *traceInfo) (err error) {
if trInfo != nil {
defer trInfo.tr.Finish()
trInfo.firstLine.client = false
trInfo.tr.LazyLog(&trInfo.firstLine, false)
defer func() {
if err != nil && err != io.EOF {
trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
trInfo.tr.SetError()
}
}()
}
if s.opts.cp != nil {
// NOTE: this needs to be ahead of all handling, https://github.com/grpc/grpc-go/issues/686.
stream.SetSendCompress(s.opts.cp.Type())
}
p := &parser{r: stream}
for {
pf, req, err := p.recvMsg()
if err == io.EOF {
// The entire stream is done (for unary RPC only).
return err
}
if err == io.ErrUnexpectedEOF {
err = transport.StreamError{Code: codes.Internal, Desc: "io.ErrUnexpectedEOF"}
}
if err != nil {
switch err := err.(type) {
case transport.ConnectionError:
// Nothing to do here.
case transport.StreamError:
if err := t.WriteStatus(stream, err.Code, err.Desc); err != nil {
grpclog.Printf("grpc: Server.processUnaryRPC failed to write status %v", err)
}
default:
panic(fmt.Sprintf("grpc: Unexpected error (%T) from recvMsg: %v", err, err))
}
return err
}
if err := checkRecvPayload(pf, stream.RecvCompress(), s.opts.dc); err != nil {
switch err := err.(type) {
case transport.StreamError:
if err := t.WriteStatus(stream, err.Code, err.Desc); err != nil {
grpclog.Printf("grpc: Server.processUnaryRPC failed to write status %v", err)
}
default:
if err := t.WriteStatus(stream, codes.Internal, err.Error()); err != nil {
grpclog.Printf("grpc: Server.processUnaryRPC failed to write status %v", err)
}
}
return err
}
statusCode := codes.OK
statusDesc := ""
df := func(v interface{}) error {
if pf == compressionMade {
var err error
req, err = s.opts.dc.Do(bytes.NewReader(req))
if err != nil {
if err := t.WriteStatus(stream, codes.Internal, err.Error()); err != nil {
grpclog.Printf("grpc: Server.processUnaryRPC failed to write status %v", err)
}
return err
}
}
if err := s.opts.codec.Unmarshal(req, v); err != nil {
return err
}
if trInfo != nil {
trInfo.tr.LazyLog(&payload{sent: false, msg: v}, true)
}
return nil
}
reply, appErr := md.Handler(srv.server, stream.Context(), df, s.opts.unaryInt)
if appErr != nil {
if err, ok := appErr.(*rpcError); ok {
statusCode = err.code
statusDesc = err.desc
} else {
statusCode = convertCode(appErr)
statusDesc = appErr.Error()
}
if trInfo != nil && statusCode != codes.OK {
trInfo.tr.LazyLog(stringer(statusDesc), true)
trInfo.tr.SetError()
}
if err := t.WriteStatus(stream, statusCode, statusDesc); err != nil {
grpclog.Printf("grpc: Server.processUnaryRPC failed to write status: %v", err)
return err
}
return nil
}
if trInfo != nil {
trInfo.tr.LazyLog(stringer("OK"), false)
}
opts := &transport.Options{
Last: true,
Delay: false,
}
if err := s.sendResponse(t, stream, reply, s.opts.cp, opts); err != nil {
switch err := err.(type) {
case transport.ConnectionError:
// Nothing to do here.
case transport.StreamError:
statusCode = err.Code
statusDesc = err.Desc
default:
statusCode = codes.Unknown
statusDesc = err.Error()
}
return err
}
if trInfo != nil {
trInfo.tr.LazyLog(&payload{sent: true, msg: reply}, true)
}
return t.WriteStatus(stream, statusCode, statusDesc)
}
}
func (s *Server) processStreamingRPC(t transport.ServerTransport, stream *transport.Stream, srv *service, sd *StreamDesc, trInfo *traceInfo) (err error) {
if s.opts.cp != nil {
stream.SetSendCompress(s.opts.cp.Type())
}
ss := &serverStream{
t: t,
s: stream,
p: &parser{r: stream},
codec: s.opts.codec,
cp: s.opts.cp,
dc: s.opts.dc,
trInfo: trInfo,
}
if ss.cp != nil {
ss.cbuf = new(bytes.Buffer)
}
if trInfo != nil {
trInfo.tr.LazyLog(&trInfo.firstLine, false)
defer func() {
ss.mu.Lock()
if err != nil && err != io.EOF {
ss.trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
ss.trInfo.tr.SetError()
}
ss.trInfo.tr.Finish()
ss.trInfo.tr = nil
ss.mu.Unlock()
}()
}
var appErr error
if s.opts.streamInt == nil {
appErr = sd.Handler(srv.server, ss)
} else {
info := &StreamServerInfo{
FullMethod: stream.Method(),
IsClientStream: sd.ClientStreams,
IsServerStream: sd.ServerStreams,
}
appErr = s.opts.streamInt(srv.server, ss, info, sd.Handler)
}
if appErr != nil {
if err, ok := appErr.(*rpcError); ok {
ss.statusCode = err.code
ss.statusDesc = err.desc
} else if err, ok := appErr.(transport.StreamError); ok {
ss.statusCode = err.Code
ss.statusDesc = err.Desc
} else {
ss.statusCode = convertCode(appErr)
ss.statusDesc = appErr.Error()
}
}
if trInfo != nil {
ss.mu.Lock()
if ss.statusCode != codes.OK {
ss.trInfo.tr.LazyLog(stringer(ss.statusDesc), true)
ss.trInfo.tr.SetError()
} else {
ss.trInfo.tr.LazyLog(stringer("OK"), false)
}
ss.mu.Unlock()
}
return t.WriteStatus(ss.s, ss.statusCode, ss.statusDesc)
}
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()
}
if err := t.WriteStatus(stream, codes.InvalidArgument, fmt.Sprintf("malformed method name: %q", stream.Method())); err != nil {
if trInfo != nil {
trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
trInfo.tr.SetError()
}
grpclog.Printf("grpc: Server.handleStream failed to write status: %v", err)
}
if trInfo != nil {
trInfo.tr.Finish()
}
return
}
service := sm[:pos]
method := sm[pos+1:]
srv, ok := s.m[service]
if !ok {
if trInfo != nil {
trInfo.tr.LazyLog(&fmtStringer{"Unknown service %v", []interface{}{service}}, true)
trInfo.tr.SetError()
}
if err := t.WriteStatus(stream, codes.Unimplemented, fmt.Sprintf("unknown service %v", service)); err != nil {
if trInfo != nil {
trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
trInfo.tr.SetError()
}
grpclog.Printf("grpc: Server.handleStream failed to write status: %v", err)
}
if trInfo != nil {
trInfo.tr.Finish()
}
return
}
// Unary RPC or Streaming RPC?
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
}
if trInfo != nil {
trInfo.tr.LazyLog(&fmtStringer{"Unknown method %v", []interface{}{method}}, true)
trInfo.tr.SetError()
}
if err := t.WriteStatus(stream, codes.Unimplemented, fmt.Sprintf("unknown method %v", method)); err != nil {
if trInfo != nil {
trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
trInfo.tr.SetError()
}
grpclog.Printf("grpc: Server.handleStream failed to write status: %v", err)
}
if trInfo != nil {
trInfo.tr.Finish()
}
}
// Stop stops the gRPC server. It immediately closes all open
// connections and listeners.
// It cancels all active RPCs on the server side and the corresponding
// pending RPCs on the client side will get notified by connection
// errors.
func (s *Server) Stop() {
s.mu.Lock()
listeners := s.lis
s.lis = nil
cs := s.conns
s.conns = nil
s.mu.Unlock()
for lis := range listeners {
lis.Close()
}
for c := range cs {
c.Close()
}
s.mu.Lock()
if s.events != nil {
s.events.Finish()
s.events = nil
}
s.mu.Unlock()
}
func init() {
internal.TestingCloseConns = func(arg interface{}) {
arg.(*Server).testingCloseConns()
}
internal.TestingUseHandlerImpl = func(arg interface{}) {
arg.(*Server).opts.useHandlerImpl = true
}
}
// testingCloseConns closes all existing transports but keeps s.lis
// accepting new connections.
func (s *Server) testingCloseConns() {
s.mu.Lock()
for c := range s.conns {
c.Close()
delete(s.conns, c)
}
s.mu.Unlock()
}
// SendHeader sends header metadata. It may be called at most once from a unary
// RPC handler. The ctx is the RPC handler's Context or one derived from it.
func SendHeader(ctx context.Context, md metadata.MD) error {
if md.Len() == 0 {
return nil
}
stream, ok := transport.StreamFromContext(ctx)
if !ok {
return fmt.Errorf("grpc: failed to fetch the stream from the context %v", ctx)
}
t := stream.ServerTransport()
if t == nil {
grpclog.Fatalf("grpc: SendHeader: %v has no ServerTransport to send header metadata.", stream)
}
return t.WriteHeader(stream, md)
}
// SetTrailer sets the trailer metadata that will be sent when an RPC returns.
// It may be called at most once from a unary RPC handler. The ctx is the RPC
// handler's Context or one derived from it.
func SetTrailer(ctx context.Context, md metadata.MD) error {
if md.Len() == 0 {
return nil
}
stream, ok := transport.StreamFromContext(ctx)
if !ok {
return fmt.Errorf("grpc: failed to fetch the stream from the context %v", ctx)
}
return stream.SetTrailer(md)
}