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server.go
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/*
*
* Copyright 2014 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http:https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package grpc
import (
"context"
"errors"
"fmt"
"io"
"math"
"net"
"net/http"
"reflect"
"runtime"
"strings"
"sync"
"sync/atomic"
"time"
"golang.org/x/net/trace"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/credentials"
"google.golang.org/grpc/encoding"
"google.golang.org/grpc/encoding/proto"
"google.golang.org/grpc/grpclog"
"google.golang.org/grpc/internal"
"google.golang.org/grpc/internal/binarylog"
"google.golang.org/grpc/internal/channelz"
"google.golang.org/grpc/internal/grpcrand"
"google.golang.org/grpc/internal/grpcsync"
"google.golang.org/grpc/internal/transport"
"google.golang.org/grpc/keepalive"
"google.golang.org/grpc/metadata"
"google.golang.org/grpc/peer"
"google.golang.org/grpc/stats"
"google.golang.org/grpc/status"
"google.golang.org/grpc/tap"
)
const (
defaultServerMaxReceiveMessageSize = 1024 * 1024 * 4
defaultServerMaxSendMessageSize = math.MaxInt32
// Server transports are tracked in a map which is keyed on listener
// address. For regular gRPC traffic, connections are accepted in Serve()
// through a call to Accept(), and we use the actual listener address as key
// when we add it to the map. But for connections received through
// ServeHTTP(), we do not have a listener and hence use this dummy value.
listenerAddressForServeHTTP = "listenerAddressForServeHTTP"
)
func init() {
internal.GetServerCredentials = func(srv *Server) credentials.TransportCredentials {
return srv.opts.creds
}
internal.DrainServerTransports = func(srv *Server, addr string) {
srv.drainServerTransports(addr)
}
}
var statusOK = status.New(codes.OK, "")
var logger = grpclog.Component("core")
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{}
}
// serviceInfo wraps information about a service. It is very similar to
// ServiceDesc and is constructed from it for internal purposes.
type serviceInfo struct {
// Contains the implementation for the methods in this service.
serviceImpl interface{}
methods map[string]*MethodDesc
streams map[string]*StreamDesc
mdata interface{}
}
type serverWorkerData struct {
st transport.ServerTransport
wg *sync.WaitGroup
stream *transport.Stream
}
// Server is a gRPC server to serve RPC requests.
type Server struct {
opts serverOptions
mu sync.Mutex // guards following
lis map[net.Listener]bool
// conns contains all active server transports. It is a map keyed on a
// listener address with the value being the set of active transports
// belonging to that listener.
conns map[string]map[transport.ServerTransport]bool
serve bool
drain bool
cv *sync.Cond // signaled when connections close for GracefulStop
services map[string]*serviceInfo // service name -> service info
events trace.EventLog
quit *grpcsync.Event
done *grpcsync.Event
channelzRemoveOnce sync.Once
serveWG sync.WaitGroup // counts active Serve goroutines for GracefulStop
channelzID int64 // channelz unique identification number
czData *channelzData
serverWorkerChannels []chan *serverWorkerData
}
type serverOptions struct {
creds credentials.TransportCredentials
codec baseCodec
cp Compressor
dc Decompressor
unaryInt UnaryServerInterceptor
streamInt StreamServerInterceptor
chainUnaryInts []UnaryServerInterceptor
chainStreamInts []StreamServerInterceptor
inTapHandle tap.ServerInHandle
statsHandler stats.Handler
maxConcurrentStreams uint32
maxReceiveMessageSize int
maxSendMessageSize int
unknownStreamDesc *StreamDesc
keepaliveParams keepalive.ServerParameters
keepalivePolicy keepalive.EnforcementPolicy
initialWindowSize int32
initialConnWindowSize int32
writeBufferSize int
readBufferSize int
connectionTimeout time.Duration
maxHeaderListSize *uint32
headerTableSize *uint32
numServerWorkers uint32
}
var defaultServerOptions = serverOptions{
maxReceiveMessageSize: defaultServerMaxReceiveMessageSize,
maxSendMessageSize: defaultServerMaxSendMessageSize,
connectionTimeout: 120 * time.Second,
writeBufferSize: defaultWriteBufSize,
readBufferSize: defaultReadBufSize,
}
// A ServerOption sets options such as credentials, codec and keepalive parameters, etc.
type ServerOption interface {
apply(*serverOptions)
}
// EmptyServerOption does not alter the server configuration. It can be embedded
// in another structure to build custom server options.
//
// Experimental
//
// Notice: This type is EXPERIMENTAL and may be changed or removed in a
// later release.
type EmptyServerOption struct{}
func (EmptyServerOption) apply(*serverOptions) {}
// funcServerOption wraps a function that modifies serverOptions into an
// implementation of the ServerOption interface.
type funcServerOption struct {
f func(*serverOptions)
}
func (fdo *funcServerOption) apply(do *serverOptions) {
fdo.f(do)
}
func newFuncServerOption(f func(*serverOptions)) *funcServerOption {
return &funcServerOption{
f: f,
}
}
// WriteBufferSize determines how much data can be batched before doing a write on the wire.
// The corresponding memory allocation for this buffer will be twice the size to keep syscalls low.
// The default value for this buffer is 32KB.
// Zero will disable the write buffer such that each write will be on underlying connection.
// Note: A Send call may not directly translate to a write.
func WriteBufferSize(s int) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.writeBufferSize = s
})
}
// ReadBufferSize lets you set the size of read buffer, this determines how much data can be read at most
// for one read syscall.
// The default value for this buffer is 32KB.
// Zero will disable read buffer for a connection so data framer can access the underlying
// conn directly.
func ReadBufferSize(s int) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.readBufferSize = s
})
}
// InitialWindowSize returns a ServerOption that sets window size for stream.
// The lower bound for window size is 64K and any value smaller than that will be ignored.
func InitialWindowSize(s int32) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.initialWindowSize = s
})
}
// InitialConnWindowSize returns a ServerOption that sets window size for a connection.
// The lower bound for window size is 64K and any value smaller than that will be ignored.
func InitialConnWindowSize(s int32) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.initialConnWindowSize = s
})
}
// KeepaliveParams returns a ServerOption that sets keepalive and max-age parameters for the server.
func KeepaliveParams(kp keepalive.ServerParameters) ServerOption {
if kp.Time > 0 && kp.Time < time.Second {
logger.Warning("Adjusting keepalive ping interval to minimum period of 1s")
kp.Time = time.Second
}
return newFuncServerOption(func(o *serverOptions) {
o.keepaliveParams = kp
})
}
// KeepaliveEnforcementPolicy returns a ServerOption that sets keepalive enforcement policy for the server.
func KeepaliveEnforcementPolicy(kep keepalive.EnforcementPolicy) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.keepalivePolicy = kep
})
}
// CustomCodec returns a ServerOption that sets a codec for message marshaling and unmarshaling.
//
// This will override any lookups by content-subtype for Codecs registered with RegisterCodec.
//
// Deprecated: register codecs using encoding.RegisterCodec. The server will
// automatically use registered codecs based on the incoming requests' headers.
// See also
// https://github.com/grpc/grpc-go/blob/master/Documentation/encoding.md#using-a-codec.
// Will be supported throughout 1.x.
func CustomCodec(codec Codec) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.codec = codec
})
}
// ForceServerCodec returns a ServerOption that sets a codec for message
// marshaling and unmarshaling.
//
// This will override any lookups by content-subtype for Codecs registered
// with RegisterCodec.
//
// See Content-Type on
// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
// more details. Also see the documentation on RegisterCodec and
// CallContentSubtype for more details on the interaction between encoding.Codec
// and content-subtype.
//
// This function is provided for advanced users; prefer to register codecs
// using encoding.RegisterCodec.
// The server will automatically use registered codecs based on the incoming
// requests' headers. See also
// https://github.com/grpc/grpc-go/blob/master/Documentation/encoding.md#using-a-codec.
// Will be supported throughout 1.x.
//
// Experimental
//
// Notice: This API is EXPERIMENTAL and may be changed or removed in a
// later release.
func ForceServerCodec(codec encoding.Codec) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.codec = codec
})
}
// RPCCompressor returns a ServerOption that sets a compressor for outbound
// messages. For backward compatibility, all outbound messages will be sent
// using this compressor, regardless of incoming message compression. By
// default, server messages will be sent using the same compressor with which
// request messages were sent.
//
// Deprecated: use encoding.RegisterCompressor instead. Will be supported
// throughout 1.x.
func RPCCompressor(cp Compressor) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.cp = cp
})
}
// RPCDecompressor returns a ServerOption that sets a decompressor for inbound
// messages. It has higher priority than decompressors registered via
// encoding.RegisterCompressor.
//
// Deprecated: use encoding.RegisterCompressor instead. Will be supported
// throughout 1.x.
func RPCDecompressor(dc Decompressor) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.dc = dc
})
}
// MaxMsgSize returns a ServerOption to set the max message size in bytes the server can receive.
// If this is not set, gRPC uses the default limit.
//
// Deprecated: use MaxRecvMsgSize instead. Will be supported throughout 1.x.
func MaxMsgSize(m int) ServerOption {
return MaxRecvMsgSize(m)
}
// MaxRecvMsgSize returns a ServerOption to set the max message size in bytes the server can receive.
// If this is not set, gRPC uses the default 4MB.
func MaxRecvMsgSize(m int) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.maxReceiveMessageSize = m
})
}
// MaxSendMsgSize returns a ServerOption to set the max message size in bytes the server can send.
// If this is not set, gRPC uses the default `math.MaxInt32`.
func MaxSendMsgSize(m int) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.maxSendMessageSize = m
})
}
// MaxConcurrentStreams returns a ServerOption that will apply a limit on the number
// of concurrent streams to each ServerTransport.
func MaxConcurrentStreams(n uint32) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.maxConcurrentStreams = n
})
}
// Creds returns a ServerOption that sets credentials for server connections.
func Creds(c credentials.TransportCredentials) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
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 newFuncServerOption(func(o *serverOptions) {
if o.unaryInt != nil {
panic("The unary server interceptor was already set and may not be reset.")
}
o.unaryInt = i
})
}
// ChainUnaryInterceptor returns a ServerOption that specifies the chained interceptor
// for unary RPCs. The first interceptor will be the outer most,
// while the last interceptor will be the inner most wrapper around the real call.
// All unary interceptors added by this method will be chained.
func ChainUnaryInterceptor(interceptors ...UnaryServerInterceptor) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.chainUnaryInts = append(o.chainUnaryInts, interceptors...)
})
}
// StreamInterceptor returns a ServerOption that sets the StreamServerInterceptor for the
// server. Only one stream interceptor can be installed.
func StreamInterceptor(i StreamServerInterceptor) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
if o.streamInt != nil {
panic("The stream server interceptor was already set and may not be reset.")
}
o.streamInt = i
})
}
// ChainStreamInterceptor returns a ServerOption that specifies the chained interceptor
// for streaming RPCs. The first interceptor will be the outer most,
// while the last interceptor will be the inner most wrapper around the real call.
// All stream interceptors added by this method will be chained.
func ChainStreamInterceptor(interceptors ...StreamServerInterceptor) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.chainStreamInts = append(o.chainStreamInts, interceptors...)
})
}
// InTapHandle returns a ServerOption that sets the tap handle for all the server
// transport to be created. Only one can be installed.
//
// Experimental
//
// Notice: This API is EXPERIMENTAL and may be changed or removed in a
// later release.
func InTapHandle(h tap.ServerInHandle) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
if o.inTapHandle != nil {
panic("The tap handle was already set and may not be reset.")
}
o.inTapHandle = h
})
}
// StatsHandler returns a ServerOption that sets the stats handler for the server.
func StatsHandler(h stats.Handler) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.statsHandler = h
})
}
// UnknownServiceHandler returns a ServerOption that allows for adding a custom
// unknown service handler. The provided method is a bidi-streaming RPC service
// handler that will be invoked instead of returning the "unimplemented" gRPC
// error whenever a request is received for an unregistered service or method.
// The handling function and stream interceptor (if set) have full access to
// the ServerStream, including its Context.
func UnknownServiceHandler(streamHandler StreamHandler) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.unknownStreamDesc = &StreamDesc{
StreamName: "unknown_service_handler",
Handler: streamHandler,
// We need to assume that the users of the streamHandler will want to use both.
ClientStreams: true,
ServerStreams: true,
}
})
}
// ConnectionTimeout returns a ServerOption that sets the timeout for
// connection establishment (up to and including HTTP/2 handshaking) for all
// new connections. If this is not set, the default is 120 seconds. A zero or
// negative value will result in an immediate timeout.
//
// Experimental
//
// Notice: This API is EXPERIMENTAL and may be changed or removed in a
// later release.
func ConnectionTimeout(d time.Duration) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.connectionTimeout = d
})
}
// MaxHeaderListSize returns a ServerOption that sets the max (uncompressed) size
// of header list that the server is prepared to accept.
func MaxHeaderListSize(s uint32) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.maxHeaderListSize = &s
})
}
// HeaderTableSize returns a ServerOption that sets the size of dynamic
// header table for stream.
//
// Experimental
//
// Notice: This API is EXPERIMENTAL and may be changed or removed in a
// later release.
func HeaderTableSize(s uint32) ServerOption {
return newFuncServerOption(func(o *serverOptions) {
o.headerTableSize = &s
})
}
// NumStreamWorkers returns a ServerOption that sets the number of worker
// goroutines that should be used to process incoming streams. Setting this to
// zero (default) will disable workers and spawn a new goroutine for each
// stream.
//
// Experimental
//
// Notice: This API is EXPERIMENTAL and may be changed or removed in a
// later release.
func NumStreamWorkers(numServerWorkers uint32) ServerOption {
// TODO: If/when this API gets stabilized (i.e. stream workers become the
// only way streams are processed), change the behavior of the zero value to
// a sane default. Preliminary experiments suggest that a value equal to the
// number of CPUs available is most performant; requires thorough testing.
return newFuncServerOption(func(o *serverOptions) {
o.numServerWorkers = numServerWorkers
})
}
// serverWorkerResetThreshold defines how often the stack must be reset. Every
// N requests, by spawning a new goroutine in its place, a worker can reset its
// stack so that large stacks don't live in memory forever. 2^16 should allow
// each goroutine stack to live for at least a few seconds in a typical
// workload (assuming a QPS of a few thousand requests/sec).
const serverWorkerResetThreshold = 1 << 16
// serverWorkers blocks on a *transport.Stream channel forever and waits for
// data to be fed by serveStreams. This allows different requests to be
// processed by the same goroutine, removing the need for expensive stack
// re-allocations (see the runtime.morestack problem [1]).
//
// [1] https://github.com/golang/go/issues/18138
func (s *Server) serverWorker(ch chan *serverWorkerData) {
// To make sure all server workers don't reset at the same time, choose a
// random number of iterations before resetting.
threshold := serverWorkerResetThreshold + grpcrand.Intn(serverWorkerResetThreshold)
for completed := 0; completed < threshold; completed++ {
data, ok := <-ch
if !ok {
return
}
s.handleStream(data.st, data.stream, s.traceInfo(data.st, data.stream))
data.wg.Done()
}
go s.serverWorker(ch)
}
// initServerWorkers creates worker goroutines and channels to process incoming
// connections to reduce the time spent overall on runtime.morestack.
func (s *Server) initServerWorkers() {
s.serverWorkerChannels = make([]chan *serverWorkerData, s.opts.numServerWorkers)
for i := uint32(0); i < s.opts.numServerWorkers; i++ {
s.serverWorkerChannels[i] = make(chan *serverWorkerData)
go s.serverWorker(s.serverWorkerChannels[i])
}
}
func (s *Server) stopServerWorkers() {
for i := uint32(0); i < s.opts.numServerWorkers; i++ {
close(s.serverWorkerChannels[i])
}
}
// NewServer creates a gRPC server which has no service registered and has not
// started to accept requests yet.
func NewServer(opt ...ServerOption) *Server {
opts := defaultServerOptions
for _, o := range opt {
o.apply(&opts)
}
s := &Server{
lis: make(map[net.Listener]bool),
opts: opts,
conns: make(map[string]map[transport.ServerTransport]bool),
services: make(map[string]*serviceInfo),
quit: grpcsync.NewEvent(),
done: grpcsync.NewEvent(),
czData: new(channelzData),
}
chainUnaryServerInterceptors(s)
chainStreamServerInterceptors(s)
s.cv = sync.NewCond(&s.mu)
if EnableTracing {
_, file, line, _ := runtime.Caller(1)
s.events = trace.NewEventLog("grpc.Server", fmt.Sprintf("%s:%d", file, line))
}
if s.opts.numServerWorkers > 0 {
s.initServerWorkers()
}
if channelz.IsOn() {
s.channelzID = channelz.RegisterServer(&channelzServer{s}, "")
}
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...)
}
}
// ServiceRegistrar wraps a single method that supports service registration. It
// enables users to pass concrete types other than grpc.Server to the service
// registration methods exported by the IDL generated code.
type ServiceRegistrar interface {
// RegisterService registers a service and its implementation to the
// concrete type implementing this interface. It may not be called
// once the server has started serving.
// desc describes the service and its methods and handlers. impl is the
// service implementation which is passed to the method handlers.
RegisterService(desc *ServiceDesc, impl interface{})
}
// RegisterService registers a service and its implementation to the gRPC
// server. It is called from the IDL generated code. This must be called before
// invoking Serve. If ss is non-nil (for legacy code), its type is checked to
// ensure it implements sd.HandlerType.
func (s *Server) RegisterService(sd *ServiceDesc, ss interface{}) {
if ss != nil {
ht := reflect.TypeOf(sd.HandlerType).Elem()
st := reflect.TypeOf(ss)
if !st.Implements(ht) {
logger.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 s.serve {
logger.Fatalf("grpc: Server.RegisterService after Server.Serve for %q", sd.ServiceName)
}
if _, ok := s.services[sd.ServiceName]; ok {
logger.Fatalf("grpc: Server.RegisterService found duplicate service registration for %q", sd.ServiceName)
}
info := &serviceInfo{
serviceImpl: ss,
methods: make(map[string]*MethodDesc),
streams: make(map[string]*StreamDesc),
mdata: sd.Metadata,
}
for i := range sd.Methods {
d := &sd.Methods[i]
info.methods[d.MethodName] = d
}
for i := range sd.Streams {
d := &sd.Streams[i]
info.streams[d.StreamName] = d
}
s.services[sd.ServiceName] = info
}
// MethodInfo contains the information of an RPC including its method name and type.
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 method 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.services {
methods := make([]MethodInfo, 0, len(srv.methods)+len(srv.streams))
for m := range srv.methods {
methods = append(methods, MethodInfo{
Name: m,
IsClientStream: false,
IsServerStream: false,
})
}
for m, d := range srv.streams {
methods = append(methods, MethodInfo{
Name: m,
IsClientStream: d.ClientStreams,
IsServerStream: d.ServerStreams,
})
}
ret[n] = ServiceInfo{
Methods: methods,
Metadata: srv.mdata,
}
}
return ret
}
// ErrServerStopped indicates that the operation is now illegal because of
// the server being stopped.
var ErrServerStopped = errors.New("grpc: the server has been stopped")
type listenSocket struct {
net.Listener
channelzID int64
}
func (l *listenSocket) ChannelzMetric() *channelz.SocketInternalMetric {
return &channelz.SocketInternalMetric{
SocketOptions: channelz.GetSocketOption(l.Listener),
LocalAddr: l.Listener.Addr(),
}
}
func (l *listenSocket) Close() error {
err := l.Listener.Close()
if channelz.IsOn() {
channelz.RemoveEntry(l.channelzID)
}
return err
}
// 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.
// Serve returns when lis.Accept fails with fatal errors. lis will be closed when
// this method returns.
// Serve will return a non-nil error unless Stop or GracefulStop is called.
func (s *Server) Serve(lis net.Listener) error {
s.mu.Lock()
s.printf("serving")
s.serve = true
if s.lis == nil {
// Serve called after Stop or GracefulStop.
s.mu.Unlock()
lis.Close()
return ErrServerStopped
}
s.serveWG.Add(1)
defer func() {
s.serveWG.Done()
if s.quit.HasFired() {
// Stop or GracefulStop called; block until done and return nil.
<-s.done.Done()
}
}()
ls := &listenSocket{Listener: lis}
s.lis[ls] = true
if channelz.IsOn() {
ls.channelzID = channelz.RegisterListenSocket(ls, s.channelzID, lis.Addr().String())
}
s.mu.Unlock()
defer func() {
s.mu.Lock()
if s.lis != nil && s.lis[ls] {
ls.Close()
delete(s.lis, ls)
}
s.mu.Unlock()
}()
var tempDelay time.Duration // how long to sleep on accept failure
for {
rawConn, err := lis.Accept()
if err != nil {
if ne, ok := err.(interface {
Temporary() bool
}); ok && ne.Temporary() {
if tempDelay == 0 {
tempDelay = 5 * time.Millisecond
} else {
tempDelay *= 2
}
if max := 1 * time.Second; tempDelay > max {
tempDelay = max
}
s.mu.Lock()
s.printf("Accept error: %v; retrying in %v", err, tempDelay)
s.mu.Unlock()
timer := time.NewTimer(tempDelay)
select {
case <-timer.C:
case <-s.quit.Done():
timer.Stop()
return nil
}
continue
}
s.mu.Lock()
s.printf("done serving; Accept = %v", err)
s.mu.Unlock()
if s.quit.HasFired() {
return nil
}
return err
}
tempDelay = 0
// Start a new goroutine to deal with rawConn so we don't stall this Accept
// loop goroutine.
//
// Make sure we account for the goroutine so GracefulStop doesn't nil out
// s.conns before this conn can be added.
s.serveWG.Add(1)
go func() {
s.handleRawConn(lis.Addr().String(), rawConn)
s.serveWG.Done()
}()
}
}
// 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(lisAddr string, rawConn net.Conn) {
if s.quit.HasFired() {
rawConn.Close()
return
}
rawConn.SetDeadline(time.Now().Add(s.opts.connectionTimeout))
// Finish handshaking (HTTP2)
st := s.newHTTP2Transport(rawConn)
rawConn.SetDeadline(time.Time{})
if st == nil {
return
}
if !s.addConn(lisAddr, st) {
return
}
go func() {
s.serveStreams(st)
s.removeConn(lisAddr, st)
}()
}
func (s *Server) drainServerTransports(addr string) {
s.mu.Lock()
conns := s.conns[addr]
for st := range conns {
st.Drain()
}
s.mu.Unlock()
}
// 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) transport.ServerTransport {
config := &transport.ServerConfig{
MaxStreams: s.opts.maxConcurrentStreams,
ConnectionTimeout: s.opts.connectionTimeout,
Credentials: s.opts.creds,
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(c, config)
if err != nil {
s.mu.Lock()
s.errorf("NewServerTransport(%q) failed: %v", c.RemoteAddr(), err)
s.mu.Unlock()
// ErrConnDispatched means that the connection was dispatched away from
// gRPC; those connections should be left open.
if err != credentials.ErrConnDispatched {
// Don't log on ErrConnDispatched and io.EOF to prevent log spam.
if err != io.EOF {
channelz.Warning(logger, s.channelzID, "grpc: Server.Serve failed to create ServerTransport: ", err)
}
c.Close()
}
return nil
}
return st
}
func (s *Server) serveStreams(st transport.ServerTransport) {
defer st.Close()
var wg sync.WaitGroup
var roundRobinCounter uint32
st.HandleStreams(func(stream *transport.Stream) {
wg.Add(1)
if s.opts.numServerWorkers > 0 {
data := &serverWorkerData{st: st, wg: &wg, stream: stream}
select {
case s.serverWorkerChannels[atomic.AddUint32(&roundRobinCounter, 1)%s.opts.numServerWorkers] <- data:
default:
// If all stream workers are busy, fallback to the default code path.
go func() {
s.handleStream(st, stream, s.traceInfo(st, stream))
wg.Done()
}()
}
} else {
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()
}
var _ http.Handler = (*Server)(nil)
// ServeHTTP implements the Go standard library's http.Handler
// interface by responding to the gRPC request r, by looking up
// the requested gRPC method in the gRPC server s.
//
// The provided HTTP request must have arrived on an HTTP/2
// connection. When using the Go standard library's server,
// practically this means that the Request must also have arrived
// over TLS.
//
// To share one port (such as 443 for https) between gRPC and an
// existing http.Handler, use a root http.Handler such as:
//
// if r.ProtoMajor == 2 && strings.HasPrefix(
// r.Header.Get("Content-Type"), "application/grpc") {
// grpcServer.ServeHTTP(w, r)
// } else {
// yourMux.ServeHTTP(w, r)
// }
//
// Note that ServeHTTP uses Go's HTTP/2 server implementation which is totally
// separate from grpc-go's HTTP/2 server. Performance and features may vary
// between the two paths. ServeHTTP does not support some gRPC features
// available through grpc-go's HTTP/2 server.
//
// Experimental
//
// Notice: This API is EXPERIMENTAL and may be changed or removed in a
// later release.
func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
st, err := transport.NewServerHandlerTransport(w, r, s.opts.statsHandler)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
if !s.addConn(listenerAddressForServeHTTP, st) {
return
}
defer s.removeConn(listenerAddressForServeHTTP, 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
}
tr, ok := trace.FromContext(stream.Context())
if !ok {
return nil
}
trInfo = &traceInfo{
tr: tr,
firstLine: firstLine{
client: false,
remoteAddr: st.RemoteAddr(),
},
}
if dl, ok := stream.Context().Deadline(); ok {
trInfo.firstLine.deadline = time.Until(dl)
}
return trInfo
}