diff options
Diffstat (limited to 'vendor/google.golang.org/grpc/clientconn.go')
| -rw-r--r-- | vendor/google.golang.org/grpc/clientconn.go | 1647 |
1 files changed, 1647 insertions, 0 deletions
diff --git a/vendor/google.golang.org/grpc/clientconn.go b/vendor/google.golang.org/grpc/clientconn.go new file mode 100644 index 000000000..d607d4e9e --- /dev/null +++ b/vendor/google.golang.org/grpc/clientconn.go @@ -0,0 +1,1647 @@ +/* + * + * 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://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" + "math" + "net/url" + "reflect" + "strings" + "sync" + "sync/atomic" + "time" + + "google.golang.org/grpc/balancer" + "google.golang.org/grpc/balancer/base" + "google.golang.org/grpc/codes" + "google.golang.org/grpc/connectivity" + "google.golang.org/grpc/credentials" + "google.golang.org/grpc/internal/backoff" + "google.golang.org/grpc/internal/channelz" + "google.golang.org/grpc/internal/grpcsync" + iresolver "google.golang.org/grpc/internal/resolver" + "google.golang.org/grpc/internal/transport" + "google.golang.org/grpc/keepalive" + "google.golang.org/grpc/resolver" + "google.golang.org/grpc/serviceconfig" + "google.golang.org/grpc/status" + + _ "google.golang.org/grpc/balancer/roundrobin" // To register roundrobin. + _ "google.golang.org/grpc/internal/resolver/dns" // To register dns resolver. + _ "google.golang.org/grpc/internal/resolver/passthrough" // To register passthrough resolver. + _ "google.golang.org/grpc/internal/resolver/unix" // To register unix resolver. +) + +const ( + // minimum time to give a connection to complete + minConnectTimeout = 20 * time.Second + // must match grpclbName in grpclb/grpclb.go + grpclbName = "grpclb" +) + +var ( + // ErrClientConnClosing indicates that the operation is illegal because + // the ClientConn is closing. + // + // Deprecated: this error should not be relied upon by users; use the status + // code of Canceled instead. + ErrClientConnClosing = status.Error(codes.Canceled, "grpc: the client connection is closing") + // errConnDrain indicates that the connection starts to be drained and does not accept any new RPCs. + errConnDrain = errors.New("grpc: the connection is drained") + // errConnClosing indicates that the connection is closing. + errConnClosing = errors.New("grpc: the connection is closing") + // invalidDefaultServiceConfigErrPrefix is used to prefix the json parsing error for the default + // service config. + invalidDefaultServiceConfigErrPrefix = "grpc: the provided default service config is invalid" +) + +// The following errors are returned from Dial and DialContext +var ( + // errNoTransportSecurity indicates that there is no transport security + // being set for ClientConn. Users should either set one or explicitly + // call WithInsecure DialOption to disable security. + errNoTransportSecurity = errors.New("grpc: no transport security set (use grpc.WithTransportCredentials(insecure.NewCredentials()) explicitly or set credentials)") + // errTransportCredsAndBundle indicates that creds bundle is used together + // with other individual Transport Credentials. + errTransportCredsAndBundle = errors.New("grpc: credentials.Bundle may not be used with individual TransportCredentials") + // errNoTransportCredsInBundle indicated that the configured creds bundle + // returned a transport credentials which was nil. + errNoTransportCredsInBundle = errors.New("grpc: credentials.Bundle must return non-nil transport credentials") + // errTransportCredentialsMissing indicates that users want to transmit + // security information (e.g., OAuth2 token) which requires secure + // connection on an insecure connection. + errTransportCredentialsMissing = errors.New("grpc: the credentials require transport level security (use grpc.WithTransportCredentials() to set)") +) + +const ( + defaultClientMaxReceiveMessageSize = 1024 * 1024 * 4 + defaultClientMaxSendMessageSize = math.MaxInt32 + // http2IOBufSize specifies the buffer size for sending frames. + defaultWriteBufSize = 32 * 1024 + defaultReadBufSize = 32 * 1024 +) + +// Dial creates a client connection to the given target. +func Dial(target string, opts ...DialOption) (*ClientConn, error) { + return DialContext(context.Background(), target, opts...) +} + +type defaultConfigSelector struct { + sc *ServiceConfig +} + +func (dcs *defaultConfigSelector) SelectConfig(rpcInfo iresolver.RPCInfo) (*iresolver.RPCConfig, error) { + return &iresolver.RPCConfig{ + Context: rpcInfo.Context, + MethodConfig: getMethodConfig(dcs.sc, rpcInfo.Method), + }, nil +} + +// DialContext creates a client connection to the given target. By default, it's +// a non-blocking dial (the function won't wait for connections to be +// established, and connecting happens in the background). To make it a blocking +// dial, use WithBlock() dial option. +// +// In the non-blocking case, the ctx does not act against the connection. It +// only controls the setup steps. +// +// In the blocking case, ctx can be used to cancel or expire the pending +// connection. Once this function returns, the cancellation and expiration of +// ctx will be noop. Users should call ClientConn.Close to terminate all the +// pending operations after this function returns. +// +// The target name syntax is defined in +// https://github.com/grpc/grpc/blob/master/doc/naming.md. +// e.g. to use dns resolver, a "dns:///" prefix should be applied to the target. +func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *ClientConn, err error) { + cc := &ClientConn{ + target: target, + csMgr: &connectivityStateManager{}, + conns: make(map[*addrConn]struct{}), + dopts: defaultDialOptions(), + blockingpicker: newPickerWrapper(), + czData: new(channelzData), + firstResolveEvent: grpcsync.NewEvent(), + } + cc.retryThrottler.Store((*retryThrottler)(nil)) + cc.safeConfigSelector.UpdateConfigSelector(&defaultConfigSelector{nil}) + cc.ctx, cc.cancel = context.WithCancel(context.Background()) + + for _, opt := range extraDialOptions { + opt.apply(&cc.dopts) + } + + for _, opt := range opts { + opt.apply(&cc.dopts) + } + + chainUnaryClientInterceptors(cc) + chainStreamClientInterceptors(cc) + + defer func() { + if err != nil { + cc.Close() + } + }() + + pid := cc.dopts.channelzParentID + cc.channelzID = channelz.RegisterChannel(&channelzChannel{cc}, pid, target) + ted := &channelz.TraceEventDesc{ + Desc: "Channel created", + Severity: channelz.CtInfo, + } + if cc.dopts.channelzParentID != nil { + ted.Parent = &channelz.TraceEventDesc{ + Desc: fmt.Sprintf("Nested Channel(id:%d) created", cc.channelzID.Int()), + Severity: channelz.CtInfo, + } + } + channelz.AddTraceEvent(logger, cc.channelzID, 1, ted) + cc.csMgr.channelzID = cc.channelzID + + if cc.dopts.copts.TransportCredentials == nil && cc.dopts.copts.CredsBundle == nil { + return nil, errNoTransportSecurity + } + if cc.dopts.copts.TransportCredentials != nil && cc.dopts.copts.CredsBundle != nil { + return nil, errTransportCredsAndBundle + } + if cc.dopts.copts.CredsBundle != nil && cc.dopts.copts.CredsBundle.TransportCredentials() == nil { + return nil, errNoTransportCredsInBundle + } + transportCreds := cc.dopts.copts.TransportCredentials + if transportCreds == nil { + transportCreds = cc.dopts.copts.CredsBundle.TransportCredentials() + } + if transportCreds.Info().SecurityProtocol == "insecure" { + for _, cd := range cc.dopts.copts.PerRPCCredentials { + if cd.RequireTransportSecurity() { + return nil, errTransportCredentialsMissing + } + } + } + + if cc.dopts.defaultServiceConfigRawJSON != nil { + scpr := parseServiceConfig(*cc.dopts.defaultServiceConfigRawJSON) + if scpr.Err != nil { + return nil, fmt.Errorf("%s: %v", invalidDefaultServiceConfigErrPrefix, scpr.Err) + } + cc.dopts.defaultServiceConfig, _ = scpr.Config.(*ServiceConfig) + } + cc.mkp = cc.dopts.copts.KeepaliveParams + + if cc.dopts.copts.UserAgent != "" { + cc.dopts.copts.UserAgent += " " + grpcUA + } else { + cc.dopts.copts.UserAgent = grpcUA + } + + if cc.dopts.timeout > 0 { + var cancel context.CancelFunc + ctx, cancel = context.WithTimeout(ctx, cc.dopts.timeout) + defer cancel() + } + defer func() { + select { + case <-ctx.Done(): + switch { + case ctx.Err() == err: + conn = nil + case err == nil || !cc.dopts.returnLastError: + conn, err = nil, ctx.Err() + default: + conn, err = nil, fmt.Errorf("%v: %v", ctx.Err(), err) + } + default: + } + }() + + scSet := false + if cc.dopts.scChan != nil { + // Try to get an initial service config. + select { + case sc, ok := <-cc.dopts.scChan: + if ok { + cc.sc = &sc + cc.safeConfigSelector.UpdateConfigSelector(&defaultConfigSelector{&sc}) + scSet = true + } + default: + } + } + if cc.dopts.bs == nil { + cc.dopts.bs = backoff.DefaultExponential + } + + // Determine the resolver to use. + resolverBuilder, err := cc.parseTargetAndFindResolver() + if err != nil { + return nil, err + } + cc.authority, err = determineAuthority(cc.parsedTarget.Endpoint(), cc.target, cc.dopts) + if err != nil { + return nil, err + } + channelz.Infof(logger, cc.channelzID, "Channel authority set to %q", cc.authority) + + if cc.dopts.scChan != nil && !scSet { + // Blocking wait for the initial service config. + select { + case sc, ok := <-cc.dopts.scChan: + if ok { + cc.sc = &sc + cc.safeConfigSelector.UpdateConfigSelector(&defaultConfigSelector{&sc}) + } + case <-ctx.Done(): + return nil, ctx.Err() + } + } + if cc.dopts.scChan != nil { + go cc.scWatcher() + } + + var credsClone credentials.TransportCredentials + if creds := cc.dopts.copts.TransportCredentials; creds != nil { + credsClone = creds.Clone() + } + cc.balancerWrapper = newCCBalancerWrapper(cc, balancer.BuildOptions{ + DialCreds: credsClone, + CredsBundle: cc.dopts.copts.CredsBundle, + Dialer: cc.dopts.copts.Dialer, + Authority: cc.authority, + CustomUserAgent: cc.dopts.copts.UserAgent, + ChannelzParentID: cc.channelzID, + Target: cc.parsedTarget, + }) + + // Build the resolver. + rWrapper, err := newCCResolverWrapper(cc, resolverBuilder) + if err != nil { + return nil, fmt.Errorf("failed to build resolver: %v", err) + } + cc.mu.Lock() + cc.resolverWrapper = rWrapper + cc.mu.Unlock() + + // A blocking dial blocks until the clientConn is ready. + if cc.dopts.block { + for { + cc.Connect() + s := cc.GetState() + if s == connectivity.Ready { + break + } else if cc.dopts.copts.FailOnNonTempDialError && s == connectivity.TransientFailure { + if err = cc.connectionError(); err != nil { + terr, ok := err.(interface { + Temporary() bool + }) + if ok && !terr.Temporary() { + return nil, err + } + } + } + if !cc.WaitForStateChange(ctx, s) { + // ctx got timeout or canceled. + if err = cc.connectionError(); err != nil && cc.dopts.returnLastError { + return nil, err + } + return nil, ctx.Err() + } + } + } + + return cc, nil +} + +// chainUnaryClientInterceptors chains all unary client interceptors into one. +func chainUnaryClientInterceptors(cc *ClientConn) { + interceptors := cc.dopts.chainUnaryInts + // Prepend dopts.unaryInt to the chaining interceptors if it exists, since unaryInt will + // be executed before any other chained interceptors. + if cc.dopts.unaryInt != nil { + interceptors = append([]UnaryClientInterceptor{cc.dopts.unaryInt}, interceptors...) + } + var chainedInt UnaryClientInterceptor + if len(interceptors) == 0 { + chainedInt = nil + } else if len(interceptors) == 1 { + chainedInt = interceptors[0] + } else { + chainedInt = func(ctx context.Context, method string, req, reply interface{}, cc *ClientConn, invoker UnaryInvoker, opts ...CallOption) error { + return interceptors[0](ctx, method, req, reply, cc, getChainUnaryInvoker(interceptors, 0, invoker), opts...) + } + } + cc.dopts.unaryInt = chainedInt +} + +// getChainUnaryInvoker recursively generate the chained unary invoker. +func getChainUnaryInvoker(interceptors []UnaryClientInterceptor, curr int, finalInvoker UnaryInvoker) UnaryInvoker { + if curr == len(interceptors)-1 { + return finalInvoker + } + return func(ctx context.Context, method string, req, reply interface{}, cc *ClientConn, opts ...CallOption) error { + return interceptors[curr+1](ctx, method, req, reply, cc, getChainUnaryInvoker(interceptors, curr+1, finalInvoker), opts...) + } +} + +// chainStreamClientInterceptors chains all stream client interceptors into one. +func chainStreamClientInterceptors(cc *ClientConn) { + interceptors := cc.dopts.chainStreamInts + // Prepend dopts.streamInt to the chaining interceptors if it exists, since streamInt will + // be executed before any other chained interceptors. + if cc.dopts.streamInt != nil { + interceptors = append([]StreamClientInterceptor{cc.dopts.streamInt}, interceptors...) + } + var chainedInt StreamClientInterceptor + if len(interceptors) == 0 { + chainedInt = nil + } else if len(interceptors) == 1 { + chainedInt = interceptors[0] + } else { + chainedInt = func(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, streamer Streamer, opts ...CallOption) (ClientStream, error) { + return interceptors[0](ctx, desc, cc, method, getChainStreamer(interceptors, 0, streamer), opts...) + } + } + cc.dopts.streamInt = chainedInt +} + +// getChainStreamer recursively generate the chained client stream constructor. +func getChainStreamer(interceptors []StreamClientInterceptor, curr int, finalStreamer Streamer) Streamer { + if curr == len(interceptors)-1 { + return finalStreamer + } + return func(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (ClientStream, error) { + return interceptors[curr+1](ctx, desc, cc, method, getChainStreamer(interceptors, curr+1, finalStreamer), opts...) + } +} + +// connectivityStateManager keeps the connectivity.State of ClientConn. +// This struct will eventually be exported so the balancers can access it. +type connectivityStateManager struct { + mu sync.Mutex + state connectivity.State + notifyChan chan struct{} + channelzID *channelz.Identifier +} + +// updateState updates the connectivity.State of ClientConn. +// If there's a change it notifies goroutines waiting on state change to +// happen. +func (csm *connectivityStateManager) updateState(state connectivity.State) { + csm.mu.Lock() + defer csm.mu.Unlock() + if csm.state == connectivity.Shutdown { + return + } + if csm.state == state { + return + } + csm.state = state + channelz.Infof(logger, csm.channelzID, "Channel Connectivity change to %v", state) + if csm.notifyChan != nil { + // There are other goroutines waiting on this channel. + close(csm.notifyChan) + csm.notifyChan = nil + } +} + +func (csm *connectivityStateManager) getState() connectivity.State { + csm.mu.Lock() + defer csm.mu.Unlock() + return csm.state +} + +func (csm *connectivityStateManager) getNotifyChan() <-chan struct{} { + csm.mu.Lock() + defer csm.mu.Unlock() + if csm.notifyChan == nil { + csm.notifyChan = make(chan struct{}) + } + return csm.notifyChan +} + +// ClientConnInterface defines the functions clients need to perform unary and +// streaming RPCs. It is implemented by *ClientConn, and is only intended to +// be referenced by generated code. +type ClientConnInterface interface { + // Invoke performs a unary RPC and returns after the response is received + // into reply. + Invoke(ctx context.Context, method string, args interface{}, reply interface{}, opts ...CallOption) error + // NewStream begins a streaming RPC. + NewStream(ctx context.Context, desc *StreamDesc, method string, opts ...CallOption) (ClientStream, error) +} + +// Assert *ClientConn implements ClientConnInterface. +var _ ClientConnInterface = (*ClientConn)(nil) + +// ClientConn represents a virtual connection to a conceptual endpoint, to +// perform RPCs. +// +// A ClientConn is free to have zero or more actual connections to the endpoint +// based on configuration, load, etc. It is also free to determine which actual +// endpoints to use and may change it every RPC, permitting client-side load +// balancing. +// +// A ClientConn encapsulates a range of functionality including name +// resolution, TCP connection establishment (with retries and backoff) and TLS +// handshakes. It also handles errors on established connections by +// re-resolving the name and reconnecting. +type ClientConn struct { + ctx context.Context // Initialized using the background context at dial time. + cancel context.CancelFunc // Cancelled on close. + + // The following are initialized at dial time, and are read-only after that. + target string // User's dial target. + parsedTarget resolver.Target // See parseTargetAndFindResolver(). + authority string // See determineAuthority(). + dopts dialOptions // Default and user specified dial options. + channelzID *channelz.Identifier // Channelz identifier for the channel. + balancerWrapper *ccBalancerWrapper // Uses gracefulswitch.balancer underneath. + + // The following provide their own synchronization, and therefore don't + // require cc.mu to be held to access them. + csMgr *connectivityStateManager + blockingpicker *pickerWrapper + safeConfigSelector iresolver.SafeConfigSelector + czData *channelzData + retryThrottler atomic.Value // Updated from service config. + + // firstResolveEvent is used to track whether the name resolver sent us at + // least one update. RPCs block on this event. + firstResolveEvent *grpcsync.Event + + // mu protects the following fields. + // TODO: split mu so the same mutex isn't used for everything. + mu sync.RWMutex + resolverWrapper *ccResolverWrapper // Initialized in Dial; cleared in Close. + sc *ServiceConfig // Latest service config received from the resolver. + conns map[*addrConn]struct{} // Set to nil on close. + mkp keepalive.ClientParameters // May be updated upon receipt of a GoAway. + + lceMu sync.Mutex // protects lastConnectionError + lastConnectionError error +} + +// WaitForStateChange waits until the connectivity.State of ClientConn changes from sourceState or +// ctx expires. A true value is returned in former case and false in latter. +// +// # Experimental +// +// Notice: This API is EXPERIMENTAL and may be changed or removed in a +// later release. +func (cc *ClientConn) WaitForStateChange(ctx context.Context, sourceState connectivity.State) bool { + ch := cc.csMgr.getNotifyChan() + if cc.csMgr.getState() != sourceState { + return true + } + select { + case <-ctx.Done(): + return false + case <-ch: + return true + } +} + +// GetState returns the connectivity.State of ClientConn. +// +// # Experimental +// +// Notice: This API is EXPERIMENTAL and may be changed or removed in a later +// release. +func (cc *ClientConn) GetState() connectivity.State { + return cc.csMgr.getState() +} + +// Connect causes all subchannels in the ClientConn to attempt to connect if +// the channel is idle. Does not wait for the connection attempts to begin +// before returning. +// +// # Experimental +// +// Notice: This API is EXPERIMENTAL and may be changed or removed in a later +// release. +func (cc *ClientConn) Connect() { + cc.balancerWrapper.exitIdle() +} + +func (cc *ClientConn) scWatcher() { + for { + select { + case sc, ok := <-cc.dopts.scChan: + if !ok { + return + } + cc.mu.Lock() + // TODO: load balance policy runtime change is ignored. + // We may revisit this decision in the future. + cc.sc = &sc + cc.safeConfigSelector.UpdateConfigSelector(&defaultConfigSelector{&sc}) + cc.mu.Unlock() + case <-cc.ctx.Done(): + return + } + } +} + +// waitForResolvedAddrs blocks until the resolver has provided addresses or the +// context expires. Returns nil unless the context expires first; otherwise +// returns a status error based on the context. +func (cc *ClientConn) waitForResolvedAddrs(ctx context.Context) error { + // This is on the RPC path, so we use a fast path to avoid the + // more-expensive "select" below after the resolver has returned once. + if cc.firstResolveEvent.HasFired() { + return nil + } + select { + case <-cc.firstResolveEvent.Done(): + return nil + case <-ctx.Done(): + return status.FromContextError(ctx.Err()).Err() + case <-cc.ctx.Done(): + return ErrClientConnClosing + } +} + +var emptyServiceConfig *ServiceConfig + +func init() { + cfg := parseServiceConfig("{}") + if cfg.Err != nil { + panic(fmt.Sprintf("impossible error parsing empty service config: %v", cfg.Err)) + } + emptyServiceConfig = cfg.Config.(*ServiceConfig) +} + +func (cc *ClientConn) maybeApplyDefaultServiceConfig(addrs []resolver.Address) { + if cc.sc != nil { + cc.applyServiceConfigAndBalancer(cc.sc, nil, addrs) + return + } + if cc.dopts.defaultServiceConfig != nil { + cc.applyServiceConfigAndBalancer(cc.dopts.defaultServiceConfig, &defaultConfigSelector{cc.dopts.defaultServiceConfig}, addrs) + } else { + cc.applyServiceConfigAndBalancer(emptyServiceConfig, &defaultConfigSelector{emptyServiceConfig}, addrs) + } +} + +func (cc *ClientConn) updateResolverState(s resolver.State, err error) error { + defer cc.firstResolveEvent.Fire() + cc.mu.Lock() + // Check if the ClientConn is already closed. Some fields (e.g. + // balancerWrapper) are set to nil when closing the ClientConn, and could + // cause nil pointer panic if we don't have this check. + if cc.conns == nil { + cc.mu.Unlock() + return nil + } + + if err != nil { + // May need to apply the initial service config in case the resolver + // doesn't support service configs, or doesn't provide a service config + // with the new addresses. + cc.maybeApplyDefaultServiceConfig(nil) + + cc.balancerWrapper.resolverError(err) + + // No addresses are valid with err set; return early. + cc.mu.Unlock() + return balancer.ErrBadResolverState + } + + var ret error + if cc.dopts.disableServiceConfig { + channelz.Infof(logger, cc.channelzID, "ignoring service config from resolver (%v) and applying the default because service config is disabled", s.ServiceConfig) + cc.maybeApplyDefaultServiceConfig(s.Addresses) + } else if s.ServiceConfig == nil { + cc.maybeApplyDefaultServiceConfig(s.Addresses) + // TODO: do we need to apply a failing LB policy if there is no + // default, per the error handling design? + } else { + if sc, ok := s.ServiceConfig.Config.(*ServiceConfig); s.ServiceConfig.Err == nil && ok { + configSelector := iresolver.GetConfigSelector(s) + if configSelector != nil { + if len(s.ServiceConfig.Config.(*ServiceConfig).Methods) != 0 { + channelz.Infof(logger, cc.channelzID, "method configs in service config will be ignored due to presence of config selector") + } + } else { + configSelector = &defaultConfigSelector{sc} + } + cc.applyServiceConfigAndBalancer(sc, configSelector, s.Addresses) + } else { + ret = balancer.ErrBadResolverState + if cc.sc == nil { + // Apply the failing LB only if we haven't received valid service config + // from the name resolver in the past. + cc.applyFailingLB(s.ServiceConfig) + cc.mu.Unlock() + return ret + } + } + } + + var balCfg serviceconfig.LoadBalancingConfig + if cc.sc != nil && cc.sc.lbConfig != nil { + balCfg = cc.sc.lbConfig.cfg + } + bw := cc.balancerWrapper + cc.mu.Unlock() + + uccsErr := bw.updateClientConnState(&balancer.ClientConnState{ResolverState: s, BalancerConfig: balCfg}) + if ret == nil { + ret = uccsErr // prefer ErrBadResolver state since any other error is + // currently meaningless to the caller. + } + return ret +} + +// applyFailingLB is akin to configuring an LB policy on the channel which +// always fails RPCs. Here, an actual LB policy is not configured, but an always +// erroring picker is configured, which returns errors with information about +// what was invalid in the received service config. A config selector with no +// service config is configured, and the connectivity state of the channel is +// set to TransientFailure. +// +// Caller must hold cc.mu. +func (cc *ClientConn) applyFailingLB(sc *serviceconfig.ParseResult) { + var err error + if sc.Err != nil { + err = status.Errorf(codes.Unavailable, "error parsing service config: %v", sc.Err) + } else { + err = status.Errorf(codes.Unavailable, "illegal service config type: %T", sc.Config) + } + cc.safeConfigSelector.UpdateConfigSelector(&defaultConfigSelector{nil}) + cc.blockingpicker.updatePicker(base.NewErrPicker(err)) + cc.csMgr.updateState(connectivity.TransientFailure) +} + +func (cc *ClientConn) handleSubConnStateChange(sc balancer.SubConn, s connectivity.State, err error) { + cc.balancerWrapper.updateSubConnState(sc, s, err) +} + +// newAddrConn creates an addrConn for addrs and adds it to cc.conns. +// +// Caller needs to make sure len(addrs) > 0. +func (cc *ClientConn) newAddrConn(addrs []resolver.Address, opts balancer.NewSubConnOptions) (*addrConn, error) { + ac := &addrConn{ + state: connectivity.Idle, + cc: cc, + addrs: addrs, + scopts: opts, + dopts: cc.dopts, + czData: new(channelzData), + resetBackoff: make(chan struct{}), + } + ac.ctx, ac.cancel = context.WithCancel(cc.ctx) + // Track ac in cc. This needs to be done before any getTransport(...) is called. + cc.mu.Lock() + defer cc.mu.Unlock() + if cc.conns == nil { + return nil, ErrClientConnClosing + } + + var err error + ac.channelzID, err = channelz.RegisterSubChannel(ac, cc.channelzID, "") + if err != nil { + return nil, err + } + channelz.AddTraceEvent(logger, ac.channelzID, 0, &channelz.TraceEventDesc{ + Desc: "Subchannel created", + Severity: channelz.CtInfo, + Parent: &channelz.TraceEventDesc{ + Desc: fmt.Sprintf("Subchannel(id:%d) created", ac.channelzID.Int()), + Severity: channelz.CtInfo, + }, + }) + + cc.conns[ac] = struct{}{} + return ac, nil +} + +// removeAddrConn removes the addrConn in the subConn from clientConn. +// It also tears down the ac with the given error. +func (cc *ClientConn) removeAddrConn(ac *addrConn, err error) { + cc.mu.Lock() + if cc.conns == nil { + cc.mu.Unlock() + return + } + delete(cc.conns, ac) + cc.mu.Unlock() + ac.tearDown(err) +} + +func (cc *ClientConn) channelzMetric() *channelz.ChannelInternalMetric { + return &channelz.ChannelInternalMetric{ + State: cc.GetState(), + Target: cc.target, + CallsStarted: atomic.LoadInt64(&cc.czData.callsStarted), + CallsSucceeded: atomic.LoadInt64(&cc.czData.callsSucceeded), + CallsFailed: atomic.LoadInt64(&cc.czData.callsFailed), + LastCallStartedTimestamp: time.Unix(0, atomic.LoadInt64(&cc.czData.lastCallStartedTime)), + } +} + +// Target returns the target string of the ClientConn. +// +// # Experimental +// +// Notice: This API is EXPERIMENTAL and may be changed or removed in a +// later release. +func (cc *ClientConn) Target() string { + return cc.target +} + +func (cc *ClientConn) incrCallsStarted() { + atomic.AddInt64(&cc.czData.callsStarted, 1) + atomic.StoreInt64(&cc.czData.lastCallStartedTime, time.Now().UnixNano()) +} + +func (cc *ClientConn) incrCallsSucceeded() { + atomic.AddInt64(&cc.czData.callsSucceeded, 1) +} + +func (cc *ClientConn) incrCallsFailed() { + atomic.AddInt64(&cc.czData.callsFailed, 1) +} + +// connect starts creating a transport. +// It does nothing if the ac is not IDLE. +// TODO(bar) Move this to the addrConn section. +func (ac *addrConn) connect() error { + ac.mu.Lock() + if ac.state == connectivity.Shutdown { + if logger.V(2) { + logger.Infof("connect called on shutdown addrConn; ignoring.") + } + ac.mu.Unlock() + return errConnClosing + } + if ac.state != connectivity.Idle { + if logger.V(2) { + logger.Infof("connect called on addrConn in non-idle state (%v); ignoring.", ac.state) + } + ac.mu.Unlock() + return nil + } + // Update connectivity state within the lock to prevent subsequent or + // concurrent calls from resetting the transport more than once. + ac.updateConnectivityState(connectivity.Connecting, nil) + ac.mu.Unlock() + + ac.resetTransport() + return nil +} + +func equalAddresses(a, b []resolver.Address) bool { + if len(a) != len(b) { + return false + } + for i, v := range a { + if !v.Equal(b[i]) { + return false + } + } + return true +} + +// tryUpdateAddrs tries to update ac.addrs with the new addresses list. +// +// If ac is TransientFailure, it updates ac.addrs and returns true. The updated +// addresses will be picked up by retry in the next iteration after backoff. +// +// If ac is Shutdown or Idle, it updates ac.addrs and returns true. +// +// If the addresses is the same as the old list, it does nothing and returns +// true. +// +// If ac is Connecting, it returns false. The caller should tear down the ac and +// create a new one. Note that the backoff will be reset when this happens. +// +// If ac is Ready, it checks whether current connected address of ac is in the +// new addrs list. +// - If true, it updates ac.addrs and returns true. The ac will keep using +// the existing connection. +// - If false, it does nothing and returns false. +func (ac *addrConn) tryUpdateAddrs(addrs []resolver.Address) bool { + ac.mu.Lock() + defer ac.mu.Unlock() + channelz.Infof(logger, ac.channelzID, "addrConn: tryUpdateAddrs curAddr: %v, addrs: %v", ac.curAddr, addrs) + if ac.state == connectivity.Shutdown || + ac.state == connectivity.TransientFailure || + ac.state == connectivity.Idle { + ac.addrs = addrs + return true + } + + if equalAddresses(ac.addrs, addrs) { + return true + } + + if ac.state == connectivity.Connecting { + return false + } + + // ac.state is Ready, try to find the connected address. + var curAddrFound bool + for _, a := range addrs { + a.ServerName = ac.cc.getServerName(a) + if reflect.DeepEqual(ac.curAddr, a) { + curAddrFound = true + break + } + } + channelz.Infof(logger, ac.channelzID, "addrConn: tryUpdateAddrs curAddrFound: %v", curAddrFound) + if curAddrFound { + ac.addrs = addrs + } + + return curAddrFound +} + +// getServerName determines the serverName to be used in the connection +// handshake. The default value for the serverName is the authority on the +// ClientConn, which either comes from the user's dial target or through an +// authority override specified using the WithAuthority dial option. Name +// resolvers can specify a per-address override for the serverName through the +// resolver.Address.ServerName field which is used only if the WithAuthority +// dial option was not used. The rationale is that per-address authority +// overrides specified by the name resolver can represent a security risk, while +// an override specified by the user is more dependable since they probably know +// what they are doing. +func (cc *ClientConn) getServerName(addr resolver.Address) string { + if cc.dopts.authority != "" { + return cc.dopts.authority + } + if addr.ServerName != "" { + return addr.ServerName + } + return cc.authority +} + +func getMethodConfig(sc *ServiceConfig, method string) MethodConfig { + if sc == nil { + return MethodConfig{} + } + if m, ok := sc.Methods[method]; ok { + return m + } + i := strings.LastIndex(method, "/") + if m, ok := sc.Methods[method[:i+1]]; ok { + return m + } + return sc.Methods[""] +} + +// GetMethodConfig gets the method config of the input method. +// If there's an exact match for input method (i.e. /service/method), we return +// the corresponding MethodConfig. +// If there isn't an exact match for the input method, we look for the service's default +// config under the service (i.e /service/) and then for the default for all services (empty string). +// +// If there is a default MethodConfig for the service, we return it. +// Otherwise, we return an empty MethodConfig. +func (cc *ClientConn) GetMethodConfig(method string) MethodConfig { + // TODO: Avoid the locking here. + cc.mu.RLock() + defer cc.mu.RUnlock() + return getMethodConfig(cc.sc, method) +} + +func (cc *ClientConn) healthCheckConfig() *healthCheckConfig { + cc.mu.RLock() + defer cc.mu.RUnlock() + if cc.sc == nil { + return nil + } + return cc.sc.healthCheckConfig +} + +func (cc *ClientConn) getTransport(ctx context.Context, failfast bool, method string) (transport.ClientTransport, balancer.PickResult, error) { + return cc.blockingpicker.pick(ctx, failfast, balancer.PickInfo{ + Ctx: ctx, + FullMethodName: method, + }) +} + +func (cc *ClientConn) applyServiceConfigAndBalancer(sc *ServiceConfig, configSelector iresolver.ConfigSelector, addrs []resolver.Address) { + if sc == nil { + // should never reach here. + return + } + cc.sc = sc + if configSelector != nil { + cc.safeConfigSelector.UpdateConfigSelector(configSelector) + } + + if cc.sc.retryThrottling != nil { + newThrottler := &retryThrottler{ + tokens: cc.sc.retryThrottling.MaxTokens, + max: cc.sc.retryThrottling.MaxTokens, + thresh: cc.sc.retryThrottling.MaxTokens / 2, + ratio: cc.sc.retryThrottling.TokenRatio, + } + cc.retryThrottler.Store(newThrottler) + } else { + cc.retryThrottler.Store((*retryThrottler)(nil)) + } + + var newBalancerName string + if cc.sc != nil && cc.sc.lbConfig != nil { + newBalancerName = cc.sc.lbConfig.name + } else { + var isGRPCLB bool + for _, a := range addrs { + if a.Type == resolver.GRPCLB { + isGRPCLB = true + break + } + } + if isGRPCLB { + newBalancerName = grpclbName + } else if cc.sc != nil && cc.sc.LB != nil { + newBalancerName = *cc.sc.LB + } else { + newBalancerName = PickFirstBalancerName + } + } + cc.balancerWrapper.switchTo(newBalancerName) +} + +func (cc *ClientConn) resolveNow(o resolver.ResolveNowOptions) { + cc.mu.RLock() + r := cc.resolverWrapper + cc.mu.RUnlock() + if r == nil { + return + } + go r.resolveNow(o) +} + +// ResetConnectBackoff wakes up all subchannels in transient failure and causes +// them to attempt another connection immediately. It also resets the backoff +// times used for subsequent attempts regardless of the current state. +// +// In general, this function should not be used. Typical service or network +// outages result in a reasonable client reconnection strategy by default. +// However, if a previously unavailable network becomes available, this may be +// used to trigger an immediate reconnect. +// +// # Experimental +// +// Notice: This API is EXPERIMENTAL and may be changed or removed in a +// later release. +func (cc *ClientConn) ResetConnectBackoff() { + cc.mu.Lock() + conns := cc.conns + cc.mu.Unlock() + for ac := range conns { + ac.resetConnectBackoff() + } +} + +// Close tears down the ClientConn and all underlying connections. +func (cc *ClientConn) Close() error { + defer cc.cancel() + + cc.mu.Lock() + if cc.conns == nil { + cc.mu.Unlock() + return ErrClientConnClosing + } + conns := cc.conns + cc.conns = nil + cc.csMgr.updateState(connectivity.Shutdown) + + rWrapper := cc.resolverWrapper + cc.resolverWrapper = nil + bWrapper := cc.balancerWrapper + cc.mu.Unlock() + + // The order of closing matters here since the balancer wrapper assumes the + // picker is closed before it is closed. + cc.blockingpicker.close() + if bWrapper != nil { + bWrapper.close() + } + if rWrapper != nil { + rWrapper.close() + } + + for ac := range conns { + ac.tearDown(ErrClientConnClosing) + } + ted := &channelz.TraceEventDesc{ + Desc: "Channel deleted", + Severity: channelz.CtInfo, + } + if cc.dopts.channelzParentID != nil { + ted.Parent = &channelz.TraceEventDesc{ + Desc: fmt.Sprintf("Nested channel(id:%d) deleted", cc.channelzID.Int()), + Severity: channelz.CtInfo, + } + } + channelz.AddTraceEvent(logger, cc.channelzID, 0, ted) + // TraceEvent needs to be called before RemoveEntry, as TraceEvent may add + // trace reference to the entity being deleted, and thus prevent it from being + // deleted right away. + channelz.RemoveEntry(cc.channelzID) + + return nil +} + +// addrConn is a network connection to a given address. +type addrConn struct { + ctx context.Context + cancel context.CancelFunc + + cc *ClientConn + dopts dialOptions + acbw balancer.SubConn + scopts balancer.NewSubConnOptions + + // transport is set when there's a viable transport (note: ac state may not be READY as LB channel + // health checking may require server to report healthy to set ac to READY), and is reset + // to nil when the current transport should no longer be used to create a stream (e.g. after GoAway + // is received, transport is closed, ac has been torn down). + transport transport.ClientTransport // The current transport. + + mu sync.Mutex + curAddr resolver.Address // The current address. + addrs []resolver.Address // All addresses that the resolver resolved to. + + // Use updateConnectivityState for updating addrConn's connectivity state. + state connectivity.State + + backoffIdx int // Needs to be stateful for resetConnectBackoff. + resetBackoff chan struct{} + + channelzID *channelz.Identifier + czData *channelzData +} + +// Note: this requires a lock on ac.mu. +func (ac *addrConn) updateConnectivityState(s connectivity.State, lastErr error) { + if ac.state == s { + return + } + ac.state = s + channelz.Infof(logger, ac.channelzID, "Subchannel Connectivity change to %v", s) + ac.cc.handleSubConnStateChange(ac.acbw, s, lastErr) +} + +// adjustParams updates parameters used to create transports upon +// receiving a GoAway. +func (ac *addrConn) adjustParams(r transport.GoAwayReason) { + switch r { + case transport.GoAwayTooManyPings: + v := 2 * ac.dopts.copts.KeepaliveParams.Time + ac.cc.mu.Lock() + if v > ac.cc.mkp.Time { + ac.cc.mkp.Time = v + } + ac.cc.mu.Unlock() + } +} + +func (ac *addrConn) resetTransport() { + ac.mu.Lock() + if ac.state == connectivity.Shutdown { + ac.mu.Unlock() + return + } + + addrs := ac.addrs + backoffFor := ac.dopts.bs.Backoff(ac.backoffIdx) + // This will be the duration that dial gets to finish. + dialDuration := minConnectTimeout + if ac.dopts.minConnectTimeout != nil { + dialDuration = ac.dopts.minConnectTimeout() + } + + if dialDuration < backoffFor { + // Give dial more time as we keep failing to connect. + dialDuration = backoffFor + } + // We can potentially spend all the time trying the first address, and + // if the server accepts the connection and then hangs, the following + // addresses will never be tried. + // + // The spec doesn't mention what should be done for multiple addresses. + // https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md#proposed-backoff-algorithm + connectDeadline := time.Now().Add(dialDuration) + + ac.updateConnectivityState(connectivity.Connecting, nil) + ac.mu.Unlock() + + if err := ac.tryAllAddrs(addrs, connectDeadline); err != nil { + ac.cc.resolveNow(resolver.ResolveNowOptions{}) + // After exhausting all addresses, the addrConn enters + // TRANSIENT_FAILURE. + ac.mu.Lock() + if ac.state == connectivity.Shutdown { + ac.mu.Unlock() + return + } + ac.updateConnectivityState(connectivity.TransientFailure, err) + + // Backoff. + b := ac.resetBackoff + ac.mu.Unlock() + + timer := time.NewTimer(backoffFor) + select { + case <-timer.C: + ac.mu.Lock() + ac.backoffIdx++ + ac.mu.Unlock() + case <-b: + timer.Stop() + case <-ac.ctx.Done(): + timer.Stop() + return + } + + ac.mu.Lock() + if ac.state != connectivity.Shutdown { + ac.updateConnectivityState(connectivity.Idle, err) + } + ac.mu.Unlock() + return + } + // Success; reset backoff. + ac.mu.Lock() + ac.backoffIdx = 0 + ac.mu.Unlock() +} + +// tryAllAddrs tries to creates a connection to the addresses, and stop when at +// the first successful one. It returns an error if no address was successfully +// connected, or updates ac appropriately with the new transport. +func (ac *addrConn) tryAllAddrs(addrs []resolver.Address, connectDeadline time.Time) error { + var firstConnErr error + for _, addr := range addrs { + ac.mu.Lock() + if ac.state == connectivity.Shutdown { + ac.mu.Unlock() + return errConnClosing + } + + ac.cc.mu.RLock() + ac.dopts.copts.KeepaliveParams = ac.cc.mkp + ac.cc.mu.RUnlock() + + copts := ac.dopts.copts + if ac.scopts.CredsBundle != nil { + copts.CredsBundle = ac.scopts.CredsBundle + } + ac.mu.Unlock() + + channelz.Infof(logger, ac.channelzID, "Subchannel picks a new address %q to connect", addr.Addr) + + err := ac.createTransport(addr, copts, connectDeadline) + if err == nil { + return nil + } + if firstConnErr == nil { + firstConnErr = err + } + ac.cc.updateConnectionError(err) + } + + // Couldn't connect to any address. + return firstConnErr +} + +// createTransport creates a connection to addr. It returns an error if the +// address was not successfully connected, or updates ac appropriately with the +// new transport. +func (ac *addrConn) createTransport(addr resolver.Address, copts transport.ConnectOptions, connectDeadline time.Time) error { + addr.ServerName = ac.cc.getServerName(addr) + hctx, hcancel := context.WithCancel(ac.ctx) + + onClose := func(r transport.GoAwayReason) { + ac.mu.Lock() + defer ac.mu.Unlock() + // adjust params based on GoAwayReason + ac.adjustParams(r) + if ac.state == connectivity.Shutdown { + // Already shut down. tearDown() already cleared the transport and + // canceled hctx via ac.ctx, and we expected this connection to be + // closed, so do nothing here. + return + } + hcancel() + if ac.transport == nil { + // We're still connecting to this address, which could error. Do + // not update the connectivity state or resolve; these will happen + // at the end of the tryAllAddrs connection loop in the event of an + // error. + return + } + ac.transport = nil + // Refresh the name resolver on any connection loss. + ac.cc.resolveNow(resolver.ResolveNowOptions{}) + // Always go idle and wait for the LB policy to initiate a new + // connection attempt. + ac.updateConnectivityState(connectivity.Idle, nil) + } + + connectCtx, cancel := context.WithDeadline(ac.ctx, connectDeadline) + defer cancel() + copts.ChannelzParentID = ac.channelzID + + newTr, err := transport.NewClientTransport(connectCtx, ac.cc.ctx, addr, copts, onClose) + if err != nil { + if logger.V(2) { + logger.Infof("Creating new client transport to %q: %v", addr, err) + } + // newTr is either nil, or closed. + hcancel() + channelz.Warningf(logger, ac.channelzID, "grpc: addrConn.createTransport failed to connect to %s. Err: %v", addr, err) + return err + } + + ac.mu.Lock() + defer ac.mu.Unlock() + if ac.state == connectivity.Shutdown { + // This can happen if the subConn was removed while in `Connecting` + // state. tearDown() would have set the state to `Shutdown`, but + // would not have closed the transport since ac.transport would not + // have been set at that point. + // + // We run this in a goroutine because newTr.Close() calls onClose() + // inline, which requires locking ac.mu. + // + // The error we pass to Close() is immaterial since there are no open + // streams at this point, so no trailers with error details will be sent + // out. We just need to pass a non-nil error. + go newTr.Close(transport.ErrConnClosing) + return nil + } + if hctx.Err() != nil { + // onClose was already called for this connection, but the connection + // was successfully established first. Consider it a success and set + // the new state to Idle. + ac.updateConnectivityState(connectivity.Idle, nil) + return nil + } + ac.curAddr = addr + ac.transport = newTr + ac.startHealthCheck(hctx) // Will set state to READY if appropriate. + return nil +} + +// startHealthCheck starts the health checking stream (RPC) to watch the health +// stats of this connection if health checking is requested and configured. +// +// LB channel health checking is enabled when all requirements below are met: +// 1. it is not disabled by the user with the WithDisableHealthCheck DialOption +// 2. internal.HealthCheckFunc is set by importing the grpc/health package +// 3. a service config with non-empty healthCheckConfig field is provided +// 4. the load balancer requests it +// +// It sets addrConn to READY if the health checking stream is not started. +// +// Caller must hold ac.mu. +func (ac *addrConn) startHealthCheck(ctx context.Context) { + var healthcheckManagingState bool + defer func() { + if !healthcheckManagingState { + ac.updateConnectivityState(connectivity.Ready, nil) + } + }() + + if ac.cc.dopts.disableHealthCheck { + return + } + healthCheckConfig := ac.cc.healthCheckConfig() + if healthCheckConfig == nil { + return + } + if !ac.scopts.HealthCheckEnabled { + return + } + healthCheckFunc := ac.cc.dopts.healthCheckFunc + if healthCheckFunc == nil { + // The health package is not imported to set health check function. + // + // TODO: add a link to the health check doc in the error message. + channelz.Error(logger, ac.channelzID, "Health check is requested but health check function is not set.") + return + } + + healthcheckManagingState = true + + // Set up the health check helper functions. + currentTr := ac.transport + newStream := func(method string) (interface{}, error) { + ac.mu.Lock() + if ac.transport != currentTr { + ac.mu.Unlock() + return nil, status.Error(codes.Canceled, "the provided transport is no longer valid to use") + } + ac.mu.Unlock() + return newNonRetryClientStream(ctx, &StreamDesc{ServerStreams: true}, method, currentTr, ac) + } + setConnectivityState := func(s connectivity.State, lastErr error) { + ac.mu.Lock() + defer ac.mu.Unlock() + if ac.transport != currentTr { + return + } + ac.updateConnectivityState(s, lastErr) + } + // Start the health checking stream. + go func() { + err := ac.cc.dopts.healthCheckFunc(ctx, newStream, setConnectivityState, healthCheckConfig.ServiceName) + if err != nil { + if status.Code(err) == codes.Unimplemented { + channelz.Error(logger, ac.channelzID, "Subchannel health check is unimplemented at server side, thus health check is disabled") + } else { + channelz.Errorf(logger, ac.channelzID, "Health checking failed: %v", err) + } + } + }() +} + +func (ac *addrConn) resetConnectBackoff() { + ac.mu.Lock() + close(ac.resetBackoff) + ac.backoffIdx = 0 + ac.resetBackoff = make(chan struct{}) + ac.mu.Unlock() +} + +// getReadyTransport returns the transport if ac's state is READY or nil if not. +func (ac *addrConn) getReadyTransport() transport.ClientTransport { + ac.mu.Lock() + defer ac.mu.Unlock() + if ac.state == connectivity.Ready { + return ac.transport + } + return nil +} + +// tearDown starts to tear down the addrConn. +// +// Note that tearDown doesn't remove ac from ac.cc.conns, so the addrConn struct +// will leak. In most cases, call cc.removeAddrConn() instead. +func (ac *addrConn) tearDown(err error) { + ac.mu.Lock() + if ac.state == connectivity.Shutdown { + ac.mu.Unlock() + return + } + curTr := ac.transport + ac.transport = nil + // We have to set the state to Shutdown before anything else to prevent races + // between setting the state and logic that waits on context cancellation / etc. + ac.updateConnectivityState(connectivity.Shutdown, nil) + ac.cancel() + ac.curAddr = resolver.Address{} + if err == errConnDrain && curTr != nil { + // GracefulClose(...) may be executed multiple times when + // i) receiving multiple GoAway frames from the server; or + // ii) there are concurrent name resolver/Balancer triggered + // address removal and GoAway. + // We have to unlock and re-lock here because GracefulClose => Close => onClose, which requires locking ac.mu. + ac.mu.Unlock() + curTr.GracefulClose() + ac.mu.Lock() + } + channelz.AddTraceEvent(logger, ac.channelzID, 0, &channelz.TraceEventDesc{ + Desc: "Subchannel deleted", + Severity: channelz.CtInfo, + Parent: &channelz.TraceEventDesc{ + Desc: fmt.Sprintf("Subchannel(id:%d) deleted", ac.channelzID.Int()), + Severity: channelz.CtInfo, + }, + }) + // TraceEvent needs to be called before RemoveEntry, as TraceEvent may add + // trace reference to the entity being deleted, and thus prevent it from + // being deleted right away. + channelz.RemoveEntry(ac.channelzID) + ac.mu.Unlock() +} + +func (ac *addrConn) getState() connectivity.State { + ac.mu.Lock() + defer ac.mu.Unlock() + return ac.state +} + +func (ac *addrConn) ChannelzMetric() *channelz.ChannelInternalMetric { + ac.mu.Lock() + addr := ac.curAddr.Addr + ac.mu.Unlock() + return &channelz.ChannelInternalMetric{ + State: ac.getState(), + Target: addr, + CallsStarted: atomic.LoadInt64(&ac.czData.callsStarted), + CallsSucceeded: atomic.LoadInt64(&ac.czData.callsSucceeded), + CallsFailed: atomic.LoadInt64(&ac.czData.callsFailed), + LastCallStartedTimestamp: time.Unix(0, atomic.LoadInt64(&ac.czData.lastCallStartedTime)), + } +} + +func (ac *addrConn) incrCallsStarted() { + atomic.AddInt64(&ac.czData.callsStarted, 1) + atomic.StoreInt64(&ac.czData.lastCallStartedTime, time.Now().UnixNano()) +} + +func (ac *addrConn) incrCallsSucceeded() { + atomic.AddInt64(&ac.czData.callsSucceeded, 1) +} + +func (ac *addrConn) incrCallsFailed() { + atomic.AddInt64(&ac.czData.callsFailed, 1) +} + +type retryThrottler struct { + max float64 + thresh float64 + ratio float64 + + mu sync.Mutex + tokens float64 // TODO(dfawley): replace with atomic and remove lock. +} + +// throttle subtracts a retry token from the pool and returns whether a retry +// should be throttled (disallowed) based upon the retry throttling policy in +// the service config. +func (rt *retryThrottler) throttle() bool { + if rt == nil { + return false + } + rt.mu.Lock() + defer rt.mu.Unlock() + rt.tokens-- + if rt.tokens < 0 { + rt.tokens = 0 + } + return rt.tokens <= rt.thresh +} + +func (rt *retryThrottler) successfulRPC() { + if rt == nil { + return + } + rt.mu.Lock() + defer rt.mu.Unlock() + rt.tokens += rt.ratio + if rt.tokens > rt.max { + rt.tokens = rt.max + } +} + +type channelzChannel struct { + cc *ClientConn +} + +func (c *channelzChannel) ChannelzMetric() *channelz.ChannelInternalMetric { + return c.cc.channelzMetric() +} + +// ErrClientConnTimeout indicates that the ClientConn cannot establish the +// underlying connections within the specified timeout. +// +// Deprecated: This error is never returned by grpc and should not be +// referenced by users. +var ErrClientConnTimeout = errors.New("grpc: timed out when dialing") + +func (cc *ClientConn) getResolver(scheme string) resolver.Builder { + for _, rb := range cc.dopts.resolvers { + if scheme == rb.Scheme() { + return rb + } + } + return resolver.Get(scheme) +} + +func (cc *ClientConn) updateConnectionError(err error) { + cc.lceMu.Lock() + cc.lastConnectionError = err + cc.lceMu.Unlock() +} + +func (cc *ClientConn) connectionError() error { + cc.lceMu.Lock() + defer cc.lceMu.Unlock() + return cc.lastConnectionError +} + +func (cc *ClientConn) parseTargetAndFindResolver() (resolver.Builder, error) { + channelz.Infof(logger, cc.channelzID, "original dial target is: %q", cc.target) + + var rb resolver.Builder + parsedTarget, err := parseTarget(cc.target) + if err != nil { + channelz.Infof(logger, cc.channelzID, "dial target %q parse failed: %v", cc.target, err) + } else { + channelz.Infof(logger, cc.channelzID, "parsed dial target is: %+v", parsedTarget) + rb = cc.getResolver(parsedTarget.URL.Scheme) + if rb != nil { + cc.parsedTarget = parsedTarget + return rb, nil + } + } + + // We are here because the user's dial target did not contain a scheme or + // specified an unregistered scheme. We should fallback to the default + // scheme, except when a custom dialer is specified in which case, we should + // always use passthrough scheme. + defScheme := resolver.GetDefaultScheme() + channelz.Infof(logger, cc.channelzID, "fallback to scheme %q", defScheme) + canonicalTarget := defScheme + ":///" + cc.target + + parsedTarget, err = parseTarget(canonicalTarget) + if err != nil { + channelz.Infof(logger, cc.channelzID, "dial target %q parse failed: %v", canonicalTarget, err) + return nil, err + } + channelz.Infof(logger, cc.channelzID, "parsed dial target is: %+v", parsedTarget) + rb = cc.getResolver(parsedTarget.URL.Scheme) + if rb == nil { + return nil, fmt.Errorf("could not get resolver for default scheme: %q", parsedTarget.URL.Scheme) + } + cc.parsedTarget = parsedTarget + return rb, nil +} + +// parseTarget uses RFC 3986 semantics to parse the given target into a +// resolver.Target struct containing scheme, authority and url. Query +// params are stripped from the endpoint. +func parseTarget(target string) (resolver.Target, error) { + u, err := url.Parse(target) + if err != nil { + return resolver.Target{}, err + } + + return resolver.Target{ + Scheme: u.Scheme, + Authority: u.Host, + URL: *u, + }, nil +} + +// Determine channel authority. The order of precedence is as follows: +// - user specified authority override using `WithAuthority` dial option +// - creds' notion of server name for the authentication handshake +// - endpoint from dial target of the form "scheme://[authority]/endpoint" +func determineAuthority(endpoint, target string, dopts dialOptions) (string, error) { + // Historically, we had two options for users to specify the serverName or + // authority for a channel. One was through the transport credentials + // (either in its constructor, or through the OverrideServerName() method). + // The other option (for cases where WithInsecure() dial option was used) + // was to use the WithAuthority() dial option. + // + // A few things have changed since: + // - `insecure` package with an implementation of the `TransportCredentials` + // interface for the insecure case + // - WithAuthority() dial option support for secure credentials + authorityFromCreds := "" + if creds := dopts.copts.TransportCredentials; creds != nil && creds.Info().ServerName != "" { + authorityFromCreds = creds.Info().ServerName + } + authorityFromDialOption := dopts.authority + if (authorityFromCreds != "" && authorityFromDialOption != "") && authorityFromCreds != authorityFromDialOption { + return "", fmt.Errorf("ClientConn's authority from transport creds %q and dial option %q don't match", authorityFromCreds, authorityFromDialOption) + } + + switch { + case authorityFromDialOption != "": + return authorityFromDialOption, nil + case authorityFromCreds != "": + return authorityFromCreds, nil + case strings.HasPrefix(target, "unix:") || strings.HasPrefix(target, "unix-abstract:"): + // TODO: remove when the unix resolver implements optional interface to + // return channel authority. + return "localhost", nil + case strings.HasPrefix(endpoint, ":"): + return "localhost" + endpoint, nil + default: + // TODO: Define an optional interface on the resolver builder to return + // the channel authority given the user's dial target. For resolvers + // which don't implement this interface, we will use the endpoint from + // "scheme://authority/endpoint" as the default authority. + return endpoint, nil + } +} |