diff options
Diffstat (limited to 'vendor/google.golang.org/grpc/balancer_wrapper.go')
| -rw-r--r-- | vendor/google.golang.org/grpc/balancer_wrapper.go | 452 |
1 files changed, 0 insertions, 452 deletions
diff --git a/vendor/google.golang.org/grpc/balancer_wrapper.go b/vendor/google.golang.org/grpc/balancer_wrapper.go deleted file mode 100644 index 905817b5f..000000000 --- a/vendor/google.golang.org/grpc/balancer_wrapper.go +++ /dev/null @@ -1,452 +0,0 @@ -/* - * - * Copyright 2017 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" - "fmt" - "sync" - - "google.golang.org/grpc/balancer" - "google.golang.org/grpc/codes" - "google.golang.org/grpc/connectivity" - "google.golang.org/grpc/internal" - "google.golang.org/grpc/internal/balancer/gracefulswitch" - "google.golang.org/grpc/internal/channelz" - "google.golang.org/grpc/internal/grpcsync" - "google.golang.org/grpc/resolver" - "google.golang.org/grpc/status" -) - -var setConnectedAddress = internal.SetConnectedAddress.(func(*balancer.SubConnState, resolver.Address)) - -// ccBalancerWrapper sits between the ClientConn and the Balancer. -// -// ccBalancerWrapper implements methods corresponding to the ones on the -// balancer.Balancer interface. The ClientConn is free to call these methods -// concurrently and the ccBalancerWrapper ensures that calls from the ClientConn -// to the Balancer happen in order by performing them in the serializer, without -// any mutexes held. -// -// ccBalancerWrapper also implements the balancer.ClientConn interface and is -// passed to the Balancer implementations. It invokes unexported methods on the -// ClientConn to handle these calls from the Balancer. -// -// It uses the gracefulswitch.Balancer internally to ensure that balancer -// switches happen in a graceful manner. -type ccBalancerWrapper struct { - // The following fields are initialized when the wrapper is created and are - // read-only afterwards, and therefore can be accessed without a mutex. - cc *ClientConn - opts balancer.BuildOptions - serializer *grpcsync.CallbackSerializer - serializerCancel context.CancelFunc - - // The following fields are only accessed within the serializer or during - // initialization. - curBalancerName string - balancer *gracefulswitch.Balancer - - // The following field is protected by mu. Caller must take cc.mu before - // taking mu. - mu sync.Mutex - closed bool -} - -// newCCBalancerWrapper creates a new balancer wrapper in idle state. The -// underlying balancer is not created until the updateClientConnState() method -// is invoked. -func newCCBalancerWrapper(cc *ClientConn) *ccBalancerWrapper { - ctx, cancel := context.WithCancel(cc.ctx) - ccb := &ccBalancerWrapper{ - cc: cc, - opts: balancer.BuildOptions{ - DialCreds: cc.dopts.copts.TransportCredentials, - CredsBundle: cc.dopts.copts.CredsBundle, - Dialer: cc.dopts.copts.Dialer, - Authority: cc.authority, - CustomUserAgent: cc.dopts.copts.UserAgent, - ChannelzParent: cc.channelz, - Target: cc.parsedTarget, - MetricsRecorder: cc.metricsRecorderList, - }, - serializer: grpcsync.NewCallbackSerializer(ctx), - serializerCancel: cancel, - } - ccb.balancer = gracefulswitch.NewBalancer(ccb, ccb.opts) - return ccb -} - -// updateClientConnState is invoked by grpc to push a ClientConnState update to -// the underlying balancer. This is always executed from the serializer, so -// it is safe to call into the balancer here. -func (ccb *ccBalancerWrapper) updateClientConnState(ccs *balancer.ClientConnState) error { - errCh := make(chan error) - uccs := func(ctx context.Context) { - defer close(errCh) - if ctx.Err() != nil || ccb.balancer == nil { - return - } - name := gracefulswitch.ChildName(ccs.BalancerConfig) - if ccb.curBalancerName != name { - ccb.curBalancerName = name - channelz.Infof(logger, ccb.cc.channelz, "Channel switches to new LB policy %q", name) - } - err := ccb.balancer.UpdateClientConnState(*ccs) - if logger.V(2) && err != nil { - logger.Infof("error from balancer.UpdateClientConnState: %v", err) - } - errCh <- err - } - onFailure := func() { close(errCh) } - - // UpdateClientConnState can race with Close, and when the latter wins, the - // serializer is closed, and the attempt to schedule the callback will fail. - // It is acceptable to ignore this failure. But since we want to handle the - // state update in a blocking fashion (when we successfully schedule the - // callback), we have to use the ScheduleOr method and not the MaybeSchedule - // method on the serializer. - ccb.serializer.ScheduleOr(uccs, onFailure) - return <-errCh -} - -// resolverError is invoked by grpc to push a resolver error to the underlying -// balancer. The call to the balancer is executed from the serializer. -func (ccb *ccBalancerWrapper) resolverError(err error) { - ccb.serializer.TrySchedule(func(ctx context.Context) { - if ctx.Err() != nil || ccb.balancer == nil { - return - } - ccb.balancer.ResolverError(err) - }) -} - -// close initiates async shutdown of the wrapper. cc.mu must be held when -// calling this function. To determine the wrapper has finished shutting down, -// the channel should block on ccb.serializer.Done() without cc.mu held. -func (ccb *ccBalancerWrapper) close() { - ccb.mu.Lock() - ccb.closed = true - ccb.mu.Unlock() - channelz.Info(logger, ccb.cc.channelz, "ccBalancerWrapper: closing") - ccb.serializer.TrySchedule(func(context.Context) { - if ccb.balancer == nil { - return - } - ccb.balancer.Close() - ccb.balancer = nil - }) - ccb.serializerCancel() -} - -// exitIdle invokes the balancer's exitIdle method in the serializer. -func (ccb *ccBalancerWrapper) exitIdle() { - ccb.serializer.TrySchedule(func(ctx context.Context) { - if ctx.Err() != nil || ccb.balancer == nil { - return - } - ccb.balancer.ExitIdle() - }) -} - -func (ccb *ccBalancerWrapper) NewSubConn(addrs []resolver.Address, opts balancer.NewSubConnOptions) (balancer.SubConn, error) { - ccb.cc.mu.Lock() - defer ccb.cc.mu.Unlock() - - ccb.mu.Lock() - if ccb.closed { - ccb.mu.Unlock() - return nil, fmt.Errorf("balancer is being closed; no new SubConns allowed") - } - ccb.mu.Unlock() - - if len(addrs) == 0 { - return nil, fmt.Errorf("grpc: cannot create SubConn with empty address list") - } - ac, err := ccb.cc.newAddrConnLocked(addrs, opts) - if err != nil { - channelz.Warningf(logger, ccb.cc.channelz, "acBalancerWrapper: NewSubConn: failed to newAddrConn: %v", err) - return nil, err - } - acbw := &acBalancerWrapper{ - ccb: ccb, - ac: ac, - producers: make(map[balancer.ProducerBuilder]*refCountedProducer), - stateListener: opts.StateListener, - healthData: newHealthData(connectivity.Idle), - } - ac.acbw = acbw - return acbw, nil -} - -func (ccb *ccBalancerWrapper) RemoveSubConn(balancer.SubConn) { - // The graceful switch balancer will never call this. - logger.Errorf("ccb RemoveSubConn(%v) called unexpectedly, sc") -} - -func (ccb *ccBalancerWrapper) UpdateAddresses(sc balancer.SubConn, addrs []resolver.Address) { - acbw, ok := sc.(*acBalancerWrapper) - if !ok { - return - } - acbw.UpdateAddresses(addrs) -} - -func (ccb *ccBalancerWrapper) UpdateState(s balancer.State) { - ccb.cc.mu.Lock() - defer ccb.cc.mu.Unlock() - if ccb.cc.conns == nil { - // The CC has been closed; ignore this update. - return - } - - ccb.mu.Lock() - if ccb.closed { - ccb.mu.Unlock() - return - } - ccb.mu.Unlock() - // Update picker before updating state. Even though the ordering here does - // not matter, it can lead to multiple calls of Pick in the common start-up - // case where we wait for ready and then perform an RPC. If the picker is - // updated later, we could call the "connecting" picker when the state is - // updated, and then call the "ready" picker after the picker gets updated. - - // Note that there is no need to check if the balancer wrapper was closed, - // as we know the graceful switch LB policy will not call cc if it has been - // closed. - ccb.cc.pickerWrapper.updatePicker(s.Picker) - ccb.cc.csMgr.updateState(s.ConnectivityState) -} - -func (ccb *ccBalancerWrapper) ResolveNow(o resolver.ResolveNowOptions) { - ccb.cc.mu.RLock() - defer ccb.cc.mu.RUnlock() - - ccb.mu.Lock() - if ccb.closed { - ccb.mu.Unlock() - return - } - ccb.mu.Unlock() - ccb.cc.resolveNowLocked(o) -} - -func (ccb *ccBalancerWrapper) Target() string { - return ccb.cc.target -} - -// acBalancerWrapper is a wrapper on top of ac for balancers. -// It implements balancer.SubConn interface. -type acBalancerWrapper struct { - internal.EnforceSubConnEmbedding - ac *addrConn // read-only - ccb *ccBalancerWrapper // read-only - stateListener func(balancer.SubConnState) - - producersMu sync.Mutex - producers map[balancer.ProducerBuilder]*refCountedProducer - - // Access to healthData is protected by healthMu. - healthMu sync.Mutex - // healthData is stored as a pointer to detect when the health listener is - // dropped or updated. This is required as closures can't be compared for - // equality. - healthData *healthData -} - -// healthData holds data related to health state reporting. -type healthData struct { - // connectivityState stores the most recent connectivity state delivered - // to the LB policy. This is stored to avoid sending updates when the - // SubConn has already exited connectivity state READY. - connectivityState connectivity.State -} - -func newHealthData(s connectivity.State) *healthData { - return &healthData{connectivityState: s} -} - -// updateState is invoked by grpc to push a subConn state update to the -// underlying balancer. -func (acbw *acBalancerWrapper) updateState(s connectivity.State, curAddr resolver.Address, err error) { - acbw.ccb.serializer.TrySchedule(func(ctx context.Context) { - if ctx.Err() != nil || acbw.ccb.balancer == nil { - return - } - // Invalidate all producers on any state change. - acbw.closeProducers() - - // Even though it is optional for balancers, gracefulswitch ensures - // opts.StateListener is set, so this cannot ever be nil. - // TODO: delete this comment when UpdateSubConnState is removed. - scs := balancer.SubConnState{ConnectivityState: s, ConnectionError: err} - if s == connectivity.Ready { - setConnectedAddress(&scs, curAddr) - } - // Invalidate the health listener by updating the healthData. - acbw.healthMu.Lock() - // A race may occur if a health listener is registered soon after the - // connectivity state is set but before the stateListener is called. - // Two cases may arise: - // 1. The new state is not READY: RegisterHealthListener has checks to - // ensure no updates are sent when the connectivity state is not - // READY. - // 2. The new state is READY: This means that the old state wasn't Ready. - // The RegisterHealthListener API mentions that a health listener - // must not be registered when a SubConn is not ready to avoid such - // races. When this happens, the LB policy would get health updates - // on the old listener. When the LB policy registers a new listener - // on receiving the connectivity update, the health updates will be - // sent to the new health listener. - acbw.healthData = newHealthData(scs.ConnectivityState) - acbw.healthMu.Unlock() - - acbw.stateListener(scs) - }) -} - -func (acbw *acBalancerWrapper) String() string { - return fmt.Sprintf("SubConn(id:%d)", acbw.ac.channelz.ID) -} - -func (acbw *acBalancerWrapper) UpdateAddresses(addrs []resolver.Address) { - acbw.ac.updateAddrs(addrs) -} - -func (acbw *acBalancerWrapper) Connect() { - go acbw.ac.connect() -} - -func (acbw *acBalancerWrapper) Shutdown() { - acbw.closeProducers() - acbw.ccb.cc.removeAddrConn(acbw.ac, errConnDrain) -} - -// NewStream begins a streaming RPC on the addrConn. If the addrConn is not -// ready, blocks until it is or ctx expires. Returns an error when the context -// expires or the addrConn is shut down. -func (acbw *acBalancerWrapper) NewStream(ctx context.Context, desc *StreamDesc, method string, opts ...CallOption) (ClientStream, error) { - transport := acbw.ac.getReadyTransport() - if transport == nil { - return nil, status.Errorf(codes.Unavailable, "SubConn state is not Ready") - - } - return newNonRetryClientStream(ctx, desc, method, transport, acbw.ac, opts...) -} - -// Invoke performs a unary RPC. If the addrConn is not ready, returns -// errSubConnNotReady. -func (acbw *acBalancerWrapper) Invoke(ctx context.Context, method string, args any, reply any, opts ...CallOption) error { - cs, err := acbw.NewStream(ctx, unaryStreamDesc, method, opts...) - if err != nil { - return err - } - if err := cs.SendMsg(args); err != nil { - return err - } - return cs.RecvMsg(reply) -} - -type refCountedProducer struct { - producer balancer.Producer - refs int // number of current refs to the producer - close func() // underlying producer's close function -} - -func (acbw *acBalancerWrapper) GetOrBuildProducer(pb balancer.ProducerBuilder) (balancer.Producer, func()) { - acbw.producersMu.Lock() - defer acbw.producersMu.Unlock() - - // Look up existing producer from this builder. - pData := acbw.producers[pb] - if pData == nil { - // Not found; create a new one and add it to the producers map. - p, closeFn := pb.Build(acbw) - pData = &refCountedProducer{producer: p, close: closeFn} - acbw.producers[pb] = pData - } - // Account for this new reference. - pData.refs++ - - // Return a cleanup function wrapped in a OnceFunc to remove this reference - // and delete the refCountedProducer from the map if the total reference - // count goes to zero. - unref := func() { - acbw.producersMu.Lock() - // If closeProducers has already closed this producer instance, refs is - // set to 0, so the check after decrementing will never pass, and the - // producer will not be double-closed. - pData.refs-- - if pData.refs == 0 { - defer pData.close() // Run outside the acbw mutex - delete(acbw.producers, pb) - } - acbw.producersMu.Unlock() - } - return pData.producer, grpcsync.OnceFunc(unref) -} - -func (acbw *acBalancerWrapper) closeProducers() { - acbw.producersMu.Lock() - defer acbw.producersMu.Unlock() - for pb, pData := range acbw.producers { - pData.refs = 0 - pData.close() - delete(acbw.producers, pb) - } -} - -// RegisterHealthListener accepts a health listener from the LB policy. It sends -// updates to the health listener as long as the SubConn's connectivity state -// doesn't change and a new health listener is not registered. To invalidate -// the currently registered health listener, acbw updates the healthData. If a -// nil listener is registered, the active health listener is dropped. -func (acbw *acBalancerWrapper) RegisterHealthListener(listener func(balancer.SubConnState)) { - acbw.healthMu.Lock() - defer acbw.healthMu.Unlock() - // listeners should not be registered when the connectivity state - // isn't Ready. This may happen when the balancer registers a listener - // after the connectivityState is updated, but before it is notified - // of the update. - if acbw.healthData.connectivityState != connectivity.Ready { - return - } - // Replace the health data to stop sending updates to any previously - // registered health listeners. - hd := newHealthData(connectivity.Ready) - acbw.healthData = hd - if listener == nil { - return - } - - acbw.ccb.serializer.TrySchedule(func(ctx context.Context) { - if ctx.Err() != nil || acbw.ccb.balancer == nil { - return - } - // Don't send updates if a new listener is registered. - acbw.healthMu.Lock() - defer acbw.healthMu.Unlock() - curHD := acbw.healthData - if curHD != hd { - return - } - listener(balancer.SubConnState{ConnectivityState: connectivity.Ready}) - }) -} |