diff options
Diffstat (limited to 'vendor/google.golang.org/grpc/balancer_conn_wrappers.go')
| -rw-r--r-- | vendor/google.golang.org/grpc/balancer_conn_wrappers.go | 481 |
1 files changed, 0 insertions, 481 deletions
diff --git a/vendor/google.golang.org/grpc/balancer_conn_wrappers.go b/vendor/google.golang.org/grpc/balancer_conn_wrappers.go deleted file mode 100644 index 0359956..0000000 --- a/vendor/google.golang.org/grpc/balancer_conn_wrappers.go +++ /dev/null @@ -1,481 +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" - "strings" - "sync" - - "google.golang.org/grpc/balancer" - "google.golang.org/grpc/codes" - "google.golang.org/grpc/connectivity" - "google.golang.org/grpc/internal/balancer/gracefulswitch" - "google.golang.org/grpc/internal/buffer" - "google.golang.org/grpc/internal/channelz" - "google.golang.org/grpc/internal/grpcsync" - "google.golang.org/grpc/resolver" - "google.golang.org/grpc/status" -) - -// 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 synchronously and in order. -// -// 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 { - cc *ClientConn - - // Since these fields are accessed only from handleXxx() methods which are - // synchronized by the watcher goroutine, we do not need a mutex to protect - // these fields. - balancer *gracefulswitch.Balancer - curBalancerName string - - updateCh *buffer.Unbounded // Updates written on this channel are processed by watcher(). - resultCh *buffer.Unbounded // Results of calls to UpdateClientConnState() are pushed here. - closed *grpcsync.Event // Indicates if close has been called. - done *grpcsync.Event // Indicates if close has completed its work. -} - -// newCCBalancerWrapper creates a new balancer wrapper. The underlying balancer -// is not created until the switchTo() method is invoked. -func newCCBalancerWrapper(cc *ClientConn, bopts balancer.BuildOptions) *ccBalancerWrapper { - ccb := &ccBalancerWrapper{ - cc: cc, - updateCh: buffer.NewUnbounded(), - resultCh: buffer.NewUnbounded(), - closed: grpcsync.NewEvent(), - done: grpcsync.NewEvent(), - } - go ccb.watcher() - ccb.balancer = gracefulswitch.NewBalancer(ccb, bopts) - return ccb -} - -// The following xxxUpdate structs wrap the arguments received as part of the -// corresponding update. The watcher goroutine uses the 'type' of the update to -// invoke the appropriate handler routine to handle the update. - -type ccStateUpdate struct { - ccs *balancer.ClientConnState -} - -type scStateUpdate struct { - sc balancer.SubConn - state connectivity.State - err error -} - -type exitIdleUpdate struct{} - -type resolverErrorUpdate struct { - err error -} - -type switchToUpdate struct { - name string -} - -type subConnUpdate struct { - acbw *acBalancerWrapper -} - -// watcher is a long-running goroutine which reads updates from a channel and -// invokes corresponding methods on the underlying balancer. It ensures that -// these methods are invoked in a synchronous fashion. It also ensures that -// these methods are invoked in the order in which the updates were received. -func (ccb *ccBalancerWrapper) watcher() { - for { - select { - case u := <-ccb.updateCh.Get(): - ccb.updateCh.Load() - if ccb.closed.HasFired() { - break - } - switch update := u.(type) { - case *ccStateUpdate: - ccb.handleClientConnStateChange(update.ccs) - case *scStateUpdate: - ccb.handleSubConnStateChange(update) - case *exitIdleUpdate: - ccb.handleExitIdle() - case *resolverErrorUpdate: - ccb.handleResolverError(update.err) - case *switchToUpdate: - ccb.handleSwitchTo(update.name) - case *subConnUpdate: - ccb.handleRemoveSubConn(update.acbw) - default: - logger.Errorf("ccBalancerWrapper.watcher: unknown update %+v, type %T", update, update) - } - case <-ccb.closed.Done(): - } - - if ccb.closed.HasFired() { - ccb.handleClose() - return - } - } -} - -// updateClientConnState is invoked by grpc to push a ClientConnState update to -// the underlying balancer. -// -// Unlike other methods invoked by grpc to push updates to the underlying -// balancer, this method cannot simply push the update onto the update channel -// and return. It needs to return the error returned by the underlying balancer -// back to grpc which propagates that to the resolver. -func (ccb *ccBalancerWrapper) updateClientConnState(ccs *balancer.ClientConnState) error { - ccb.updateCh.Put(&ccStateUpdate{ccs: ccs}) - - var res interface{} - select { - case res = <-ccb.resultCh.Get(): - ccb.resultCh.Load() - case <-ccb.closed.Done(): - // Return early if the balancer wrapper is closed while we are waiting for - // the underlying balancer to process a ClientConnState update. - return nil - } - // If the returned error is nil, attempting to type assert to error leads to - // panic. So, this needs to handled separately. - if res == nil { - return nil - } - return res.(error) -} - -// handleClientConnStateChange handles a ClientConnState update from the update -// channel and invokes the appropriate method on the underlying balancer. -// -// If the addresses specified in the update contain addresses of type "grpclb" -// and the selected LB policy is not "grpclb", these addresses will be filtered -// out and ccs will be modified with the updated address list. -func (ccb *ccBalancerWrapper) handleClientConnStateChange(ccs *balancer.ClientConnState) { - if ccb.curBalancerName != grpclbName { - // Filter any grpclb addresses since we don't have the grpclb balancer. - var addrs []resolver.Address - for _, addr := range ccs.ResolverState.Addresses { - if addr.Type == resolver.GRPCLB { - continue - } - addrs = append(addrs, addr) - } - ccs.ResolverState.Addresses = addrs - } - ccb.resultCh.Put(ccb.balancer.UpdateClientConnState(*ccs)) -} - -// updateSubConnState is invoked by grpc to push a subConn state update to the -// underlying balancer. -func (ccb *ccBalancerWrapper) updateSubConnState(sc balancer.SubConn, s connectivity.State, err error) { - // When updating addresses for a SubConn, if the address in use is not in - // the new addresses, the old ac will be tearDown() and a new ac will be - // created. tearDown() generates a state change with Shutdown state, we - // don't want the balancer to receive this state change. So before - // tearDown() on the old ac, ac.acbw (acWrapper) will be set to nil, and - // this function will be called with (nil, Shutdown). We don't need to call - // balancer method in this case. - if sc == nil { - return - } - ccb.updateCh.Put(&scStateUpdate{ - sc: sc, - state: s, - err: err, - }) -} - -// handleSubConnStateChange handles a SubConnState update from the update -// channel and invokes the appropriate method on the underlying balancer. -func (ccb *ccBalancerWrapper) handleSubConnStateChange(update *scStateUpdate) { - ccb.balancer.UpdateSubConnState(update.sc, balancer.SubConnState{ConnectivityState: update.state, ConnectionError: update.err}) -} - -func (ccb *ccBalancerWrapper) exitIdle() { - ccb.updateCh.Put(&exitIdleUpdate{}) -} - -func (ccb *ccBalancerWrapper) handleExitIdle() { - if ccb.cc.GetState() != connectivity.Idle { - return - } - ccb.balancer.ExitIdle() -} - -func (ccb *ccBalancerWrapper) resolverError(err error) { - ccb.updateCh.Put(&resolverErrorUpdate{err: err}) -} - -func (ccb *ccBalancerWrapper) handleResolverError(err error) { - ccb.balancer.ResolverError(err) -} - -// switchTo is invoked by grpc to instruct the balancer wrapper to switch to the -// LB policy identified by name. -// -// ClientConn calls newCCBalancerWrapper() at creation time. Upon receipt of the -// first good update from the name resolver, it determines the LB policy to use -// and invokes the switchTo() method. Upon receipt of every subsequent update -// from the name resolver, it invokes this method. -// -// the ccBalancerWrapper keeps track of the current LB policy name, and skips -// the graceful balancer switching process if the name does not change. -func (ccb *ccBalancerWrapper) switchTo(name string) { - ccb.updateCh.Put(&switchToUpdate{name: name}) -} - -// handleSwitchTo handles a balancer switch update from the update channel. It -// calls the SwitchTo() method on the gracefulswitch.Balancer with a -// balancer.Builder corresponding to name. If no balancer.Builder is registered -// for the given name, it uses the default LB policy which is "pick_first". -func (ccb *ccBalancerWrapper) handleSwitchTo(name string) { - // TODO: Other languages use case-insensitive balancer registries. We should - // switch as well. See: https://github.com/grpc/grpc-go/issues/5288. - if strings.EqualFold(ccb.curBalancerName, name) { - return - } - - // TODO: Ensure that name is a registered LB policy when we get here. - // We currently only validate the `loadBalancingConfig` field. We need to do - // the same for the `loadBalancingPolicy` field and reject the service config - // if the specified policy is not registered. - builder := balancer.Get(name) - if builder == nil { - channelz.Warningf(logger, ccb.cc.channelzID, "Channel switches to new LB policy %q, since the specified LB policy %q was not registered", PickFirstBalancerName, name) - builder = newPickfirstBuilder() - } else { - channelz.Infof(logger, ccb.cc.channelzID, "Channel switches to new LB policy %q", name) - } - - if err := ccb.balancer.SwitchTo(builder); err != nil { - channelz.Errorf(logger, ccb.cc.channelzID, "Channel failed to build new LB policy %q: %v", name, err) - return - } - ccb.curBalancerName = builder.Name() -} - -// handleRemoveSucConn handles a request from the underlying balancer to remove -// a subConn. -// -// See comments in RemoveSubConn() for more details. -func (ccb *ccBalancerWrapper) handleRemoveSubConn(acbw *acBalancerWrapper) { - ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain) -} - -func (ccb *ccBalancerWrapper) close() { - ccb.closed.Fire() - <-ccb.done.Done() -} - -func (ccb *ccBalancerWrapper) handleClose() { - ccb.balancer.Close() - ccb.done.Fire() -} - -func (ccb *ccBalancerWrapper) NewSubConn(addrs []resolver.Address, opts balancer.NewSubConnOptions) (balancer.SubConn, error) { - if len(addrs) <= 0 { - return nil, fmt.Errorf("grpc: cannot create SubConn with empty address list") - } - ac, err := ccb.cc.newAddrConn(addrs, opts) - if err != nil { - channelz.Warningf(logger, ccb.cc.channelzID, "acBalancerWrapper: NewSubConn: failed to newAddrConn: %v", err) - return nil, err - } - acbw := &acBalancerWrapper{ac: ac, producers: make(map[balancer.ProducerBuilder]*refCountedProducer)} - acbw.ac.mu.Lock() - ac.acbw = acbw - acbw.ac.mu.Unlock() - return acbw, nil -} - -func (ccb *ccBalancerWrapper) RemoveSubConn(sc balancer.SubConn) { - // Before we switched the ccBalancerWrapper to use gracefulswitch.Balancer, it - // was required to handle the RemoveSubConn() method asynchronously by pushing - // the update onto the update channel. This was done to avoid a deadlock as - // switchBalancer() was holding cc.mu when calling Close() on the old - // balancer, which would in turn call RemoveSubConn(). - // - // With the use of gracefulswitch.Balancer in ccBalancerWrapper, handling this - // asynchronously is probably not required anymore since the switchTo() method - // handles the balancer switch by pushing the update onto the channel. - // TODO(easwars): Handle this inline. - acbw, ok := sc.(*acBalancerWrapper) - if !ok { - return - } - ccb.updateCh.Put(&subConnUpdate{acbw: acbw}) -} - -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) { - // 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. - ccb.cc.blockingpicker.updatePicker(s.Picker) - ccb.cc.csMgr.updateState(s.ConnectivityState) -} - -func (ccb *ccBalancerWrapper) ResolveNow(o resolver.ResolveNowOptions) { - ccb.cc.resolveNow(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 { - mu sync.Mutex - ac *addrConn - producers map[balancer.ProducerBuilder]*refCountedProducer -} - -func (acbw *acBalancerWrapper) UpdateAddresses(addrs []resolver.Address) { - acbw.mu.Lock() - defer acbw.mu.Unlock() - if len(addrs) <= 0 { - acbw.ac.cc.removeAddrConn(acbw.ac, errConnDrain) - return - } - if !acbw.ac.tryUpdateAddrs(addrs) { - cc := acbw.ac.cc - opts := acbw.ac.scopts - acbw.ac.mu.Lock() - // Set old ac.acbw to nil so the Shutdown state update will be ignored - // by balancer. - // - // TODO(bar) the state transition could be wrong when tearDown() old ac - // and creating new ac, fix the transition. - acbw.ac.acbw = nil - acbw.ac.mu.Unlock() - acState := acbw.ac.getState() - acbw.ac.cc.removeAddrConn(acbw.ac, errConnDrain) - - if acState == connectivity.Shutdown { - return - } - - newAC, err := cc.newAddrConn(addrs, opts) - if err != nil { - channelz.Warningf(logger, acbw.ac.channelzID, "acBalancerWrapper: UpdateAddresses: failed to newAddrConn: %v", err) - return - } - acbw.ac = newAC - newAC.mu.Lock() - newAC.acbw = acbw - newAC.mu.Unlock() - if acState != connectivity.Idle { - go newAC.connect() - } - } -} - -func (acbw *acBalancerWrapper) Connect() { - acbw.mu.Lock() - defer acbw.mu.Unlock() - go acbw.ac.connect() -} - -func (acbw *acBalancerWrapper) getAddrConn() *addrConn { - acbw.mu.Lock() - defer acbw.mu.Unlock() - return acbw.ac -} - -var errSubConnNotReady = status.Error(codes.Unavailable, "SubConn not currently connected") - -// NewStream begins a streaming RPC on the addrConn. If the addrConn is not -// ready, returns errSubConnNotReady. -func (acbw *acBalancerWrapper) NewStream(ctx context.Context, desc *StreamDesc, method string, opts ...CallOption) (ClientStream, error) { - transport := acbw.ac.getReadyTransport() - if transport == nil { - return nil, errSubConnNotReady - } - 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 interface{}, reply interface{}, 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.mu.Lock() - defer acbw.mu.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, close := pb.Build(acbw) - pData = &refCountedProducer{producer: p, close: close} - 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.mu.Lock() - pData.refs-- - if pData.refs == 0 { - defer pData.close() // Run outside the acbw mutex - delete(acbw.producers, pb) - } - acbw.mu.Unlock() - } - return pData.producer, grpcsync.OnceFunc(unref) -} |