diff options
Diffstat (limited to 'vendor/google.golang.org/grpc/balancer_v1_wrapper.go')
| -rw-r--r-- | vendor/google.golang.org/grpc/balancer_v1_wrapper.go | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/vendor/google.golang.org/grpc/balancer_v1_wrapper.go b/vendor/google.golang.org/grpc/balancer_v1_wrapper.go new file mode 100644 index 0000000..9d06160 --- /dev/null +++ b/vendor/google.golang.org/grpc/balancer_v1_wrapper.go @@ -0,0 +1,367 @@ +/* + * + * 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 ( + "sync" + + "golang.org/x/net/context" + "google.golang.org/grpc/balancer" + "google.golang.org/grpc/codes" + "google.golang.org/grpc/connectivity" + "google.golang.org/grpc/grpclog" + "google.golang.org/grpc/resolver" +) + +type balancerWrapperBuilder struct { + b Balancer // The v1 balancer. +} + +func (bwb *balancerWrapperBuilder) Build(cc balancer.ClientConn, opts balancer.BuildOptions) balancer.Balancer { + bwb.b.Start(cc.Target(), BalancerConfig{ + DialCreds: opts.DialCreds, + Dialer: opts.Dialer, + }) + _, pickfirst := bwb.b.(*pickFirst) + bw := &balancerWrapper{ + balancer: bwb.b, + pickfirst: pickfirst, + cc: cc, + startCh: make(chan struct{}), + conns: make(map[resolver.Address]balancer.SubConn), + connSt: make(map[balancer.SubConn]*scState), + csEvltr: &connectivityStateEvaluator{}, + state: connectivity.Idle, + } + cc.UpdateBalancerState(connectivity.Idle, bw) + go bw.lbWatcher() + return bw +} + +func (bwb *balancerWrapperBuilder) Name() string { + return "wrapper" +} + +type scState struct { + addr Address // The v1 address type. + s connectivity.State + down func(error) +} + +type balancerWrapper struct { + balancer Balancer // The v1 balancer. + pickfirst bool + + cc balancer.ClientConn + + // To aggregate the connectivity state. + csEvltr *connectivityStateEvaluator + state connectivity.State + + mu sync.Mutex + conns map[resolver.Address]balancer.SubConn + connSt map[balancer.SubConn]*scState + // This channel is closed when handling the first resolver result. + // lbWatcher blocks until this is closed, to avoid race between + // - NewSubConn is created, cc wants to notify balancer of state changes; + // - Build hasn't return, cc doesn't have access to balancer. + startCh chan struct{} +} + +// lbWatcher watches the Notify channel of the balancer and manages +// connections accordingly. +func (bw *balancerWrapper) lbWatcher() { + <-bw.startCh + grpclog.Infof("balancerWrapper: is pickfirst: %v\n", bw.pickfirst) + notifyCh := bw.balancer.Notify() + if notifyCh == nil { + // There's no resolver in the balancer. Connect directly. + a := resolver.Address{ + Addr: bw.cc.Target(), + Type: resolver.Backend, + } + sc, err := bw.cc.NewSubConn([]resolver.Address{a}, balancer.NewSubConnOptions{}) + if err != nil { + grpclog.Warningf("Error creating connection to %v. Err: %v", a, err) + } else { + bw.mu.Lock() + bw.conns[a] = sc + bw.connSt[sc] = &scState{ + addr: Address{Addr: bw.cc.Target()}, + s: connectivity.Idle, + } + bw.mu.Unlock() + sc.Connect() + } + return + } + + for addrs := range notifyCh { + grpclog.Infof("balancerWrapper: got update addr from Notify: %v\n", addrs) + if bw.pickfirst { + var ( + oldA resolver.Address + oldSC balancer.SubConn + ) + bw.mu.Lock() + for oldA, oldSC = range bw.conns { + break + } + bw.mu.Unlock() + if len(addrs) <= 0 { + if oldSC != nil { + // Teardown old sc. + bw.mu.Lock() + delete(bw.conns, oldA) + delete(bw.connSt, oldSC) + bw.mu.Unlock() + bw.cc.RemoveSubConn(oldSC) + } + continue + } + + var newAddrs []resolver.Address + for _, a := range addrs { + newAddr := resolver.Address{ + Addr: a.Addr, + Type: resolver.Backend, // All addresses from balancer are all backends. + ServerName: "", + Metadata: a.Metadata, + } + newAddrs = append(newAddrs, newAddr) + } + if oldSC == nil { + // Create new sc. + sc, err := bw.cc.NewSubConn(newAddrs, balancer.NewSubConnOptions{}) + if err != nil { + grpclog.Warningf("Error creating connection to %v. Err: %v", newAddrs, err) + } else { + bw.mu.Lock() + // For pickfirst, there should be only one SubConn, so the + // address doesn't matter. All states updating (up and down) + // and picking should all happen on that only SubConn. + bw.conns[resolver.Address{}] = sc + bw.connSt[sc] = &scState{ + addr: addrs[0], // Use the first address. + s: connectivity.Idle, + } + bw.mu.Unlock() + sc.Connect() + } + } else { + oldSC.UpdateAddresses(newAddrs) + bw.mu.Lock() + bw.connSt[oldSC].addr = addrs[0] + bw.mu.Unlock() + } + } else { + var ( + add []resolver.Address // Addresses need to setup connections. + del []balancer.SubConn // Connections need to tear down. + ) + resAddrs := make(map[resolver.Address]Address) + for _, a := range addrs { + resAddrs[resolver.Address{ + Addr: a.Addr, + Type: resolver.Backend, // All addresses from balancer are all backends. + ServerName: "", + Metadata: a.Metadata, + }] = a + } + bw.mu.Lock() + for a := range resAddrs { + if _, ok := bw.conns[a]; !ok { + add = append(add, a) + } + } + for a, c := range bw.conns { + if _, ok := resAddrs[a]; !ok { + del = append(del, c) + delete(bw.conns, a) + // Keep the state of this sc in bw.connSt until its state becomes Shutdown. + } + } + bw.mu.Unlock() + for _, a := range add { + sc, err := bw.cc.NewSubConn([]resolver.Address{a}, balancer.NewSubConnOptions{}) + if err != nil { + grpclog.Warningf("Error creating connection to %v. Err: %v", a, err) + } else { + bw.mu.Lock() + bw.conns[a] = sc + bw.connSt[sc] = &scState{ + addr: resAddrs[a], + s: connectivity.Idle, + } + bw.mu.Unlock() + sc.Connect() + } + } + for _, c := range del { + bw.cc.RemoveSubConn(c) + } + } + } +} + +func (bw *balancerWrapper) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) { + grpclog.Infof("balancerWrapper: handle subconn state change: %p, %v", sc, s) + bw.mu.Lock() + defer bw.mu.Unlock() + scSt, ok := bw.connSt[sc] + if !ok { + return + } + if s == connectivity.Idle { + sc.Connect() + } + oldS := scSt.s + scSt.s = s + if oldS != connectivity.Ready && s == connectivity.Ready { + scSt.down = bw.balancer.Up(scSt.addr) + } else if oldS == connectivity.Ready && s != connectivity.Ready { + if scSt.down != nil { + scSt.down(errConnClosing) + } + } + sa := bw.csEvltr.recordTransition(oldS, s) + if bw.state != sa { + bw.state = sa + } + bw.cc.UpdateBalancerState(bw.state, bw) + if s == connectivity.Shutdown { + // Remove state for this sc. + delete(bw.connSt, sc) + } + return +} + +func (bw *balancerWrapper) HandleResolvedAddrs([]resolver.Address, error) { + bw.mu.Lock() + defer bw.mu.Unlock() + select { + case <-bw.startCh: + default: + close(bw.startCh) + } + // There should be a resolver inside the balancer. + // All updates here, if any, are ignored. + return +} + +func (bw *balancerWrapper) Close() { + bw.mu.Lock() + defer bw.mu.Unlock() + select { + case <-bw.startCh: + default: + close(bw.startCh) + } + bw.balancer.Close() + return +} + +// The picker is the balancerWrapper itself. +// Pick should never return ErrNoSubConnAvailable. +// It either blocks or returns error, consistent with v1 balancer Get(). +func (bw *balancerWrapper) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) { + failfast := true // Default failfast is true. + if ss, ok := rpcInfoFromContext(ctx); ok { + failfast = ss.failfast + } + a, p, err := bw.balancer.Get(ctx, BalancerGetOptions{BlockingWait: !failfast}) + if err != nil { + return nil, nil, err + } + var done func(balancer.DoneInfo) + if p != nil { + done = func(i balancer.DoneInfo) { p() } + } + var sc balancer.SubConn + bw.mu.Lock() + defer bw.mu.Unlock() + if bw.pickfirst { + // Get the first sc in conns. + for _, sc = range bw.conns { + break + } + } else { + var ok bool + sc, ok = bw.conns[resolver.Address{ + Addr: a.Addr, + Type: resolver.Backend, + ServerName: "", + Metadata: a.Metadata, + }] + if !ok && failfast { + return nil, nil, Errorf(codes.Unavailable, "there is no connection available") + } + if s, ok := bw.connSt[sc]; failfast && (!ok || s.s != connectivity.Ready) { + // If the returned sc is not ready and RPC is failfast, + // return error, and this RPC will fail. + return nil, nil, Errorf(codes.Unavailable, "there is no connection available") + } + } + + return sc, done, nil +} + +// connectivityStateEvaluator gets updated by addrConns when their +// states transition, based on which it evaluates the state of +// ClientConn. +type connectivityStateEvaluator struct { + mu sync.Mutex + numReady uint64 // Number of addrConns in ready state. + numConnecting uint64 // Number of addrConns in connecting state. + numTransientFailure uint64 // Number of addrConns in transientFailure. +} + +// recordTransition records state change happening in every subConn and based on +// that it evaluates what aggregated state should be. +// It can only transition between Ready, Connecting and TransientFailure. Other states, +// Idle and Shutdown are transitioned into by ClientConn; in the beginning of the connection +// before any subConn is created ClientConn is in idle state. In the end when ClientConn +// closes it is in Shutdown state. +// TODO Note that in later releases, a ClientConn with no activity will be put into an Idle state. +func (cse *connectivityStateEvaluator) recordTransition(oldState, newState connectivity.State) connectivity.State { + cse.mu.Lock() + defer cse.mu.Unlock() + + // Update counters. + for idx, state := range []connectivity.State{oldState, newState} { + updateVal := 2*uint64(idx) - 1 // -1 for oldState and +1 for new. + switch state { + case connectivity.Ready: + cse.numReady += updateVal + case connectivity.Connecting: + cse.numConnecting += updateVal + case connectivity.TransientFailure: + cse.numTransientFailure += updateVal + } + } + + // Evaluate. + if cse.numReady > 0 { + return connectivity.Ready + } + if cse.numConnecting > 0 { + return connectivity.Connecting + } + return connectivity.TransientFailure +} |