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author | Christopher Speller <crspeller@gmail.com> | 2018-06-25 12:33:13 -0700 |
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committer | GitHub <noreply@github.com> | 2018-06-25 12:33:13 -0700 |
commit | 1e5c432e1029601a664454388ae366ef69618d62 (patch) | |
tree | cb9e8bfb66640ac3b29c934bb2c3202d25aeb368 /vendor/google.golang.org/grpc/balancer/base/balancer.go | |
parent | ecefa6cdd1e7376046bbec82c1b47f7756fea646 (diff) | |
download | chat-1e5c432e1029601a664454388ae366ef69618d62.tar.gz chat-1e5c432e1029601a664454388ae366ef69618d62.tar.bz2 chat-1e5c432e1029601a664454388ae366ef69618d62.zip |
MM-10702 Moving plugins to use hashicorp go-plugin. (#8978)
* Moving plugins to use hashicorp go-plugin.
* Tweaks from feedback.
Diffstat (limited to 'vendor/google.golang.org/grpc/balancer/base/balancer.go')
-rw-r--r-- | vendor/google.golang.org/grpc/balancer/base/balancer.go | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/vendor/google.golang.org/grpc/balancer/base/balancer.go b/vendor/google.golang.org/grpc/balancer/base/balancer.go new file mode 100644 index 000000000..23d13511b --- /dev/null +++ b/vendor/google.golang.org/grpc/balancer/base/balancer.go @@ -0,0 +1,208 @@ +/* + * + * 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 base + +import ( + "golang.org/x/net/context" + "google.golang.org/grpc/balancer" + "google.golang.org/grpc/connectivity" + "google.golang.org/grpc/grpclog" + "google.golang.org/grpc/resolver" +) + +type baseBuilder struct { + name string + pickerBuilder PickerBuilder +} + +func (bb *baseBuilder) Build(cc balancer.ClientConn, opt balancer.BuildOptions) balancer.Balancer { + return &baseBalancer{ + cc: cc, + pickerBuilder: bb.pickerBuilder, + + subConns: make(map[resolver.Address]balancer.SubConn), + scStates: make(map[balancer.SubConn]connectivity.State), + csEvltr: &connectivityStateEvaluator{}, + // Initialize picker to a picker that always return + // ErrNoSubConnAvailable, because when state of a SubConn changes, we + // may call UpdateBalancerState with this picker. + picker: NewErrPicker(balancer.ErrNoSubConnAvailable), + } +} + +func (bb *baseBuilder) Name() string { + return bb.name +} + +type baseBalancer struct { + cc balancer.ClientConn + pickerBuilder PickerBuilder + + csEvltr *connectivityStateEvaluator + state connectivity.State + + subConns map[resolver.Address]balancer.SubConn + scStates map[balancer.SubConn]connectivity.State + picker balancer.Picker +} + +func (b *baseBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error) { + if err != nil { + grpclog.Infof("base.baseBalancer: HandleResolvedAddrs called with error %v", err) + return + } + grpclog.Infoln("base.baseBalancer: got new resolved addresses: ", addrs) + // addrsSet is the set converted from addrs, it's used for quick lookup of an address. + addrsSet := make(map[resolver.Address]struct{}) + for _, a := range addrs { + addrsSet[a] = struct{}{} + if _, ok := b.subConns[a]; !ok { + // a is a new address (not existing in b.subConns). + sc, err := b.cc.NewSubConn([]resolver.Address{a}, balancer.NewSubConnOptions{}) + if err != nil { + grpclog.Warningf("base.baseBalancer: failed to create new SubConn: %v", err) + continue + } + b.subConns[a] = sc + b.scStates[sc] = connectivity.Idle + sc.Connect() + } + } + for a, sc := range b.subConns { + // a was removed by resolver. + if _, ok := addrsSet[a]; !ok { + b.cc.RemoveSubConn(sc) + delete(b.subConns, a) + // Keep the state of this sc in b.scStates until sc's state becomes Shutdown. + // The entry will be deleted in HandleSubConnStateChange. + } + } +} + +// regeneratePicker takes a snapshot of the balancer, and generates a picker +// from it. The picker is +// - errPicker with ErrTransientFailure if the balancer is in TransientFailure, +// - built by the pickerBuilder with all READY SubConns otherwise. +func (b *baseBalancer) regeneratePicker() { + if b.state == connectivity.TransientFailure { + b.picker = NewErrPicker(balancer.ErrTransientFailure) + return + } + readySCs := make(map[resolver.Address]balancer.SubConn) + + // Filter out all ready SCs from full subConn map. + for addr, sc := range b.subConns { + if st, ok := b.scStates[sc]; ok && st == connectivity.Ready { + readySCs[addr] = sc + } + } + b.picker = b.pickerBuilder.Build(readySCs) +} + +func (b *baseBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) { + grpclog.Infof("base.baseBalancer: handle SubConn state change: %p, %v", sc, s) + oldS, ok := b.scStates[sc] + if !ok { + grpclog.Infof("base.baseBalancer: got state changes for an unknown SubConn: %p, %v", sc, s) + return + } + b.scStates[sc] = s + switch s { + case connectivity.Idle: + sc.Connect() + case connectivity.Shutdown: + // When an address was removed by resolver, b called RemoveSubConn but + // kept the sc's state in scStates. Remove state for this sc here. + delete(b.scStates, sc) + } + + oldAggrState := b.state + b.state = b.csEvltr.recordTransition(oldS, s) + + // Regenerate picker when one of the following happens: + // - this sc became ready from not-ready + // - this sc became not-ready from ready + // - the aggregated state of balancer became TransientFailure from non-TransientFailure + // - the aggregated state of balancer became non-TransientFailure from TransientFailure + if (s == connectivity.Ready) != (oldS == connectivity.Ready) || + (b.state == connectivity.TransientFailure) != (oldAggrState == connectivity.TransientFailure) { + b.regeneratePicker() + } + + b.cc.UpdateBalancerState(b.state, b.picker) +} + +// Close is a nop because base balancer doesn't have internal state to clean up, +// and it doesn't need to call RemoveSubConn for the SubConns. +func (b *baseBalancer) Close() { +} + +// NewErrPicker returns a picker that always returns err on Pick(). +func NewErrPicker(err error) balancer.Picker { + return &errPicker{err: err} +} + +type errPicker struct { + err error // Pick() always returns this err. +} + +func (p *errPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) { + return nil, nil, p.err +} + +// connectivityStateEvaluator gets updated by addrConns when their +// states transition, based on which it evaluates the state of +// ClientConn. +type connectivityStateEvaluator struct { + 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. +// +// recordTransition should only be called synchronously from the same goroutine. +func (cse *connectivityStateEvaluator) recordTransition(oldState, newState connectivity.State) connectivity.State { + // 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 +} |