diff options
Diffstat (limited to 'vendor/google.golang.org/grpc/balancer')
4 files changed, 567 insertions, 0 deletions
diff --git a/vendor/google.golang.org/grpc/balancer/balancer.go b/vendor/google.golang.org/grpc/balancer/balancer.go new file mode 100644 index 000000000..63b8d7137 --- /dev/null +++ b/vendor/google.golang.org/grpc/balancer/balancer.go @@ -0,0 +1,228 @@ +/* + * + * 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 balancer defines APIs for load balancing in gRPC. +// All APIs in this package are experimental. +package balancer + +import ( + "errors" + "net" + "strings" + + "golang.org/x/net/context" + "google.golang.org/grpc/connectivity" + "google.golang.org/grpc/credentials" + "google.golang.org/grpc/resolver" +) + +var ( + // m is a map from name to balancer builder. + m = make(map[string]Builder) +) + +// Register registers the balancer builder to the balancer map. b.Name +// (lowercased) will be used as the name registered with this builder. +// +// NOTE: this function must only be called during initialization time (i.e. in +// an init() function), and is not thread-safe. If multiple Balancers are +// registered with the same name, the one registered last will take effect. +func Register(b Builder) { + m[strings.ToLower(b.Name())] = b +} + +// Get returns the resolver builder registered with the given name. +// Note that the compare is done in a case-insenstive fashion. +// If no builder is register with the name, nil will be returned. +func Get(name string) Builder { + if b, ok := m[strings.ToLower(name)]; ok { + return b + } + return nil +} + +// SubConn represents a gRPC sub connection. +// Each sub connection contains a list of addresses. gRPC will +// try to connect to them (in sequence), and stop trying the +// remainder once one connection is successful. +// +// The reconnect backoff will be applied on the list, not a single address. +// For example, try_on_all_addresses -> backoff -> try_on_all_addresses. +// +// All SubConns start in IDLE, and will not try to connect. To trigger +// the connecting, Balancers must call Connect. +// When the connection encounters an error, it will reconnect immediately. +// When the connection becomes IDLE, it will not reconnect unless Connect is +// called. +// +// This interface is to be implemented by gRPC. Users should not need a +// brand new implementation of this interface. For the situations like +// testing, the new implementation should embed this interface. This allows +// gRPC to add new methods to this interface. +type SubConn interface { + // UpdateAddresses updates the addresses used in this SubConn. + // gRPC checks if currently-connected address is still in the new list. + // If it's in the list, the connection will be kept. + // If it's not in the list, the connection will gracefully closed, and + // a new connection will be created. + // + // This will trigger a state transition for the SubConn. + UpdateAddresses([]resolver.Address) + // Connect starts the connecting for this SubConn. + Connect() +} + +// NewSubConnOptions contains options to create new SubConn. +type NewSubConnOptions struct{} + +// ClientConn represents a gRPC ClientConn. +// +// This interface is to be implemented by gRPC. Users should not need a +// brand new implementation of this interface. For the situations like +// testing, the new implementation should embed this interface. This allows +// gRPC to add new methods to this interface. +type ClientConn interface { + // NewSubConn is called by balancer to create a new SubConn. + // It doesn't block and wait for the connections to be established. + // Behaviors of the SubConn can be controlled by options. + NewSubConn([]resolver.Address, NewSubConnOptions) (SubConn, error) + // RemoveSubConn removes the SubConn from ClientConn. + // The SubConn will be shutdown. + RemoveSubConn(SubConn) + + // UpdateBalancerState is called by balancer to nofity gRPC that some internal + // state in balancer has changed. + // + // gRPC will update the connectivity state of the ClientConn, and will call pick + // on the new picker to pick new SubConn. + UpdateBalancerState(s connectivity.State, p Picker) + + // ResolveNow is called by balancer to notify gRPC to do a name resolving. + ResolveNow(resolver.ResolveNowOption) + + // Target returns the dial target for this ClientConn. + Target() string +} + +// BuildOptions contains additional information for Build. +type BuildOptions struct { + // DialCreds is the transport credential the Balancer implementation can + // use to dial to a remote load balancer server. The Balancer implementations + // can ignore this if it does not need to talk to another party securely. + DialCreds credentials.TransportCredentials + // Dialer is the custom dialer the Balancer implementation can use to dial + // to a remote load balancer server. The Balancer implementations + // can ignore this if it doesn't need to talk to remote balancer. + Dialer func(context.Context, string) (net.Conn, error) + // ChannelzParentID is the entity parent's channelz unique identification number. + ChannelzParentID int64 +} + +// Builder creates a balancer. +type Builder interface { + // Build creates a new balancer with the ClientConn. + Build(cc ClientConn, opts BuildOptions) Balancer + // Name returns the name of balancers built by this builder. + // It will be used to pick balancers (for example in service config). + Name() string +} + +// PickOptions contains addition information for the Pick operation. +type PickOptions struct{} + +// DoneInfo contains additional information for done. +type DoneInfo struct { + // Err is the rpc error the RPC finished with. It could be nil. + Err error + // BytesSent indicates if any bytes have been sent to the server. + BytesSent bool + // BytesReceived indicates if any byte has been received from the server. + BytesReceived bool +} + +var ( + // ErrNoSubConnAvailable indicates no SubConn is available for pick(). + // gRPC will block the RPC until a new picker is available via UpdateBalancerState(). + ErrNoSubConnAvailable = errors.New("no SubConn is available") + // ErrTransientFailure indicates all SubConns are in TransientFailure. + // WaitForReady RPCs will block, non-WaitForReady RPCs will fail. + ErrTransientFailure = errors.New("all SubConns are in TransientFailure") +) + +// Picker is used by gRPC to pick a SubConn to send an RPC. +// Balancer is expected to generate a new picker from its snapshot every time its +// internal state has changed. +// +// The pickers used by gRPC can be updated by ClientConn.UpdateBalancerState(). +type Picker interface { + // Pick returns the SubConn to be used to send the RPC. + // The returned SubConn must be one returned by NewSubConn(). + // + // This functions is expected to return: + // - a SubConn that is known to be READY; + // - ErrNoSubConnAvailable if no SubConn is available, but progress is being + // made (for example, some SubConn is in CONNECTING mode); + // - other errors if no active connecting is happening (for example, all SubConn + // are in TRANSIENT_FAILURE mode). + // + // If a SubConn is returned: + // - If it is READY, gRPC will send the RPC on it; + // - If it is not ready, or becomes not ready after it's returned, gRPC will block + // until UpdateBalancerState() is called and will call pick on the new picker. + // + // If the returned error is not nil: + // - If the error is ErrNoSubConnAvailable, gRPC will block until UpdateBalancerState() + // - If the error is ErrTransientFailure: + // - If the RPC is wait-for-ready, gRPC will block until UpdateBalancerState() + // is called to pick again; + // - Otherwise, RPC will fail with unavailable error. + // - Else (error is other non-nil error): + // - The RPC will fail with unavailable error. + // + // The returned done() function will be called once the rpc has finished, with the + // final status of that RPC. + // done may be nil if balancer doesn't care about the RPC status. + Pick(ctx context.Context, opts PickOptions) (conn SubConn, done func(DoneInfo), err error) +} + +// Balancer takes input from gRPC, manages SubConns, and collects and aggregates +// the connectivity states. +// +// It also generates and updates the Picker used by gRPC to pick SubConns for RPCs. +// +// HandleSubConnectionStateChange, HandleResolvedAddrs and Close are guaranteed +// to be called synchronously from the same goroutine. +// There's no guarantee on picker.Pick, it may be called anytime. +type Balancer interface { + // HandleSubConnStateChange is called by gRPC when the connectivity state + // of sc has changed. + // Balancer is expected to aggregate all the state of SubConn and report + // that back to gRPC. + // Balancer should also generate and update Pickers when its internal state has + // been changed by the new state. + HandleSubConnStateChange(sc SubConn, state connectivity.State) + // HandleResolvedAddrs is called by gRPC to send updated resolved addresses to + // balancers. + // Balancer can create new SubConn or remove SubConn with the addresses. + // An empty address slice and a non-nil error will be passed if the resolver returns + // non-nil error to gRPC. + HandleResolvedAddrs([]resolver.Address, error) + // Close closes the balancer. The balancer is not required to call + // ClientConn.RemoveSubConn for its existing SubConns. + Close() +} 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 +} diff --git a/vendor/google.golang.org/grpc/balancer/base/base.go b/vendor/google.golang.org/grpc/balancer/base/base.go new file mode 100644 index 000000000..012ace2f2 --- /dev/null +++ b/vendor/google.golang.org/grpc/balancer/base/base.go @@ -0,0 +1,52 @@ +/* + * + * 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 defines a balancer base that can be used to build balancers with +// different picking algorithms. +// +// The base balancer creates a new SubConn for each resolved address. The +// provided picker will only be notified about READY SubConns. +// +// This package is the base of round_robin balancer, its purpose is to be used +// to build round_robin like balancers with complex picking algorithms. +// Balancers with more complicated logic should try to implement a balancer +// builder from scratch. +// +// All APIs in this package are experimental. +package base + +import ( + "google.golang.org/grpc/balancer" + "google.golang.org/grpc/resolver" +) + +// PickerBuilder creates balancer.Picker. +type PickerBuilder interface { + // Build takes a slice of ready SubConns, and returns a picker that will be + // used by gRPC to pick a SubConn. + Build(readySCs map[resolver.Address]balancer.SubConn) balancer.Picker +} + +// NewBalancerBuilder returns a balancer builder. The balancers +// built by this builder will use the picker builder to build pickers. +func NewBalancerBuilder(name string, pb PickerBuilder) balancer.Builder { + return &baseBuilder{ + name: name, + pickerBuilder: pb, + } +} diff --git a/vendor/google.golang.org/grpc/balancer/roundrobin/roundrobin.go b/vendor/google.golang.org/grpc/balancer/roundrobin/roundrobin.go new file mode 100644 index 000000000..2eda0a1c2 --- /dev/null +++ b/vendor/google.golang.org/grpc/balancer/roundrobin/roundrobin.go @@ -0,0 +1,79 @@ +/* + * + * 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 roundrobin defines a roundrobin balancer. Roundrobin balancer is +// installed as one of the default balancers in gRPC, users don't need to +// explicitly install this balancer. +package roundrobin + +import ( + "sync" + + "golang.org/x/net/context" + "google.golang.org/grpc/balancer" + "google.golang.org/grpc/balancer/base" + "google.golang.org/grpc/grpclog" + "google.golang.org/grpc/resolver" +) + +// Name is the name of round_robin balancer. +const Name = "round_robin" + +// newBuilder creates a new roundrobin balancer builder. +func newBuilder() balancer.Builder { + return base.NewBalancerBuilder(Name, &rrPickerBuilder{}) +} + +func init() { + balancer.Register(newBuilder()) +} + +type rrPickerBuilder struct{} + +func (*rrPickerBuilder) Build(readySCs map[resolver.Address]balancer.SubConn) balancer.Picker { + grpclog.Infof("roundrobinPicker: newPicker called with readySCs: %v", readySCs) + var scs []balancer.SubConn + for _, sc := range readySCs { + scs = append(scs, sc) + } + return &rrPicker{ + subConns: scs, + } +} + +type rrPicker struct { + // subConns is the snapshot of the roundrobin balancer when this picker was + // created. The slice is immutable. Each Get() will do a round robin + // selection from it and return the selected SubConn. + subConns []balancer.SubConn + + mu sync.Mutex + next int +} + +func (p *rrPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) { + if len(p.subConns) <= 0 { + return nil, nil, balancer.ErrNoSubConnAvailable + } + + p.mu.Lock() + sc := p.subConns[p.next] + p.next = (p.next + 1) % len(p.subConns) + p.mu.Unlock() + return sc, nil, nil +} |