mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
synced 2024-12-30 07:40:06 +01:00
287 lines
9.0 KiB
Go
287 lines
9.0 KiB
Go
/*
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*
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* Copyright 2017 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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package base
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import (
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"context"
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"errors"
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"fmt"
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"google.golang.org/grpc/balancer"
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"google.golang.org/grpc/connectivity"
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"google.golang.org/grpc/grpclog"
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"google.golang.org/grpc/resolver"
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)
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type baseBuilder struct {
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name string
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pickerBuilder PickerBuilder
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v2PickerBuilder V2PickerBuilder
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config Config
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}
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func (bb *baseBuilder) Build(cc balancer.ClientConn, opt balancer.BuildOptions) balancer.Balancer {
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bal := &baseBalancer{
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cc: cc,
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pickerBuilder: bb.pickerBuilder,
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v2PickerBuilder: bb.v2PickerBuilder,
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subConns: make(map[resolver.Address]balancer.SubConn),
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scStates: make(map[balancer.SubConn]connectivity.State),
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csEvltr: &balancer.ConnectivityStateEvaluator{},
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config: bb.config,
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}
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// Initialize picker to a picker that always returns
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// ErrNoSubConnAvailable, because when state of a SubConn changes, we
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// may call UpdateState with this picker.
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if bb.pickerBuilder != nil {
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bal.picker = NewErrPicker(balancer.ErrNoSubConnAvailable)
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} else {
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bal.v2Picker = NewErrPickerV2(balancer.ErrNoSubConnAvailable)
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}
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return bal
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}
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func (bb *baseBuilder) Name() string {
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return bb.name
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}
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var _ balancer.V2Balancer = (*baseBalancer)(nil) // Assert that we implement V2Balancer
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type baseBalancer struct {
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cc balancer.ClientConn
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pickerBuilder PickerBuilder
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v2PickerBuilder V2PickerBuilder
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csEvltr *balancer.ConnectivityStateEvaluator
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state connectivity.State
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subConns map[resolver.Address]balancer.SubConn
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scStates map[balancer.SubConn]connectivity.State
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picker balancer.Picker
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v2Picker balancer.V2Picker
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config Config
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resolverErr error // the last error reported by the resolver; cleared on successful resolution
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connErr error // the last connection error; cleared upon leaving TransientFailure
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}
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func (b *baseBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error) {
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panic("not implemented")
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}
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func (b *baseBalancer) ResolverError(err error) {
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b.resolverErr = err
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if len(b.subConns) == 0 {
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b.state = connectivity.TransientFailure
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}
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if b.state != connectivity.TransientFailure {
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// The picker will not change since the balancer does not currently
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// report an error.
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return
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}
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b.regeneratePicker()
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if b.picker != nil {
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b.cc.UpdateBalancerState(b.state, b.picker)
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} else {
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b.cc.UpdateState(balancer.State{
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ConnectivityState: b.state,
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Picker: b.v2Picker,
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})
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}
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}
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func (b *baseBalancer) UpdateClientConnState(s balancer.ClientConnState) error {
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// TODO: handle s.ResolverState.Err (log if not nil) once implemented.
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// TODO: handle s.ResolverState.ServiceConfig?
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if grpclog.V(2) {
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grpclog.Infoln("base.baseBalancer: got new ClientConn state: ", s)
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}
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// Successful resolution; clear resolver error and ensure we return nil.
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b.resolverErr = nil
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// addrsSet is the set converted from addrs, it's used for quick lookup of an address.
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addrsSet := make(map[resolver.Address]struct{})
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for _, a := range s.ResolverState.Addresses {
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addrsSet[a] = struct{}{}
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if _, ok := b.subConns[a]; !ok {
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// a is a new address (not existing in b.subConns).
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sc, err := b.cc.NewSubConn([]resolver.Address{a}, balancer.NewSubConnOptions{HealthCheckEnabled: b.config.HealthCheck})
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if err != nil {
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grpclog.Warningf("base.baseBalancer: failed to create new SubConn: %v", err)
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continue
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}
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b.subConns[a] = sc
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b.scStates[sc] = connectivity.Idle
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sc.Connect()
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}
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}
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for a, sc := range b.subConns {
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// a was removed by resolver.
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if _, ok := addrsSet[a]; !ok {
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b.cc.RemoveSubConn(sc)
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delete(b.subConns, a)
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// Keep the state of this sc in b.scStates until sc's state becomes Shutdown.
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// The entry will be deleted in HandleSubConnStateChange.
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}
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}
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// If resolver state contains no addresses, return an error so ClientConn
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// will trigger re-resolve. Also records this as an resolver error, so when
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// the overall state turns transient failure, the error message will have
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// the zero address information.
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if len(s.ResolverState.Addresses) == 0 {
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b.ResolverError(errors.New("produced zero addresses"))
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return balancer.ErrBadResolverState
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}
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return nil
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}
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// mergeErrors builds an error from the last connection error and the last
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// resolver error. Must only be called if b.state is TransientFailure.
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func (b *baseBalancer) mergeErrors() error {
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// connErr must always be non-nil unless there are no SubConns, in which
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// case resolverErr must be non-nil.
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if b.connErr == nil {
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return fmt.Errorf("last resolver error: %v", b.resolverErr)
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}
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if b.resolverErr == nil {
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return fmt.Errorf("last connection error: %v", b.connErr)
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}
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return fmt.Errorf("last connection error: %v; last resolver error: %v", b.connErr, b.resolverErr)
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}
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// regeneratePicker takes a snapshot of the balancer, and generates a picker
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// from it. The picker is
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// - errPicker if the balancer is in TransientFailure,
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// - built by the pickerBuilder with all READY SubConns otherwise.
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func (b *baseBalancer) regeneratePicker() {
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if b.state == connectivity.TransientFailure {
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if b.pickerBuilder != nil {
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b.picker = NewErrPicker(balancer.ErrTransientFailure)
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} else {
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b.v2Picker = NewErrPickerV2(balancer.TransientFailureError(b.mergeErrors()))
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}
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return
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}
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if b.pickerBuilder != nil {
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readySCs := make(map[resolver.Address]balancer.SubConn)
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// Filter out all ready SCs from full subConn map.
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for addr, sc := range b.subConns {
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if st, ok := b.scStates[sc]; ok && st == connectivity.Ready {
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readySCs[addr] = sc
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}
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}
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b.picker = b.pickerBuilder.Build(readySCs)
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} else {
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readySCs := make(map[balancer.SubConn]SubConnInfo)
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// Filter out all ready SCs from full subConn map.
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for addr, sc := range b.subConns {
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if st, ok := b.scStates[sc]; ok && st == connectivity.Ready {
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readySCs[sc] = SubConnInfo{Address: addr}
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}
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}
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b.v2Picker = b.v2PickerBuilder.Build(PickerBuildInfo{ReadySCs: readySCs})
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}
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}
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func (b *baseBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
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panic("not implemented")
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}
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func (b *baseBalancer) UpdateSubConnState(sc balancer.SubConn, state balancer.SubConnState) {
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s := state.ConnectivityState
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if grpclog.V(2) {
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grpclog.Infof("base.baseBalancer: handle SubConn state change: %p, %v", sc, s)
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}
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oldS, ok := b.scStates[sc]
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if !ok {
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if grpclog.V(2) {
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grpclog.Infof("base.baseBalancer: got state changes for an unknown SubConn: %p, %v", sc, s)
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}
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return
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}
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if oldS == connectivity.TransientFailure && s == connectivity.Connecting {
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// Once a subconn enters TRANSIENT_FAILURE, ignore subsequent
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// CONNECTING transitions to prevent the aggregated state from being
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// always CONNECTING when many backends exist but are all down.
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return
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}
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b.scStates[sc] = s
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switch s {
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case connectivity.Idle:
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sc.Connect()
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case connectivity.Shutdown:
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// When an address was removed by resolver, b called RemoveSubConn but
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// kept the sc's state in scStates. Remove state for this sc here.
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delete(b.scStates, sc)
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case connectivity.TransientFailure:
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// Save error to be reported via picker.
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b.connErr = state.ConnectionError
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}
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b.state = b.csEvltr.RecordTransition(oldS, s)
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// Regenerate picker when one of the following happens:
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// - this sc entered or left ready
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// - the aggregated state of balancer is TransientFailure
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// (may need to update error message)
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if (s == connectivity.Ready) != (oldS == connectivity.Ready) ||
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b.state == connectivity.TransientFailure {
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b.regeneratePicker()
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}
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if b.picker != nil {
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b.cc.UpdateBalancerState(b.state, b.picker)
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} else {
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b.cc.UpdateState(balancer.State{ConnectivityState: b.state, Picker: b.v2Picker})
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}
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}
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// Close is a nop because base balancer doesn't have internal state to clean up,
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// and it doesn't need to call RemoveSubConn for the SubConns.
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func (b *baseBalancer) Close() {
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}
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// NewErrPicker returns a picker that always returns err on Pick().
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func NewErrPicker(err error) balancer.Picker {
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return &errPicker{err: err}
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}
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type errPicker struct {
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err error // Pick() always returns this err.
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}
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func (p *errPicker) Pick(context.Context, balancer.PickInfo) (balancer.SubConn, func(balancer.DoneInfo), error) {
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return nil, nil, p.err
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}
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// NewErrPickerV2 returns a V2Picker that always returns err on Pick().
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func NewErrPickerV2(err error) balancer.V2Picker {
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return &errPickerV2{err: err}
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}
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type errPickerV2 struct {
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err error // Pick() always returns this err.
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}
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func (p *errPickerV2) Pick(info balancer.PickInfo) (balancer.PickResult, error) {
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return balancer.PickResult{}, p.err
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}
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