2aa18cafc6
With CoreDNS now supporting etcdv3 as the DNS backend, we can update our federation target to etcdv3. Users will now be able to use etcdv3 server as the federation backbone. Minio will update bucket data to etcdv3 and CoreDNS can pick that data up and serve it as bucket style DNS path.
108 lines
2.8 KiB
Go
108 lines
2.8 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 grpc
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import (
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"golang.org/x/net/context"
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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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// PickFirstBalancerName is the name of the pick_first balancer.
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const PickFirstBalancerName = "pick_first"
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func newPickfirstBuilder() balancer.Builder {
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return &pickfirstBuilder{}
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}
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type pickfirstBuilder struct{}
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func (*pickfirstBuilder) Build(cc balancer.ClientConn, opt balancer.BuildOptions) balancer.Balancer {
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return &pickfirstBalancer{cc: cc}
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}
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func (*pickfirstBuilder) Name() string {
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return PickFirstBalancerName
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}
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type pickfirstBalancer struct {
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cc balancer.ClientConn
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sc balancer.SubConn
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}
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func (b *pickfirstBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error) {
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if err != nil {
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grpclog.Infof("pickfirstBalancer: HandleResolvedAddrs called with error %v", err)
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return
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}
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if b.sc == nil {
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b.sc, err = b.cc.NewSubConn(addrs, balancer.NewSubConnOptions{})
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if err != nil {
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grpclog.Errorf("pickfirstBalancer: failed to NewSubConn: %v", err)
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return
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}
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b.cc.UpdateBalancerState(connectivity.Idle, &picker{sc: b.sc})
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b.sc.Connect()
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} else {
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b.sc.UpdateAddresses(addrs)
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b.sc.Connect()
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}
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}
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func (b *pickfirstBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
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grpclog.Infof("pickfirstBalancer: HandleSubConnStateChange: %p, %v", sc, s)
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if b.sc != sc {
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grpclog.Infof("pickfirstBalancer: ignored state change because sc is not recognized")
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return
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}
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if s == connectivity.Shutdown {
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b.sc = nil
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return
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}
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switch s {
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case connectivity.Ready, connectivity.Idle:
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b.cc.UpdateBalancerState(s, &picker{sc: sc})
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case connectivity.Connecting:
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b.cc.UpdateBalancerState(s, &picker{err: balancer.ErrNoSubConnAvailable})
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case connectivity.TransientFailure:
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b.cc.UpdateBalancerState(s, &picker{err: balancer.ErrTransientFailure})
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}
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}
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func (b *pickfirstBalancer) Close() {
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}
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type picker struct {
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err error
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sc balancer.SubConn
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}
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func (p *picker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
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if p.err != nil {
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return nil, nil, p.err
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}
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return p.sc, nil, nil
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}
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func init() {
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balancer.Register(newPickfirstBuilder())
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}
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