mirror of
https://github.com/etcd-io/etcd.git
synced 2024-09-27 06:25:44 +00:00
120 lines
3.0 KiB
Go
120 lines
3.0 KiB
Go
// Copyright 2018 The etcd 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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// resolves to etcd entpoints for grpc targets of the form 'etcd://<cluster-name>/<endpoint>'.
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package endpoint
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import (
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"fmt"
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"sync"
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"google.golang.org/grpc/resolver"
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)
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const (
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scheme = "etcd"
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)
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var (
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bldr *builder
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)
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func init() {
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bldr = &builder{
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clusterResolvers: make(map[string]*Resolver),
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}
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resolver.Register(bldr)
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}
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type builder struct {
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clusterResolvers map[string]*Resolver
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sync.RWMutex
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}
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// Build creates or reuses an etcd resolver for the etcd cluster name identified by the authority part of the target.
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func (b *builder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
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if len(target.Authority) < 1 {
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return nil, fmt.Errorf("'etcd' target scheme requires non-empty authority identifying etcd cluster being routed to")
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}
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r := b.getResolver(target.Authority)
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r.cc = cc
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if r.bootstrapAddrs != nil {
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r.NewAddress(r.bootstrapAddrs)
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}
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return r, nil
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}
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func (b *builder) getResolver(clusterName string) *Resolver {
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b.RLock()
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r, ok := b.clusterResolvers[clusterName]
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b.RUnlock()
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if !ok {
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r = &Resolver{
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clusterName: clusterName,
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}
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b.Lock()
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b.clusterResolvers[clusterName] = r
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b.Unlock()
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}
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return r
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}
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func (b *builder) addResolver(r *Resolver) {
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bldr.Lock()
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bldr.clusterResolvers[r.clusterName] = r
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bldr.Unlock()
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}
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func (b *builder) removeResolver(r *Resolver) {
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bldr.Lock()
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delete(bldr.clusterResolvers, r.clusterName)
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bldr.Unlock()
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}
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func (r *builder) Scheme() string {
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return scheme
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}
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// EndpointResolver gets the resolver for given etcd cluster name.
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func EndpointResolver(clusterName string) *Resolver {
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return bldr.getResolver(clusterName)
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}
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// Resolver provides a resolver for a single etcd cluster, identified by name.
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type Resolver struct {
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clusterName string
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cc resolver.ClientConn
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bootstrapAddrs []resolver.Address
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}
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// InitialAddrs sets the initial endpoint addresses for the resolver.
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func (r *Resolver) InitialAddrs(addrs []resolver.Address) {
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r.bootstrapAddrs = addrs
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}
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// NewAddress updates the addresses of the resolver.
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func (r *Resolver) NewAddress(addrs []resolver.Address) error {
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if r.cc == nil {
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return fmt.Errorf("resolver not yet built, use InitialAddrs to provide initialization endpoints")
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}
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r.cc.NewAddress(addrs)
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return nil
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}
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func (*Resolver) ResolveNow(o resolver.ResolveNowOption) {}
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func (r *Resolver) Close() {
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bldr.removeResolver(r)
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}
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