mirror of
https://github.com/etcd-io/etcd.git
synced 2024-09-27 06:25:44 +00:00
129 lines
3.1 KiB
Go
129 lines
3.1 KiB
Go
// Copyright 2021 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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package resolver
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import (
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"context"
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"strings"
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"sync"
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"google.golang.org/grpc/codes"
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gresolver "google.golang.org/grpc/resolver"
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"google.golang.org/grpc/status"
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clientv3 "go.etcd.io/etcd/client/v3"
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"go.etcd.io/etcd/client/v3/naming/endpoints"
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)
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type builder struct {
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c *clientv3.Client
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}
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func (b builder) Build(target gresolver.Target, cc gresolver.ClientConn, opts gresolver.BuildOptions) (gresolver.Resolver, error) {
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// Refer to https://github.com/grpc/grpc-go/blob/16d3df80f029f57cff5458f1d6da6aedbc23545d/clientconn.go#L1587-L1611
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endpoint := target.URL.Path
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if endpoint == "" {
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endpoint = target.URL.Opaque
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}
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endpoint = strings.TrimPrefix(endpoint, "/")
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r := &resolver{
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c: b.c,
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target: endpoint,
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cc: cc,
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}
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r.ctx, r.cancel = context.WithCancel(context.Background())
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em, err := endpoints.NewManager(r.c, r.target)
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if err != nil {
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return nil, status.Errorf(codes.InvalidArgument, "resolver: failed to new endpoint manager: %s", err)
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}
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r.wch, err = em.NewWatchChannel(r.ctx)
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if err != nil {
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return nil, status.Errorf(codes.Internal, "resolver: failed to new watch channer: %s", err)
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}
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r.wg.Add(1)
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go r.watch()
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return r, nil
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}
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func (b builder) Scheme() string {
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return "etcd"
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}
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// NewBuilder creates a resolver builder.
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func NewBuilder(client *clientv3.Client) (gresolver.Builder, error) {
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return builder{c: client}, nil
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}
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type resolver struct {
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c *clientv3.Client
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target string
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cc gresolver.ClientConn
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wch endpoints.WatchChannel
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ctx context.Context
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cancel context.CancelFunc
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wg sync.WaitGroup
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}
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func (r *resolver) watch() {
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defer r.wg.Done()
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allUps := make(map[string]*endpoints.Update)
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for {
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select {
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case <-r.ctx.Done():
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return
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case ups, ok := <-r.wch:
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if !ok {
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return
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}
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for _, up := range ups {
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switch up.Op {
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case endpoints.Add:
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allUps[up.Key] = up
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case endpoints.Delete:
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delete(allUps, up.Key)
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}
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}
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addrs := convertToGRPCAddress(allUps)
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r.cc.UpdateState(gresolver.State{Addresses: addrs})
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}
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}
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}
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func convertToGRPCAddress(ups map[string]*endpoints.Update) []gresolver.Address {
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var addrs []gresolver.Address
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for _, up := range ups {
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addr := gresolver.Address{
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Addr: up.Endpoint.Addr,
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Metadata: up.Endpoint.Metadata,
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}
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addrs = append(addrs, addr)
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}
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return addrs
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}
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// ResolveNow is a no-op here.
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// It's just a hint, resolver can ignore this if it's not necessary.
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func (r *resolver) ResolveNow(gresolver.ResolveNowOptions) {}
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func (r *resolver) Close() {
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r.cancel()
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r.wg.Wait()
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}
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