117 lines
2.9 KiB
Go
117 lines
2.9 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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package concurrency_test
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import (
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"context"
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"log"
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"strings"
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"testing"
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"time"
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"go.etcd.io/etcd/clientv3"
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"go.etcd.io/etcd/clientv3/concurrency"
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)
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func TestResumeElection(t *testing.T) {
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const prefix = "/resume-election/"
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cli, err := clientv3.New(clientv3.Config{Endpoints: endpoints})
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if err != nil {
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log.Fatal(err)
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}
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defer cli.Close()
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var s *concurrency.Session
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s, err = concurrency.NewSession(cli)
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if err != nil {
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log.Fatal(err)
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}
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defer s.Close()
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e := concurrency.NewElection(s, prefix)
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// entire test should never take more than 10 seconds
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ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
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defer cancel()
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// become leader
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if err = e.Campaign(ctx, "candidate1"); err != nil {
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t.Fatalf("Campaign() returned non nil err: %s", err)
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}
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// get the leadership details of the current election
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var leader *clientv3.GetResponse
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leader, err = e.Leader(ctx)
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if err != nil {
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t.Fatalf("Leader() returned non nil err: %s", err)
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}
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// Recreate the election
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e = concurrency.ResumeElection(s, prefix,
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string(leader.Kvs[0].Key), leader.Kvs[0].CreateRevision)
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respChan := make(chan *clientv3.GetResponse)
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go func() {
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o := e.Observe(ctx)
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respChan <- nil
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for {
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select {
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case resp, ok := <-o:
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if !ok {
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t.Fatal("Observe() channel closed prematurely")
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}
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// Ignore any observations that candidate1 was elected
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if string(resp.Kvs[0].Value) == "candidate1" {
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continue
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}
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respChan <- &resp
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return
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}
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}
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}()
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// wait until observe goroutine is running
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<-respChan
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// put some random data to generate a change event, this put should be
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// ignored by Observe() because it is not under the election prefix.
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_, err = cli.Put(ctx, "foo", "bar")
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if err != nil {
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t.Fatalf("Put('foo') returned non nil err: %s", err)
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}
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// resign as leader
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if err := e.Resign(ctx); err != nil {
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t.Fatalf("Resign() returned non nil err: %s", err)
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}
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// elect a different candidate
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if err := e.Campaign(ctx, "candidate2"); err != nil {
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t.Fatalf("Campaign() returned non nil err: %s", err)
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}
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// wait for observed leader change
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resp := <-respChan
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kv := resp.Kvs[0]
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if !strings.HasPrefix(string(kv.Key), prefix) {
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t.Errorf("expected observed election to have prefix '%s' got %q", prefix, string(kv.Key))
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}
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if string(kv.Value) != "candidate2" {
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t.Errorf("expected new leader to be 'candidate1' got %q", string(kv.Value))
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}
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}
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