mirror of
https://github.com/etcd-io/etcd.git
synced 2024-09-27 06:25:44 +00:00
concurrency: add examples
This commit is contained in:
Anthony Romano
parent
e77ecb593c
commit
b7b31e5770
90
clientv3/concurrency/example_election_test.go
Normal file
90
clientv3/concurrency/example_election_test.go
Normal file
@ -0,0 +1,90 @@
|
||||
// Copyright 2017 The etcd Authors
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 (the "License");
|
||||
// you may not use this file except in compliance with the License.
|
||||
// You may obtain a copy of the License at
|
||||
//
|
||||
// http://www.apache.org/licenses/LICENSE-2.0
|
||||
//
|
||||
// Unless required by applicable law or agreed to in writing, software
|
||||
// distributed under the License is distributed on an "AS IS" BASIS,
|
||||
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||||
// See the License for the specific language governing permissions and
|
||||
// limitations under the License.
|
||||
|
||||
package concurrency_test
|
||||
|
||||
import (
|
||||
"context"
|
||||
"fmt"
|
||||
"log"
|
||||
"sync"
|
||||
"time"
|
||||
|
||||
"github.com/coreos/etcd/clientv3"
|
||||
"github.com/coreos/etcd/clientv3/concurrency"
|
||||
)
|
||||
|
||||
func ExampleElection_Campaign() {
|
||||
cli, err := clientv3.New(clientv3.Config{Endpoints: endpoints})
|
||||
if err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
defer cli.Close()
|
||||
|
||||
// create two separate sessions for election competition
|
||||
s1, err := concurrency.NewSession(cli)
|
||||
if err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
defer s1.Close()
|
||||
e1 := concurrency.NewElection(s1, "/my-election/")
|
||||
|
||||
s2, err := concurrency.NewSession(cli)
|
||||
if err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
defer s2.Close()
|
||||
e2 := concurrency.NewElection(s2, "/my-election/")
|
||||
|
||||
// create competing candidates, with e1 initially losing to e2
|
||||
var wg sync.WaitGroup
|
||||
wg.Add(2)
|
||||
electc := make(chan *concurrency.Election, 2)
|
||||
go func() {
|
||||
defer wg.Done()
|
||||
// delay candidacy so e2 wins first
|
||||
time.Sleep(3 * time.Second)
|
||||
if err := e1.Campaign(context.Background(), "e1"); err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
electc <- e1
|
||||
}()
|
||||
go func() {
|
||||
defer wg.Done()
|
||||
if err := e2.Campaign(context.Background(), "e2"); err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
electc <- e2
|
||||
}()
|
||||
|
||||
cctx, cancel := context.WithCancel(context.TODO())
|
||||
defer cancel()
|
||||
|
||||
e := <-electc
|
||||
fmt.Println("completed first election with", string((<-e.Observe(cctx)).Kvs[0].Value))
|
||||
|
||||
// resign so next candidate can be elected
|
||||
if err := e.Resign(context.TODO()); err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
|
||||
e = <-electc
|
||||
fmt.Println("completed second election with", string((<-e.Observe(cctx)).Kvs[0].Value))
|
||||
|
||||
wg.Wait()
|
||||
|
||||
// Output:
|
||||
// completed first election with e2
|
||||
// completed second election with e1
|
||||
}
|
||||
75
clientv3/concurrency/example_mutex_test.go
Normal file
75
clientv3/concurrency/example_mutex_test.go
Normal file
@ -0,0 +1,75 @@
|
||||
// Copyright 2017 The etcd Authors
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 (the "License");
|
||||
// you may not use this file except in compliance with the License.
|
||||
// You may obtain a copy of the License at
|
||||
//
|
||||
// http://www.apache.org/licenses/LICENSE-2.0
|
||||
//
|
||||
// Unless required by applicable law or agreed to in writing, software
|
||||
// distributed under the License is distributed on an "AS IS" BASIS,
|
||||
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||||
// See the License for the specific language governing permissions and
|
||||
// limitations under the License.
|
||||
|
||||
package concurrency_test
|
||||
|
||||
import (
|
||||
"context"
|
||||
"fmt"
|
||||
"log"
|
||||
|
||||
"github.com/coreos/etcd/clientv3"
|
||||
"github.com/coreos/etcd/clientv3/concurrency"
|
||||
)
|
||||
|
||||
func ExampleMutex_Lock() {
|
||||
cli, err := clientv3.New(clientv3.Config{Endpoints: endpoints})
|
||||
if err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
defer cli.Close()
|
||||
|
||||
// create two separate sessions for lock competition
|
||||
s1, err := concurrency.NewSession(cli)
|
||||
if err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
defer s1.Close()
|
||||
m1 := concurrency.NewMutex(s1, "/my-lock/")
|
||||
|
||||
s2, err := concurrency.NewSession(cli)
|
||||
if err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
defer s2.Close()
|
||||
m2 := concurrency.NewMutex(s2, "/my-lock/")
|
||||
|
||||
// acquire lock for s1
|
||||
if err := m1.Lock(context.TODO()); err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
fmt.Println("acquired lock for s1")
|
||||
|
||||
m2Locked := make(chan struct{})
|
||||
go func() {
|
||||
defer close(m2Locked)
|
||||
// wait until s1 is locks /my-lock/
|
||||
if err := m2.Lock(context.TODO()); err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
}()
|
||||
|
||||
if err := m1.Unlock(context.TODO()); err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
fmt.Println("released lock for s1")
|
||||
|
||||
<-m2Locked
|
||||
fmt.Println("acquired lock for s2")
|
||||
|
||||
// Output:
|
||||
// acquired lock for s1
|
||||
// released lock for s1
|
||||
// acquired lock for s2
|
||||
}
|
||||
97
clientv3/concurrency/example_stm_test.go
Normal file
97
clientv3/concurrency/example_stm_test.go
Normal file
@ -0,0 +1,97 @@
|
||||
// Copyright 2017 The etcd Authors
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 (the "License");
|
||||
// you may not use this file except in compliance with the License.
|
||||
// You may obtain a copy of the License at
|
||||
//
|
||||
// http://www.apache.org/licenses/LICENSE-2.0
|
||||
//
|
||||
// Unless required by applicable law or agreed to in writing, software
|
||||
// distributed under the License is distributed on an "AS IS" BASIS,
|
||||
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||||
// See the License for the specific language governing permissions and
|
||||
// limitations under the License.
|
||||
|
||||
package concurrency_test
|
||||
|
||||
import (
|
||||
"context"
|
||||
"fmt"
|
||||
"log"
|
||||
"math/rand"
|
||||
"sync"
|
||||
|
||||
"github.com/coreos/etcd/clientv3"
|
||||
"github.com/coreos/etcd/clientv3/concurrency"
|
||||
)
|
||||
|
||||
// ExampleSTM_apply shows how to use STM with a transactional
|
||||
// transfer between balances.
|
||||
func ExampleSTM_apply() {
|
||||
cli, err := clientv3.New(clientv3.Config{Endpoints: endpoints})
|
||||
if err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
defer cli.Close()
|
||||
|
||||
// set up "accounts"
|
||||
totalAccounts := 5
|
||||
for i := 0; i < totalAccounts; i++ {
|
||||
k := fmt.Sprintf("accts/%d", i)
|
||||
if _, err = cli.Put(context.TODO(), k, "100"); err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
}
|
||||
|
||||
exchange := func(stm concurrency.STM) error {
|
||||
from, to := rand.Intn(totalAccounts), rand.Intn(totalAccounts)
|
||||
if from == to {
|
||||
// nothing to do
|
||||
return nil
|
||||
}
|
||||
// read values
|
||||
fromK, toK := fmt.Sprintf("accts/%d", from), fmt.Sprintf("accts/%d", to)
|
||||
fromV, toV := stm.Get(fromK), stm.Get(toK)
|
||||
fromInt, toInt := 0, 0
|
||||
fmt.Sscanf(fromV, "%d", &fromInt)
|
||||
fmt.Sscanf(toV, "%d", &toInt)
|
||||
|
||||
// transfer amount
|
||||
xfer := fromInt / 2
|
||||
fromInt, toInt = fromInt-xfer, toInt-xfer
|
||||
|
||||
// writeback
|
||||
stm.Put(fromK, fmt.Sprintf("%d", fromInt))
|
||||
stm.Put(toK, fmt.Sprintf("%d", toInt))
|
||||
return nil
|
||||
}
|
||||
|
||||
// concurrently exchange values between accounts
|
||||
var wg sync.WaitGroup
|
||||
wg.Add(10)
|
||||
for i := 0; i < 10; i++ {
|
||||
go func() {
|
||||
defer wg.Done()
|
||||
if _, serr := concurrency.NewSTM(cli, exchange); serr != nil {
|
||||
log.Fatal(serr)
|
||||
}
|
||||
}()
|
||||
}
|
||||
wg.Wait()
|
||||
|
||||
// confirm account sum matches sum from beginning.
|
||||
sum := 0
|
||||
accts, err := cli.Get(context.TODO(), "accts/", clientv3.WithPrefix())
|
||||
if err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
for _, kv := range accts.Kvs {
|
||||
v := 0
|
||||
fmt.Sscanf(string(kv.Value), "%d", &v)
|
||||
sum += v
|
||||
}
|
||||
|
||||
fmt.Println("account sum is", sum)
|
||||
// Output:
|
||||
// account sum is 500
|
||||
}
|
||||
44
clientv3/concurrency/main_test.go
Normal file
44
clientv3/concurrency/main_test.go
Normal file
@ -0,0 +1,44 @@
|
||||
// Copyright 2017 The etcd Authors
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 (the "License");
|
||||
// you may not use this file except in compliance with the License.
|
||||
// You may obtain a copy of the License at
|
||||
//
|
||||
// http://www.apache.org/licenses/LICENSE-2.0
|
||||
//
|
||||
// Unless required by applicable law or agreed to in writing, software
|
||||
// distributed under the License is distributed on an "AS IS" BASIS,
|
||||
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||||
// See the License for the specific language governing permissions and
|
||||
// limitations under the License.
|
||||
|
||||
package concurrency_test
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"os"
|
||||
"testing"
|
||||
"time"
|
||||
|
||||
"github.com/coreos/etcd/integration"
|
||||
"github.com/coreos/etcd/pkg/testutil"
|
||||
)
|
||||
|
||||
var endpoints []string
|
||||
|
||||
// TestMain sets up an etcd cluster for running the examples.
|
||||
func TestMain(m *testing.M) {
|
||||
cfg := integration.ClusterConfig{Size: 1}
|
||||
clus := integration.NewClusterV3(nil, &cfg)
|
||||
endpoints = []string{clus.Client(0).Endpoints()[0]}
|
||||
v := m.Run()
|
||||
clus.Terminate(nil)
|
||||
if err := testutil.CheckAfterTest(time.Second); err != nil {
|
||||
fmt.Fprintf(os.Stderr, "%v", err)
|
||||
os.Exit(1)
|
||||
}
|
||||
if v == 0 && testutil.CheckLeakedGoroutine() {
|
||||
os.Exit(1)
|
||||
}
|
||||
os.Exit(v)
|
||||
}
|
||||
Loading…
x
Reference in New Issue
Block a user