Golang context.Background函数代码示例

// Leases returns map binary.BigEndian.Uint32(IP) and Lease of all assigned leases
func (p *LeasePool) Leases() (map[string]Lease, error) {
	p.dataLock.Lock()
	defer p.dataLock.Unlock()
	leases := make(map[string]Lease, 10)

	ctxGet, cancelGet := context.WithTimeout(context.Background(), 2*time.Second)
	defer cancelGet()
	response, err := p.dataSource.Get(ctxGet, path.Join(p.etcdDir, "/leases"), &etcd.GetOptions{Recursive: true})

	if err != nil {
		etcdError, found := err.(etcd.Error)
		if found && etcdError.Code == etcd.ErrorCodeKeyNotFound {
			// handle key not found
			ctxSet, cancelSet := context.WithTimeout(context.Background(), 2*time.Second)
			defer cancelSet()
			_, err := p.dataSource.Set(ctxSet, path.Join(p.etcdDir, "/leases"), "", &etcd.SetOptions{Dir: true})
			if err != nil {
				return nil, err
			}
			return leases, nil
		}
		return nil, err
	}
	for i := range response.Node.Nodes {
		var lease Lease
		err := json.Unmarshal([]byte(response.Node.Nodes[i].Value), &lease)
		if err == nil {
			leases[lease.IP.String()] = lease
		} else {
			return nil, ErrFoundInvalidLease
		}
	}
	return leases, nil
}

func main() {
	cfg := client.Config{
		Endpoints: []string{"http://172.16.235.128:4001"},
		Transport: client.DefaultTransport,
		// set timeout per request to fail fast when the target endpoint is unavailable
		HeaderTimeoutPerRequest: time.Second,
	}
	c, err := client.New(cfg)
	if err != nil {
		log.Fatal(err)
	}
	kapi := client.NewKeysAPI(c)
	// set "/woo" key with "bar" value
	log.Print("Setting '/woo' key with 'bar' value")
	resp, err := kapi.Set(context.Background(), "/woo", "bar", nil)
	if err != nil {
		log.Fatal(err)
	} else {
		// print common key info
		log.Printf("Set is done. Metadata is %q\n", resp)
	}
	// get "/woo" key's value
	log.Print("Getting '/woo' key value")
	resp, err = kapi.Get(context.Background(), "/woo", nil)
	if err != nil {
		log.Fatal(err)
	} else {
		// print common key info
		log.Printf("Get is done. Metadata is %q\n", resp)
		// print value
		log.Printf("%q key has %q value\n", resp.Node.Key, resp.Node.Value)
	}
}

// helper function to store our data in etcd
func (etcdO *EtcdWObject) EtcdPut(hostname, key, res string, obj interface{}) bool {
	kapi := etcdO.GetKAPI()
	output, ok := ObjToB64(obj)
	if !ok {
		log.Printf("Etcd: Could not encode %v key.", key)
		return false
	}

	path := fmt.Sprintf("/exported/%s/resources/%s/res", hostname, key)
	_, err := kapi.Set(etcd_context.Background(), path, res, nil)
	// XXX validate...

	path = fmt.Sprintf("/exported/%s/resources/%s/value", hostname, key)
	resp, err := kapi.Set(etcd_context.Background(), path, output, nil)
	if err != nil {
		if cerr, ok := err.(*etcd.ClusterError); ok {
			// not running or disconnected
			for _, e := range cerr.Errors {
				if strings.HasSuffix(e.Error(), "getsockopt: connection refused") {
				}
				//if e == etcd.ErrClusterUnavailable
			}
		}
		log.Printf("Etcd: Could not store %v key.", key)
		return false
	}
	log.Print("Etcd: ", resp) // w00t... bonus
	return true
}

func TestMemberUpdate(t *testing.T) {
	defer testutil.AfterTest(t)

	clus := integration.NewClusterV3(t, &integration.ClusterConfig{Size: 3})
	defer clus.Terminate(t)

	capi := clientv3.NewCluster(clus.RandClient())
	resp, err := capi.MemberList(context.Background())
	if err != nil {
		t.Fatalf("failed to list member %v", err)
	}

	urls := []string{"http://127.0.0.1:1234"}
	_, err = capi.MemberUpdate(context.Background(), resp.Members[0].ID, urls)
	if err != nil {
		t.Fatalf("failed to update member %v", err)
	}

	resp, err = capi.MemberList(context.Background())
	if err != nil {
		t.Fatalf("failed to list member %v", err)
	}

	if !reflect.DeepEqual(resp.Members[0].PeerURLs, urls) {
		t.Errorf("urls = %v, want %v", urls, resp.Members[0].PeerURLs)
	}
}

func TestMemberRemove(t *testing.T) {
	defer testutil.AfterTest(t)

	clus := integration.NewClusterV3(t, &integration.ClusterConfig{Size: 3})
	defer clus.Terminate(t)

	capi := clientv3.NewCluster(clus.Client(1))
	resp, err := capi.MemberList(context.Background())
	if err != nil {
		t.Fatalf("failed to list member %v", err)
	}

	_, err = capi.MemberRemove(context.Background(), resp.Members[0].ID)
	if err != nil {
		t.Fatalf("failed to remove member %v", err)
	}

	resp, err = capi.MemberList(context.Background())
	if err != nil {
		t.Fatalf("failed to list member %v", err)
	}

	if len(resp.Members) != 2 {
		t.Errorf("number of members = %d, want %d", len(resp.Members), 2)
	}
}

func main() {
	cfg := client.Config{
		Endpoints: []string{"http://127.0.0.1:2379"},
		Transport: client.DefaultTransport,
		// set timeout per request to fail fast when the target endpoint is unavailable
		HeaderTimeoutPerRequest: time.Second,
	}
	c, err := client.New(cfg)
	if err != nil {
		log.Fatal(err)
	}
	kapi := client.NewKeysAPI(c)
	resp, err := kapi.Get(context.Background(), "/foo", nil)
	if err != nil {
		//		fmt.Println("oops:", err)
		msg := fmt.Sprintf("%s", err)
		if strings.HasPrefix(msg, "100:") {
			fmt.Println("oops:", msg)
		}
		_, err2 := kapi.Set(context.Background(), "foo", "bar", nil)
		if err != nil {
			log.Fatal(err2)
		}
	} else {
		fmt.Println(resp.Node.Value)
	}
}

// TestV3LeaseExists creates a lease on a random client, then sends a keepalive on another
// client to confirm it's visible to the whole cluster.
func TestV3LeaseExists(t *testing.T) {
	defer testutil.AfterTest(t)
	clus := NewClusterV3(t, &ClusterConfig{Size: 3})
	defer clus.Terminate(t)

	// create lease
	ctx0, cancel0 := context.WithCancel(context.Background())
	defer cancel0()
	lresp, err := clus.RandClient().Lease.LeaseCreate(
		ctx0,
		&pb.LeaseCreateRequest{TTL: 30})
	if err != nil {
		t.Fatal(err)
	}
	if lresp.Error != "" {
		t.Fatal(lresp.Error)
	}

	// confirm keepalive
	ctx1, cancel1 := context.WithCancel(context.Background())
	defer cancel1()
	lac, err := clus.RandClient().Lease.LeaseKeepAlive(ctx1)
	if err != nil {
		t.Fatal(err)
	}
	defer lac.CloseSend()
	if err = lac.Send(&pb.LeaseKeepAliveRequest{ID: lresp.ID}); err != nil {
		t.Fatal(err)
	}
	if _, err = lac.Recv(); err != nil {
		t.Fatal(err)
	}
}

func Conn() {
	cfg := client.Config{
		Endpoints:               []string{"http://127.0.0.1:2379/", "http://127.0.0.1:4001"},
		Transport:               client.DefaultTransport,
		HeaderTimeoutPerRequest: time.Second,
	}

	c, err := client.New(cfg)

	if err != nil {
		log.Fatal(err)
	}

	kapi := client.NewKeysAPI(c)

	log.Print("Setting '/foo' key with 'bar' value")
	resp, err := kapi.Set(context.Background(), "/foo", "bar", nil)
	if err != nil {
		log.Fatal(err)
	} else {
		log.Printf("Set is done.Metadata is %q\n", resp)
	}

	log.Print("Getting '/foo' key value")
	resp, err = kapi.Get(context.Background(), "/foo", nil)
	if err != nil {
		log.Fatal(err)
	} else {
		log.Printf("Get is done,Metadata is %q\n", resp)
		log.Printf("%q key has %q value\n", resp.Node.Key, resp.Node.Value)
	}

}

func TestLeaseRevoke(t *testing.T) {
	defer testutil.AfterTest(t)

	clus := integration.NewClusterV3(t, &integration.ClusterConfig{Size: 3})
	defer clus.Terminate(t)

	lapi := clientv3.NewLease(clus.RandClient())
	defer lapi.Close()

	kv := clientv3.NewKV(clus.RandClient())

	resp, err := lapi.Create(context.Background(), 10)
	if err != nil {
		t.Errorf("failed to create lease %v", err)
	}

	_, err = lapi.Revoke(context.Background(), lease.LeaseID(resp.ID))
	if err != nil {
		t.Errorf("failed to revoke lease %v", err)
	}

	_, err = kv.Put(context.TODO(), "foo", "bar", clientv3.WithLease(lease.LeaseID(resp.ID)))
	if err != v3rpc.ErrLeaseNotFound {
		t.Fatalf("err = %v, want %v", err, v3rpc.ErrLeaseNotFound)
	}
}

func TestLeaseKeepAlive(t *testing.T) {
	defer testutil.AfterTest(t)

	clus := integration.NewClusterV3(t, &integration.ClusterConfig{Size: 3})
	defer clus.Terminate(t)

	lapi := clientv3.NewLease(clus.RandClient())

	resp, err := lapi.Create(context.Background(), 10)
	if err != nil {
		t.Errorf("failed to create lease %v", err)
	}

	rc, kerr := lapi.KeepAlive(context.Background(), lease.LeaseID(resp.ID))
	if kerr != nil {
		t.Errorf("failed to keepalive lease %v", kerr)
	}

	kresp, ok := <-rc
	if !ok {
		t.Errorf("chan is closed, want not closed")
	}

	if kresp.ID != resp.ID {
		t.Errorf("ID = %x, want %x", kresp.ID, resp.ID)
	}

	lapi.Close()

	_, ok = <-rc
	if ok {
		t.Errorf("chan is not closed, want lease Close() closes chan")
	}
}

func ExampleKV_compact() {
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   endpoints,
		DialTimeout: dialTimeout,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer cli.Close()

	kvc := clientv3.NewKV(cli)

	ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
	resp, err := kvc.Get(ctx, "foo")
	cancel()
	if err != nil {
		log.Fatal(err)
	}
	compRev := resp.Header.Revision // specify compact revision of your choice

	ctx, cancel = context.WithTimeout(context.Background(), requestTimeout)
	err = kvc.Compact(ctx, compRev)
	cancel()
	if err != nil {
		log.Fatal(err)
	}
}

func TestEmptyAddrs(t *testing.T) {
	servers, r := startServers(t, 1, 0, math.MaxUint32)
	cc, err := Dial("foo.bar.com", WithPicker(NewUnicastNamingPicker(r)), WithBlock(), WithInsecure(), WithCodec(testCodec{}))
	if err != nil {
		t.Fatalf("Failed to create ClientConn: %v", err)
	}
	var reply string
	if err := Invoke(context.Background(), "/foo/bar", &expectedRequest, &reply, cc); err != nil || reply != expectedResponse {
		t.Fatalf("grpc.Invoke(_, _, _, _, _) = %v, want <nil>", err)
	}
	// Inject name resolution change to remove the server address so that there is no address
	// available after that.
	var updates []*naming.Update
	updates = append(updates, &naming.Update{
		Op:   naming.Delete,
		Addr: "127.0.0.1:" + servers[0].port,
	})
	r.w.inject(updates)
	// Loop until the above updates apply.
	for {
		time.Sleep(10 * time.Millisecond)
		ctx, _ := context.WithTimeout(context.Background(), 10*time.Millisecond)
		if err := Invoke(ctx, "/foo/bar", &expectedRequest, &reply, cc); err != nil {
			break
		}
	}
	cc.Close()
	servers[0].stop()
}

func ExampleKV_getSortedPrefix() {
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   endpoints,
		DialTimeout: dialTimeout,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer cli.Close()

	kvc := clientv3.NewKV(cli)

	for i := range make([]int, 3) {
		ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
		_, err = kvc.Put(ctx, fmt.Sprintf("key_%d", i), "value")
		cancel()
		if err != nil {
			log.Fatal(err)
		}
	}

	ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
	resp, err := kvc.Get(ctx, "key", clientv3.WithPrefix(), clientv3.WithSort(clientv3.SortByKey, clientv3.SortDescend))
	cancel()
	if err != nil {
		log.Fatal(err)
	}
	for _, ev := range resp.Kvs {
		fmt.Printf("%s : %s\n", ev.Key, ev.Value)
	}
	// key_2 : value
	// key_1 : value
	// key_0 : value
}

func actionUserPasswd(c *cli.Context) {
	api, user := mustUserAPIAndName(c)
	ctx, cancel := context.WithTimeout(context.Background(), client.DefaultRequestTimeout)
	currentUser, err := api.GetUser(ctx, user)
	cancel()
	if currentUser == nil {
		fmt.Fprintln(os.Stderr, err.Error())
		os.Exit(1)
	}
	pass, err := speakeasy.Ask("New password: ")
	if err != nil {
		fmt.Fprintln(os.Stderr, "Error reading password:", err)
		os.Exit(1)
	}

	ctx, cancel = context.WithTimeout(context.Background(), client.DefaultRequestTimeout)
	_, err = api.ChangePassword(ctx, user, pass)
	cancel()
	if err != nil {
		fmt.Fprintln(os.Stderr, err.Error())
		os.Exit(1)
	}

	fmt.Printf("Password updated\n")
}

func (d *discovery) checkCluster() ([]*client.Node, int, uint64, error) {
	configKey := path.Join("/", d.cluster, "_config")
	ctx, cancel := context.WithTimeout(context.Background(), client.DefaultRequestTimeout)
	// find cluster size
	resp, err := d.c.Get(ctx, path.Join(configKey, "size"), nil)
	cancel()
	if err != nil {
		if eerr, ok := err.(*client.Error); ok && eerr.Code == client.ErrorCodeKeyNotFound {
			return nil, 0, 0, ErrSizeNotFound
		}
		if err == client.ErrInvalidJSON {
			return nil, 0, 0, ErrBadDiscoveryEndpoint
		}
		if ce, ok := err.(*client.ClusterError); ok {
			plog.Error(ce.Detail())
			return d.checkClusterRetry()
		}
		return nil, 0, 0, err
	}
	size, err := strconv.Atoi(resp.Node.Value)
	if err != nil {
		return nil, 0, 0, ErrBadSizeKey
	}

	ctx, cancel = context.WithTimeout(context.Background(), client.DefaultRequestTimeout)
	resp, err = d.c.Get(ctx, d.cluster, nil)
	cancel()
	if err != nil {
		if ce, ok := err.(*client.ClusterError); ok {
			plog.Error(ce.Detail())
			return d.checkClusterRetry()
		}
		return nil, 0, 0, err
	}
	nodes := make([]*client.Node, 0)
	// append non-config keys to nodes
	for _, n := range resp.Node.Nodes {
		if !(path.Base(n.Key) == path.Base(configKey)) {
			nodes = append(nodes, n)
		}
	}

	snodes := sortableNodes{nodes}
	sort.Sort(snodes)

	// find self position
	for i := range nodes {
		if path.Base(nodes[i].Key) == path.Base(d.selfKey()) {
			break
		}
		if i >= size-1 {
			return nodes[:size], size, resp.Index, ErrFullCluster
		}
	}
	return nodes, size, resp.Index, nil
}