func setupFakeServer(opt ...grpc.ServerOption) (tbl *Table, cleanup func(), err error) {
	srv, err := bttest.NewServer("127.0.0.1:0", opt...)
	if err != nil {
		return nil, nil, err
	}
	conn, err := grpc.Dial(srv.Addr, grpc.WithInsecure())
	if err != nil {
		return nil, nil, err
	}

	client, err := NewClient(context.Background(), "client", "instance", option.WithGRPCConn(conn))
	if err != nil {
		return nil, nil, err
	}

	adminClient, err := NewAdminClient(context.Background(), "client", "instance", option.WithGRPCConn(conn))
	if err != nil {
		return nil, nil, err
	}
	if err := adminClient.CreateTable(context.Background(), "table"); err != nil {
		return nil, nil, err
	}
	if err := adminClient.CreateColumnFamily(context.Background(), "table", "cf"); err != nil {
		return nil, nil, err
	}
	t := client.Open("table")

	cleanupFunc := func() {
		adminClient.Close()
		client.Close()
		srv.Close()
	}
	return t, cleanupFunc, nil
}

func ExampleNewServer() {

	srv, err := bttest.NewServer("127.0.0.1:0")

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

	ctx := context.Background()

	conn, err := grpc.Dial(srv.Addr, grpc.WithInsecure())
	if err != nil {
		log.Fatalln(err)
	}

	proj, instance := "proj", "instance"

	adminClient, err := bigtable.NewAdminClient(ctx, proj, instance, option.WithGRPCConn(conn))
	if err != nil {
		log.Fatalln(err)
	}

	if err = adminClient.CreateTable(ctx, "example"); err != nil {
		log.Fatalln(err)
	}

	if err = adminClient.CreateColumnFamily(ctx, "example", "links"); err != nil {
		log.Fatalln(err)
	}

	client, err := bigtable.NewClient(ctx, proj, instance, option.WithGRPCConn(conn))
	if err != nil {
		log.Fatalln(err)
	}
	tbl := client.Open("example")

	mut := bigtable.NewMutation()
	mut.Set("links", "golang.org", bigtable.Now(), []byte("Gophers!"))
	if err = tbl.Apply(ctx, "com.google.cloud", mut); err != nil {
		log.Fatalln(err)
	}

	if row, err := tbl.ReadRow(ctx, "com.google.cloud"); err != nil {
		log.Fatalln(err)
	} else {
		for _, column := range row["links"] {
			fmt.Println(column.Column)
			fmt.Println(string(column.Value))
		}
	}

	// Output:
	// links:golang.org
	// Gophers!
}

// NewClient returns a new logging client associated with the provided project ID.
//
// By default NewClient uses WriteScope. To use a different scope, call
// NewClient using a WithScopes option.
func NewClient(ctx context.Context, projectID string, opts ...option.ClientOption) (*Client, error) {
	// Check for '/' in project ID to reserve the ability to support various owning resources,
	// in the form "{Collection}/{Name}", for instance "organizations/my-org".
	if strings.ContainsRune(projectID, '/') {
		return nil, errors.New("logging: project ID contains '/'")
	}
	opts = append([]option.ClientOption{option.WithEndpoint(prodAddr), option.WithScopes(WriteScope)},
		opts...)
	lc, err := vkit.NewClient(ctx, opts...)
	if err != nil {
		return nil, err
	}
	// TODO(jba): pass along any client options that should be provided to all clients.
	sc, err := vkit.NewConfigClient(ctx, option.WithGRPCConn(lc.Connection()))
	if err != nil {
		return nil, err
	}
	mc, err := vkit.NewMetricsClient(ctx, option.WithGRPCConn(lc.Connection()))
	if err != nil {
		return nil, err
	}
	lc.SetGoogleClientInfo("logging", version)
	sc.SetGoogleClientInfo("logging", version)
	mc.SetGoogleClientInfo("logging", version)
	client := &Client{
		lClient:   lc,
		sClient:   sc,
		mClient:   mc,
		projectID: projectID,
		errc:      make(chan error, defaultErrorCapacity), // create a small buffer for errors
		donec:     make(chan struct{}),
		OnError:   func(e error) { log.Printf("logging client: %v", e) },
	}
	// Call the user's function synchronously, to make life easier for them.
	go func() {
		for err := range client.errc {
			// This reference to OnError is memory-safe if the user sets OnError before
			// calling any client methods. The reference happens before the first read from
			// client.errc, which happens before the first write to client.errc, which
			// happens before any call, which happens before the user sets OnError.
			if fn := client.OnError; fn != nil {
				fn(err)
			} else {
				log.Printf("logging (project ID %q): %v", projectID, err)
			}
		}
	}()
	return client, nil
}

// NewClient creates a new PubSub client.
func NewClient(ctx context.Context, projectID string, opts ...option.ClientOption) (*Client, error) {
	var o []option.ClientOption
	// Environment variables for gcloud emulator:
	// https://cloud.google.com/sdk/gcloud/reference/beta/emulators/pubsub/
	if addr := os.Getenv("PUBSUB_EMULATOR_HOST"); addr != "" {
		conn, err := grpc.Dial(addr, grpc.WithInsecure())
		if err != nil {
			return nil, fmt.Errorf("grpc.Dial: %v", err)
		}
		o = []option.ClientOption{option.WithGRPCConn(conn)}
	} else {
		o = []option.ClientOption{option.WithUserAgent(userAgent)}
	}
	o = append(o, opts...)
	s, err := newPubSubService(ctx, o)
	if err != nil {
		return nil, fmt.Errorf("constructing pubsub client: %v", err)
	}

	c := &Client{
		projectID: projectID,
		s:         s,
	}

	return c, nil
}

// NewClient builds a new connected data client for this environment
func (e *EmulatedEnv) NewClient() (*Client, error) {
	timeout := 20 * time.Second
	ctx, _ := context.WithTimeout(context.Background(), timeout)
	conn, err := grpc.Dial(e.server.Addr, grpc.WithInsecure())
	if err != nil {
		return nil, err
	}
	return NewClient(ctx, e.config.Project, e.config.Instance, option.WithGRPCConn(conn))
}

func newPubSubService(ctx context.Context, opts []option.ClientOption) (*apiService, error) {
	pubc, err := vkit.NewPublisherClient(ctx, opts...)
	if err != nil {
		return nil, err
	}
	subc, err := vkit.NewSubscriberClient(ctx, option.WithGRPCConn(pubc.Connection()))
	if err != nil {
		_ = pubc.Close() // ignore error
		return nil, err
	}
	pubc.SetGoogleClientInfo("pubsub", version)
	subc.SetGoogleClientInfo("pubsub", version)
	return &apiService{pubc: pubc, subc: subc}, nil
}

func TestAdminIntegration(t *testing.T) {
	srv, err := bttest.NewServer("127.0.0.1:0")
	if err != nil {
		t.Fatal(err)
	}
	defer srv.Close()
	t.Logf("bttest.Server running on %s", srv.Addr)

	ctx, _ := context.WithTimeout(context.Background(), 2*time.Second)

	conn, err := grpc.Dial(srv.Addr, grpc.WithInsecure())
	if err != nil {
		t.Fatalf("grpc.Dial: %v", err)
	}

	adminClient, err := NewAdminClient(ctx, "proj", "instance", option.WithGRPCConn(conn))
	if err != nil {
		t.Fatalf("NewAdminClient: %v", err)
	}
	defer adminClient.Close()

	list := func() []string {
		tbls, err := adminClient.Tables(ctx)
		if err != nil {
			t.Fatalf("Fetching list of tables: %v", err)
		}
		sort.Strings(tbls)
		return tbls
	}
	if err := adminClient.CreateTable(ctx, "mytable"); err != nil {
		t.Fatalf("Creating table: %v", err)
	}
	if err := adminClient.CreateTable(ctx, "myothertable"); err != nil {
		t.Fatalf("Creating table: %v", err)
	}
	if got, want := list(), []string{"myothertable", "mytable"}; !reflect.DeepEqual(got, want) {
		t.Errorf("adminClient.Tables returned %#v, want %#v", got, want)
	}
	if err := adminClient.DeleteTable(ctx, "myothertable"); err != nil {
		t.Fatalf("Deleting table: %v", err)
	}
	if got, want := list(), []string{"mytable"}; !reflect.DeepEqual(got, want) {
		t.Errorf("adminClient.Tables returned %#v, want %#v", got, want)
	}
}

// NewClient creates a new Client for a given dataset.
// If the project ID is empty, it is derived from the DATASTORE_PROJECT_ID environment variable.
// If the DATASTORE_EMULATOR_HOST environment variable is set, client will use its value
// to connect to a locally-running datastore emulator.
func NewClient(ctx context.Context, projectID string, opts ...option.ClientOption) (*Client, error) {
	var o []option.ClientOption
	// Environment variables for gcd emulator:
	// https://cloud.google.com/datastore/docs/tools/datastore-emulator
	// If the emulator is available, dial it directly (and don't pass any credentials).
	if addr := os.Getenv("DATASTORE_EMULATOR_HOST"); addr != "" {
		conn, err := grpc.Dial(addr, grpc.WithInsecure())
		if err != nil {
			return nil, fmt.Errorf("grpc.Dial: %v", err)
		}
		o = []option.ClientOption{option.WithGRPCConn(conn)}
	} else {
		o = []option.ClientOption{
			option.WithEndpoint(prodAddr),
			option.WithScopes(ScopeDatastore),
			option.WithUserAgent(userAgent),
		}
	}
	// Warn if we see the legacy emulator environment variables.
	if os.Getenv("DATASTORE_HOST") != "" && os.Getenv("DATASTORE_EMULATOR_HOST") == "" {
		log.Print("WARNING: legacy environment variable DATASTORE_HOST is ignored. Use DATASTORE_EMULATOR_HOST instead.")
	}
	if os.Getenv("DATASTORE_DATASET") != "" && os.Getenv("DATASTORE_PROJECT_ID") == "" {
		log.Print("WARNING: legacy environment variable DATASTORE_DATASET is ignored. Use DATASTORE_PROJECT_ID instead.")
	}
	if projectID == "" {
		projectID = os.Getenv("DATASTORE_PROJECT_ID")
	}
	if projectID == "" {
		return nil, errors.New("datastore: missing project/dataset id")
	}
	o = append(o, opts...)
	conn, err := transport.DialGRPC(ctx, o...)
	if err != nil {
		return nil, fmt.Errorf("dialing: %v", err)
	}
	return &Client{
		conn:    conn,
		client:  newDatastoreClient(conn, projectID),
		dataset: projectID,
	}, nil

}

// DefaultClientOptions returns the default client options to use for the
// client's gRPC connection.
func DefaultClientOptions(endpoint, scope, userAgent string) ([]option.ClientOption, error) {
	var o []option.ClientOption
	// Check the environment variables for the bigtable emulator.
	// Dial it directly and don't pass any credentials.
	if addr := os.Getenv("BIGTABLE_EMULATOR_HOST"); addr != "" {
		conn, err := grpc.Dial(addr, grpc.WithInsecure())
		if err != nil {
			return nil, fmt.Errorf("emulator grpc.Dial: %v", err)
		}
		o = []option.ClientOption{option.WithGRPCConn(conn)}
	} else {
		o = []option.ClientOption{
			option.WithEndpoint(endpoint),
			option.WithScopes(scope),
			option.WithUserAgent(userAgent),
		}
	}
	return o, nil
}

func TestMain(m *testing.M) {
	flag.Parse()

	serv := grpc.NewServer()
	languagepb.RegisterLanguageServiceServer(serv, &mockLanguage)

	lis, err := net.Listen("tcp", "localhost:0")
	if err != nil {
		log.Fatal(err)
	}
	go serv.Serve(lis)

	conn, err := grpc.Dial(lis.Addr().String(), grpc.WithInsecure())
	if err != nil {
		log.Fatal(err)
	}
	clientOpt = option.WithGRPCConn(conn)

	os.Exit(m.Run())
}

func TestMain(m *testing.M) {
	flag.Parse()

	serv := grpc.NewServer()
	clouddebuggerpb.RegisterDebugger2Server(serv, &mockDebugger2)
	clouddebuggerpb.RegisterController2Server(serv, &mockController2)

	lis, err := net.Listen("tcp", "localhost:0")
	if err != nil {
		log.Fatal(err)
	}
	go serv.Serve(lis)

	conn, err := grpc.Dial(lis.Addr().String(), grpc.WithInsecure())
	if err != nil {
		log.Fatal(err)
	}
	clientOpt = option.WithGRPCConn(conn)

	os.Exit(m.Run())
}

func TestMain(m *testing.M) {
	flag.Parse()

	serv := grpc.NewServer()
	pubsubpb.RegisterPublisherServer(serv, &mockPublisher)
	iampb.RegisterIAMPolicyServer(serv, &mockIamPolicy)
	pubsubpb.RegisterSubscriberServer(serv, &mockSubscriber)

	lis, err := net.Listen("tcp", "localhost:0")
	if err != nil {
		log.Fatal(err)
	}
	go serv.Serve(lis)

	conn, err := grpc.Dial(lis.Addr().String(), grpc.WithInsecure())
	if err != nil {
		log.Fatal(err)
	}
	clientOpt = option.WithGRPCConn(conn)

	os.Exit(m.Run())
}

func NewClient(bt *BigTable) (client *api.Client, err error) {
	if bt.testing {
		testSrv, err := bttest.NewServer() //TODO close the testSrv if neccesary
		if err != nil {
			return nil, fmt.Errorf("Unable to create bigTable local test server. %v", err)
		}
		testConn, err := grpc.Dial(testSrv.Addr, grpc.WithInsecure())
		if err != nil {
			return nil, fmt.Errorf("Unable to create bigTable local test server. %v", err)
		}
		//Connects to a local bigtable.
		//It with no security; The project, zone, cluster values are ignored.
		client, err = api.NewClient(bt.ctx, bt.project, bt.zone, bt.cluster, option.WithGRPCConn(testConn))
	} else {
		//Uses Application Default Credentials to authenticate into Google's Cloud.
		client, err = api.NewClient(bt.ctx, bt.project, bt.zone, bt.cluster)
	}
	if err != nil {
		return nil, fmt.Errorf("Unable to create a table client. %v", err)
	}
	return
}

func TestMain(m *testing.M) {
	flag.Parse()

	serv := grpc.NewServer()
	clouderrorreportingpb.RegisterErrorGroupServiceServer(serv, &mockErrorGroup)
	clouderrorreportingpb.RegisterErrorStatsServiceServer(serv, &mockErrorStats)
	clouderrorreportingpb.RegisterReportErrorsServiceServer(serv, &mockReportErrors)

	lis, err := net.Listen("tcp", "localhost:0")
	if err != nil {
		log.Fatal(err)
	}
	go serv.Serve(lis)

	conn, err := grpc.Dial(lis.Addr().String(), grpc.WithInsecure())
	if err != nil {
		log.Fatal(err)
	}
	clientOpt = option.WithGRPCConn(conn)

	os.Exit(m.Run())
}

func TestClientIntegration(t *testing.T) {
	start := time.Now()
	lastCheckpoint := start
	checkpoint := func(s string) {
		n := time.Now()
		t.Logf("[%s] %v since start, %v since last checkpoint", s, n.Sub(start), n.Sub(lastCheckpoint))
		lastCheckpoint = n
	}

	proj, instance, table := "proj", "instance", "mytable"
	var clientOpts []option.ClientOption
	timeout := 20 * time.Second
	if *useProd == "" {
		srv, err := bttest.NewServer("127.0.0.1:0")
		if err != nil {
			t.Fatal(err)
		}
		defer srv.Close()
		t.Logf("bttest.Server running on %s", srv.Addr)
		conn, err := grpc.Dial(srv.Addr, grpc.WithInsecure())
		if err != nil {
			t.Fatalf("grpc.Dial: %v", err)
		}
		clientOpts = []option.ClientOption{option.WithGRPCConn(conn)}
	} else {
		t.Logf("Running test against production")
		a := strings.SplitN(*useProd, ",", 3)
		proj, instance, table = a[0], a[1], a[2]
		timeout = 5 * time.Minute
	}

	ctx, _ := context.WithTimeout(context.Background(), timeout)

	client, err := NewClient(ctx, proj, instance, clientOpts...)
	if err != nil {
		t.Fatalf("NewClient: %v", err)
	}
	defer client.Close()
	checkpoint("dialed Client")

	adminClient, err := NewAdminClient(ctx, proj, instance, clientOpts...)
	if err != nil {
		t.Fatalf("NewAdminClient: %v", err)
	}
	defer adminClient.Close()
	checkpoint("dialed AdminClient")

	// Delete the table at the end of the test.
	// Do this even before creating the table so that if this is running
	// against production and CreateTable fails there's a chance of cleaning it up.
	defer adminClient.DeleteTable(ctx, table)

	if err := adminClient.CreateTable(ctx, table); err != nil {
		t.Fatalf("Creating table: %v", err)
	}
	checkpoint("created table")
	if err := adminClient.CreateColumnFamily(ctx, table, "follows"); err != nil {
		t.Fatalf("Creating column family: %v", err)
	}
	checkpoint(`created "follows" column family`)

	tbl := client.Open(table)

	// Insert some data.
	initialData := map[string][]string{
		"wmckinley":   {"tjefferson"},
		"gwashington": {"jadams"},
		"tjefferson":  {"gwashington", "jadams"}, // wmckinley set conditionally below
		"jadams":      {"gwashington", "tjefferson"},
	}
	for row, ss := range initialData {
		mut := NewMutation()
		for _, name := range ss {
			mut.Set("follows", name, 0, []byte("1"))
		}
		if err := tbl.Apply(ctx, row, mut); err != nil {
			t.Errorf("Mutating row %q: %v", row, err)
		}
	}
	checkpoint("inserted initial data")

	// Do a conditional mutation with a complex filter.
	mutTrue := NewMutation()
	mutTrue.Set("follows", "wmckinley", 0, []byte("1"))
	filter := ChainFilters(ColumnFilter("gwash[iz].*"), ValueFilter("."))
	mut := NewCondMutation(filter, mutTrue, nil)
	if err := tbl.Apply(ctx, "tjefferson", mut); err != nil {
		t.Errorf("Conditionally mutating row: %v", err)
	}
	// Do a second condition mutation with a filter that does not match,
	// and thus no changes should be made.
	mutTrue = NewMutation()
	mutTrue.DeleteRow()
	filter = ColumnFilter("snoop.dogg")
	mut = NewCondMutation(filter, mutTrue, nil)
	if err := tbl.Apply(ctx, "tjefferson", mut); err != nil {
		t.Errorf("Conditionally mutating row: %v", err)
	}
	checkpoint("did two conditional mutations")

//.........这里部分代码省略.........

// makeRequests makes some requests.
// req is an incoming request used to construct the trace.  traceClient is the
// client used to upload the trace.  rt is the trace client's http client's
// transport.  This is used to retrieve the trace uploaded by the client, if
// any.  If expectTrace is true, we expect a trace will be uploaded.  If
// synchronous is true, the call to Finish is expected not to return before the
// client has uploaded any traces.
func makeRequests(t *testing.T, req *http.Request, traceClient *Client, rt *fakeRoundTripper, synchronous bool, expectTrace bool) *http.Request {
	span := traceClient.SpanFromRequest(req)
	ctx := NewContext(context.Background(), span)

	// An HTTP request.
	{
		req2, err := http.NewRequest("GET", "http://example.com/bar", nil)
		if err != nil {
			t.Fatal(err)
		}
		resp := &http.Response{StatusCode: 200}
		s := span.NewRemoteChild(req2)
		s.Finish(WithResponse(resp))
	}

	// An autogenerated API call.
	{
		rt := &fakeRoundTripper{reqc: make(chan *http.Request, 1)}
		hc := &http.Client{Transport: rt}
		computeClient, err := compute.New(hc)
		if err != nil {
			t.Fatal(err)
		}
		_, err = computeClient.Zones.List(testProjectID).Context(ctx).Do()
		if err != nil {
			t.Fatal(err)
		}
	}

	// A cloud library call that uses the autogenerated API.
	{
		rt := &fakeRoundTripper{reqc: make(chan *http.Request, 1)}
		hc := &http.Client{Transport: rt}
		storageClient, err := storage.NewClient(context.Background(), option.WithHTTPClient(hc))
		if err != nil {
			t.Fatal(err)
		}
		var objAttrsList []*storage.ObjectAttrs
		it := storageClient.Bucket("testbucket").Objects(ctx, nil)
		for {
			objAttrs, err := it.Next()
			if err != nil && err != iterator.Done {
				t.Fatal(err)
			}
			if err == iterator.Done {
				break
			}
			objAttrsList = append(objAttrsList, objAttrs)
		}
	}

	// A cloud library call that uses grpc internally.
	for _, fail := range []bool{false, true} {
		srv, err := testutil.NewServer()
		if err != nil {
			t.Fatalf("creating test datastore server: %v", err)
		}
		dspb.RegisterDatastoreServer(srv.Gsrv, &fakeDatastoreServer{fail: fail})
		srv.Start()
		conn, err := grpc.Dial(srv.Addr, grpc.WithInsecure(), EnableGRPCTracingDialOption)
		if err != nil {
			t.Fatalf("connecting to test datastore server: %v", err)
		}
		datastoreClient, err := datastore.NewClient(ctx, testProjectID, option.WithGRPCConn(conn))
		if err != nil {
			t.Fatalf("creating datastore client: %v", err)
		}
		k := datastore.NameKey("Entity", "stringID", nil)
		e := new(datastore.Entity)
		datastoreClient.Get(ctx, k, e)
	}

	done := make(chan struct{})
	go func() {
		if synchronous {
			err := span.FinishWait()
			if err != nil {
				t.Errorf("Unexpected error from span.FinishWait: %v", err)
			}
		} else {
			span.Finish()
		}
		done <- struct{}{}
	}()
	if !expectTrace {
		<-done
		select {
		case <-rt.reqc:
			t.Errorf("Got a trace, expected none.")
		case <-time.After(5 * time.Millisecond):
		}
		return nil
	} else if !synchronous {
//.........这里部分代码省略.........

// WithBaseGRPC returns a ClientOption that specifies the gRPC client
// connection to use as the basis of communications. This option many only be
// used with services that support gRPC as their communication transport.
func WithBaseGRPC(conn *grpc.ClientConn) ClientOption {
	return wrapOpt{option.WithGRPCConn(conn)}
}