// TestSendToOneClient verifies that Send correctly sends a request
// to one server using the heartbeat RPC.
func TestSendToOneClient(t *testing.T) {
	defer leaktest.AfterTest(t)()

	stopper := stop.NewStopper()
	defer stopper.Stop()

	ctx := newNodeTestContext(nil, stopper)
	s, ln := newTestServer(t, ctx)
	roachpb.RegisterInternalServer(s, Node(0))

	sp := tracing.NewTracer().StartSpan("node test")
	defer sp.Finish()

	opts := SendOptions{
		Ordering:        orderStable,
		SendNextTimeout: 1 * time.Second,
		Timeout:         10 * time.Second,
		Trace:           sp,
	}
	reply, err := sendBatch(opts, []net.Addr{ln.Addr()}, ctx)
	if err != nil {
		t.Fatal(err)
	}
	if reply == nil {
		t.Errorf("expected reply")
	}
}

// TestRetryableError verifies that Send returns a retryable error
// when it hits an RPC error.
func TestRetryableError(t *testing.T) {
	defer leaktest.AfterTest(t)()

	clientStopper := stop.NewStopper()
	defer clientStopper.Stop()
	clientContext := newNodeTestContext(nil, clientStopper)

	serverStopper := stop.NewStopper()
	serverContext := newNodeTestContext(nil, serverStopper)

	s, ln := newTestServer(t, serverContext)
	roachpb.RegisterInternalServer(s, Node(0))

	conn, err := clientContext.GRPCDial(ln.Addr().String())
	if err != nil {
		t.Fatal(err)
	}
	ctx := context.Background()
	waitForConnState := func(desiredState grpc.ConnectivityState) {
		clientState, err := conn.State()
		for clientState != desiredState {
			if err != nil {
				t.Fatal(err)
			}
			if clientState == grpc.Shutdown {
				t.Fatalf("%v has unexpectedly shut down", conn)
			}
			clientState, err = conn.WaitForStateChange(ctx, clientState)
		}
	}
	// Wait until the client becomes healthy and shut down the server.
	waitForConnState(grpc.Ready)
	serverStopper.Stop()
	// Wait until the client becomes unhealthy.
	waitForConnState(grpc.TransientFailure)

	sp := tracing.NewTracer().StartSpan("node test")
	defer sp.Finish()

	opts := SendOptions{
		Ordering:        orderStable,
		SendNextTimeout: 100 * time.Millisecond,
		Timeout:         100 * time.Millisecond,
		Trace:           sp,
	}
	if _, err := sendBatch(opts, []net.Addr{ln.Addr()}, clientContext); err != nil {
		retryErr, ok := err.(retry.Retryable)
		if !ok {
			t.Fatalf("Unexpected error type: %v", err)
		}
		if !retryErr.CanRetry() {
			t.Errorf("Expected retryable error: %v", retryErr)
		}
	} else {
		t.Fatalf("Unexpected success")
	}
}

// createTestNode creates an rpc server using the specified address,
// gossip instance, KV database and a node using the specified slice
// of engines. The server, clock and node are returned. If gossipBS is
// not nil, the gossip bootstrap address is set to gossipBS.
func createTestNode(addr net.Addr, engines []engine.Engine, gossipBS net.Addr, t *testing.T) (
	*grpc.Server, net.Addr, *hlc.Clock, *Node, *stop.Stopper) {
	ctx := storage.StoreContext{}

	stopper := stop.NewStopper()
	ctx.Clock = hlc.NewClock(hlc.UnixNano)
	nodeRPCContext := rpc.NewContext(nodeTestBaseContext, ctx.Clock, stopper)
	ctx.ScanInterval = 10 * time.Hour
	ctx.ConsistencyCheckInterval = 10 * time.Hour
	grpcServer := rpc.NewServer(nodeRPCContext)
	serverCtx := makeTestContext()
	g := gossip.New(
		context.Background(),
		nodeRPCContext,
		grpcServer,
		serverCtx.GossipBootstrapResolvers,
		stopper,
		metric.NewRegistry())
	ln, err := netutil.ListenAndServeGRPC(stopper, grpcServer, addr)
	if err != nil {
		t.Fatal(err)
	}
	if gossipBS != nil {
		// Handle possibility of a :0 port specification.
		if gossipBS.Network() == addr.Network() && gossipBS.String() == addr.String() {
			gossipBS = ln.Addr()
		}
		r, err := resolver.NewResolverFromAddress(gossipBS)
		if err != nil {
			t.Fatalf("bad gossip address %s: %s", gossipBS, err)
		}
		g.SetResolvers([]resolver.Resolver{r})
		g.Start(ln.Addr())
	}
	ctx.Gossip = g
	retryOpts := base.DefaultRetryOptions()
	retryOpts.Closer = stopper.ShouldQuiesce()
	distSender := kv.NewDistSender(&kv.DistSenderConfig{
		Clock:           ctx.Clock,
		RPCContext:      nodeRPCContext,
		RPCRetryOptions: &retryOpts,
	}, g)
	ctx.Ctx = tracing.WithTracer(context.Background(), tracing.NewTracer())
	sender := kv.NewTxnCoordSender(ctx.Ctx, distSender, ctx.Clock, false, stopper,
		kv.MakeTxnMetrics())
	ctx.DB = client.NewDB(sender)
	ctx.Transport = storage.NewDummyRaftTransport()
	node := NewNode(ctx, status.NewMetricsRecorder(ctx.Clock), metric.NewRegistry(), stopper,
		kv.MakeTxnMetrics(), sql.MakeEventLogger(nil))
	roachpb.RegisterInternalServer(grpcServer, node)
	return grpcServer, ln.Addr(), ctx.Clock, node, stopper
}

//.........这里部分代码省略.........
		mux:     http.NewServeMux(),
		clock:   hlc.NewClock(hlc.UnixNano),
		stopper: stopper,
	}
	s.clock.SetMaxOffset(ctx.MaxOffset)

	s.rpcContext = rpc.NewContext(&ctx.Context, s.clock, stopper)
	s.rpcContext.HeartbeatCB = func() {
		if err := s.rpcContext.RemoteClocks.VerifyClockOffset(); err != nil {
			log.Fatal(err)
		}
	}

	s.gossip = gossip.New(s.rpcContext, s.ctx.GossipBootstrapResolvers, stopper)
	s.storePool = storage.NewStorePool(s.gossip, s.clock, ctx.TimeUntilStoreDead, stopper)

	// A custom RetryOptions is created which uses stopper.ShouldDrain() as
	// the Closer. This prevents infinite retry loops from occurring during
	// graceful server shutdown
	//
	// Such a loop loop occurs with the DistSender attempts a connection to the
	// local server during shutdown, and receives an internal server error (HTTP
	// Code 5xx). This is the correct error for a server to return when it is
	// shutting down, and is normally retryable in a cluster environment.
	// However, on a single-node setup (such as a test), retries will never
	// succeed because the only server has been shut down; thus, thus the
	// DistSender needs to know that it should not retry in this situation.
	retryOpts := kv.GetDefaultDistSenderRetryOptions()
	retryOpts.Closer = stopper.ShouldDrain()
	ds := kv.NewDistSender(&kv.DistSenderContext{
		Clock:           s.clock,
		RPCContext:      s.rpcContext,
		RPCRetryOptions: &retryOpts,
	}, s.gossip)
	txnRegistry := metric.NewRegistry()
	txnMetrics := kv.NewTxnMetrics(txnRegistry)
	sender := kv.NewTxnCoordSender(ds, s.clock, ctx.Linearizable, s.Tracer, s.stopper, txnMetrics)
	s.db = client.NewDB(sender)

	s.grpc = rpc.NewServer(s.rpcContext)
	s.raftTransport = storage.NewRaftTransport(storage.GossipAddressResolver(s.gossip), s.grpc, s.rpcContext)

	s.kvDB = kv.NewDBServer(&s.ctx.Context, sender, stopper)
	roachpb.RegisterExternalServer(s.grpc, s.kvDB)

	s.leaseMgr = sql.NewLeaseManager(0, *s.db, s.clock)
	s.leaseMgr.RefreshLeases(s.stopper, s.db, s.gossip)
	eCtx := sql.ExecutorContext{
		DB:           s.db,
		Gossip:       s.gossip,
		LeaseManager: s.leaseMgr,
		Clock:        s.clock,
		TestingKnobs: &ctx.TestingKnobs.ExecutorTestingKnobs,
	}

	sqlRegistry := metric.NewRegistry()
	s.sqlExecutor = sql.NewExecutor(eCtx, s.stopper, sqlRegistry)

	s.pgServer = pgwire.MakeServer(&s.ctx.Context, s.sqlExecutor, sqlRegistry)

	// TODO(bdarnell): make StoreConfig configurable.
	nCtx := storage.StoreContext{
		Clock:                          s.clock,
		DB:                             s.db,
		Gossip:                         s.gossip,
		Transport:                      s.raftTransport,
		ScanInterval:                   s.ctx.ScanInterval,
		ScanMaxIdleTime:                s.ctx.ScanMaxIdleTime,
		ConsistencyCheckInterval:       s.ctx.ConsistencyCheckInterval,
		ConsistencyCheckPanicOnFailure: s.ctx.ConsistencyCheckPanicOnFailure,
		Tracer:    s.Tracer,
		StorePool: s.storePool,
		SQLExecutor: sql.InternalExecutor{
			LeaseManager: s.leaseMgr,
		},
		LogRangeEvents: true,
		AllocatorOptions: storage.AllocatorOptions{
			AllowRebalance: true,
		},
		TestingKnobs: ctx.TestingKnobs.StoreTestingKnobs,
	}

	s.recorder = status.NewMetricsRecorder(s.clock)
	s.recorder.AddNodeRegistry("sql.%s", sqlRegistry)
	s.recorder.AddNodeRegistry("txn.%s", txnRegistry)
	s.recorder.AddNodeRegistry("clock-offset.%s", s.rpcContext.RemoteClocks.Registry())

	s.runtime = status.MakeRuntimeStatSampler(s.clock)
	s.recorder.AddNodeRegistry("sys.%s", s.runtime.Registry())

	s.node = NewNode(nCtx, s.recorder, s.stopper, txnMetrics)
	roachpb.RegisterInternalServer(s.grpc, s.node)

	s.admin = newAdminServer(s.db, s.stopper, s.sqlExecutor, ds, s.node)
	s.tsDB = ts.NewDB(s.db)
	s.tsServer = ts.NewServer(s.tsDB)
	s.status = newStatusServer(s.db, s.gossip, s.recorder, s.ctx)

	return s, nil
}

//.........这里部分代码省略.........
		RPCContext:      s.rpcContext,
		RPCRetryOptions: &retryOpts,
	}
	s.distSender = kv.NewDistSender(&distSenderCfg, s.gossip)

	txnMetrics := kv.MakeTxnMetrics()
	s.registry.AddMetricStruct(txnMetrics)
	s.txnCoordSender = kv.NewTxnCoordSender(s.Ctx(), s.distSender, s.clock, srvCtx.Linearizable,
		s.stopper, txnMetrics)
	s.db = client.NewDB(s.txnCoordSender)

	s.raftTransport = storage.NewRaftTransport(storage.GossipAddressResolver(s.gossip), s.grpc, s.rpcContext)

	s.kvDB = kv.NewDBServer(s.ctx.Context, s.txnCoordSender, s.stopper)
	roachpb.RegisterExternalServer(s.grpc, s.kvDB)

	// Set up Lease Manager
	var lmKnobs sql.LeaseManagerTestingKnobs
	if srvCtx.TestingKnobs.SQLLeaseManager != nil {
		lmKnobs = *srvCtx.TestingKnobs.SQLLeaseManager.(*sql.LeaseManagerTestingKnobs)
	}
	s.leaseMgr = sql.NewLeaseManager(0, *s.db, s.clock, lmKnobs, s.stopper)
	s.leaseMgr.RefreshLeases(s.stopper, s.db, s.gossip)

	// Set up the DistSQL server
	distSQLCfg := distsql.ServerConfig{
		Context:    s.Ctx(),
		DB:         s.db,
		RPCContext: s.rpcContext,
	}
	s.distSQLServer = distsql.NewServer(distSQLCfg)
	distsql.RegisterDistSQLServer(s.grpc, s.distSQLServer)

	// Set up Executor
	execCfg := sql.ExecutorConfig{
		Context:      s.Ctx(),
		DB:           s.db,
		Gossip:       s.gossip,
		LeaseManager: s.leaseMgr,
		Clock:        s.clock,
		DistSQLSrv:   s.distSQLServer,
	}
	if srvCtx.TestingKnobs.SQLExecutor != nil {
		execCfg.TestingKnobs = srvCtx.TestingKnobs.SQLExecutor.(*sql.ExecutorTestingKnobs)
	} else {
		execCfg.TestingKnobs = &sql.ExecutorTestingKnobs{}
	}

	s.sqlExecutor = sql.NewExecutor(execCfg, s.stopper)
	s.registry.AddMetricStruct(s.sqlExecutor)

	s.pgServer = pgwire.MakeServer(s.ctx.Context, s.sqlExecutor)
	s.registry.AddMetricStruct(s.pgServer.Metrics())

	// TODO(bdarnell): make StoreConfig configurable.
	nCtx := storage.StoreContext{
		Ctx:                            s.Ctx(),
		Clock:                          s.clock,
		DB:                             s.db,
		Gossip:                         s.gossip,
		Transport:                      s.raftTransport,
		RaftTickInterval:               s.ctx.RaftTickInterval,
		ScanInterval:                   s.ctx.ScanInterval,
		ScanMaxIdleTime:                s.ctx.ScanMaxIdleTime,
		ConsistencyCheckInterval:       s.ctx.ConsistencyCheckInterval,
		ConsistencyCheckPanicOnFailure: s.ctx.ConsistencyCheckPanicOnFailure,
		StorePool:                      s.storePool,
		SQLExecutor: sql.InternalExecutor{
			LeaseManager: s.leaseMgr,
		},
		LogRangeEvents: true,
		AllocatorOptions: storage.AllocatorOptions{
			AllowRebalance: true,
		},
	}
	if srvCtx.TestingKnobs.Store != nil {
		nCtx.TestingKnobs = *srvCtx.TestingKnobs.Store.(*storage.StoreTestingKnobs)
	}

	s.recorder = status.NewMetricsRecorder(s.clock)
	s.registry.AddMetricStruct(s.rpcContext.RemoteClocks.Metrics())

	s.runtime = status.MakeRuntimeStatSampler(s.clock)
	s.registry.AddMetricStruct(s.runtime)

	s.node = NewNode(nCtx, s.recorder, s.registry, s.stopper, txnMetrics, sql.MakeEventLogger(s.leaseMgr))
	roachpb.RegisterInternalServer(s.grpc, s.node)
	storage.RegisterStoresServer(s.grpc, s.node.storesServer)

	s.tsDB = ts.NewDB(s.db)
	s.tsServer = ts.MakeServer(s.tsDB)

	s.admin = makeAdminServer(s)
	s.status = newStatusServer(s.db, s.gossip, s.recorder, s.ctx.Context, s.rpcContext, s.node.stores)
	for _, gw := range []grpcGatewayServer{&s.admin, s.status, &s.tsServer} {
		gw.RegisterService(s.grpc)
	}

	return s, nil
}