// startFakeServerGossips creates local gossip instances and remote
// faked gossip instance. The remote gossip instance launches its
// faked gossip service just for check the client message.
func startFakeServerGossips(
	t *testing.T, localNodeID roachpb.NodeID,
) (*Gossip, *fakeGossipServer, *stop.Stopper) {
	stopper := stop.NewStopper()
	lRPCContext := rpc.NewContext(log.AmbientContext{}, &base.Config{Insecure: true}, nil, stopper)

	lserver := rpc.NewServer(lRPCContext)
	local := NewTest(localNodeID, lRPCContext, lserver, nil, stopper, metric.NewRegistry())
	lln, err := netutil.ListenAndServeGRPC(stopper, lserver, util.IsolatedTestAddr)
	if err != nil {
		t.Fatal(err)
	}
	local.start(lln.Addr())

	rRPCContext := rpc.NewContext(log.AmbientContext{}, &base.Config{Insecure: true}, nil, stopper)

	rserver := rpc.NewServer(rRPCContext)
	rln, err := netutil.ListenAndServeGRPC(stopper, rserver, util.IsolatedTestAddr)
	if err != nil {
		t.Fatal(err)
	}
	remote := newFakeGossipServer(rserver, stopper)
	addr := rln.Addr()
	remote.nodeAddr = util.MakeUnresolvedAddr(addr.Network(), addr.String())
	return local, remote, stopper
}

func startGossipAtAddr(
	nodeID roachpb.NodeID,
	addr net.Addr,
	stopper *stop.Stopper,
	t *testing.T,
	registry *metric.Registry,
) *Gossip {
	rpcContext := rpc.NewContext(log.AmbientContext{}, &base.Config{Insecure: true}, nil, stopper)
	server := rpc.NewServer(rpcContext)
	g := NewTest(nodeID, rpcContext, server, nil, stopper, registry)
	ln, err := netutil.ListenAndServeGRPC(stopper, server, addr)
	if err != nil {
		t.Fatal(err)
	}
	addr = ln.Addr()
	if err := g.SetNodeDescriptor(&roachpb.NodeDescriptor{
		NodeID:  nodeID,
		Address: util.MakeUnresolvedAddr(addr.Network(), addr.String()),
	}); err != nil {
		t.Fatal(err)
	}
	g.start(addr)
	time.Sleep(time.Millisecond)
	return g
}

// 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) {
	cfg := storage.StoreConfig{}

	stopper := stop.NewStopper()
	cfg.Clock = hlc.NewClock(hlc.UnixNano)
	nodeRPCContext := rpc.NewContext(log.AmbientContext{}, nodeTestBaseContext, cfg.Clock, stopper)
	cfg.ScanInterval = 10 * time.Hour
	cfg.ConsistencyCheckInterval = 10 * time.Hour
	grpcServer := rpc.NewServer(nodeRPCContext)
	serverCfg := makeTestConfig()
	cfg.Gossip = gossip.NewTest(
		0,
		nodeRPCContext,
		grpcServer,
		serverCfg.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)
		}
		cfg.Gossip.SetResolvers([]resolver.Resolver{r})
		cfg.Gossip.Start(ln.Addr())
	}
	retryOpts := base.DefaultRetryOptions()
	retryOpts.Closer = stopper.ShouldQuiesce()
	distSender := kv.NewDistSender(kv.DistSenderConfig{
		Clock:           cfg.Clock,
		RPCContext:      nodeRPCContext,
		RPCRetryOptions: &retryOpts,
	}, cfg.Gossip)
	cfg.AmbientCtx.Tracer = tracing.NewTracer()
	sender := kv.NewTxnCoordSender(
		cfg.AmbientCtx,
		distSender,
		cfg.Clock,
		false,
		stopper,
		kv.MakeTxnMetrics(metric.TestSampleInterval),
	)
	cfg.DB = client.NewDB(sender)
	cfg.Transport = storage.NewDummyRaftTransport()
	cfg.MetricsSampleInterval = metric.TestSampleInterval
	node := NewNode(cfg, status.NewMetricsRecorder(cfg.Clock), metric.NewRegistry(), stopper,
		kv.MakeTxnMetrics(metric.TestSampleInterval), sql.MakeEventLogger(nil))
	roachpb.RegisterInternalServer(grpcServer, node)
	return grpcServer, ln.Addr(), cfg.Clock, node, stopper
}

func newTestServer(t *testing.T, ctx *rpc.Context) (*grpc.Server, net.Listener) {
	s := rpc.NewServer(ctx)

	ln, err := netutil.ListenAndServeGRPC(ctx.Stopper, s, util.TestAddr)
	if err != nil {
		t.Fatal(err)
	}

	return s, ln
}

// Start starts the test cluster by bootstrapping an in-memory store
// (defaults to maximum of 50M). The server is started, launching the
// node RPC server and all HTTP endpoints. Use the value of
// TestServer.Addr after Start() for client connections. Use Stop()
// to shutdown the server after the test completes.
func (ltc *LocalTestCluster) Start(t util.Tester, baseCtx *base.Config, initSender InitSenderFn) {
	ambient := log.AmbientContext{Tracer: tracing.NewTracer()}
	nc := &base.NodeIDContainer{}
	ambient.AddLogTag("n", nc)

	nodeID := roachpb.NodeID(1)
	nodeDesc := &roachpb.NodeDescriptor{NodeID: nodeID}

	ltc.tester = t
	ltc.Manual = hlc.NewManualClock(0)
	ltc.Clock = hlc.NewClock(ltc.Manual.UnixNano)
	ltc.Stopper = stop.NewStopper()
	rpcContext := rpc.NewContext(ambient, baseCtx, ltc.Clock, ltc.Stopper)
	server := rpc.NewServer(rpcContext) // never started
	ltc.Gossip = gossip.New(ambient, nc, rpcContext, server, nil, ltc.Stopper, metric.NewRegistry())
	ltc.Eng = engine.NewInMem(roachpb.Attributes{}, 50<<20)
	ltc.Stopper.AddCloser(ltc.Eng)

	ltc.Stores = storage.NewStores(ambient, ltc.Clock)

	ltc.Sender = initSender(nodeDesc, ambient.Tracer, ltc.Clock, ltc.Latency, ltc.Stores, ltc.Stopper,
		ltc.Gossip)
	if ltc.DBContext == nil {
		dbCtx := client.DefaultDBContext()
		ltc.DBContext = &dbCtx
	}
	ltc.DB = client.NewDBWithContext(ltc.Sender, *ltc.DBContext)
	transport := storage.NewDummyRaftTransport()
	cfg := storage.TestStoreConfig()
	if ltc.RangeRetryOptions != nil {
		cfg.RangeRetryOptions = *ltc.RangeRetryOptions
	}
	cfg.AmbientCtx = ambient
	cfg.Clock = ltc.Clock
	cfg.DB = ltc.DB
	cfg.Gossip = ltc.Gossip
	cfg.Transport = transport
	cfg.MetricsSampleInterval = metric.TestSampleInterval
	ltc.Store = storage.NewStore(cfg, ltc.Eng, nodeDesc)
	if err := ltc.Store.Bootstrap(roachpb.StoreIdent{NodeID: nodeID, StoreID: 1}); err != nil {
		t.Fatalf("unable to start local test cluster: %s", err)
	}
	ltc.Stores.AddStore(ltc.Store)
	if err := ltc.Store.BootstrapRange(nil); err != nil {
		t.Fatalf("unable to start local test cluster: %s", err)
	}
	if err := ltc.Store.Start(context.Background(), ltc.Stopper); err != nil {
		t.Fatalf("unable to start local test cluster: %s", err)
	}
	nc.Set(context.TODO(), nodeDesc.NodeID)
	if err := ltc.Gossip.SetNodeDescriptor(nodeDesc); err != nil {
		t.Fatalf("unable to set node descriptor: %s", err)
	}
}

func newRaftTransportTestContext(t testing.TB) *raftTransportTestContext {
	rttc := &raftTransportTestContext{
		t:          t,
		stopper:    stop.NewStopper(),
		transports: map[roachpb.NodeID]*storage.RaftTransport{},
	}
	rttc.nodeRPCContext = rpc.NewContext(
		log.AmbientContext{}, testutils.NewNodeTestBaseContext(), nil, rttc.stopper,
	)
	server := rpc.NewServer(rttc.nodeRPCContext) // never started
	rttc.gossip = gossip.NewTest(
		1, rttc.nodeRPCContext, server, nil, rttc.stopper, metric.NewRegistry(),
	)
	return rttc
}

// TestClientRegisterInitNodeID verifies two client's gossip request with NodeID 0.
func TestClientRegisterWithInitNodeID(t *testing.T) {
	defer leaktest.AfterTest(t)()
	stopper := stop.NewStopper()
	defer stopper.Stop()

	// Create three gossip nodes, and connect to the first with NodeID 0.
	var g []*Gossip
	var gossipAddr string
	for i := 0; i < 3; i++ {
		RPCContext := rpc.NewContext(log.AmbientContext{}, &base.Config{Insecure: true}, nil, stopper)

		server := rpc.NewServer(RPCContext)
		ln, err := netutil.ListenAndServeGRPC(stopper, server, util.IsolatedTestAddr)
		if err != nil {
			t.Fatal(err)
		}

		// Connect to the first gossip node.
		if gossipAddr == "" {
			gossipAddr = ln.Addr().String()
		}

		var resolvers []resolver.Resolver
		resolver, err := resolver.NewResolver(gossipAddr)
		if err != nil {
			t.Fatal(err)
		}
		resolvers = append(resolvers, resolver)
		// node ID must be non-zero
		gnode := NewTest(
			roachpb.NodeID(i+1), RPCContext, server, resolvers, stopper, metric.NewRegistry(),
		)
		g = append(g, gnode)
		gnode.Start(ln.Addr())
	}

	util.SucceedsSoon(t, func() error {
		// The first gossip node should have two gossip client address
		// in nodeMap if these three gossip nodes registered success.
		g[0].mu.Lock()
		defer g[0].mu.Unlock()
		if a, e := len(g[0].mu.nodeMap), 2; a != e {
			return errors.Errorf("expected %s to contain %d nodes, got %d", g[0].mu.nodeMap, e, a)
		}
		return nil
	})
}

// AddNodeWithoutGossip registers a node with the cluster. Nodes must
// be added before they can be used in other methods of
// raftTransportTestContext. Unless you are testing the effects of
// delaying gossip, use AddNode instead.
func (rttc *raftTransportTestContext) AddNodeWithoutGossip(
	nodeID roachpb.NodeID,
) (*storage.RaftTransport, net.Addr) {
	grpcServer := rpc.NewServer(rttc.nodeRPCContext)
	ln, err := netutil.ListenAndServeGRPC(rttc.stopper, grpcServer, util.TestAddr)
	if err != nil {
		rttc.t.Fatal(err)
	}
	transport := storage.NewRaftTransport(
		log.AmbientContext{},
		storage.GossipAddressResolver(rttc.gossip),
		grpcServer,
		rttc.nodeRPCContext,
	)
	rttc.transports[nodeID] = transport
	return transport, ln.Addr()
}

// TestGossipOverwriteNode verifies that if a new node is added with the same
// address as an old node, that old node is removed from the cluster.
func TestGossipOverwriteNode(t *testing.T) {
	defer leaktest.AfterTest(t)()
	stopper := stop.NewStopper()
	defer stopper.Stop()
	rpcContext := newInsecureRPCContext(stopper)
	g := NewTest(1, rpcContext, rpc.NewServer(rpcContext), nil, stopper, metric.NewRegistry())
	node1 := &roachpb.NodeDescriptor{NodeID: 1, Address: util.MakeUnresolvedAddr("tcp", "1.1.1.1:1")}
	node2 := &roachpb.NodeDescriptor{NodeID: 2, Address: util.MakeUnresolvedAddr("tcp", "2.2.2.2:2")}
	if err := g.SetNodeDescriptor(node1); err != nil {
		t.Fatal(err)
	}
	if err := g.SetNodeDescriptor(node2); err != nil {
		t.Fatal(err)
	}
	if val, err := g.GetNodeDescriptor(node1.NodeID); err != nil {
		t.Error(err)
	} else if val.NodeID != node1.NodeID {
		t.Errorf("expected node %d, got %+v", node1.NodeID, val)
	}
	if val, err := g.GetNodeDescriptor(node2.NodeID); err != nil {
		t.Error(err)
	} else if val.NodeID != node2.NodeID {
		t.Errorf("expected node %d, got %+v", node2.NodeID, val)
	}

	// Give node3 the same address as node1, which should cause node1 to be
	// removed from the cluster.
	node3 := &roachpb.NodeDescriptor{NodeID: 3, Address: node1.Address}
	if err := g.SetNodeDescriptor(node3); err != nil {
		t.Fatal(err)
	}
	if val, err := g.GetNodeDescriptor(node3.NodeID); err != nil {
		t.Error(err)
	} else if val.NodeID != node3.NodeID {
		t.Errorf("expected node %d, got %+v", node3.NodeID, val)
	}

	// Quiesce the stopper now to ensure that the update has propagated before
	// checking whether node 1 has been removed from the infoStore.
	stopper.Quiesce()
	expectedErr := "unable to look up descriptor for node"
	if val, err := g.GetNodeDescriptor(node1.NodeID); !testutils.IsError(err, expectedErr) {
		t.Errorf("expected error %q fetching node %d; got error %v and node %+v",
			expectedErr, node1.NodeID, err, val)
	}
}

// TestGossipInfoStore verifies operation of gossip instance infostore.
func TestGossipInfoStore(t *testing.T) {
	defer leaktest.AfterTest(t)()
	stopper := stop.NewStopper()
	defer stopper.Stop()
	rpcContext := newInsecureRPCContext(stopper)
	g := NewTest(1, rpcContext, rpc.NewServer(rpcContext), nil, stopper, metric.NewRegistry())
	slice := []byte("b")
	if err := g.AddInfo("s", slice, time.Hour); err != nil {
		t.Fatal(err)
	}
	if val, err := g.GetInfo("s"); !bytes.Equal(val, slice) || err != nil {
		t.Errorf("error fetching string: %v", err)
	}
	if _, err := g.GetInfo("s2"); err == nil {
		t.Errorf("expected error fetching nonexistent key \"s2\"")
	}
}

// CreateNode creates a simulation node and starts an RPC server for it.
func (n *Network) CreateNode() (*Node, error) {
	server := rpc.NewServer(n.rpcContext)
	ln, err := net.Listen(util.TestAddr.Network(), util.TestAddr.String())
	if err != nil {
		return nil, err
	}
	node := &Node{Server: server, Listener: ln, Registry: metric.NewRegistry()}
	node.Gossip = gossip.NewTest(0, n.rpcContext, server, nil, n.Stopper, node.Registry)
	n.Stopper.RunWorker(func() {
		<-n.Stopper.ShouldQuiesce()
		netutil.FatalIfUnexpected(ln.Close())
		<-n.Stopper.ShouldStop()
		server.Stop()
		node.Gossip.EnableSimulationCycler(false)
	})
	n.Nodes = append(n.Nodes, node)
	return node, nil
}

// createTestStorePool creates a stopper, gossip and storePool for use in
// tests. Stopper must be stopped by the caller.
func createTestStorePool(
	timeUntilStoreDead time.Duration,
) (*stop.Stopper, *gossip.Gossip, *hlc.ManualClock, *StorePool) {
	stopper := stop.NewStopper()
	mc := hlc.NewManualClock(0)
	clock := hlc.NewClock(mc.UnixNano)
	rpcContext := rpc.NewContext(log.AmbientContext{}, &base.Config{Insecure: true}, clock, stopper)
	server := rpc.NewServer(rpcContext) // never started
	g := gossip.NewTest(1, rpcContext, server, nil, stopper, metric.NewRegistry())
	storePool := NewStorePool(
		log.AmbientContext{},
		g,
		clock,
		rpcContext,
		timeUntilStoreDead,
		stopper,
	)
	return stopper, g, mc, storePool
}

// createTestStorePool creates a stopper, gossip and storePool for use in
// tests. Stopper must be stopped by the caller.
func createTestStorePool(
	timeUntilStoreDead time.Duration, deterministic bool, defaultNodeLiveness bool,
) (*stop.Stopper, *gossip.Gossip, *hlc.ManualClock, *StorePool, *mockNodeLiveness) {
	stopper := stop.NewStopper()
	mc := hlc.NewManualClock(123)
	clock := hlc.NewClock(mc.UnixNano, time.Nanosecond)
	rpcContext := rpc.NewContext(log.AmbientContext{}, &base.Config{Insecure: true}, clock, stopper)
	server := rpc.NewServer(rpcContext) // never started
	g := gossip.NewTest(1, rpcContext, server, nil, stopper, metric.NewRegistry())
	mnl := newMockNodeLiveness(defaultNodeLiveness)
	storePool := NewStorePool(
		log.AmbientContext{},
		g,
		clock,
		mnl.nodeLivenessFunc,
		timeUntilStoreDead,
		deterministic,
	)
	return stopper, g, mc, storePool, mnl
}

func TestGossipGetNextBootstrapAddress(t *testing.T) {
	defer leaktest.AfterTest(t)()
	stopper := stop.NewStopper()
	defer stopper.Stop()

	resolverSpecs := []string{
		"127.0.0.1:9000",
		"127.0.0.1:9001",
		"localhost:9004",
	}

	resolvers := []resolver.Resolver{}
	for _, rs := range resolverSpecs {
		resolver, err := resolver.NewResolver(rs)
		if err == nil {
			resolvers = append(resolvers, resolver)
		}
	}
	if len(resolvers) != 3 {
		t.Errorf("expected 3 resolvers; got %d", len(resolvers))
	}
	server := rpc.NewServer(
		rpc.NewContext(log.AmbientContext{}, &base.Config{Insecure: true}, nil, stopper),
	)
	g := NewTest(0, nil, server, resolvers, stop.NewStopper(), metric.NewRegistry())

	// Using specified resolvers, fetch bootstrap addresses 3 times
	// and verify the results match expected addresses.
	expAddresses := []string{
		"127.0.0.1:9000",
		"127.0.0.1:9001",
		"localhost:9004",
	}
	for i := 0; i < len(expAddresses); i++ {
		if addr := g.getNextBootstrapAddress(); addr == nil {
			t.Errorf("%d: unexpected nil addr when expecting %s", i, expAddresses[i])
		} else if addrStr := addr.String(); addrStr != expAddresses[i] {
			t.Errorf("%d: expected addr %s; got %s", i, expAddresses[i], addrStr)
		}
	}
}

// createCluster generates a new cluster using the provided stopper and the
// number of nodes supplied. Each node will have one store to start.
func createCluster(
	stopper *stop.Stopper,
	nodeCount int,
	epochWriter, actionWriter io.Writer,
	script Script,
	rand *rand.Rand,
) *Cluster {
	clock := hlc.NewClock(hlc.UnixNano, time.Nanosecond)
	rpcContext := rpc.NewContext(log.AmbientContext{}, &base.Config{Insecure: true}, clock, stopper)
	server := rpc.NewServer(rpcContext)
	// We set the node ID to MaxInt32 for the cluster Gossip instance to prevent
	// conflicts with real node IDs.
	g := gossip.NewTest(math.MaxInt32, rpcContext, server, nil, stopper, metric.NewRegistry())
	// Set the store pool to deterministic so that a run with the exact same
	// input will always produce the same output.
	storePool := storage.NewStorePool(
		log.AmbientContext{},
		g,
		clock,
		rpcContext,
		storage.TestTimeUntilStoreDeadOff,
		stopper,
		/* deterministic */ true,
	)
	c := &Cluster{
		stopper:   stopper,
		clock:     clock,
		rpc:       rpcContext,
		gossip:    g,
		storePool: storePool,
		allocator: storage.MakeAllocator(storePool, storage.AllocatorOptions{
			AllowRebalance: true,
		}),
		storeGossiper:   gossiputil.NewStoreGossiper(g),
		nodes:           make(map[roachpb.NodeID]*Node),
		stores:          make(map[roachpb.StoreID]*Store),
		ranges:          make(map[roachpb.RangeID]*Range),
		rangeIDsByStore: make(map[roachpb.StoreID]roachpb.RangeIDSlice),
		rand:            rand,
		epochWriter:     tabwriter.NewWriter(epochWriter, 8, 1, 2, ' ', 0),
		actionWriter:    tabwriter.NewWriter(actionWriter, 8, 1, 2, ' ', 0),
		script:          script,
		epoch:           -1,
	}

	// Add the nodes.
	for i := 0; i < nodeCount; i++ {
		c.addNewNodeWithStore()
	}

	// Add a single range and add to this first node's first store.
	firstRange := c.addRange()
	firstRange.addReplica(c.stores[0])

	c.calculateRangeIDsByStore()

	// Output the first epoch header.
	c.epoch = 0
	c.OutputEpochHeader()
	c.OutputEpoch()
	c.flush()

	return c
}

// NewServer creates a Server from a server.Context.
func NewServer(cfg Config, stopper *stop.Stopper) (*Server, error) {
	if _, err := net.ResolveTCPAddr("tcp", cfg.AdvertiseAddr); err != nil {
		return nil, errors.Errorf("unable to resolve RPC address %q: %v", cfg.AdvertiseAddr, err)
	}

	if cfg.AmbientCtx.Tracer == nil {
		cfg.AmbientCtx.Tracer = tracing.NewTracer()
	}

	// Try loading the TLS configs before anything else.
	if _, err := cfg.GetServerTLSConfig(); err != nil {
		return nil, err
	}
	if _, err := cfg.GetClientTLSConfig(); err != nil {
		return nil, err
	}

	s := &Server{
		mux:     http.NewServeMux(),
		clock:   hlc.NewClock(hlc.UnixNano, cfg.MaxOffset),
		stopper: stopper,
		cfg:     cfg,
	}
	// Add a dynamic log tag value for the node ID.
	//
	// We need to pass an ambient context to the various server components, but we
	// won't know the node ID until we Start(). At that point it's too late to
	// change the ambient contexts in the components (various background processes
	// will have already started using them).
	//
	// NodeIDContainer allows us to add the log tag to the context now and update
	// the value asynchronously. It's not significantly more expensive than a
	// regular tag since it's just doing an (atomic) load when a log/trace message
	// is constructed. The node ID is set by the Store if this host was
	// bootstrapped; otherwise a new one is allocated in Node.
	s.cfg.AmbientCtx.AddLogTag("n", &s.nodeIDContainer)

	ctx := s.AnnotateCtx(context.Background())
	if s.cfg.Insecure {
		log.Warning(ctx, "running in insecure mode, this is strongly discouraged. See --insecure.")
	}

	s.rpcContext = rpc.NewContext(s.cfg.AmbientCtx, s.cfg.Config, s.clock, s.stopper)
	s.rpcContext.HeartbeatCB = func() {
		if err := s.rpcContext.RemoteClocks.VerifyClockOffset(); err != nil {
			log.Fatal(ctx, err)
		}
	}
	s.grpc = rpc.NewServer(s.rpcContext)

	s.registry = metric.NewRegistry()
	s.gossip = gossip.New(
		s.cfg.AmbientCtx,
		&s.nodeIDContainer,
		s.rpcContext,
		s.grpc,
		s.cfg.GossipBootstrapResolvers,
		s.stopper,
		s.registry,
	)
	s.storePool = storage.NewStorePool(
		s.cfg.AmbientCtx,
		s.gossip,
		s.clock,
		s.rpcContext,
		s.cfg.TimeUntilStoreDead,
		s.stopper,
		/* deterministic */ false,
	)

	// A custom RetryOptions is created which uses stopper.ShouldQuiesce() 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 := base.DefaultRetryOptions()
	retryOpts.Closer = s.stopper.ShouldQuiesce()
	distSenderCfg := kv.DistSenderConfig{
		AmbientCtx:      s.cfg.AmbientCtx,
		Clock:           s.clock,
		RPCContext:      s.rpcContext,
		RPCRetryOptions: &retryOpts,
	}
	s.distSender = kv.NewDistSender(distSenderCfg, s.gossip)

	txnMetrics := kv.MakeTxnMetrics(s.cfg.MetricsSampleInterval)
	s.registry.AddMetricStruct(txnMetrics)
	s.txnCoordSender = kv.NewTxnCoordSender(
		s.cfg.AmbientCtx,
		s.distSender,
		s.clock,
		s.cfg.Linearizable,
		s.stopper,
//.........这里部分代码省略.........