// 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) *Cluster {
	rand, seed := randutil.NewPseudoRand()
	clock := hlc.NewClock(hlc.UnixNano)
	rpcContext := rpc.NewContext(&base.Context{}, clock, stopper)
	g := gossip.New(rpcContext, gossip.TestInterval, gossip.TestBootstrap)
	storePool := storage.NewStorePool(g, storage.TestTimeUntilStoreDeadOff, stopper)
	c := &Cluster{
		stopper:       stopper,
		clock:         clock,
		rpc:           rpcContext,
		gossip:        g,
		storePool:     storePool,
		allocator:     storage.MakeAllocator(storePool, storage.RebalancingOptions{}),
		storeGossiper: gossiputil.NewStoreGossiper(g),
		nodes:         make(map[proto.NodeID]*Node),
		stores:        make(map[proto.StoreID]*Store),
		ranges:        make(map[proto.RangeID]*Range),
		rand:          rand,
		seed:          seed,
	}

	// 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.attachRangeToStore(c.stores[proto.StoreID(0)])
	return c
}

func (m *multiTestContext) Start(t *testing.T, numStores int) {
	m.t = t
	if m.manualClock == nil {
		m.manualClock = hlc.NewManualClock(0)
	}
	if m.clock == nil {
		m.clock = hlc.NewClock(m.manualClock.UnixNano)
	}
	if m.gossip == nil {
		rpcContext := rpc.NewContext(&base.Context{}, m.clock, nil)
		m.gossip = gossip.New(rpcContext, gossip.TestInterval, gossip.TestBootstrap)
	}
	if m.clientStopper == nil {
		m.clientStopper = stop.NewStopper()
	}
	if m.transport == nil {
		m.transport = multiraft.NewLocalRPCTransport(m.clientStopper)
	}
	if m.storePool == nil {
		if m.timeUntilStoreDead == 0 {
			m.timeUntilStoreDead = storage.TestTimeUntilStoreDeadOff
		}
		m.storePool = storage.NewStorePool(m.gossip, m.timeUntilStoreDead, m.clientStopper)
	}

	// Always create the first sender.
	m.senders = append(m.senders, kv.NewLocalSender())

	rpcSend := func(_ rpc.Options, _ string, _ []net.Addr,
		getArgs func(addr net.Addr) gogoproto.Message, getReply func() gogoproto.Message,
		_ *rpc.Context) ([]gogoproto.Message, error) {
		call := proto.Call{
			Args:  getArgs(nil /* net.Addr */).(proto.Request),
			Reply: getReply().(proto.Response),
		}
		m.senders[0].Send(context.Background(), call)
		return []gogoproto.Message{call.Reply}, call.Reply.Header().GoError()
	}

	if m.db == nil {
		distSender := kv.NewDistSender(&kv.DistSenderContext{
			Clock:             m.clock,
			RangeDescriptorDB: m.senders[0],
			RPCSend:           rpcSend,
		}, m.gossip)
		sender := kv.NewTxnCoordSender(distSender, m.clock, false, nil, m.clientStopper)
		m.db = client.NewDB(sender)
	}

	for i := 0; i < numStores; i++ {
		m.addStore()
	}
	if m.transportStopper == nil {
		m.transportStopper = stop.NewStopper()
	}
	m.transportStopper.AddCloser(m.transport)
}

// 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)
	rpcContext := rpc.NewContext(nil, clock, stopper)
	g := gossip.New(rpcContext, nil, stopper)
	// NodeID is required for Gossip, so set it to -1 for the cluster Gossip
	// instance to prevent conflicts with real NodeIDs.
	g.SetNodeID(-1)
	storePool := storage.NewStorePool(g, clock, storage.TestTimeUntilStoreDeadOff, stopper)
	c := &Cluster{
		stopper:   stopper,
		clock:     clock,
		rpc:       rpcContext,
		gossip:    g,
		storePool: storePool,
		allocator: storage.MakeAllocator(storePool, storage.AllocatorOptions{
			AllowRebalance: true,
			Deterministic:  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
}

// 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) *Cluster {
	rand, seed := randutil.NewPseudoRand()
	clock := hlc.NewClock(hlc.UnixNano)
	rpcContext := rpc.NewContext(&base.Context{}, clock, stopper)
	g := gossip.New(rpcContext, gossip.TestInterval, gossip.TestBootstrap)
	storePool := storage.NewStorePool(g, storage.TestTimeUntilStoreDeadOff, stopper)
	c := &Cluster{
		stopper:   stopper,
		clock:     clock,
		rpc:       rpcContext,
		gossip:    g,
		storePool: storePool,
		allocator: storage.MakeAllocator(storePool, storage.RebalancingOptions{
			AllowRebalance: true,
			Deterministic:  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,
		seed:            seed,
		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
}

func (m *multiTestContext) Start(t *testing.T, numStores int) {
	m.t = t
	if m.manualClock == nil {
		m.manualClock = hlc.NewManualClock(0)
	}
	if m.clock == nil {
		m.clock = hlc.NewClock(m.manualClock.UnixNano)
	}
	if m.gossip == nil {
		rpcContext := rpc.NewContext(&base.Context{}, m.clock, nil)
		m.gossip = gossip.New(rpcContext, gossip.TestInterval, gossip.TestBootstrap)
	}
	if m.clientStopper == nil {
		m.clientStopper = stop.NewStopper()
	}
	if m.transport == nil {
		m.transport = multiraft.NewLocalRPCTransport(m.clientStopper)
	}
	if m.storePool == nil {
		m.storePool = storage.NewStorePool(m.gossip, storage.TestTimeUntilStoreDeadOff, m.clientStopper)
	}

	// Always create the first sender.
	m.senders = append(m.senders, kv.NewLocalSender())

	if m.db == nil {
		sender := kv.NewTxnCoordSender(m.senders[0], m.clock, false, nil, m.clientStopper)
		var err error
		if m.db, err = client.Open("//", client.SenderOpt(sender)); err != nil {
			t.Fatal(err)
		}
	}

	for i := 0; i < numStores; i++ {
		m.addStore()
	}
	if m.transportStopper == nil {
		m.transportStopper = stop.NewStopper()
	}
	m.transportStopper.AddCloser(m.transport)
}

// NewServer creates a Server from a server.Context.
func NewServer(ctx *Context, stopper *stop.Stopper) (*Server, error) {
	if ctx == nil {
		return nil, util.Errorf("ctx must not be null")
	}

	if _, err := net.ResolveTCPAddr("tcp", ctx.Addr); err != nil {
		return nil, util.Errorf("unable to resolve RPC address %q: %v", ctx.Addr, err)
	}

	if ctx.Insecure {
		log.Warning("running in insecure mode, this is strongly discouraged. See --insecure and --certs.")
	}
	// Try loading the TLS configs before anything else.
	if _, err := ctx.GetServerTLSConfig(); err != nil {
		return nil, err
	}
	if _, err := ctx.GetClientTLSConfig(); err != nil {
		return nil, err
	}

	s := &Server{
		ctx:     ctx,
		mux:     http.NewServeMux(),
		clock:   hlc.NewClock(hlc.UnixNano),
		stopper: stopper,
	}
	s.clock.SetMaxOffset(ctx.MaxOffset)

	s.rpcContext = crpc.NewContext(&ctx.Context, s.clock, stopper)
	stopper.RunWorker(func() {
		s.rpcContext.RemoteClocks.MonitorRemoteOffsets(stopper)
	})

	s.rpc = crpc.NewServer(s.rpcContext)

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

	feed := util.NewFeed(stopper)
	tracer := tracer.NewTracer(feed, ctx.Addr)

	ds := kv.NewDistSender(&kv.DistSenderContext{Clock: s.clock, RPCContext: s.rpcContext}, s.gossip)
	sender := kv.NewTxnCoordSender(ds, s.clock, ctx.Linearizable, tracer, s.stopper)
	s.db = client.NewDB(sender)

	var err error
	s.raftTransport, err = newRPCTransport(s.gossip, s.rpc, s.rpcContext)
	if err != nil {
		return nil, err
	}
	s.stopper.AddCloser(s.raftTransport)

	s.kvDB = kv.NewDBServer(&s.ctx.Context, sender)
	if err := s.kvDB.RegisterRPC(s.rpc); err != nil {
		return nil, err
	}

	leaseMgr := sql.NewLeaseManager(0, *s.db, s.clock)
	leaseMgr.RefreshLeases(s.stopper, s.db, s.gossip)
	s.sqlServer = sql.MakeServer(&s.ctx.Context, *s.db, s.gossip, leaseMgr)
	if err := s.sqlServer.RegisterRPC(s.rpc); err != nil {
		return nil, err
	}

	s.pgServer = pgwire.NewServer(&pgwire.Context{
		Context:  &s.ctx.Context,
		Executor: s.sqlServer.Executor,
		Stopper:  stopper,
	})

	// 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,
		EventFeed:       feed,
		Tracer:          tracer,
		StorePool:       s.storePool,
		AllocatorOptions: storage.AllocatorOptions{
			AllowRebalance: true,
			Mode:           s.ctx.BalanceMode,
		},
	}
	s.node = NewNode(nCtx)
	s.admin = newAdminServer(s.db, s.stopper)
	s.status = newStatusServer(s.db, s.gossip, ctx)
	s.tsDB = ts.NewDB(s.db)
	s.tsServer = ts.NewServer(s.tsDB)

	return s, nil
}

// NewServer creates a Server from a server.Context.
func NewServer(ctx *Context, stopper *stop.Stopper) (*Server, error) {
	if ctx == nil {
		return nil, util.Errorf("ctx must not be null")
	}

	if _, err := net.ResolveTCPAddr("tcp", ctx.Addr); err != nil {
		return nil, util.Errorf("unable to resolve RPC address %q: %v", ctx.Addr, err)
	}

	if ctx.Insecure {
		log.Warning("running in insecure mode, this is strongly discouraged. See --insecure and --certs.")
	}
	// Try loading the TLS configs before anything else.
	if _, err := ctx.GetServerTLSConfig(); err != nil {
		return nil, err
	}
	if _, err := ctx.GetClientTLSConfig(); err != nil {
		return nil, err
	}

	s := &Server{
		Tracer:  tracing.NewTracer(),
		ctx:     ctx,
		mux:     http.NewServeMux(),
		clock:   hlc.NewClock(hlc.UnixNano),
		stopper: stopper,
	}
	s.clock.SetMaxOffset(ctx.MaxOffset)

	s.rpcContext = crpc.NewContext(&ctx.Context, s.clock, stopper)
	stopper.RunWorker(func() {
		s.rpcContext.RemoteClocks.MonitorRemoteOffsets(stopper)
	})

	s.rpc = crpc.NewServer(s.rpcContext)

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

	feed := util.NewFeed(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 = grpc.NewServer()
	s.raftTransport = storage.NewRaftTransport(storage.GossipAddressResolver(s.gossip), s.grpc, s.rpcContext)

	s.kvDB = kv.NewDBServer(&s.ctx.Context, sender, stopper)
	if err := s.kvDB.RegisterRPC(s.rpc); err != nil {
		return nil, err
	}

	s.leaseMgr = sql.NewLeaseManager(0, *s.db, s.clock)
	s.leaseMgr.RefreshLeases(s.stopper, s.db, s.gossip)
	sqlRegistry := metric.NewRegistry()
	s.sqlExecutor = sql.NewExecutor(*s.db, s.gossip, s.leaseMgr, 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,
		EventFeed:       feed,
		Tracer:          s.Tracer,
		StorePool:       s.storePool,
		SQLExecutor: sql.InternalExecutor{
			LeaseManager: s.leaseMgr,
		},
		LogRangeEvents: true,
		AllocatorOptions: storage.AllocatorOptions{
			AllowRebalance: true,
			Mode:           s.ctx.BalanceMode,
		},
	}
//.........这里部分代码省略.........

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

	if srvCtx.Ctx == nil {
		srvCtx.Ctx = context.Background()
	}
	if srvCtx.Ctx.Done() != nil {
		panic("context with cancel or deadline")
	}
	if tracing.TracerFromCtx(srvCtx.Ctx) == nil {
		// TODO(radu): instead of modifying srvCtx.Ctx, we should have a separate
		// context.Context inside Server. We will need to rename server.Context
		// though.
		srvCtx.Ctx = tracing.WithTracer(srvCtx.Ctx, tracing.NewTracer())
	}

	if srvCtx.Insecure {
		log.Warning(srvCtx.Ctx, "running in insecure mode, this is strongly discouraged. See --insecure.")
	}
	// Try loading the TLS configs before anything else.
	if _, err := srvCtx.GetServerTLSConfig(); err != nil {
		return nil, err
	}
	if _, err := srvCtx.GetClientTLSConfig(); err != nil {
		return nil, err
	}

	s := &Server{
		mux:     http.NewServeMux(),
		clock:   hlc.NewClock(hlc.UnixNano),
		stopper: stopper,
	}
	// Add a dynamic log tag value for the node ID.
	//
	// We need to pass the server's Ctx as a base context for 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 contexts in the components (various background
	// processes will have already started using the contexts).
	//
	// The dynamic value 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.
	s.nodeLogTagVal.Set(log.DynamicIntValueUnknown)
	srvCtx.Ctx = log.WithLogTag(srvCtx.Ctx, "n", &s.nodeLogTagVal)
	s.ctx = srvCtx

	s.clock.SetMaxOffset(srvCtx.MaxOffset)

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

	s.registry = metric.NewRegistry()
	s.gossip = gossip.New(
		s.Ctx(), s.rpcContext, s.grpc, s.ctx.GossipBootstrapResolvers, s.stopper, s.registry)
	s.storePool = storage.NewStorePool(
		s.gossip,
		s.clock,
		s.rpcContext,
		srvCtx.ReservationsEnabled,
		srvCtx.TimeUntilStoreDead,
		s.stopper,
	)

	// 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{
		Ctx:             s.Ctx(),
		Clock:           s.clock,
		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)
//.........这里部分代码省略.........

// NewServer creates a Server from a server.Context.
func NewServer(ctx *Context, stopper *stop.Stopper) (*Server, error) {
	if ctx == nil {
		return nil, util.Errorf("ctx must not be null")
	}

	addr := ctx.Addr
	_, err := net.ResolveTCPAddr("tcp", addr)
	if err != nil {
		return nil, util.Errorf("unable to resolve RPC address %q: %v", addr, err)
	}

	if ctx.Insecure {
		log.Warning("running in insecure mode, this is strongly discouraged. See --insecure and --certs.")
	}
	// Try loading the TLS configs before anything else.
	if _, err := ctx.GetServerTLSConfig(); err != nil {
		return nil, err
	}
	if _, err := ctx.GetClientTLSConfig(); err != nil {
		return nil, err
	}

	s := &Server{
		ctx:     ctx,
		mux:     http.NewServeMux(),
		clock:   hlc.NewClock(hlc.UnixNano),
		stopper: stopper,
	}
	s.clock.SetMaxOffset(ctx.MaxOffset)

	rpcContext := rpc.NewContext(&ctx.Context, s.clock, stopper)
	stopper.RunWorker(func() {
		rpcContext.RemoteClocks.MonitorRemoteOffsets(stopper)
	})

	s.rpc = rpc.NewServer(util.MakeUnresolvedAddr("tcp", addr), rpcContext)
	s.stopper.AddCloser(s.rpc)
	s.gossip = gossip.New(rpcContext, s.ctx.GossipInterval, s.ctx.GossipBootstrapResolvers)
	s.storePool = storage.NewStorePool(s.gossip, ctx.TimeUntilStoreDead, stopper)

	feed := util.NewFeed(stopper)
	tracer := tracer.NewTracer(feed, addr)

	ds := kv.NewDistSender(&kv.DistSenderContext{Clock: s.clock}, s.gossip)
	sender := kv.NewTxnCoordSender(ds, s.clock, ctx.Linearizable, tracer, s.stopper)
	if s.db, err = client.Open("//", client.SenderOpt(sender)); err != nil {
		return nil, err
	}

	s.raftTransport, err = newRPCTransport(s.gossip, s.rpc, rpcContext)
	if err != nil {
		return nil, err
	}
	s.stopper.AddCloser(s.raftTransport)

	s.kvDB = kv.NewDBServer(&s.ctx.Context, sender)
	if s.ctx.ExperimentalRPCServer {
		if err = s.kvDB.RegisterRPC(s.rpc); err != nil {
			return nil, err
		}
	}

	s.sqlServer = sql.MakeHTTPServer(&s.ctx.Context, *s.db)

	// 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,
		EventFeed:       feed,
		Tracer:          tracer,
		StorePool:       s.storePool,
	}
	s.node = NewNode(nCtx)
	s.admin = newAdminServer(s.db, s.stopper)
	s.status = newStatusServer(s.db, s.gossip, ctx)
	s.tsDB = ts.NewDB(s.db)
	s.tsServer = ts.NewServer(s.tsDB)

	return s, nil
}

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

	if ctx.Insecure {
		log.Warning(context.TODO(), "running in insecure mode, this is strongly discouraged. See --insecure.")
	}
	// Try loading the TLS configs before anything else.
	if _, err := ctx.GetServerTLSConfig(); err != nil {
		return nil, err
	}
	if _, err := ctx.GetClientTLSConfig(); err != nil {
		return nil, err
	}

	s := &Server{
		Tracer:  tracing.NewTracer(),
		ctx:     ctx,
		mux:     http.NewServeMux(),
		clock:   hlc.NewClock(hlc.UnixNano),
		stopper: stopper,
	}
	s.clock.SetMaxOffset(ctx.MaxOffset)

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

	s.registry = metric.NewRegistry()
	s.gossip = gossip.New(s.rpcContext, s.grpc, s.ctx.GossipBootstrapResolvers, s.stopper, s.registry)
	s.storePool = storage.NewStorePool(
		s.gossip,
		s.clock,
		s.rpcContext,
		ctx.ReservationsEnabled,
		ctx.TimeUntilStoreDead,
		s.stopper,
	)

	// 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()
	s.distSender = kv.NewDistSender(&kv.DistSenderContext{
		Clock:           s.clock,
		RPCContext:      s.rpcContext,
		RPCRetryOptions: &retryOpts,
	}, s.gossip)
	txnMetrics := kv.NewTxnMetrics(s.registry)
	sender := kv.NewTxnCoordSender(s.distSender, s.clock, ctx.Linearizable, s.Tracer,
		s.stopper, txnMetrics)
	s.db = client.NewDB(sender)

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

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

	// Set up Lease Manager
	var lmKnobs sql.LeaseManagerTestingKnobs
	if ctx.TestingKnobs.SQLLeaseManager != nil {
		lmKnobs = *ctx.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
	distSQLCtx := distsql.ServerContext{
		Context:    context.Background(),
		DB:         s.db,
		RPCContext: s.rpcContext,
	}
	s.distSQLServer = distsql.NewServer(distSQLCtx)
	distsql.RegisterDistSQLServer(s.grpc, s.distSQLServer)

	// Set up Executor
	eCtx := sql.ExecutorContext{
		Context:      context.Background(),
		DB:           s.db,
		Gossip:       s.gossip,
		LeaseManager: s.leaseMgr,
		Clock:        s.clock,
		DistSQLSrv:   s.distSQLServer,
	}
	if ctx.TestingKnobs.SQLExecutor != nil {
//.........这里部分代码省略.........