// TestingSetupZoneConfigHook initializes the zone config hook
// to 'testingZoneConfigHook' which uses 'testingZoneConfig'.
// Settings go back to their previous values when the stopper runs our closer.
func TestingSetupZoneConfigHook(stopper *stop.Stopper) {
	stopper.AddCloser(stop.CloserFn(testingResetZoneConfigHook))

	testingLock.Lock()
	defer testingLock.Unlock()
	if testingHasHook {
		panic("TestingSetupZoneConfigHook called without restoring state")
	}
	testingHasHook = true
	testingZoneConfig = make(zoneConfigMap)
	testingPreviousHook = ZoneConfigHook
	ZoneConfigHook = testingZoneConfigHook
	testingLargestIDHook = func(maxID uint32) (max uint32) {
		testingLock.Lock()
		defer testingLock.Unlock()
		for id := range testingZoneConfig {
			if maxID > 0 && id > maxID {
				continue
			}
			if id > max {
				max = id
			}
		}
		return
	}
}

// Start starts the TestServer by bootstrapping an in-memory store
// (defaults to maximum of 100M). The server is started, launching the
// node RPC server and all HTTP endpoints. Use the value of
// TestServer.ServingAddr() after Start() for client connections.
// Use TestServer.Stopper().Stop() to shutdown the server after the test
// completes.
func (ts *TestServer) Start(params base.TestServerArgs) error {
	if ts.Cfg == nil {
		panic("Cfg not set")
	}

	if params.Stopper == nil {
		params.Stopper = stop.NewStopper()
	}

	if !params.PartOfCluster {
		// Change the replication requirements so we don't get log spam about ranges
		// not being replicated enough.
		cfg := config.DefaultZoneConfig()
		cfg.NumReplicas = 1
		fn := config.TestingSetDefaultZoneConfig(cfg)
		params.Stopper.AddCloser(stop.CloserFn(fn))
	}

	// Needs to be called before NewServer to ensure resolvers are initialized.
	if err := ts.Cfg.InitNode(); err != nil {
		return err
	}

	var err error
	ts.Server, err = NewServer(*ts.Cfg, params.Stopper)
	if err != nil {
		return err
	}

	// Our context must be shared with our server.
	ts.Cfg = &ts.Server.cfg

	if err := ts.Server.Start(context.Background()); err != nil {
		return err
	}

	// If enabled, wait for initial splits to complete before returning control.
	// If initial splits do not complete, the server is stopped before
	// returning.
	if stk, ok := ts.cfg.TestingKnobs.Store.(*storage.StoreTestingKnobs); ok &&
		stk.DisableSplitQueue {
		return nil
	}
	if err := ts.WaitForInitialSplits(); err != nil {
		ts.Stop()
		return err
	}

	return nil
}

func (t *parallelTest) getClient(nodeIdx, clientIdx int) *gosql.DB {
	for len(t.clients[nodeIdx]) <= clientIdx {
		// Add a client.
		pgURL, cleanupFunc := sqlutils.PGUrl(t.T,
			t.cluster.Server(nodeIdx).ServingAddr(),
			"TestParallel",
			url.User(security.RootUser))
		db, err := gosql.Open("postgres", pgURL.String())
		if err != nil {
			t.Fatal(err)
		}
		sqlutils.MakeSQLRunner(t, db).Exec("SET DATABASE = test")
		t.cluster.Stopper().AddCloser(
			stop.CloserFn(func() {
				_ = db.Close()
				cleanupFunc()
			}))
		t.clients[nodeIdx] = append(t.clients[nodeIdx], db)
	}
	return t.clients[nodeIdx][clientIdx]
}

// StartServer creates a test server and sets up a gosql DB connection.
// The server should be stopped by calling server.Stopper().Stop().
func StartServer(
	t testing.TB, params base.TestServerArgs,
) (TestServerInterface, *gosql.DB, *client.DB) {
	server, err := StartServerRaw(params)
	if err != nil {
		t.Fatal(err)
	}

	kvClient := server.KVClient().(*client.DB)
	pgURL, cleanupGoDB := sqlutils.PGUrl(
		t, server.ServingAddr(), "StartServer", url.User(security.RootUser))
	pgURL.Path = params.UseDatabase
	goDB, err := gosql.Open("postgres", pgURL.String())
	if err != nil {
		t.Fatal(err)
	}
	server.Stopper().AddCloser(
		stop.CloserFn(func() {
			_ = goDB.Close()
			cleanupGoDB()
		}))
	return server, goDB, kvClient
}

func initBacktrace(logDir string) *stop.Stopper {
	const ptracePath = "/opt/backtrace/bin/ptrace"
	if _, err := os.Stat(ptracePath); err != nil {
		log.Infof(context.TODO(), "backtrace disabled: %s", err)
		return stop.NewStopper()
	}

	if err := bcd.EnableTracing(); err != nil {
		log.Infof(context.TODO(), "unable to enable backtrace: %s", err)
		return stop.NewStopper()
	}

	bcd.UpdateConfig(bcd.GlobalConfig{
		PanicOnKillFailure: true,
		ResendSignal:       true,
		RateLimit:          time.Second * 3,
		SynchronousPut:     true,
	})

	// Use the default tracer implementation.
	// false: Exclude system goroutines.
	tracer := bcd.New(bcd.NewOptions{
		IncludeSystemGs: false,
	})
	if err := tracer.SetOutputPath(logDir, 0755); err != nil {
		log.Infof(context.TODO(), "unable to set output path: %s", err)
		// Not a fatal error, continue.
	}

	// Enable WARNING log output from the tracer.
	tracer.AddOptions(nil, "-L", "WARNING")

	info := build.GetInfo()
	tracer.AddKV(nil, "cgo-compiler", info.CgoCompiler)
	tracer.AddKV(nil, "go-version", info.GoVersion)
	tracer.AddKV(nil, "platform", info.Platform)
	tracer.AddKV(nil, "tag", info.Tag)
	tracer.AddKV(nil, "time", info.Time)

	// Register for traces on signal reception.
	tracer.SetSigset(
		[]os.Signal{
			syscall.SIGABRT,
			syscall.SIGFPE,
			syscall.SIGSEGV,
			syscall.SIGILL,
			syscall.SIGBUS}...)
	bcd.Register(tracer)

	// Hook log.Fatal*.
	log.SetExitFunc(func(code int) {
		_ = bcd.Trace(tracer, fmt.Errorf("exit %d", code), nil)
		os.Exit(code)
	})

	stopper := stop.NewStopper(stop.OnPanic(func(val interface{}) {
		err, ok := val.(error)
		if !ok {
			err = fmt.Errorf("%v", val)
		}
		_ = bcd.Trace(tracer, err, nil)
		panic(val)
	}))

	// Internally, backtrace uses an external program (/opt/backtrace/bin/ptrace)
	// to generate traces. We direct the stdout for this program to a file for
	// debugging our usage of backtrace.
	if f, err := os.OpenFile(filepath.Join(logDir, "backtrace.out"),
		os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666); err != nil {
		log.Infof(context.TODO(), "unable to open: %s", err)
	} else {
		stopper.AddCloser(stop.CloserFn(func() {
			f.Close()
		}))
		tracer.SetPipes(nil, f)
	}

	tracer.SetLogLevel(bcd.LogMax)
	log.Infof(context.TODO(), "backtrace enabled")
	return stopper
}

// StartTestCluster starts up a TestCluster made up of `nodes` in-memory testing
// servers.
// The cluster should be stopped using cluster.Stop().
func StartTestCluster(t testing.TB, nodes int, args base.TestClusterArgs) *TestCluster {
	if nodes < 1 {
		t.Fatal("invalid cluster size: ", nodes)
	}
	if args.ServerArgs.JoinAddr != "" {
		t.Fatal("can't specify a join addr when starting a cluster")
	}
	if args.ServerArgs.Stopper != nil {
		t.Fatal("can't set individual server stoppers when starting a cluster")
	}
	storeKnobs := args.ServerArgs.Knobs.Store
	if storeKnobs != nil &&
		(storeKnobs.(*storage.StoreTestingKnobs).DisableSplitQueue ||
			storeKnobs.(*storage.StoreTestingKnobs).DisableReplicateQueue) {
		t.Fatal("can't disable an individual server's queues when starting a cluster; " +
			"the cluster controls replication")
	}

	switch args.ReplicationMode {
	case base.ReplicationAuto:
	case base.ReplicationManual:
		if args.ServerArgs.Knobs.Store == nil {
			args.ServerArgs.Knobs.Store = &storage.StoreTestingKnobs{}
		}
		storeKnobs := args.ServerArgs.Knobs.Store.(*storage.StoreTestingKnobs)
		storeKnobs.DisableSplitQueue = true
		storeKnobs.DisableReplicateQueue = true
	default:
		t.Fatal("unexpected replication mode")
	}

	tc := &TestCluster{}
	tc.stopper = stop.NewStopper()

	for i := 0; i < nodes; i++ {
		var serverArgs base.TestServerArgs
		if perNodeServerArgs, ok := args.ServerArgsPerNode[i]; ok {
			serverArgs = perNodeServerArgs
		} else {
			serverArgs = args.ServerArgs
		}
		serverArgs.PartOfCluster = true
		if i > 0 {
			serverArgs.JoinAddr = tc.Servers[0].ServingAddr()
		}
		tc.AddServer(t, serverArgs)
	}

	// Create a closer that will stop the individual server stoppers when the
	// cluster stopper is stopped.
	tc.stopper.AddCloser(stop.CloserFn(tc.stopServers))

	tc.WaitForStores(t, tc.Servers[0].Gossip())

	// TODO(peter): We should replace the hardcoded 3 with the default ZoneConfig
	// replication factor.
	if args.ReplicationMode == base.ReplicationAuto && nodes >= 3 {
		if err := tc.waitForFullReplication(); err != nil {
			t.Fatal(err)
		}
	}
	return tc
}

//.........这里部分代码省略.........
	// Begin recording time series data collected by the status monitor.
	s.tsDB.PollSource(
		s.cfg.AmbientCtx, s.recorder, s.cfg.MetricsSampleInterval, ts.Resolution10s, s.stopper,
	)

	// Begin recording status summaries.
	s.node.startWriteSummaries(s.cfg.MetricsSampleInterval)

	// Create and start the schema change manager only after a NodeID
	// has been assigned.
	testingKnobs := &sql.SchemaChangerTestingKnobs{}
	if s.cfg.TestingKnobs.SQLSchemaChanger != nil {
		testingKnobs = s.cfg.TestingKnobs.SQLSchemaChanger.(*sql.SchemaChangerTestingKnobs)
	}
	sql.NewSchemaChangeManager(testingKnobs, *s.db, s.gossip, s.leaseMgr).Start(s.stopper)

	s.distSQLServer.Start()

	log.Infof(ctx, "starting %s server at %s", s.cfg.HTTPRequestScheme(), unresolvedHTTPAddr)
	log.Infof(ctx, "starting grpc/postgres server at %s", unresolvedListenAddr)
	log.Infof(ctx, "advertising CockroachDB node at %s", unresolvedAdvertAddr)
	if len(s.cfg.SocketFile) != 0 {
		log.Infof(ctx, "starting postgres server at unix:%s", s.cfg.SocketFile)
	}

	s.stopper.RunWorker(func() {
		netutil.FatalIfUnexpected(m.Serve())
	})

	log.Event(ctx, "accepting connections")

	// Initialize grpc-gateway mux and context.
	jsonpb := &protoutil.JSONPb{
		EnumsAsInts:  true,
		EmitDefaults: true,
		Indent:       "  ",
	}
	protopb := new(protoutil.ProtoPb)
	gwMux := gwruntime.NewServeMux(
		gwruntime.WithMarshalerOption(gwruntime.MIMEWildcard, jsonpb),
		gwruntime.WithMarshalerOption(httputil.JSONContentType, jsonpb),
		gwruntime.WithMarshalerOption(httputil.AltJSONContentType, jsonpb),
		gwruntime.WithMarshalerOption(httputil.ProtoContentType, protopb),
		gwruntime.WithMarshalerOption(httputil.AltProtoContentType, protopb),
	)
	gwCtx, gwCancel := context.WithCancel(s.AnnotateCtx(context.Background()))
	s.stopper.AddCloser(stop.CloserFn(gwCancel))

	// Setup HTTP<->gRPC handlers.
	conn, err := s.rpcContext.GRPCDial(s.cfg.Addr)
	if err != nil {
		return errors.Errorf("error constructing grpc-gateway: %s; are your certificates valid?", err)
	}

	for _, gw := range []grpcGatewayServer{s.admin, s.status, &s.tsServer} {
		if err := gw.RegisterGateway(gwCtx, gwMux, conn); err != nil {
			return err
		}
	}

	var uiFileSystem http.FileSystem
	uiDebug := envutil.EnvOrDefaultBool("COCKROACH_DEBUG_UI", false)
	if uiDebug {
		uiFileSystem = http.Dir("pkg/ui")
	} else {
		uiFileSystem = &assetfs.AssetFS{
			Asset:     ui.Asset,
			AssetDir:  ui.AssetDir,
			AssetInfo: ui.AssetInfo,
		}
	}
	uiFileServer := http.FileServer(uiFileSystem)

	s.mux.HandleFunc("/", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path == "/" {
			if uiDebug {
				r.URL.Path = "debug.html"
			} else {
				r.URL.Path = "release.html"
			}
		}
		uiFileServer.ServeHTTP(w, r)
	}))

	// TODO(marc): when cookie-based authentication exists,
	// apply it for all web endpoints.
	s.mux.Handle(adminPrefix, gwMux)
	s.mux.Handle(ts.URLPrefix, gwMux)
	s.mux.Handle(statusPrefix, gwMux)
	s.mux.Handle("/health", gwMux)
	s.mux.Handle(statusVars, http.HandlerFunc(s.status.handleVars))
	log.Event(ctx, "added http endpoints")

	if err := sdnotify.Ready(); err != nil {
		log.Errorf(ctx, "failed to signal readiness using systemd protocol: %s", err)
	}
	log.Event(ctx, "server ready")

	return nil
}