// NewSchemaInfo creates a new SchemaInfo.
func NewSchemaInfo(
	queryCacheSize int,
	statsPrefix string,
	endpoints map[string]string,
	reloadTime time.Duration,
	idleTimeout time.Duration,
	enablePublishStats bool,
	queryServiceStats *QueryServiceStats) *SchemaInfo {
	si := &SchemaInfo{
		queries:    cache.NewLRUCache(int64(queryCacheSize)),
		connPool:   NewConnPool("", 2, idleTimeout, enablePublishStats, queryServiceStats),
		ticks:      timer.NewTimer(reloadTime),
		endpoints:  endpoints,
		reloadTime: reloadTime,
	}
	if enablePublishStats {
		stats.Publish(statsPrefix+"QueryCacheLength", stats.IntFunc(si.queries.Length))
		stats.Publish(statsPrefix+"QueryCacheSize", stats.IntFunc(si.queries.Size))
		stats.Publish(statsPrefix+"QueryCacheCapacity", stats.IntFunc(si.queries.Capacity))
		stats.Publish(statsPrefix+"QueryCacheOldest", stats.StringFunc(func() string {
			return fmt.Sprintf("%v", si.queries.Oldest())
		}))
		stats.Publish(statsPrefix+"SchemaReloadTime", stats.DurationFunc(si.ticks.Interval))
		_ = stats.NewMultiCountersFunc(statsPrefix+"RowcacheStats", []string{"Table", "Stats"}, si.getRowcacheStats)
		_ = stats.NewMultiCountersFunc(statsPrefix+"RowcacheInvalidations", []string{"Table"}, si.getRowcacheInvalidations)
		_ = stats.NewMultiCountersFunc(statsPrefix+"QueryCounts", []string{"Table", "Plan"}, si.getQueryCount)
		_ = stats.NewMultiCountersFunc(statsPrefix+"QueryTimesNs", []string{"Table", "Plan"}, si.getQueryTime)
		_ = stats.NewMultiCountersFunc(statsPrefix+"QueryRowCounts", []string{"Table", "Plan"}, si.getQueryRowCount)
		_ = stats.NewMultiCountersFunc(statsPrefix+"QueryErrorCounts", []string{"Table", "Plan"}, si.getQueryErrorCount)
	}
	for _, ep := range endpoints {
		http.Handle(ep, si)
	}
	return si
}

func NewSchemaInfo(queryCacheSize int, reloadTime time.Duration, idleTimeout time.Duration, sensitiveMode bool) *SchemaInfo {
	si := &SchemaInfo{
		queryCacheSize: queryCacheSize,
		queries:        cache.NewLRUCache(int64(queryCacheSize)),
		rules:          NewQueryRules(),
		connPool:       NewConnectionPool("", 2, idleTimeout),
		reloadTime:     reloadTime,
		ticks:          timer.NewTimer(reloadTime),
		sensitiveMode:  sensitiveMode,
	}
	stats.Publish("QueryCacheLength", stats.IntFunc(si.queries.Length))
	stats.Publish("QueryCacheSize", stats.IntFunc(si.queries.Size))
	stats.Publish("QueryCacheCapacity", stats.IntFunc(si.queries.Capacity))
	stats.Publish("QueryCacheOldest", stats.StringFunc(func() string {
		return fmt.Sprintf("%v", si.queries.Oldest())
	}))
	stats.Publish("SchemaReloadTime", stats.DurationFunc(func() time.Duration {
		return si.reloadTime
	}))
	stats.Publish("TableStats", stats.NewMatrixFunc("Table", "Stats", si.getTableStats))
	stats.Publish("TableInvalidations", stats.CountersFunc(si.getTableInvalidations))
	stats.Publish("QueryCounts", stats.NewMatrixFunc("Table", "Plan", si.getQueryCount))
	stats.Publish("QueryTimesNs", stats.NewMatrixFunc("Table", "Plan", si.getQueryTime))
	stats.Publish("QueryRowCounts", stats.NewMatrixFunc("Table", "Plan", si.getQueryRowCount))
	stats.Publish("QueryErrorCounts", stats.NewMatrixFunc("Table", "Plan", si.getQueryErrorCount))
	// query_plans cannot be shown in sensitive mode
	if !si.sensitiveMode {
		http.Handle("/debug/query_plans", si)
	}
	http.Handle("/debug/query_stats", si)
	http.Handle("/debug/table_stats", si)
	http.Handle("/debug/schema", si)
	return si
}

// NewMemcacheStats creates a new MemcacheStats.
// main, slabs and items specify the categories of stats that need to be exported.
func NewMemcacheStats(
	statsPrefix string,
	refreshFreq time.Duration,
	flags int64,
	queryServiceStats *QueryServiceStats,
	statsFunc RetrieveCacheStats) *MemcacheStats {
	memstats := &MemcacheStats{
		ticks:             timer.NewTimer(refreshFreq),
		statsPrefix:       statsPrefix,
		statsFunc:         statsFunc,
		main:              make(map[string]string),
		slabs:             make(map[string]map[string]int64),
		items:             make(map[string]map[string]int64),
		queryServiceStats: queryServiceStats,
		flags:             flags,
	}
	if flags&enableMain > 0 {
		memstats.publishMainStats()
	}
	if flags&enableSlabs > 0 {
		memstats.publishSlabsStats()
	}
	if flags*enableItems > 0 {
		memstats.publishItemsStats()
	}
	return memstats
}

func (agent *ActionAgent) initHealthCheck() {
	if !agent.IsRunningHealthCheck() {
		log.Infof("No target_tablet_type specified, disabling any health check")
		return
	}

	tt, err := topoproto.ParseTabletType(*targetTabletType)
	if err != nil {
		log.Fatalf("Invalid target tablet type %v: %v", *targetTabletType, err)
	}

	log.Infof("Starting periodic health check every %v with target_tablet_type=%v", *healthCheckInterval, *targetTabletType)
	t := timer.NewTimer(*healthCheckInterval)
	servenv.OnTermSync(func() {
		// When we enter lameduck mode, we want to not call
		// the health check any more. After this returns, we
		// are guaranteed to not call it.
		log.Info("Stopping periodic health check timer")
		t.Stop()

		// Now we can finish up and force ourselves to not healthy.
		agent.terminateHealthChecks(tt)
	})
	t.Start(func() {
		agent.runHealthCheck(tt)
	})
	t.Trigger()
}

func NewSchemaInfo(queryCacheSize int, reloadTime time.Duration, idleTimeout time.Duration) *SchemaInfo {
	si := &SchemaInfo{
		queries:  cache.NewLRUCache(int64(queryCacheSize)),
		rules:    NewQueryRules(),
		connPool: dbconnpool.NewConnectionPool("", 2, idleTimeout),
		ticks:    timer.NewTimer(reloadTime),
	}
	stats.Publish("QueryCacheLength", stats.IntFunc(si.queries.Length))
	stats.Publish("QueryCacheSize", stats.IntFunc(si.queries.Size))
	stats.Publish("QueryCacheCapacity", stats.IntFunc(si.queries.Capacity))
	stats.Publish("QueryCacheOldest", stats.StringFunc(func() string {
		return fmt.Sprintf("%v", si.queries.Oldest())
	}))
	stats.Publish("SchemaReloadTime", stats.DurationFunc(si.ticks.Interval))
	_ = stats.NewMultiCountersFunc("TableStats", []string{"Table", "Stats"}, si.getTableStats)
	_ = stats.NewMultiCountersFunc("TableInvalidations", []string{"Table"}, si.getTableInvalidations)
	_ = stats.NewMultiCountersFunc("QueryCounts", []string{"Table", "Plan"}, si.getQueryCount)
	_ = stats.NewMultiCountersFunc("QueryTimesNs", []string{"Table", "Plan"}, si.getQueryTime)
	_ = stats.NewMultiCountersFunc("QueryRowCounts", []string{"Table", "Plan"}, si.getQueryRowCount)
	_ = stats.NewMultiCountersFunc("QueryErrorCounts", []string{"Table", "Plan"}, si.getQueryErrorCount)
	http.Handle("/debug/query_plans", si)
	http.Handle("/debug/query_stats", si)
	http.Handle("/debug/table_stats", si)
	http.Handle("/debug/schema", si)
	return si
}

// NewTxPool creates a new TxPool. It's not operational until it's Open'd.
func NewTxPool(
	name string,
	txStatsPrefix string,
	capacity int,
	timeout time.Duration,
	idleTimeout time.Duration,
	enablePublishStats bool,
	qStats *QueryServiceStats,
	checker MySQLChecker) *TxPool {

	txStatsName := ""
	if enablePublishStats {
		txStatsName = txStatsPrefix + "Transactions"
	}

	axp := &TxPool{
		pool:              NewConnPool(name, capacity, idleTimeout, enablePublishStats, qStats, checker),
		activePool:        pools.NewNumbered(),
		lastID:            sync2.NewAtomicInt64(time.Now().UnixNano()),
		timeout:           sync2.NewAtomicDuration(timeout),
		ticks:             timer.NewTimer(timeout / 10),
		txStats:           stats.NewTimings(txStatsName),
		checker:           checker,
		queryServiceStats: qStats,
	}
	// Careful: pool also exports name+"xxx" vars,
	// but we know it doesn't export Timeout.
	if enablePublishStats {
		stats.Publish(name+"Timeout", stats.DurationFunc(axp.timeout.Get))
	}
	return axp
}

func NewActivePool(queryTimeout, idleTimeout time.Duration) *ActivePool {
	return &ActivePool{
		pool:     pools.NewNumbered(),
		timeout:  sync2.AtomicDuration(queryTimeout),
		connPool: NewConnectionPool(1, idleTimeout),
		ticks:    timer.NewTimer(queryTimeout / 10),
	}
}

func NewActiveTxPool(timeout time.Duration) *ActiveTxPool {
	return &ActiveTxPool{
		pool:    pools.NewNumbered(),
		lastId:  sync2.AtomicInt64(time.Now().UnixNano()),
		timeout: sync2.AtomicDuration(timeout),
		ticks:   timer.NewTimer(timeout / 10),
		txStats: stats.NewTimings("Transactions"),
	}
}

func newLongPollingManager(m *Manager) *longPollingManager {
	lpm := &longPollingManager{
		manager:     m,
		connections: make(map[int]*longPollingConnection),
	}
	t := timer.NewTimer(dropTimeout)
	t.Start(func() {
		lpm.checkStaleConnections()
	})
	return lpm
}

func NewSchemaInfo(queryCacheSize int, reloadTime time.Duration, idleTimeout time.Duration) *SchemaInfo {
	si := &SchemaInfo{
		queryCacheSize: queryCacheSize,
		queries:        cache.NewLRUCache(uint64(queryCacheSize)),
		rules:          NewQueryRules(),
		connPool:       NewConnectionPool(2, idleTimeout),
		reloadTime:     reloadTime,
		ticks:          timer.NewTimer(reloadTime),
	}
	http.Handle("/debug/query_plans", si)
	http.Handle("/debug/query_stats", si)
	http.Handle("/debug/table_stats", si)
	return si
}

func NewActivePool(name string, queryTimeout time.Duration, connKiller *ConnectionKiller) *ActivePool {
	ap := &ActivePool{
		pool:       pools.NewNumbered(),
		timeout:    sync2.AtomicDuration(queryTimeout),
		ticks:      timer.NewTimer(queryTimeout / 10),
		connKiller: connKiller,
	}
	stats.Publish(name+"Size", stats.IntFunc(ap.pool.Size))
	stats.Publish(
		name+"Timeout",
		stats.DurationFunc(func() time.Duration { return ap.timeout.Get() }),
	)
	return ap
}

func NewActiveTxPool(name string, timeout time.Duration) *ActiveTxPool {
	axp := &ActiveTxPool{
		pool:    pools.NewNumbered(),
		lastId:  sync2.AtomicInt64(time.Now().UnixNano()),
		timeout: sync2.AtomicDuration(timeout),
		ticks:   timer.NewTimer(timeout / 10),
		txStats: stats.NewTimings("Transactions"),
	}
	stats.Publish(name+"Size", stats.IntFunc(axp.pool.Size))
	stats.Publish(
		name+"Timeout",
		stats.DurationFunc(func() time.Duration { return axp.timeout.Get() }),
	)
	return axp
}

func NewTxPool(name string, capacity int, timeout, poolTimeout, idleTimeout time.Duration) *TxPool {
	axp := &TxPool{
		pool:        dbconnpool.NewConnectionPool(name, capacity, idleTimeout),
		activePool:  pools.NewNumbered(),
		lastId:      sync2.AtomicInt64(time.Now().UnixNano()),
		timeout:     sync2.AtomicDuration(timeout),
		poolTimeout: sync2.AtomicDuration(poolTimeout),
		ticks:       timer.NewTimer(timeout / 10),
		txStats:     stats.NewTimings("Transactions"),
	}
	// Careful: pool also exports name+"xxx" vars,
	// but we know it doesn't export Timeout.
	stats.Publish(name+"Timeout", stats.DurationFunc(axp.timeout.Get))
	stats.Publish(name+"PoolTimeout", stats.DurationFunc(axp.poolTimeout.Get))
	return axp
}

// NewMemcacheStats creates a new MemcacheStats based on given CachePool.
// main, slabs and items specify the categories of stats that need to be exported.
func NewMemcacheStats(cachePool *CachePool, main, slabs, items bool) *MemcacheStats {
	s := &MemcacheStats{
		cachePool: cachePool,
		ticks:     timer.NewTimer(10 * time.Second),
	}
	if main {
		s.publishMainStats()
	}
	if slabs {
		s.publishSlabsStats()
	}
	if items {
		s.publishItemsStats()
	}
	return s
}

// initHealthCheck will start the health check background go routine,
// and configure the healthcheck shutdown. It is only run by NewActionAgent
// for real vttablet agents (not by tests, nor vtcombo).
func (agent *ActionAgent) initHealthCheck() {
	registerReplicationReporter(agent)

	log.Infof("Starting periodic health check every %v", *healthCheckInterval)
	t := timer.NewTimer(*healthCheckInterval)
	servenv.OnTermSync(func() {
		// When we enter lameduck mode, we want to not call
		// the health check any more. After this returns, we
		// are guaranteed to not call it.
		log.Info("Stopping periodic health check timer")
		t.Stop()

		// Now we can finish up and force ourselves to not healthy.
		agent.terminateHealthChecks()
	})
	t.Start(func() {
		agent.runHealthCheck()
	})
	t.Trigger()
}

func (agent *ActionAgent) initHeathCheck() {
	if !agent.IsRunningHealthCheck() {
		log.Infof("No target_tablet_type specified, disabling any health check")
		return
	}

	log.Infof("Starting periodic health check every %v with target_tablet_type=%v", *healthCheckInterval, *targetTabletType)
	t := timer.NewTimer(*healthCheckInterval)
	servenv.OnTerm(func() {
		// When we enter lameduck mode, we want to not call
		// the health check any more. After this returns, we
		// are guaranteed to not call it.
		log.Info("Stopping periodic health check timer")
		t.Stop()

		// Now we can finish up and force ourselves to not healthy.
		agent.terminateHealthChecks(topo.TabletType(*targetTabletType), *lockTimeout)
	})
	t.Start(func() {
		agent.runHealthCheck(topo.TabletType(*targetTabletType), *lockTimeout)
	})
}

func initSchema() {
	// Start schema manager service if needed.
	if *schemaChangeDir != "" {
		interval := 60
		if *schemaChangeCheckInterval > 0 {
			interval = *schemaChangeCheckInterval
		}
		timer := timer.NewTimer(time.Duration(interval) * time.Second)
		controllerFactory, err :=
			schemamanager.GetControllerFactory(*schemaChangeController)
		if err != nil {
			log.Fatalf("unable to get a controller factory, error: %v", err)
		}

		timer.Start(func() {
			controller, err := controllerFactory(map[string]string{
				schemamanager.SchemaChangeDirName: *schemaChangeDir,
				schemamanager.SchemaChangeUser:    *schemaChangeUser,
			})
			if err != nil {
				log.Errorf("failed to get controller, error: %v", err)
				return
			}
			ctx := context.Background()
			err = schemamanager.Run(
				ctx,
				controller,
				schemamanager.NewTabletExecutor(
					tmclient.NewTabletManagerClient(), ts),
			)
			if err != nil {
				log.Errorf("Schema change failed, error: %v", err)
			}
		})
		servenv.OnClose(func() { timer.Stop() })
	}
}

//.........这里部分代码省略.........
	actionRepo.RegisterTabletAction("RefreshState", acl.ADMIN,
		func(ctx context.Context, wr *wrangler.Wrangler, tabletAlias *topodatapb.TabletAlias, r *http.Request) (string, error) {
			ti, err := wr.TopoServer().GetTablet(ctx, tabletAlias)
			if err != nil {
				return "", err
			}
			return "", wr.TabletManagerClient().RefreshState(ctx, ti)
		})

	actionRepo.RegisterTabletAction("DeleteTablet", acl.ADMIN,
		func(ctx context.Context, wr *wrangler.Wrangler, tabletAlias *topodatapb.TabletAlias, r *http.Request) (string, error) {
			return "", wr.DeleteTablet(ctx, tabletAlias, false, false)
		})

	actionRepo.RegisterTabletAction("ReloadSchema", acl.ADMIN,
		func(ctx context.Context, wr *wrangler.Wrangler, tabletAlias *topodatapb.TabletAlias, r *http.Request) (string, error) {
			return "", wr.ReloadSchema(ctx, tabletAlias)
		})

	// Anything unrecognized gets redirected to the main app page.
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		http.Redirect(w, r, appPrefix, http.StatusFound)
	})

	// Serve the static files for the vtctld web app.
	http.HandleFunc(appPrefix, func(w http.ResponseWriter, r *http.Request) {
		// Strip the prefix.
		parts := strings.SplitN(r.URL.Path, "/", 3)
		if len(parts) != 3 {
			http.NotFound(w, r)
			return
		}
		rest := parts[2]
		if rest == "" {
			rest = "index.html"
		}
		http.ServeFile(w, r, path.Join(*webDir, rest))
	})

	// Serve the REST API for the vtctld web app.
	initAPI(context.Background(), ts, actionRepo)

	// redirects for explorers
	http.HandleFunc("/explorers/redirect", func(w http.ResponseWriter, r *http.Request) {
		if explorer == nil {
			http.Error(w, "no explorer configured", http.StatusInternalServerError)
			return
		}
		if err := r.ParseForm(); err != nil {
			httpErrorf(w, r, "cannot parse form: %s", err)
			return
		}

		target, err := handleExplorerRedirect(context.Background(), ts, r)
		if err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}

		http.Redirect(w, r, target, http.StatusFound)
	})

	// Start schema manager service.
	if *schemaChangeDir != "" {
		interval := 60
		if *schemaChangeCheckInterval > 0 {
			interval = *schemaChangeCheckInterval
		}
		timer := timer.NewTimer(time.Duration(interval) * time.Second)
		controllerFactory, err :=
			schemamanager.GetControllerFactory(*schemaChangeController)
		if err != nil {
			log.Fatalf("unable to get a controller factory, error: %v", err)
		}

		timer.Start(func() {
			controller, err := controllerFactory(map[string]string{
				schemamanager.SchemaChangeDirName: *schemaChangeDir,
				schemamanager.SchemaChangeUser:    *schemaChangeUser,
			})
			if err != nil {
				log.Errorf("failed to get controller, error: %v", err)
				return
			}
			ctx := context.Background()
			err = schemamanager.Run(
				ctx,
				controller,
				schemamanager.NewTabletExecutor(
					tmclient.NewTabletManagerClient(), ts),
			)
			if err != nil {
				log.Errorf("Schema change failed, error: %v", err)
			}
		})
		servenv.OnClose(func() { timer.Stop() })
	}

	servenv.RunDefault()
}

//.........这里部分代码省略.........
			httpErrorf(w, r, "error getting shard: %v", err)
			return
		}
		w.Write(result)
	})

	cellShardTabletsCache := newCellShardTabletsCache(ts)
	http.HandleFunc("/json/CellShardTablets", func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseForm(); err != nil {
			httpErrorf(w, r, "cannot parse form: %s", err)
			return
		}
		cell := r.FormValue("cell")
		if cell == "" {
			http.Error(w, "no cell provided", http.StatusBadRequest)
			return
		}
		keyspace := r.FormValue("keyspace")
		if keyspace == "" {
			http.Error(w, "no keyspace provided", http.StatusBadRequest)
			return
		}
		shard := r.FormValue("shard")
		if shard == "" {
			http.Error(w, "no shard provided", http.StatusBadRequest)
			return
		}
		ctx := context.Background()
		result, err := cellShardTabletsCache.Get(ctx, cell+"/"+keyspace+"/"+shard)
		if err != nil {
			httpErrorf(w, r, "error getting shard: %v", err)
			return
		}
		w.Write(result)
	})

	// flush all data and will force a full client reload
	http.HandleFunc("/json/flush", func(w http.ResponseWriter, r *http.Request) {
		knownCellsCache.Flush()
		keyspacesCache.Flush()
		keyspaceCache.Flush()
		shardNamesCache.Flush()
		shardCache.Flush()
		cellShardTabletsCache.Flush()
	})

	http.HandleFunc("/json/schema-manager", func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseForm(); err != nil {
			httpErrorf(w, r, "cannot parse form: %s", err)
			return
		}
		sqlStr := r.FormValue("data")
		keyspace := r.FormValue("keyspace")
		executor := schemamanager.NewTabletExecutor(
			tmclient.NewTabletManagerClient(),
			ts)

		ctx := context.Background()
		schemamanager.Run(
			ctx,
			schemamanager.NewUIController(sqlStr, keyspace, w),
			executor,
		)
	})
	if *schemaChangeDir != "" {
		interval := 60
		if *schemaChangeCheckInterval > 0 {
			interval = *schemaChangeCheckInterval
		}
		timer := timer.NewTimer(time.Duration(interval) * time.Second)
		controllerFactory, err :=
			schemamanager.GetControllerFactory(*schemaChangeController)
		if err != nil {
			log.Fatalf("unable to get a controller factory, error: %v", err)
		}

		timer.Start(func() {
			controller, err := controllerFactory(map[string]string{
				schemamanager.SchemaChangeDirName: *schemaChangeDir,
				schemamanager.SchemaChangeUser:    *schemaChangeUser,
			})
			if err != nil {
				log.Errorf("failed to get controller, error: %v", err)
				return
			}
			ctx := context.Background()
			err = schemamanager.Run(
				ctx,
				controller,
				schemamanager.NewTabletExecutor(
					tmclient.NewTabletManagerClient(), ts),
			)
			if err != nil {
				log.Errorf("Schema change failed, error: %v", err)
			}
		})
		servenv.OnClose(func() { timer.Stop() })
	}
	servenv.RunDefault()
}