func getClusterName(clusterAlias string, instanceKey *inst.InstanceKey) (clusterName string) {
	var err error
	if clusterAlias != "" {
		clusterName, err = inst.ReadClusterByAlias(clusterAlias)
		if err != nil {
			log.Fatale(err)
		}
	} else {
		// deduce cluster by instance
		if instanceKey == nil {
			instanceKey = thisInstanceKey
		}
		if instanceKey == nil {
			log.Fatalf("Unable to get cluster instances: unresolved instance")
		}
		instance, _, err := inst.ReadInstance(instanceKey)
		if err != nil {
			log.Fatale(err)
		}
		if instance == nil {
			log.Fatalf("Instance not found: %+v", *instanceKey)
		}
		clusterName = instance.ClusterName
	}
	if clusterName == "" {
		log.Fatalf("Unable to determine cluster name")
	}
	return clusterName
}

// getClusterName will make a best effort to deduce a cluster name using either a given alias
// or an instanceKey. First attempt is at alias, and if that doesn't work, we try instanceKey.
func getClusterName(clusterAlias string, instanceKey *inst.InstanceKey) (clusterName string) {
	var err error
	if clusterAlias != "" {
		if clusterName, err = inst.ReadClusterNameByAlias(clusterAlias); err == nil && clusterName != "" {
			return clusterName
		}
	}
	if clusterAlias != "" {
		// We're still here? So this wasn't an exact cluster name. Let's cehck if it's fuzzy:
		fuzzyInstanceKey, err := inst.ParseRawInstanceKeyLoose(clusterAlias)
		if err != nil {
			log.Fatale(err)
		}
		if clusterName, err = inst.FindClusterNameByFuzzyInstanceKey(fuzzyInstanceKey); clusterName == "" {
			log.Fatalf("Unable to determine cluster name by alias %+v", clusterAlias)
		}
		return clusterName
	}
	// So there is no alias. Let's check by instance key
	instanceKey = inst.ReadFuzzyInstanceKeyIfPossible(instanceKey)
	if instanceKey == nil {
		instanceKey = assignThisInstanceKey()
	}
	if instanceKey == nil {
		log.Fatalf("Unable to get cluster instances: unresolved instance")
	}
	instance := validateInstanceIsFound(instanceKey)
	clusterName = instance.ClusterName

	if clusterName == "" {
		log.Fatalf("Unable to determine cluster name")
	}
	return clusterName
}

// deployIfNotAlreadyDeployed will issue given sql queries that are not already known to be deployed.
// This iterates both lists (to-run and already-deployed) and also verifies no contraditions.
func deployIfNotAlreadyDeployed(db *sql.DB, queries []string, deployedQueries []string, deploymentType string, fatalOnError bool) error {
	for i, query := range queries {
		queryAlreadyExecuted := false
		// While iterating 'queries', also iterate 'deployedQueries'. Expect identity
		if len(deployedQueries) > i {
			if deployedQueries[i] != query {
				log.Fatalf("initOrchestratorDB() PANIC: non matching %s queries between deployment requests and _orchestrator_db_deployment. Please execute 'orchestrator -c reset-internal-db-deployment'", deploymentType)
			}
			queryAlreadyExecuted = true
		}
		if queryAlreadyExecuted {
			continue
		}
		if config.Config.SmartOrchestratorDatabaseUpdate {
			log.Debugf("initOrchestratorDB executing: %.80s", strings.TrimSpace(strings.Replace(query, "\n", "", -1)))
		}

		if fatalOnError {
			if _, err := execInternal(db, query); err != nil {
				return log.Fatalf("Cannot initiate orchestrator: %+v", err)
			}
		} else {
			execInternalSilently(db, query)
		}
		writeInternalDeployment(db, deploymentType, query, i)
	}
	return nil
}

// deployIfNotAlreadyDeployed will issue given sql queries that are not already known to be deployed.
// This iterates both lists (to-run and already-deployed) and also verifies no contraditions.
func deployIfNotAlreadyDeployed(db *sql.DB, queries []string, deployedQueries []string, deploymentType string, fatalOnError bool) error {
	tx, err := db.Begin()
	if err != nil {
		log.Fatale(err)
	}
	// Ugly workaround ahead.
	// Origin of this workaround is the existence of some "timestamp NOT NULL," column definitions,
	// where in NO_ZERO_IN_DATE,NO_ZERO_DATE sql_mode are invalid (since default is implicitly "0")
	// This means installation of orchestrator fails on such configured servers, and in particular on 5.7
	// where this setting is the dfault.
	// For purpose of backwards compatability, what we do is force sql_mode to be more relaxed, create the schemas
	// along with the "invalid" definition, and then go ahead and fix those definitions via following ALTER statements.
	// My bad.
	originalSqlMode := ""
	err = tx.QueryRow(`select @@session.sql_mode`).Scan(&originalSqlMode)
	if _, err := tx.Exec(`set @@session.sql_mode=REPLACE(@@session.sql_mode, 'NO_ZERO_DATE', '')`); err != nil {
		log.Fatale(err)
	}
	if _, err := tx.Exec(`set @@session.sql_mode=REPLACE(@@session.sql_mode, 'NO_ZERO_IN_DATE', '')`); err != nil {
		log.Fatale(err)
	}

	for i, query := range queries {
		queryAlreadyExecuted := false
		// While iterating 'queries', also iterate 'deployedQueries'. Expect identity
		if len(deployedQueries) > i {
			if deployedQueries[i] != query {
				log.Fatalf("initOrchestratorDB() PANIC: non matching %s queries between deployment requests and _orchestrator_db_deployment. Please execute 'orchestrator -c reset-internal-db-deployment'", deploymentType)
			}
			queryAlreadyExecuted = true
		}
		if queryAlreadyExecuted {
			continue
		}
		if i == 0 {
			log.Debugf("sql_mode is: %+v", originalSqlMode)
		}
		if config.Config.SmartOrchestratorDatabaseUpdate {
			log.Debugf("initOrchestratorDB executing: %.80s", strings.TrimSpace(strings.Replace(query, "\n", "", -1)))
		}

		if fatalOnError {
			if _, err := tx.Exec(query); err != nil {
				return log.Fatalf("Cannot initiate orchestrator: %+v", err)
			}
		} else {
			tx.Exec(query)
			// And ignore any error
		}
		writeInternalDeployment(db, deploymentType, query, i)
	}
	if _, err := tx.Exec(`set session sql_mode=?`, originalSqlMode); err != nil {
		log.Fatale(err)
	}
	if err := tx.Commit(); err != nil {
		log.Fatale(err)
	}
	return nil
}

func postReadAdjustments() {
	if Config.MySQLOrchestratorCredentialsConfigFile != "" {
		mySQLConfig := struct {
			Client struct {
				User     string
				Password string
			}
		}{}
		err := gcfg.ReadFileInto(&mySQLConfig, Config.MySQLOrchestratorCredentialsConfigFile)
		if err != nil {
			log.Fatalf("Failed to parse gcfg data from file: %+v", err)
		} else {
			log.Debugf("Parsed orchestrator credentials from %s", Config.MySQLOrchestratorCredentialsConfigFile)
			Config.MySQLOrchestratorUser = mySQLConfig.Client.User
			Config.MySQLOrchestratorPassword = mySQLConfig.Client.Password
		}
	}
	{
		// We accept password in the form "${SOME_ENV_VARIABLE}" in which case we pull
		// the given variable from os env
		submatch := envVariableRegexp.FindStringSubmatch(Config.MySQLOrchestratorPassword)
		if len(submatch) > 1 {
			Config.MySQLOrchestratorPassword = os.Getenv(submatch[1])
		}
	}
	if Config.MySQLTopologyCredentialsConfigFile != "" {
		mySQLConfig := struct {
			Client struct {
				User     string
				Password string
			}
		}{}
		err := gcfg.ReadFileInto(&mySQLConfig, Config.MySQLTopologyCredentialsConfigFile)
		if err != nil {
			log.Fatalf("Failed to parse gcfg data from file: %+v", err)
		} else {
			log.Debugf("Parsed topology credentials from %s", Config.MySQLTopologyCredentialsConfigFile)
			Config.MySQLTopologyUser = mySQLConfig.Client.User
			Config.MySQLTopologyPassword = mySQLConfig.Client.Password
		}
	}
	{
		// We accept password in the form "${SOME_ENV_VARIABLE}" in which case we pull
		// the given variable from os env
		submatch := envVariableRegexp.FindStringSubmatch(Config.MySQLTopologyPassword)
		if len(submatch) > 1 {
			Config.MySQLTopologyPassword = os.Getenv(submatch[1])
		}
	}

	if Config.RecoveryPeriodBlockSeconds == 0 && Config.RecoveryPeriodBlockMinutes > 0 {
		// RecoveryPeriodBlockSeconds is a newer addition that overrides RecoveryPeriodBlockMinutes
		// The code does not consider RecoveryPeriodBlockMinutes anymore, but RecoveryPeriodBlockMinutes
		// still supported in config file for backwards compatibility
		Config.RecoveryPeriodBlockSeconds = Config.RecoveryPeriodBlockMinutes * 60
	}
}

// ResetInternalDeployment will clear existing deployment history (and the effect will be a complete re-deployment
// the next run). This is made available for possible operational errors, a red button
func ResetInternalDeployment() error {
	db, err := OpenOrchestrator()
	if err != nil {
		log.Fatalf("Cannot reset orchestrator internal deployment: %+v", err)
	}
	if _, err := execInternal(db, `delete from _orchestrator_db_deployment`); err != nil {
		log.Fatalf("Unable to clear _orchestrator_db_deployment: %+v", err)
	}
	return nil
}

func init() {
	var err error
	ThisHostname, err = os.Hostname()
	if err != nil {
		log.Fatalf("Cannot resolve self hostname; required. Aborting. %+v", err)
	}
}

// read reads configuration from given file, or silently skips if the file does not exist.
// If the file does exist, then it is expected to be in valid JSON format or the function bails out.
func read(file_name string) (*Configuration, error) {
	file, err := os.Open(file_name)
	if err == nil {
		decoder := json.NewDecoder(file)
		err := decoder.Decode(Config)
		if err == nil {
			log.Infof("Read config: %s", file_name)
		} else {
			log.Fatal("Cannot read config file:", file_name, err)
		}
		if Config.MySQLOrchestratorCredentialsConfigFile != "" {
			mySQLConfig := struct {
				Client struct {
					User     string
					Password string
				}
			}{}
			err := gcfg.ReadFileInto(&mySQLConfig, Config.MySQLOrchestratorCredentialsConfigFile)
			if err != nil {
				log.Fatalf("Failed to parse gcfg data from file: %+v", err)
			} else {
				log.Debugf("Parsed orchestrator credentials from %s", Config.MySQLOrchestratorCredentialsConfigFile)
				Config.MySQLOrchestratorUser = mySQLConfig.Client.User
				Config.MySQLOrchestratorPassword = mySQLConfig.Client.Password
			}
		}
		if Config.MySQLTopologyCredentialsConfigFile != "" {
			mySQLConfig := struct {
				Client struct {
					User     string
					Password string
				}
			}{}
			err := gcfg.ReadFileInto(&mySQLConfig, Config.MySQLTopologyCredentialsConfigFile)
			if err != nil {
				log.Fatalf("Failed to parse gcfg data from file: %+v", err)
			} else {
				log.Debugf("Parsed topology credentials from %s", Config.MySQLTopologyCredentialsConfigFile)
				Config.MySQLTopologyUser = mySQLConfig.Client.User
				Config.MySQLTopologyPassword = mySQLConfig.Client.Password
			}
		}

	}
	return Config, err
}

// Create a TLS configuration from the config supplied CA, Certificate, and Private key.
// Register the TLS config with the mysql drivers as the "orchestrator" config
// Modify the supplied URI to call the TLS config
func SetupMySQLOrchestratorTLS(uri string) (string, error) {
	if !orchestratorTLSConfigured {
		tlsConfig, err := ssl.NewTLSConfig(config.Config.MySQLOrchestratorSSLCAFile, true)
		if err != nil {
			return "", log.Fatalf("Can't create TLS configuration for Orchestrator connection %s: %s", uri, err)
		}
		tlsConfig.InsecureSkipVerify = config.Config.MySQLOrchestratorSSLSkipVerify
		if err = ssl.AppendKeyPair(tlsConfig, config.Config.MySQLOrchestratorSSLCertFile, config.Config.MySQLOrchestratorSSLPrivateKeyFile); err != nil {
			return "", log.Fatalf("Can't setup TLS key pairs for %s: %s", uri, err)
		}
		if err = mysql.RegisterTLSConfig("orchestrator", tlsConfig); err != nil {
			return "", log.Fatalf("Can't register mysql TLS config for orchestrator: %s", err)
		}
		orchestratorTLSConfigured = true
	}
	return fmt.Sprintf("%s&tls=orchestrator", uri), nil
}

func acceptSignal() {
	c := make(chan os.Signal, 1)
	signal.Notify(c, os.Interrupt, os.Kill, syscall.SIGHUP)

	// Block until a signal is received.
	sig := <-c
	log.Fatalf("Got signal: %+v", sig)
}

func validateInstanceIsFound(instanceKey *inst.InstanceKey) (instance *inst.Instance) {
	instance, _, err := inst.ReadInstance(instanceKey)
	if err != nil {
		log.Fatale(err)
	}
	if instance == nil {
		log.Fatalf("Instance not found: %+v", *instanceKey)
	}
	return instance
}

// Create a TLS configuration from the config supplied CA, Certificate, and Private key.
// Register the TLS config with the mysql drivers as the "topology" config
// Modify the supplied URI to call the TLS config
// TODO: Way to have password mixed with TLS for various nodes in the topology.  Currently everything is TLS or everything is password
func SetupMySQLTopologyTLS(uri string) (string, error) {
	if !topologyTLSConfigured {
		tlsConfig, err := ssl.NewTLSConfig(config.Config.MySQLTopologySSLCAFile, !config.Config.MySQLTopologySSLSkipVerify)
		// Drop to TLS 1.0 for talking to MySQL
		tlsConfig.MinVersion = tls.VersionTLS10
		if err != nil {
			return "", log.Fatalf("Can't create TLS configuration for Topology connection %s: %s", uri, err)
		}
		tlsConfig.InsecureSkipVerify = config.Config.MySQLTopologySSLSkipVerify
		if err = ssl.AppendKeyPair(tlsConfig, config.Config.MySQLTopologySSLCertFile, config.Config.MySQLTopologySSLPrivateKeyFile); err != nil {
			return "", log.Fatalf("Can't setup TLS key pairs for %s: %s", uri, err)
		}
		if err = mysql.RegisterTLSConfig("topology", tlsConfig); err != nil {
			return "", log.Fatalf("Can't register mysql TLS config for topology: %s", err)
		}
		topologyTLSConfigured = true
	}
	return fmt.Sprintf("%s&tls=topology", uri), nil
}

// readInternalDeployments reads orchestrator db deployment statements that are known to have been executed
func readInternalDeployments() (baseDeployments []string, patchDeployments []string, err error) {
	if !config.Config.SmartOrchestratorDatabaseUpdate {
		return baseDeployments, patchDeployments, nil
	}
	query := fmt.Sprintf(`
		select 
			deployment_type, 
			sql_statement  
		from 
			_orchestrator_db_deployment
		order by
			deployment_id
		`)
	db, err := OpenOrchestrator()
	if err != nil {
		log.Fatalf("Cannot initiate orchestrator internal deployment: %+v", err)
	}

	err = sqlutils.QueryRowsMap(db, query, func(m sqlutils.RowMap) error {
		deploymentType := m.GetString("deployment_type")
		sqlStatement := m.GetString("sql_statement")

		if deploymentType == "base" {
			baseDeployments = append(baseDeployments, sqlStatement)
		} else if deploymentType == "patch" {
			patchDeployments = append(patchDeployments, sqlStatement)
		} else {
			log.Fatalf("Unknown deployment type (%+v) encountered in _orchestrator_db_deployment", deploymentType)
		}

		return nil
	})
	if err != nil {
		log.Debugf("Deploying internal orchestrator tables to fix the above; this is a one time operation")
		// Table does not exist? Create it for first time
		for _, query := range internalDBDeploymentSQL {
			if _, err = execInternal(db, query); err != nil {
				log.Fatalf("Cannot initiate orchestrator internal deployment: %+v", err)
			}
		}
	}
	return baseDeployments, patchDeployments, nil
}

func postReadAdjustments() {
	if Config.MySQLOrchestratorCredentialsConfigFile != "" {
		mySQLConfig := struct {
			Client struct {
				User     string
				Password string
			}
		}{}
		err := gcfg.ReadFileInto(&mySQLConfig, Config.MySQLOrchestratorCredentialsConfigFile)
		if err != nil {
			log.Fatalf("Failed to parse gcfg data from file: %+v", err)
		} else {
			log.Debugf("Parsed orchestrator credentials from %s", Config.MySQLOrchestratorCredentialsConfigFile)
			Config.MySQLOrchestratorUser = mySQLConfig.Client.User
			Config.MySQLOrchestratorPassword = mySQLConfig.Client.Password
		}
	}
	if Config.MySQLTopologyCredentialsConfigFile != "" {
		mySQLConfig := struct {
			Client struct {
				User     string
				Password string
			}
		}{}
		err := gcfg.ReadFileInto(&mySQLConfig, Config.MySQLTopologyCredentialsConfigFile)
		if err != nil {
			log.Fatalf("Failed to parse gcfg data from file: %+v", err)
		} else {
			log.Debugf("Parsed topology credentials from %s", Config.MySQLTopologyCredentialsConfigFile)
			Config.MySQLTopologyUser = mySQLConfig.Client.User
			Config.MySQLTopologyPassword = mySQLConfig.Client.Password
		}
	}
	if Config.RecoveryPeriodBlockSeconds == 0 && Config.RecoveryPeriodBlockMinutes > 0 {
		// RecoveryPeriodBlockSeconds is a newer addition that overrides RecoveryPeriodBlockMinutes
		// The code does not consider RecoveryPeriodBlockMinutes anymore, but RecoveryPeriodBlockMinutes
		// still supported in config file for backwards compatibility
		Config.RecoveryPeriodBlockSeconds = Config.RecoveryPeriodBlockMinutes * 60
	}
}

// writeInternalDeployment will persist a successful deployment
func writeInternalDeployment(db *sql.DB, deploymentType string, sqlStatement string, statementIndex int) error {
	if !config.Config.SmartOrchestratorDatabaseUpdate {
		return nil
	}
	query := `
        	insert ignore into _orchestrator_db_deployment (
				deployment_type, sql_statement, statement_digest, statement_index) VALUES (
				?, ?, CONCAT(SHA1(?), ':', LEFT(REPLACE(REPLACE(REPLACE(?, ' ', ''), '\n', ' '), '\t', ''), 60)), ?)
				`
	if _, err := execInternal(db, query, deploymentType, sqlStatement, sqlStatement, sqlStatement, statementIndex); err != nil {
		log.Fatalf("Unable to write to _orchestrator_db_deployment: %+v", err)
	}
	return nil
}

// registerOrchestratorDeployment updates the orchestrator_metadata table upon successful deployment
func registerOrchestratorDeployment(db *sql.DB) error {
	query := `
    	replace into orchestrator_db_deployments (
				deployed_version, deployed_timestamp
			) values (
				?, NOW()
			)
				`
	if _, err := execInternal(db, query, config.RuntimeCLIFlags.ConfiguredVersion); err != nil {
		log.Fatalf("Unable to write to orchestrator_metadata: %+v", err)
	}
	log.Debugf("Migrated database schema to version [%+v]", config.RuntimeCLIFlags.ConfiguredVersion)
	return nil
}

// initOrchestratorDB attempts to create/upgrade the orchestrator backend database. It is created once in the
// application's lifetime.
func initOrchestratorDB(db *sql.DB) error {
	log.Debug("Initializing orchestrator")
	for _, query := range generateSQL {
		_, err := execInternal(db, query)
		if err != nil {
			return log.Fatalf("Cannot initiate orchestrator: %+v", err)
		}
	}
	for _, query := range generateSQLPatches {
		// Patches are allowed to fail.
		_, _ = execInternalSilently(db, query)
	}
	return nil
}

// deployStatements will issue given sql queries that are not already known to be deployed.
// This iterates both lists (to-run and already-deployed) and also verifies no contraditions.
func deployStatements(db *sql.DB, queries []string, fatalOnError bool) error {
	tx, err := db.Begin()
	if err != nil {
		log.Fatale(err)
	}
	// Ugly workaround ahead.
	// Origin of this workaround is the existence of some "timestamp NOT NULL," column definitions,
	// where in NO_ZERO_IN_DATE,NO_ZERO_DATE sql_mode are invalid (since default is implicitly "0")
	// This means installation of orchestrator fails on such configured servers, and in particular on 5.7
	// where this setting is the dfault.
	// For purpose of backwards compatability, what we do is force sql_mode to be more relaxed, create the schemas
	// along with the "invalid" definition, and then go ahead and fix those definitions via following ALTER statements.
	// My bad.
	originalSqlMode := ""
	err = tx.QueryRow(`select @@session.sql_mode`).Scan(&originalSqlMode)
	if _, err := tx.Exec(`set @@session.sql_mode=REPLACE(@@session.sql_mode, 'NO_ZERO_DATE', '')`); err != nil {
		log.Fatale(err)
	}
	if _, err := tx.Exec(`set @@session.sql_mode=REPLACE(@@session.sql_mode, 'NO_ZERO_IN_DATE', '')`); err != nil {
		log.Fatale(err)
	}

	for i, query := range queries {
		if i == 0 {
			//log.Debugf("sql_mode is: %+v", originalSqlMode)
		}

		if fatalOnError {
			if _, err := tx.Exec(query); err != nil {
				return log.Fatalf("Cannot initiate orchestrator: %+v", err)
			}
		} else {
			tx.Exec(query)
			// And ignore any error
		}
	}
	if _, err := tx.Exec(`set session sql_mode=?`, originalSqlMode); err != nil {
		log.Fatale(err)
	}
	if err := tx.Commit(); err != nil {
		log.Fatale(err)
	}
	return nil
}

func (this *Configuration) postReadAdjustments() error {
	if this.MySQLOrchestratorCredentialsConfigFile != "" {
		mySQLConfig := struct {
			Client struct {
				User     string
				Password string
			}
		}{}
		err := gcfg.ReadFileInto(&mySQLConfig, this.MySQLOrchestratorCredentialsConfigFile)
		if err != nil {
			log.Fatalf("Failed to parse gcfg data from file: %+v", err)
		} else {
			log.Debugf("Parsed orchestrator credentials from %s", this.MySQLOrchestratorCredentialsConfigFile)
			this.MySQLOrchestratorUser = mySQLConfig.Client.User
			this.MySQLOrchestratorPassword = mySQLConfig.Client.Password
		}
	}
	{
		// We accept password in the form "${SOME_ENV_VARIABLE}" in which case we pull
		// the given variable from os env
		submatch := envVariableRegexp.FindStringSubmatch(this.MySQLOrchestratorPassword)
		if len(submatch) > 1 {
			this.MySQLOrchestratorPassword = os.Getenv(submatch[1])
		}
	}
	if this.MySQLTopologyCredentialsConfigFile != "" {
		mySQLConfig := struct {
			Client struct {
				User     string
				Password string
			}
		}{}
		err := gcfg.ReadFileInto(&mySQLConfig, this.MySQLTopologyCredentialsConfigFile)
		if err != nil {
			log.Fatalf("Failed to parse gcfg data from file: %+v", err)
		} else {
			log.Debugf("Parsed topology credentials from %s", this.MySQLTopologyCredentialsConfigFile)
			this.MySQLTopologyUser = mySQLConfig.Client.User
			this.MySQLTopologyPassword = mySQLConfig.Client.Password
		}
	}
	{
		// We accept password in the form "${SOME_ENV_VARIABLE}" in which case we pull
		// the given variable from os env
		submatch := envVariableRegexp.FindStringSubmatch(this.MySQLTopologyPassword)
		if len(submatch) > 1 {
			this.MySQLTopologyPassword = os.Getenv(submatch[1])
		}
	}

	if this.RecoveryPeriodBlockSeconds == 0 && this.RecoveryPeriodBlockMinutes > 0 {
		// RecoveryPeriodBlockSeconds is a newer addition that overrides RecoveryPeriodBlockMinutes
		// The code does not consider RecoveryPeriodBlockMinutes anymore, but RecoveryPeriodBlockMinutes
		// still supported in config file for backwards compatibility
		this.RecoveryPeriodBlockSeconds = this.RecoveryPeriodBlockMinutes * 60
	}

	{
		if this.ReplicationLagQuery != "" && this.SlaveLagQuery != "" && this.ReplicationLagQuery != this.SlaveLagQuery {
			return fmt.Errorf("config's ReplicationLagQuery and SlaveLagQuery are synonyms and cannot both be defined")
		}
		if this.SlaveLagQuery != "" {
			this.ReplicationLagQuery = this.SlaveLagQuery
		}
	}

	{
		if this.DetachLostSlavesAfterMasterFailover {
			this.DetachLostReplicasAfterMasterFailover = true
		}
	}

	{
		if this.MasterFailoverDetachSlaveMasterHost {
			this.MasterFailoverDetachReplicaMasterHost = true
		}
	}

	{
		if this.PostponeReplicaRecoveryOnLagMinutes != 0 && this.PostponeSlaveRecoveryOnLagMinutes != 0 &&
			this.PostponeReplicaRecoveryOnLagMinutes != this.PostponeSlaveRecoveryOnLagMinutes {
			return fmt.Errorf("config's PostponeReplicaRecoveryOnLagMinutes and PostponeSlaveRecoveryOnLagMinutes are synonyms and cannot both be defined")
		}
		if this.PostponeSlaveRecoveryOnLagMinutes != 0 {
			this.PostponeReplicaRecoveryOnLagMinutes = this.PostponeSlaveRecoveryOnLagMinutes
		}
	}

	if this.URLPrefix != "" {
		// Ensure the prefix starts with "/" and has no trailing one.
		this.URLPrefix = strings.TrimLeft(this.URLPrefix, "/")
		this.URLPrefix = strings.TrimRight(this.URLPrefix, "/")
		this.URLPrefix = "/" + this.URLPrefix
	}
	return nil
}

// main is the application's entry point. It will either spawn a CLI or HTTP itnerfaces.
func main() {
	configFile := flag.String("config", "", "config file name")
	command := flag.String("c", "", "command, required. See full list of commands via 'orchestrator -c help'")
	strict := flag.Bool("strict", false, "strict mode (more checks, slower)")
	instance := flag.String("i", "", "instance, host_fqdn[:port] (e.g. db.company.com:3306, db.company.com)")
	sibling := flag.String("s", "", "sibling instance, host_fqdn[:port]")
	destination := flag.String("d", "", "destination instance, host_fqdn[:port] (synonym to -s)")
	owner := flag.String("owner", "", "operation owner")
	reason := flag.String("reason", "", "operation reason")
	duration := flag.String("duration", "", "maintenance duration (format: 59s, 59m, 23h, 6d, 4w)")
	pattern := flag.String("pattern", "", "regular expression pattern")
	clusterAlias := flag.String("alias", "", "cluster alias")
	pool := flag.String("pool", "", "Pool logical name (applies for pool-related commands)")
	hostnameFlag := flag.String("hostname", "", "Hostname/fqdn/CNAME/VIP (applies for hostname/resolve related commands)")
	discovery := flag.Bool("discovery", true, "auto discovery mode")
	quiet := flag.Bool("quiet", false, "quiet")
	verbose := flag.Bool("verbose", false, "verbose")
	debug := flag.Bool("debug", false, "debug mode (very verbose)")
	stack := flag.Bool("stack", false, "add stack trace upon error")
	config.RuntimeCLIFlags.Databaseless = flag.Bool("databaseless", false, "EXPERIMENTAL! Work without backend database")
	config.RuntimeCLIFlags.SkipUnresolveCheck = flag.Bool("skip-unresolve-check", false, "Skip/ignore checking an unresolve mapping (via hostname_unresolve table) resolves back to same hostname")
	config.RuntimeCLIFlags.Noop = flag.Bool("noop", false, "Dry run; do not perform destructing operations")
	config.RuntimeCLIFlags.BinlogFile = flag.String("binlog", "", "Binary log file name")
	flag.Parse()

	if *destination != "" && *sibling != "" {
		log.Fatalf("-s and -d are synonyms, yet both were specified. You're probably doing the wrong thing.")
	}
	if *destination == "" {
		*destination = *sibling
	}

	log.SetLevel(log.ERROR)
	if *verbose {
		log.SetLevel(log.INFO)
	}
	if *debug {
		log.SetLevel(log.DEBUG)
	}
	if *stack {
		log.SetPrintStackTrace(*stack)
	}

	log.Info("starting")

	runtime.GOMAXPROCS(math.MinInt(4, runtime.NumCPU()))

	if len(*configFile) > 0 {
		config.ForceRead(*configFile)
	} else {
		config.Read("/etc/orchestrator.conf.json", "conf/orchestrator.conf.json", "orchestrator.conf.json")
	}
	if *config.RuntimeCLIFlags.Databaseless {
		config.Config.DatabaselessMode__experimental = true
	}
	if config.Config.Debug {
		log.SetLevel(log.DEBUG)
	}
	if *quiet {
		// Override!!
		log.SetLevel(log.ERROR)
	}
	if config.Config.EnableSyslog {
		log.EnableSyslogWriter("orchestrator")
		log.SetSyslogLevel(log.INFO)
	}
	if config.Config.AuditToSyslog {
		inst.EnableAuditSyslog()
	}

	if len(flag.Args()) == 0 && *command == "" {
		// No command, no argument: just prompt
		fmt.Println(prompt)
		return
	}

	var executionMode OrchestratorExecutionMode
	switch {
	case len(flag.Args()) == 0 || flag.Arg(0) == "cli":
		executionMode = CliMode
	case flag.Arg(0) == "http":
		executionMode = HttpMode
	default:
		fmt.Fprintln(os.Stderr, `Usage: 
  orchestrator --options... [cli|http]
See complete list of commands:
  orchestrator -c help
Full blown documentation:
  orchestrator
`)
		os.Exit(1)
	}

	process.ContinuousRegistration(string(executionMode))
	switch executionMode {
	case CliMode:
		app.Cli(*command, *strict, *instance, *destination, *owner, *reason, *duration, *pattern, *clusterAlias, *pool, *hostnameFlag)
	case HttpMode:
		app.Http(*discovery)
//.........这里部分代码省略.........