Align fields in structs to optimize memory usage

.golangci.yml

@@ -34,6 +34,9 @@ linters-settings:
       - name: empty-block
       - name: unreachable-code
       - name: redefines-builtin-id
+  govet:
+    enable:
+      - fieldalignment
 
 linters:
   disable-all: true

internal/app/app.go

@@ -19,19 +19,19 @@ import (
 
 // App is main application structure
 type App struct {
+	dcs          dcs.DCS
+	critical     atomic.Value
 	ctx          context.Context
-	mode         appMode
-	aofMode      aofMode
 	nodeFailTime map[string]time.Time
 	splitTime    map[string]time.Time
-	state        appState
-	critical     atomic.Value
 	logger       *slog.Logger
 	config       *config.Config
-	dcs          dcs.DCS
 	shard        *valkey.Shard
 	cache        *valkey.SentiCacheNode
 	daemonLock   *flock.Flock
+	mode         appMode
+	aofMode      aofMode
+	state        appState
 }
 
 func baseContext() context.Context {

internal/app/parallel.go

@@ -6,15 +6,15 @@ import (
 
 func getHostStatesInParallel(hosts []string, getter func(string) (*HostState, error)) (map[string]*HostState, error) {
 	type result struct {
-		name  string
-		state *HostState
 		err   error
+		state *HostState
+		name  string
 	}
 	results := make(chan result, len(hosts))
 	for _, host := range hosts {
 		go func(host string) {
 			state, err := getter(host)
-			results <- result{host, state, err}
+			results <- result{err, state, host}
 		}(host)
 	}
 	shardState := make(map[string]*HostState)
@@ -35,13 +35,13 @@ func getHostStatesInParallel(hosts []string, getter func(string) (*HostState, er
 
 func runParallel(f func(string) error, arguments []string) map[string]error {
 	type pair struct {
-		key string
 		err error
+		key string
 	}
 	errs := make(chan pair, len(arguments))
 	for _, argValue := range arguments {
 		go func(host string) {
-			errs <- pair{host, f(host)}
+			errs <- pair{f(host), host}
 		}(argValue)
 	}
 	result := make(map[string]error)

internal/app/state.go

@@ -155,6 +155,17 @@ func (app *App) getHostState(fqdn string) *HostState {
 				app.setStateError(&state, fqdn, err.Error())
 				return &state
 			}
+		} else if rs.MasterLinkState && !rs.MasterSyncInProgress {
+			lastIOSeconds, ok := info["master_last_io_seconds_ago"]
+			if !ok {
+				app.setStateError(&state, fqdn, "Replica with link up but no master_last_io_seconds_ago in info")
+				return &state
+			}
+			rs.MasterLastIOSeconds, err = strconv.ParseInt(lastIOSeconds, 10, 64)
+			if err != nil {
+				app.setStateError(&state, fqdn, err.Error())
+				return &state
+			}
 		}
 		replicaOffset, ok := info["slave_repl_offset"]
 		if !ok {

internal/app/types.go

@@ -131,27 +131,27 @@ const (
 
 // HostState contains status check performed by some rdsync process
 type HostState struct {
-	CheckBy                 string           `json:"check_by"`
 	CheckAt                 time.Time        `json:"check_at"`
-	PingOk                  bool             `json:"ping_ok"`
-	PingStable              bool             `json:"ping_stable"`
+	ReplicaState            *ReplicaState    `json:"replica_state"`
+	SentiCacheState         *SentiCacheState `json:"senticache_state"`
+	ReplicationID           string           `json:"replication_id"`
 	IP                      string           `json:"ip"`
 	RunID                   string           `json:"runid"`
-	IsMaster                bool             `json:"is_master"`
-	IsOffline               bool             `json:"is_offline"`
-	IsReadOnly              bool             `json:"is_read_only"`
-	IsReplPaused            bool             `json:"is_repl_paused"`
-	MasterReplicationOffset int64            `json:"master_replication_offset"`
-	SecondReplicationOffset int64            `json:"second_replication_offset"`
+	Error                   string           `json:"error"`
+	ReplicationID2          string           `json:"replication_id2"`
+	CheckBy                 string           `json:"check_by"`
+	ConnectedReplicas       []string         `json:"connected_replicas"`
 	ReplicationBacklogStart int64            `json:"replication_backlog_start"`
+	SecondReplicationOffset int64            `json:"second_replication_offset"`
+	MasterReplicationOffset int64            `json:"master_replication_offset"`
 	ReplicationBacklogSize  int64            `json:"replication_backlog_size"`
 	MinReplicasToWrite      int64            `json:"min_replicas_to_write"`
-	ReplicationID           string           `json:"replication_id"`
-	ReplicationID2          string           `json:"replication_id2"`
-	Error                   string           `json:"error"`
-	ConnectedReplicas       []string         `json:"connected_replicas"`
-	ReplicaState            *ReplicaState    `json:"replica_state"`
-	SentiCacheState         *SentiCacheState `json:"senticache_state"`
+	IsReplPaused            bool             `json:"is_repl_paused"`
+	IsReadOnly              bool             `json:"is_read_only"`
+	IsOffline               bool             `json:"is_offline"`
+	IsMaster                bool             `json:"is_master"`
+	PingStable              bool             `json:"ping_stable"`
+	PingOk                  bool             `json:"ping_ok"`
 }
 
 func (hs *HostState) String() string {
@@ -180,10 +180,11 @@ func (hs *HostState) String() string {
 // Master always has this state empty
 type ReplicaState struct {
 	MasterHost           string `json:"master_host"`
-	MasterLinkState      bool   `json:"master_link_state"`
 	MasterLinkDownTime   int64  `json:"master_link_down_time"`
-	MasterSyncInProgress bool   `json:"master_sync_in_progress"`
 	ReplicationOffset    int64  `json:"replication_offset"`
+	MasterLastIOSeconds  int64  `json:"master_last_io_seconds"`
+	MasterLinkState      bool   `json:"master_link_state"`
+	MasterSyncInProgress bool   `json:"master_sync_in_progress"`
 }
 
 func (rs *ReplicaState) String() string {
@@ -212,15 +213,15 @@ const (
 
 // Switchover contains info about currently running or scheduled switchover/failover process
 type Switchover struct {
+	InitiatedAt time.Time           `json:"initiated_at"`
+	StartedAt   time.Time           `json:"started_at"`
+	Result      *SwitchoverResult   `json:"result"`
+	Progress    *SwitchoverProgress `json:"progress"`
 	From        string              `json:"from"`
 	To          string              `json:"to"`
 	Cause       string              `json:"cause"`
 	InitiatedBy string              `json:"initiated_by"`
-	InitiatedAt time.Time           `json:"initiated_at"`
 	StartedBy   string              `json:"started_by"`
-	StartedAt   time.Time           `json:"started_at"`
-	Result      *SwitchoverResult   `json:"result"`
-	Progress    *SwitchoverProgress `json:"progress"`
 	RunCount    int                 `json:"run_count"`
 }
 
@@ -250,23 +251,23 @@ func (sw *Switchover) String() string {
 
 // SwitchoverResult contains results of finished/failed switchover
 type SwitchoverResult struct {
-	Ok         bool      `json:"ok"`
-	Error      string    `json:"error"`
 	FinishedAt time.Time `json:"finished_at"`
+	Error      string    `json:"error"`
+	Ok         bool      `json:"ok"`
 }
 
 // SwitchoverProgress contains intents and status of running switchover
 type SwitchoverProgress struct {
-	Version    int    `json:"version"`
-	Phase      int    `json:"phase"`
 	NewMaster  string `json:"new_master"`
 	MostRecent string `json:"most_recent"`
+	Version    int    `json:"version"`
+	Phase      int    `json:"phase"`
 }
 
 // Maintenance struct presence means that cluster under manual control
 type Maintenance struct {
-	InitiatedBy  string    `json:"initiated_by"`
 	InitiatedAt  time.Time `json:"initiated_at"`
+	InitiatedBy  string    `json:"initiated_by"`
 	RdSyncPaused bool      `json:"rdsync_paused"`
 	ShouldLeave  bool      `json:"should_leave"`
 }
@@ -283,11 +284,11 @@ func (m *Maintenance) String() string {
 }
 
 type PoisonPill struct {
-	Applied     bool      `json:"applied"`
 	InitiatedAt time.Time `json:"initiated_at"`
 	InitiatedBy string    `json:"initiated_by"`
 	TargetHost  string    `json:"target_host"`
 	Cause       string    `json:"cause"`
+	Applied     bool      `json:"applied"`
 }
 
 func (pp *PoisonPill) String() string {

internal/config/config.go

@@ -15,64 +15,64 @@ import (
 
 // ValkeyConfig contains valkey connection info and params
 type ValkeyConfig struct {
-	Port                    int           `yaml:"port"`
-	ClusterBusPort          int           `yaml:"cluster_bus_port"`
-	UseTLS                  bool          `yaml:"use_tls"`
+	AuthPassword            string        `yaml:"auth_password"`
+	AofPath                 string        `yaml:"aof_path"`
+	RestartCommand          string        `yaml:"restart_command"`
 	TLSCAPath               string        `yaml:"tls_ca_path"`
 	AuthUser                string        `yaml:"auth_user"`
-	AuthPassword            string        `yaml:"auth_password"`
-	DialTimeout             time.Duration `yaml:"dial_timeout"`
+	FailoverCooldown        time.Duration `yaml:"failover_cooldown"`
+	WaitPromoteTimeout      time.Duration `yaml:"wait_promote_timeout"`
 	WriteTimeout            time.Duration `yaml:"write_timeout"`
 	DNSTTL                  time.Duration `yaml:"dns_ttl"`
 	FailoverTimeout         time.Duration `yaml:"failover_timeout"`
-	FailoverCooldown        time.Duration `yaml:"failover_cooldown"`
+	Port                    int           `yaml:"port"`
 	RestartTimeout          time.Duration `yaml:"restart_timeout"`
 	WaitReplicationTimeout  time.Duration `yaml:"wait_replication_timeout"`
 	WaitCatchupTimeout      time.Duration `yaml:"wait_catchup_timeout"`
-	WaitPromoteTimeout      time.Duration `yaml:"wait_promote_timeout"`
+	DialTimeout             time.Duration `yaml:"dial_timeout"`
 	WaitPromoteForceTimeout time.Duration `yaml:"wait_promote_force_timeout"`
 	WaitPoisonPillTimeout   time.Duration `yaml:"wait_poison_pill_timeout"`
 	MaxParallelSyncs        int           `yaml:"max_parallel_syncs"`
-	AllowDataLoss           bool          `yaml:"allow_data_loss"`
+	ClusterBusPort          int           `yaml:"cluster_bus_port"`
 	TurnBeforeSwitchover    bool          `yaml:"turn_before_switchover"`
-	RestartCommand          string        `yaml:"restart_command"`
-	AofPath                 string        `yaml:"aof_path"`
+	UseTLS                  bool          `yaml:"use_tls"`
+	AllowDataLoss           bool          `yaml:"allow_data_loss"`
 }
 
 // SentinelModeConfig contains sentinel-mode specific configuration
 type SentinelModeConfig struct {
-	AnnounceHostname    bool   `yaml:"announce_hostname"`
 	Name                string `yaml:"name"`
 	RunID               string `yaml:"run_id"`
 	ClusterName         string `yaml:"cluster_name"`
 	CacheAuthUser       string `yaml:"cache_auth_user"`
 	CacheAuthPassword   string `yaml:"cache_auth_password"`
-	CachePort           int    `yaml:"cache_port"`
 	CacheRestartCommand string `yaml:"cache_restart_command"`
 	CacheUpdateSecret   string `yaml:"cache_update_secret"`
-	UseTLS              bool   `yaml:"use_tls"`
 	TLSCAPath           string `yaml:"tls_ca_path"`
+	CachePort           int    `yaml:"cache_port"`
+	AnnounceHostname    bool   `yaml:"announce_hostname"`
+	UseTLS              bool   `yaml:"use_tls"`
 }
 
 // Config contains rdsync application configuration
 type Config struct {
-	LogLevel                string              `yaml:"loglevel"`
-	Hostname                string              `yaml:"hostname"`
 	Mode                    string              `yaml:"mode"`
-	AofMode                 string              `yaml:"aof_mode"`
 	InfoFile                string              `yaml:"info_file"`
+	Hostname                string              `yaml:"hostname"`
+	LogLevel                string              `yaml:"loglevel"`
+	AofMode                 string              `yaml:"aof_mode"`
 	MaintenanceFile         string              `yaml:"maintenance_file"`
 	DaemonLockFile          string              `yaml:"daemon_lock_file"`
-	PingStable              int                 `yaml:"ping_stable"`
-	TickInterval            time.Duration       `yaml:"tick_interval"`
-	InactivationDelay       time.Duration       `yaml:"inactivation_delay"`
-	HealthCheckInterval     time.Duration       `yaml:"healthcheck_interval"`
-	InfoFileHandlerInterval time.Duration       `yaml:"info_file_handler_interval"`
 	PprofAddr               string              `yaml:"pprof_addr"`
+	SentinelMode            SentinelModeConfig  `yaml:"sentinel_mode"`
 	Zookeeper               dcs.ZookeeperConfig `yaml:"zookeeper"`
-	DcsWaitTimeout          time.Duration       `yaml:"dcs_wait_timeout"`
 	Valkey                  ValkeyConfig        `yaml:"valkey"`
-	SentinelMode            SentinelModeConfig  `yaml:"sentinel_mode"`
+	HealthCheckInterval     time.Duration       `yaml:"healthcheck_interval"`
+	InfoFileHandlerInterval time.Duration       `yaml:"info_file_handler_interval"`
+	InactivationDelay       time.Duration       `yaml:"inactivation_delay"`
+	DcsWaitTimeout          time.Duration       `yaml:"dcs_wait_timeout"`
+	TickInterval            time.Duration       `yaml:"tick_interval"`
+	PingStable              int                 `yaml:"ping_stable"`
 }
 
 // DefaultValkeyConfig returns default configuration for valkey connection info and params

internal/dcs/config.go

@@ -9,24 +9,24 @@ import (
 
 // ZookeeperConfig contains Zookeeper connection info
 type ZookeeperConfig struct {
-	Hostname              string                   `config:"hostname" yaml:"hostname"`
-	SessionTimeout        time.Duration            `config:"session_timeout" yaml:"session_timeout"`
+	CACert                string                   `config:"ca_cert" yaml:"ca_cert"`
 	Namespace             string                   `config:"namespace,required"`
+	Hostname              string                   `config:"hostname" yaml:"hostname"`
+	CertFile              string                   `config:"certfile" yaml:"certfile"`
+	KeyFile               string                   `config:"keyfile" yaml:"keyfile"`
+	Password              string                   `config:"password" yaml:"password"`
+	Username              string                   `config:"username" yaml:"username"`
 	Hosts                 []string                 `config:"hosts,required"`
+	RandomHostProvider    RandomHostProviderConfig `config:"random_host_provider" yaml:"random_host_provider"`
 	BackoffInterval       time.Duration            `config:"backoff_interval" yaml:"backoff_interval"`
-	BackoffRandFactor     float64                  `config:"backoff_rand_factor" yaml:"backoff_rand_factor"`
-	BackoffMultiplier     float64                  `config:"backoff_multiplier" yaml:"backoff_multiplier"`
-	BackoffMaxInterval    time.Duration            `config:"backoff_max_interval" yaml:"backoff_max_interval"`
-	BackoffMaxElapsedTime time.Duration            `config:"backoff_max_elapsed_time" yaml:"backoff_max_elapsed_time"`
 	BackoffMaxRetries     uint64                   `config:"backoff_max_retries" yaml:"backoff_max_retries"`
-	RandomHostProvider    RandomHostProviderConfig `config:"random_host_provider" yaml:"random_host_provider"`
+	BackoffMaxElapsedTime time.Duration            `config:"backoff_max_elapsed_time" yaml:"backoff_max_elapsed_time"`
+	BackoffMaxInterval    time.Duration            `config:"backoff_max_interval" yaml:"backoff_max_interval"`
+	BackoffMultiplier     float64                  `config:"backoff_multiplier" yaml:"backoff_multiplier"`
+	BackoffRandFactor     float64                  `config:"backoff_rand_factor" yaml:"backoff_rand_factor"`
+	SessionTimeout        time.Duration            `config:"session_timeout" yaml:"session_timeout"`
 	Auth                  bool                     `config:"auth" yaml:"auth"`
-	Username              string                   `config:"username" yaml:"username"`
-	Password              string                   `config:"password" yaml:"password"`
 	UseSSL                bool                     `config:"use_ssl" yaml:"use_ssl"`
-	KeyFile               string                   `config:"keyfile" yaml:"keyfile"`
-	CertFile              string                   `config:"certfile" yaml:"certfile"`
-	CACert                string                   `config:"ca_cert" yaml:"ca_cert"`
 	VerifyCerts           bool                     `config:"verify_certs" yaml:"verify_certs"`
 }
 

internal/dcs/zk.go

@@ -22,11 +22,11 @@ type zkDCS struct {
 	conn               *zk.Conn
 	eventsChan         <-chan zk.Event
 	disconnectCallback func() error
-	isConnected        bool
-	connectedChans     []chan struct{}
-	connectedLock      sync.Mutex
 	closeTimer         *time.Timer
+	connectedChans     []chan struct{}
 	acl                []zk.ACL
+	connectedLock      sync.Mutex
+	isConnected        bool
 }
 
 type zkLoggerProxy struct{ *slog.Logger }

internal/dcs/zk_host_provider.go

@@ -11,21 +11,21 @@ import (
 )
 
 type zkhost struct {
-	resolved   []string
 	lastLookup time.Time
+	resolved   []string
 }
 
 type RandomHostProvider struct {
 	ctx                context.Context
+	logger             *slog.Logger
+	resolver           *net.Resolver
+	tried              map[string]struct{}
 	hosts              sync.Map
-	useAddrs           bool
 	hostsKeys          []string
-	tried              map[string]struct{}
-	logger             *slog.Logger
 	lookupTTL          time.Duration
 	lookupTimeout      time.Duration
 	lookupTickInterval time.Duration
-	resolver           *net.Resolver
+	useAddrs           bool
 }
 
 func NewRandomHostProvider(ctx context.Context, config *RandomHostProviderConfig, useAddrs bool, logger *slog.Logger) *RandomHostProvider {