relay

type Config struct {
	EnableGTID  bool     `toml:"enable-gtid" json:"enable-gtid"`
	AutoFixGTID bool     `toml:"auto-fix-gtid" json:"auto-fix-gtid"`
	RelayDir    string   `toml:"relay-dir" json:"relay-dir"`
	ServerID    uint32   `toml:"server-id" json:"server-id"`
	Flavor      string   `toml:"flavor" json:"flavor"`
	Charset     string   `toml:"charset" json:"charset"`
	From        DBConfig `toml:"data-source" json:"data-source"`

	// synchronous start point (if no meta saved before)
	// do not need to specify binlog-pos, because relay will fetch the whole file
	BinLogName string `toml:"binlog-name" json:"binlog-name"`
	BinlogGTID string `toml:"binlog-gtid" json:"binlog-gtid"`

	// for binlog reader retry
	ReaderRetry retry.ReaderRetryConfig `toml:"reader-retry" json:"reader-retry"`
}

type DBConfig struct {
	Host     string `toml:"host" json:"host"`
	User     string `toml:"user" json:"user"`
	Password string `toml:"password" json:"-"` // omit it for privacy
	Port     int    `toml:"port" json:"port"`
}

type LocalMeta struct {
	sync.RWMutex

	BinLogName string `toml:"binlog-name" json:"binlog-name"`
	BinLogPos  uint32 `toml:"binlog-pos" json:"binlog-pos"`
	BinlogGTID string `toml:"binlog-gtid" json:"binlog-gtid"`
	// contains filtered or unexported fields
}

type Meta interface {
	// Load loads meta information for the recently active server
	Load() error

	// AdjustWithStartPos adjusts current pos / GTID with start pos
	// if current pos / GTID is meaningless, update to start pos or last pos when start pos is meaningless
	// else do nothing
	AdjustWithStartPos(binlogName string, binlogGTID string, enableGTID bool, latestBinlogName string, latestBinlogGTID string) (bool, error)

	// Save saves meta information
	Save(pos mysql.Position, gset gtid.Set) error

	// Flush flushes meta information
	Flush() error

	// Dirty checks whether meta in memory is dirty (need to Flush)
	Dirty() bool

	// AddDir adds sub relay directory for server UUID (without suffix)
	// the added sub relay directory's suffix is incremented
	// after sub relay directory added, the internal binlog pos should be reset
	// and binlog pos will be set again when new binlog events received
	// @serverUUID should be a server_uuid for MySQL or MariaDB
	// if set @newPos / @newGTID, old value will be replaced
	AddDir(serverUUID string, newPos *mysql.Position, newGTID gtid.Set) error

	// Pos returns current (UUID with suffix, Position) pair
	Pos() (string, mysql.Position)

	// GTID returns current (UUID with suffix, GTID) pair
	GTID() (string, gtid.Set)

	// UUID returns current UUID (with suffix)
	UUID() string

	// TrimUUIDs trim invalid UUIDs from memory and update the server-uuid.index file
	// return trimmed UUIDs
	TrimUUIDs() ([]string, error)

	// Dir returns current relay log (sub) directory
	Dir() string

	// String returns string representation of current meta info
	String() string
}

type Process interface {
	// Init initial relat log unit
	Init(ctx context.Context) (err error)
	// Process run background logic of relay log unit
	Process(ctx context.Context, pr chan pb.ProcessResult)
	// SwitchMaster switches relay's master server
	SwitchMaster(ctx context.Context, req *pb.SwitchRelayMasterRequest) error
	// Migrate  resets  binlog position
	Migrate(ctx context.Context, binlogName string, binlogPos uint32) error
	// ActiveRelayLog returns the earliest active relay log info in this operator
	ActiveRelayLog() *pkgstreamer.RelayLogInfo
	// Reload reloads config
	Reload(newCfg *Config) error
	// Update updates config
	Update(cfg *config.SubTaskConfig) error
	// Resume resumes paused relay log process unit
	Resume(ctx context.Context, pr chan pb.ProcessResult)
	// Pause pauses a running relay log process unit
	Pause()
	// Error returns error message if having one
	Error() interface{}
	// Status returns status of relay log process unit
	Status() interface{}
	// Close does some clean works
	Close()
	// IsClosed returns whether relay log process unit was closed
	IsClosed() bool
}

type Relay struct {
	sync.RWMutex
	// contains filtered or unexported fields
}