messager

Documentation

Index

• Variables
• type Engine
  • func NewEngine(tsv TabletService, se *schema.Engine, config tabletenv.TabletConfig) *Engine
  • func (me *Engine) Close()
  • func (me *Engine) GenerateAckQuery(name string, ids []string) (string, map[string]*querypb.BindVariable, error)
  • func (me *Engine) GenerateLoadMessagesQuery(name string) (*sqlparser.ParsedQuery, error)
  • func (me *Engine) GeneratePostponeQuery(name string, ids []string) (string, map[string]*querypb.BindVariable, error)
  • func (me *Engine) GeneratePurgeQuery(name string, timeCutoff int64) (string, map[string]*querypb.BindVariable, error)
  • func (me *Engine) InitDBConfig(dbcfgs dbconfigs.DBConfigs)
  • func (me *Engine) LockDB(newMessages map[string][]*MessageRow, changedMessages map[string][]string) func()
  • func (me *Engine) Open() error
  • func (me *Engine) Subscribe(ctx context.Context, name string, send func(*sqltypes.Result) error) (done <-chan struct{}, err error)
  • func (me *Engine) UpdateCaches(newMessages map[string][]*MessageRow, changedMessages map[string][]string)
• type MessageRow
  • func BuildMessageRow(row []sqltypes.Value) (*MessageRow, error)
• type TabletService

Variables

var MessageDelayTimings = stats.NewMultiTimings(
	"MessageDelay",
	"MessageDelayTimings records total latency from queueing to client sends",
	[]string{"TableName"})

MessageDelayTimings records total latency from queueing to sent to clients.

var MessageStats = stats.NewGaugesWithMultiLabels(
	"Messages",
	"Stats for messages",
	[]string{"TableName", "Metric"})

MessageStats tracks stats for messages.

Types

type Engine

type Engine struct {
	// contains filtered or unexported fields
}

Engine is the engine for handling messages.

func NewEngine

func NewEngine(tsv TabletService, se *schema.Engine, config tabletenv.TabletConfig) *Engine

NewEngine creates a new Engine.

func (*Engine) Close

func (me *Engine) Close()

Close closes the Engine service.

func (*Engine) GenerateAckQuery

func (me *Engine) GenerateAckQuery(name string, ids []string) (string, map[string]*querypb.BindVariable, error)

GenerateAckQuery returns the query and bind vars for acking a message.

func (*Engine) GenerateLoadMessagesQuery

func (me *Engine) GenerateLoadMessagesQuery(name string) (*sqlparser.ParsedQuery, error)

GenerateLoadMessagesQuery returns the ParsedQuery for loading messages by pk. The results of the query can be used in a BuildMessageRow call.

func (*Engine) GeneratePostponeQuery

func (me *Engine) GeneratePostponeQuery(name string, ids []string) (string, map[string]*querypb.BindVariable, error)

GeneratePostponeQuery returns the query and bind vars for postponing a message.

func (*Engine) GeneratePurgeQuery

func (me *Engine) GeneratePurgeQuery(name string, timeCutoff int64) (string, map[string]*querypb.BindVariable, error)

GeneratePurgeQuery returns the query and bind vars for purging messages.

func (*Engine) InitDBConfig

func (me *Engine) InitDBConfig(dbcfgs dbconfigs.DBConfigs)

InitDBConfig must be called before Open.

func (*Engine) LockDB

func (me *Engine) LockDB(newMessages map[string][]*MessageRow, changedMessages map[string][]string) func()

LockDB obtains db locks for all messages that need to be updated and returns the counterpart unlock function.

func (*Engine) Open

func (me *Engine) Open() error

Open starts the Engine service.

func (*Engine) Subscribe

func (me *Engine) Subscribe(ctx context.Context, name string, send func(*sqltypes.Result) error) (done <-chan struct{}, err error)

Subscribe subscribes to messages from the requested table. The function returns a done channel that will be closed when the subscription ends, which can be initiated by the send function returning io.EOF. The engine can also end a subscription which is usually triggered by Close. It's the responsibility of the send function to promptly return if the done channel is closed. Otherwise, the engine's Close function will hang indefinitely.

func (*Engine) UpdateCaches

func (me *Engine) UpdateCaches(newMessages map[string][]*MessageRow, changedMessages map[string][]string)

UpdateCaches updates the caches for the committed changes.

type MessageRow

type MessageRow struct {
	TimeNext    int64
	Epoch       int64
	TimeCreated int64
	Row         []sqltypes.Value
	// contains filtered or unexported fields
}

MessageRow represents a message row. The first column in Row is always the "id".

func BuildMessageRow

func BuildMessageRow(row []sqltypes.Value) (*MessageRow, error)

BuildMessageRow builds a MessageRow for a db row.

type TabletService

type TabletService interface {
	CheckMySQL()
	PostponeMessages(ctx context.Context, target *querypb.Target, name string, ids []string) (count int64, err error)
	PurgeMessages(ctx context.Context, target *querypb.Target, name string, timeCutoff int64) (count int64, err error)
}

TabletService defines the functions of TabletServer that the messager needs for callback.