topicwriter

Documentation

Index

• Variables
• type Message
• type PublicInitialInfo
• type Writer
  • func NewWriter(writer *topicwriterinternal.Writer) *Writer
  • func (w *Writer) Close(ctx context.Context) error
  • func (w *Writer) Flush(ctx context.Context) error
  • func (w *Writer) WaitInit(ctx context.Context) (err error)
  • func (w *Writer) WaitInitInfo(ctx context.Context) (info PublicInitialInfo, err error)
  • func (w *Writer) Write(ctx context.Context, messages ...Message) error

Examples

• Writer.Write

Variables

var ErrQueueLimitExceed = topicwriterinternal.PublicErrQueueIsFull

Types

type Message

type Message = topicwriterinternal.PublicMessage

type PublicInitialInfo

type PublicInitialInfo struct {
	LastSeqNum int64
}

PublicInitialInfo is an information about writer after initialize

type Writer

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

Writer represent write session to topic It handles connection problems, reconnect to server when need and resend buffered messages

func NewWriter

func NewWriter(writer *topicwriterinternal.Writer) *Writer

NewWriter create new writer from internal type. Used internally only.

func (*Writer) Close

func (w *Writer) Close(ctx context.Context) error

Close will flush rested messages from buffer and close the writer. You can't write new messages after call Close

func (*Writer) Flush

func (w *Writer) Flush(ctx context.Context) error

Flush waits till all in-flight messages are acknowledged.

func (*Writer) WaitInit

func (w *Writer) WaitInit(ctx context.Context) (err error)

WaitInit waits until the reader is initialized or an error occurs, return PublicInitialInfo and err

func (*Writer) WaitInitInfo

func (w *Writer) WaitInitInfo(ctx context.Context) (info PublicInitialInfo, err error)

WaitInitInfo waits until the reader is initialized or an error occurs, return PublicInitialInfo and err

func (*Writer) Write

func (w *Writer) Write(ctx context.Context, messages ...Message) error

Write send messages to topic return after save messages into buffer in async mode (default) and after ack from server in sync mode. see topicoptions.WithSyncWrite

The method will wait first initial connection even for async mode, that mean first write may be slower. especially when connection has problems.

It returns ErrQueueLimitExceed (must be checked by errors.Is) if ctx cancelled before messages put to internal buffer or try to add more messages, that can be put to queue

Example

ctx := context.Background()
db, err := ydb.Open(ctx, os.Getenv("YDB_CONNECTION_STRING"))
if err != nil {
	log.Fatalf("failed ydb connection: %v", err)
}

writer, err := db.Topic().StartWriter("topicName")
if err != nil {
	log.Fatalf("failed to create topic writer: %v", err)
}

err = writer.Write(ctx,
	topicwriter.Message{Data: strings.NewReader("1")},
	topicwriter.Message{Data: strings.NewReader("2")},
	topicwriter.Message{Data: strings.NewReader("3")},
)
if err == nil {
	fmt.Println("OK")
} else {
	log.Fatalf("failed write to stream")
}