topic

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Published: Dec 9, 2022 License: Apache-2.0 Imports: 5 Imported by: 0

README

topic - pure Go native client for YDB Topic

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See ydb-go-sdk for describe all driver features.

YDB is an open-source Distributed SQL Database that combines high availability and scalability with strict consistency and ACID transactions with CDC and Data stream features.

Installation

go get -u github.com/ydb-platform/ydb-go-sdk/v3

Example Usage

  • connect to YDB
db, err := ydb.Open(ctx, "grpcs://localhost:2135/local")
if err != nil {
    log.Fatal(err)
}
  • send messages
producerAndGroupID := "group-id"
writer, err := db.Topic().StartWriter(producerAndGroupID, "topicName",
    topicoptions.WithMessageGroupID(producerAndGroupID),
    topicoptions.WithCodec(topictypes.CodecGzip),
)
if err != nil {
    log.Fatal(err)
}

data1 := []byte{1, 2, 3}
data2 := []byte{4, 5, 6}
mess1 := topicwriter.Message{Data: bytes.NewReader(data1)}
mess2 := topicwriter.Message{Data: bytes.NewReader(data2)}

err = writer.Write(ctx, mess1, mess2)
if err != nil {
	log.Fatal(err)
}
  • read messages
for {
    msg, err := reader.ReadMessage(ctx)
    if err != nil {
        log.Fatal(err)
    }
    content, err := io.ReadAll(msg)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println(string(content))
    err = reader.Commit(msg.Context(), msg)
    if err != nil {
        log.Fatal(err)
    }
}
 

Documentation

Overview

Example (AlterTopic)
package main

import (
	"context"
	"log"
	"os"

	ydb "github.com/ydb-platform/ydb-go-sdk/v3"
	"github.com/ydb-platform/ydb-go-sdk/v3/topic/topicoptions"
	"github.com/ydb-platform/ydb-go-sdk/v3/topic/topictypes"
)

func main() {
	ctx := context.TODO()
	connectionString := os.Getenv("YDB_CONNECTION_STRING")
	if connectionString == "" {
		connectionString = "grpc://localhost:2136/local"
	}
	db, err := ydb.Open(ctx, connectionString)
	if err != nil {
		log.Printf("failed connect: %v", err)
		return
	}
	defer db.Close(ctx) // cleanup resources

	err = db.Topic().Alter(ctx, "topic-path",
		topicoptions.AlterWithAddConsumers(topictypes.Consumer{
			Name:            "new-consumer",
			SupportedCodecs: []topictypes.Codec{topictypes.CodecRaw, topictypes.CodecGzip}, // optional
		}),
	)
	if err != nil {
		log.Printf("failed alter topic: %v", err)
		return
	}
}
Output:

Example (CreateTopic)
package main

import (
	"context"
	"log"
	"os"

	ydb "github.com/ydb-platform/ydb-go-sdk/v3"
	"github.com/ydb-platform/ydb-go-sdk/v3/topic/topicoptions"
	"github.com/ydb-platform/ydb-go-sdk/v3/topic/topictypes"
)

func main() {
	ctx := context.TODO()
	connectionString := os.Getenv("YDB_CONNECTION_STRING")
	if connectionString == "" {
		connectionString = "grpc://localhost:2136/local"
	}
	db, err := ydb.Open(ctx, connectionString)
	if err != nil {
		log.Printf("failed connect: %v", err)
		return
	}
	defer db.Close(ctx) // cleanup resources

	err = db.Topic().Create(ctx, "topic-path",

		// optional
		topicoptions.CreateWithSupportedCodecs(topictypes.CodecRaw, topictypes.CodecGzip),

		// optional
		topicoptions.CreateWithMinActivePartitions(3),
	)
	if err != nil {
		log.Printf("failed create topic: %v", err)
		return
	}
}
Output:

Example (DescribeTopic)
package main

import (
	"context"
	"fmt"
	"log"
	"os"

	ydb "github.com/ydb-platform/ydb-go-sdk/v3"
)

func main() {
	ctx := context.TODO()
	connectionString := os.Getenv("YDB_CONNECTION_STRING")
	if connectionString == "" {
		connectionString = "grpc://localhost:2136/local"
	}
	db, err := ydb.Open(ctx, connectionString)
	if err != nil {
		log.Printf("failed connect: %v", err)
		return
	}
	defer db.Close(ctx) // cleanup resources

	descResult, err := db.Topic().Describe(ctx, "topic-path")
	if err != nil {
		log.Printf("failed drop topic: %v", err)
		return
	}
	fmt.Printf("describe: %#v\n", descResult)
}
Output:

Example (DropTopic)
package main

import (
	"context"
	"log"
	"os"

	ydb "github.com/ydb-platform/ydb-go-sdk/v3"
)

func main() {
	ctx := context.TODO()
	connectionString := os.Getenv("YDB_CONNECTION_STRING")
	if connectionString == "" {
		connectionString = "grpc://localhost:2136/local"
	}
	db, err := ydb.Open(ctx, connectionString)
	if err != nil {
		log.Printf("failed connect: %v", err)
		return
	}
	defer db.Close(ctx) // cleanup resources

	err = db.Topic().Drop(ctx, "topic-path")
	if err != nil {
		log.Printf("failed drop topic: %v", err)
		return
	}
}
Output:

Example (ReadMessage)
package main

import (
	"context"
	"fmt"
	"io/ioutil"
	"log"
	"os"

	ydb "github.com/ydb-platform/ydb-go-sdk/v3"
	"github.com/ydb-platform/ydb-go-sdk/v3/topic/topicoptions"
)

func main() {
	ctx := context.TODO()
	connectionString := os.Getenv("YDB_CONNECTION_STRING")
	if connectionString == "" {
		connectionString = "grpc://localhost:2136/local"
	}
	db, err := ydb.Open(ctx, connectionString)
	if err != nil {
		log.Printf("failed connect: %v", err)
		return
	}
	defer db.Close(ctx) // cleanup resources

	reader, err := db.Topic().StartReader("consumer", topicoptions.ReadTopic("/topic/path"))
	if err != nil {
		fmt.Printf("failed start reader: %v", err)
		return
	}

	for {
		mess, err := reader.ReadMessage(ctx)
		if err != nil {
			fmt.Printf("failed start reader: %v", err)
			return
		}

		content, err := ioutil.ReadAll(mess)
		if err != nil {
			fmt.Printf("failed start reader: %v", err)
			return
		}
		fmt.Println(string(content))
	}
}
Output:

Index

Examples

Constants

This section is empty.

Variables

This section is empty.

Functions

This section is empty.

Types

type Client

type Client interface {
	// Alter change topic options
	//
	// Experimental
	//
	// Notice: This API is EXPERIMENTAL and may be changed or removed in a
	// later release.
	Alter(ctx context.Context, path string, opts ...topicoptions.AlterOption) error

	// Create create topic
	//
	// Experimental
	//
	// Notice: This API is EXPERIMENTAL and may be changed or removed in a
	// later release.
	Create(ctx context.Context, path string, opts ...topicoptions.CreateOption) error

	// Describe describe topic
	//
	// Experimental
	//
	// Notice: This API is EXPERIMENTAL and may be changed or removed in a
	// later release.
	Describe(ctx context.Context, path string, opts ...topicoptions.DescribeOption) (topictypes.TopicDescription, error)

	// Drop drop topic
	//
	// Experimental
	//
	// Notice: This API is EXPERIMENTAL and may be changed or removed in a
	// later release.
	Drop(ctx context.Context, path string, opts ...topicoptions.DropOption) error

	// StartReader start read messages from topic
	// it is fast non block call, connection starts in background
	//
	// Experimental
	//
	// Notice: This API is EXPERIMENTAL and may be changed or removed in a
	// later release.
	StartReader(
		consumer string,
		readSelectors topicoptions.ReadSelectors,
		opts ...topicoptions.ReaderOption,
	) (*topicreader.Reader, error)

	// StartWriter start write session to topic
	// it is fast non block call, connection starts in background
	//
	// Experimental
	//
	// Notice: This API is EXPERIMENTAL and may be changed or removed in a
	// later release.
	StartWriter(producerID, path string, opts ...topicoptions.WriterOption) (*topicwriter.Writer, error)
}

Client is interface for topic client

Experimental

Notice: This API is EXPERIMENTAL and may be changed or removed in a later release.

Directories

Path Synopsis
Package topicreader provide Reader to receive messages from YDB topics More examples in examples repository
Package topicreader provide Reader to receive messages from YDB topics More examples in examples repository

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