Apache Pulsar Go Client Library

A Go client library for Apache Pulsar. For the supported Pulsar features, see Client Feature Matrix.

Purpose

This project is a pure-Go client library for Pulsar that does not depend on the C++ Pulsar library.

Once feature parity and stability are reached, this will supersede the current CGo-based library.

Requirements

• Go 1.18+

Note:

While this library should work with Golang versions as early as 1.16, any bugs specific to versions earlier than 1.18 may not be fixed.

Status

Check the Projects page at https://github.com/apache/pulsar-client-go/projects for tracking the status and the progress.

Usage

Import the client library:

import "github.com/apache/pulsar-client-go/pulsar"

Create a Producer:

client, err := pulsar.NewClient(pulsar.ClientOptions{
    URL: "pulsar://localhost:6650",
})

defer client.Close()

producer, err := client.CreateProducer(pulsar.ProducerOptions{
    Topic: "my-topic",
})

_, err = producer.Send(context.Background(), &pulsar.ProducerMessage{
    Payload: []byte("hello"),
})

defer producer.Close()

if err != nil {
    fmt.Println("Failed to publish message", err)
} else {
    fmt.Println("Published message")
}

Create a Consumer:

client, err := pulsar.NewClient(pulsar.ClientOptions{
    URL: "pulsar://localhost:6650",
})

defer client.Close()

consumer, err := client.Subscribe(pulsar.ConsumerOptions{
        Topic:            "my-topic",
        SubscriptionName: "my-sub",
        Type:             pulsar.Shared,
    })

defer consumer.Close()

msg, err := consumer.Receive(context.Background())
    if err != nil {
        log.Fatal(err)
    }

fmt.Printf("Received message msgId: %#v -- content: '%s'\n",
            msg.ID(), string(msg.Payload()))

Create a Reader:

client, err := pulsar.NewClient(pulsar.ClientOptions{URL: "pulsar://localhost:6650"})
if err != nil {
    log.Fatal(err)
}

defer client.Close()

reader, err := client.CreateReader(pulsar.ReaderOptions{
    Topic:          "topic-1",
    StartMessageID: pulsar.EarliestMessageID(),
})
if err != nil {
    log.Fatal(err)
}
defer reader.Close()

for reader.HasNext() {
    msg, err := reader.Next(context.Background())
    if err != nil {
        log.Fatal(err)
    }

    fmt.Printf("Received message msgId: %#v -- content: '%s'\n",
        msg.ID(), string(msg.Payload()))
}

Build and Test

Build the sources:

make build

Run the tests:

make test

Run the tests with specific versions of GOLANG and PULSAR:

make test GOLANG_VERSION=1.18 PULSAR_VERSION=2.10.0

Contributing

Contributions are welcomed and greatly appreciated. See CONTRIBUTING.md for details on submitting patches and the contribution workflow.

If your contribution adds Pulsar features for Go clients, you need to update both the Pulsar docs and the Client Feature Matrix. See Contribution Guide for more details.

Community

Mailing lists

Slack

Pulsar slack channel #dev-go at https://apache-pulsar.slack.com/

You can self-register at https://apache-pulsar.herokuapp.com/

License

Licensed under the Apache License, Version 2.0: http://www.apache.org/licenses/LICENSE-2.0

Troubleshooting

Go module 'ambiguous import' error

If you've upgraded from a previous version of this library, you may run into an 'ambiguous import' error when building.

github.com/apache/pulsar-client-go/oauth2: ambiguous import: found package github.com/apache/pulsar-client-go/oauth2 in multiple modules

The fix for this is to make sure you don't have any references in your go.mod file to the old oauth2 module path. So remove any lines similar to the following, and then run go mod tidy.

github.com/apache/pulsar-client-go/oauth2 v0.0.0-20220630195735-e95cf0633348 // indirect