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# Apache Pulsar Go Client Library

A Go client library for [Apache Pulsar](https://pulsar.apache.org/). For the supported Pulsar features, see [Client Feature Matrix](https://pulsar.apache.org/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 1.24+

## 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:

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

Create a Producer:

```go
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:

```go
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:

```go
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 GO_VERSION=1.24 PULSAR_VERSION=4.0.3

## Contributing

Contributions are welcomed and greatly appreciated. See [CONTRIBUTING.md](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](https://pulsar.apache.org/docs/client-libraries/) and the [Client Feature Matrix](https://pulsar.apache.org/client-feature-matrix/). See [Contribution Guide](https://pulsar.apache.org/contribute/site-intro/#pages) for more details.

## Community

##### Mailing lists

| Name                                                      | Scope                           |                                                       |                                                           |                                                                    |
| :-------------------------------------------------------- | :------------------------------ | :---------------------------------------------------- | :-------------------------------------------------------- | :----------------------------------------------------------------- |
| [users@pulsar.apache.org](mailto:users@pulsar.apache.org) | User-related discussions        | [Subscribe](mailto:users-subscribe@pulsar.apache.org) | [Unsubscribe](mailto:users-unsubscribe@pulsar.apache.org) | [Archives](http://mail-archives.apache.org/mod_mbox/pulsar-users/) |
| [dev@pulsar.apache.org](mailto:dev@pulsar.apache.org)     | Development-related discussions | [Subscribe](mailto:dev-subscribe@pulsar.apache.org)   | [Unsubscribe](mailto:dev-unsubscribe@pulsar.apache.org)   | [Archives](http://mail-archives.apache.org/mod_mbox/pulsar-dev/)   |

##### 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
```
