Client Libraries

Danube provides official client libraries for four languages. All clients follow the same builder pattern and support the full feature set.

Supported Languages

Rust

Async client built on Tokio.

Install

cargo add danube-client

Crate · Examples

Go

Context-based client with gRPC transport.

Install

go get github.com/danube-messaging/danube-go

pkg.go.dev · Examples

Java

Java 21+ with virtual threads and reactive Flow.Publisher API.

Gradle

implementation 'com.danube-messaging:danube-client:0.4.0'

Maven

<dependency>
    <groupId>com.danube-messaging</groupId>
    <artifactId>danube-client</artifactId>
    <version>0.4.0</version>
</dependency>

Examples

Python

Async client built on asyncio and grpc.aio.

Install

pip install danube-client

Examples

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Feature Matrix

Feature	Rust	Go	Java	Python
Producers & Consumers	✅	✅	✅	✅
Partitioned Topics	✅	✅	✅	✅
Reliable Dispatch	✅	✅	✅	✅
Exclusive Subscription	✅	✅	✅	✅
Shared Subscription	✅	✅	✅	✅
Failover Subscription	✅	✅	✅	✅
Key-Shared Subscription	✅	✅	✅	✅
JSON Schema	✅	✅	✅	✅
Avro	✅	✅	✅	✅
Protobuf	✅	✅	✅	✅
TLS / mTLS	✅	✅	✅	✅
JWT Authentication	✅	✅	✅	✅

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API Pattern

All four clients use the same builder pattern. The API surface is intentionally consistent across languages:

Rust

Pattern overview

// Client
let client = DanubeClient::builder()
    .service_url("http://127.0.0.1:6650")
    .build()
    .await?;

// Producer
let mut producer = client.new_producer()
    .with_topic("/default/my-topic")
    .with_name("my-producer")
    .build()?;

// Consumer
let mut consumer = client.new_consumer()
    .with_topic("/default/my-topic")
    .with_consumer_name("my-consumer")
    .with_subscription("my-sub")
    .with_subscription_type(SubType::Exclusive)
    .build()?;

Go

Pattern overview

// Client
client, _ := danube.NewClient().ServiceURL("127.0.0.1:6650").Build()

// Producer
producer, _ := client.NewProducer().
    WithTopic("/default/my-topic").
    WithName("my-producer").
    Build()

// Consumer
consumer, _ := client.NewConsumer().
    WithTopic("/default/my-topic").
    WithConsumerName("my-consumer").
    WithSubscription("my-sub").
    WithSubscriptionType(danube.Exclusive).
    Build()

Java

Pattern overview

// Client
DanubeClient client = DanubeClient.builder()
        .serviceUrl("http://127.0.0.1:6650")
        .build();

// Producer
Producer producer = client.newProducer()
        .withTopic("/default/my-topic")
        .withName("my-producer")
        .build();

// Consumer
Consumer consumer = client.newConsumer()
        .withTopic("/default/my-topic")
        .withConsumerName("my-consumer")
        .withSubscription("my-sub")
        .withSubscriptionType(SubType.EXCLUSIVE)
        .build();

Python

Pattern overview

# Client
client = await DanubeClientBuilder().service_url("http://127.0.0.1:6650").build()

# Producer
producer = client.new_producer() \
    .with_topic("/default/my-topic") \
    .with_name("my-producer") \
    .build()

# Consumer
consumer = client.new_consumer() \
    .with_topic("/default/my-topic") \
    .with_consumer_name("my-consumer") \
    .with_subscription("my-sub") \
    .with_subscription_type(SubType.EXCLUSIVE) \
    .build()

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Next Steps

• Setup & Connection: TLS, JWT authentication, token rotation
• Producer Guide: Sending messages, partitions, reliable dispatch
• Consumer Guide: Receiving messages, ack/nack, subscription types
• Schema Registry: Type-safe messaging with validation