Spring Cloud Stream RabbitMQ Binder Reference Guide

Sabby Anandan, Marius Bogoevici, Eric Bottard, Mark Fisher, Ilayaperumal Gopinathan, Gunnar Hillert, Mark Pollack, Patrick Peralta, Glenn Renfro, Thomas Risberg, Dave Syer, David Turanski, Janne Valkealahti, Benjamin Klein

1.1.0.M1

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Table of Contents

I. Reference Guide
1. Usage
2. RabbitMQ Binder Overview
3. Configuration Options
3.1. RabbitMQ Binder Properties
3.2. RabbitMQ Consumer Properties
3.3. Rabbit Producer Properties
II. Appendices
A. Building
A.1. Basic Compile and Test
A.2. Documentation
A.3. Working with the code
A.3.1. Importing into eclipse with m2eclipse
A.3.2. Importing into eclipse without m2eclipse
A.4. Sign the Contributor License Agreement
A.5. Code Conventions and Housekeeping

Part I. Reference Guide

This guide describes the RabbitMQ implementation of the Spring Cloud Stream Binder. It contains information about its design, usage and configuration options, as well as information on how the Stream Cloud Stream concepts map into RabbitMQ specific constructs.

1. Usage

For using the RabbitMQ binder, you just need to add it to your Spring Cloud Stream application, using the following Maven coordinates:

<dependency>
  <groupId>org.springframework.cloud</groupId>
  <artifactId>spring-cloud-stream-binder-rabbit</artifactId>
</dependency>

Alternatively, you can also use the Spring Cloud Stream RabbitMQ Starter.

<dependency>
  <groupId>org.springframework.cloud</groupId>
  <artifactId>spring-cloud-starter-stream-rabbit</artifactId>
</dependency>

2. RabbitMQ Binder Overview

A simplified diagram of how the RabbitMQ binder operates can be seen below.

Figure 2.1. RabbitMQ Binder

rabbit binder

The RabbitMQ Binder implementation maps each destination to a TopicExchange. For each consumer group, a Queue will be bound to that TopicExchange. Each consumer instance have a corresponding RabbitMQ Consumer instance for its group’s Queue. For partitioned producers/consumers the queues are suffixed with the partition index and use the partition index as routing key.

3. Configuration Options

This section contains settings specific to the RabbitMQ Binder and bound channels.

For general binding configuration options and properties, please refer to the Spring Cloud Stream core documentation.

3.1 RabbitMQ Binder Properties

By default, the RabbitMQ binder uses Spring Boot’s ConnectionFactory, and it therefore supports all Spring Boot configuration options for RabbitMQ. (For reference, consult the Spring Boot documentation.) RabbitMQ configuration options use the spring.rabbitmq prefix.

In addition to Spring Boot options, the RabbitMQ binder supports the following properties:

spring.cloud.stream.rabbit.binder.adminAddresses

A comma-separated list of RabbitMQ management plugin URLs. Only used when nodes contains more than one entry. Each entry in this list must have a corresponding entry in spring.rabbitmq.addresses.

Default: empty.

spring.cloud.stream.rabbit.binder.nodes

A comma-separated list of RabbitMQ node names. When more than one entry, used to locate the server address where a queue is located. Each entry in this list must have a corresponding entry in spring.rabbitmq.addresses.

Default: empty.

spring.cloud.stream.rabbit.binder.compressionLevel

Compression level for compressed bindings. See java.util.zip.Deflater.

Default: 1 (BEST_LEVEL).

3.2 RabbitMQ Consumer Properties

The following properties are available for Rabbit consumers only and must be prefixed with spring.cloud.stream.rabbit.bindings.<channelName>.consumer..

acknowledgeMode

The acknowledge mode.

Default: AUTO.

autoBindDlq

Whether to automatically declare the DLQ and bind it to the binder DLX.

Default: false.

durableSubscription

Whether subscription should be durable. Only effective if group is also set.

Default: true.

maxConcurrency
Default: 1.
prefetch

Prefetch count.

Default: 1.

prefix

A prefix to be added to the name of the destination and queues.

Default: "".

recoveryInterval

The interval between connection recovery attempts, in milliseconds.

Default: 5000.

requeueRejected

Whether delivery failures should be requeued.

Default: true.

requestHeaderPatterns

The request headers to be transported.

Default: [STANDARD_REQUEST_HEADERS,'*'].

replyHeaderPatterns

The reply headers to be transported.

Default: [STANDARD_REPLY_HEADERS,'*'].

republishToDlq
By default, messages which fail after retries are exhausted are rejected. If a dead-letter queue (DLQ) is configured, RabbitMQ will route the failed message (unchanged) to the DLQ. If set to true, the bus will republish failed messages to the DLQ with additional headers, including the exception message and stack trace from the cause of the final failure.
transacted

Whether to use transacted channels.

Default: false.

txSize

The number of deliveries between acks.

Default: 1.

3.3 Rabbit Producer Properties

The following properties are available for Rabbit producers only and must be prefixed with spring.cloud.stream.rabbit.bindings.<channelName>.producer..

autoBindDlq

Whether to automatically declare the DLQ and bind it to the binder DLX.

Default: false.

batchingEnabled

Whether to enable message batching by producers.

Default: false.

batchSize

The number of messages to buffer when batching is enabled.

Default: 100.

batchBufferLimit
Default: 10000.
batchTimeout
Default: 5000.
compress

Whether data should be compressed when sent.

Default: false.

deliveryMode

Delivery mode.

Default: PERSISTENT.

prefix

A prefix to be added to the name of the destination exchange.

Default: "".

requestHeaderPatterns

The request headers to be transported.

Default: [STANDARD_REQUEST_HEADERS,'*'].

replyHeaderPatterns

The reply headers to be transported.

Default: [STANDARD_REPLY_HEADERS,'*'].

[Note]Note

In the case of RabbitMQ, content type headers can be set by external applications. Spring Cloud Stream supports them as part of an extended internal protocol used for any type of transport (including transports, such as Kafka, that do not normally support headers).

Part II. Appendices

Appendix A. Building

A.1 Basic Compile and Test

To build the source you will need to install JDK 1.7.

The build uses the Maven wrapper so you don’t have to install a specific version of Maven. To enable the tests, you should have Kafka server 0.9 or above running before building. See below for more information on running the servers.

The main build command is

$ ./mvnw clean install

You can also add '-DskipTests' if you like, to avoid running the tests.

[Note]Note

You can also install Maven (>=3.3.3) yourself and run the mvn command in place of ./mvnw in the examples below. If you do that you also might need to add -P spring if your local Maven settings do not contain repository declarations for spring pre-release artifacts.

[Note]Note

Be aware that you might need to increase the amount of memory available to Maven by setting a MAVEN_OPTS environment variable with a value like -Xmx512m -XX:MaxPermSize=128m. We try to cover this in the .mvn configuration, so if you find you have to do it to make a build succeed, please raise a ticket to get the settings added to source control.

The projects that require middleware generally include a docker-compose.yml, so consider using Docker Compose to run the middeware servers in Docker containers.

A.2 Documentation

There is a "full" profile that will generate documentation.

A.3 Working with the code

If you don’t have an IDE preference we would recommend that you use Spring Tools Suite or Eclipse when working with the code. We use the m2eclipe eclipse plugin for maven support. Other IDEs and tools should also work without issue.

A.3.1 Importing into eclipse with m2eclipse

We recommend the m2eclipe eclipse plugin when working with eclipse. If you don’t already have m2eclipse installed it is available from the "eclipse marketplace".

Unfortunately m2e does not yet support Maven 3.3, so once the projects are imported into Eclipse you will also need to tell m2eclipse to use the .settings.xml file for the projects. If you do not do this you may see many different errors related to the POMs in the projects. Open your Eclipse preferences, expand the Maven preferences, and select User Settings. In the User Settings field click Browse and navigate to the Spring Cloud project you imported selecting the .settings.xml file in that project. Click Apply and then OK to save the preference changes.

[Note]Note

Alternatively you can copy the repository settings from .settings.xml into your own ~/.m2/settings.xml.

A.3.2 Importing into eclipse without m2eclipse

If you prefer not to use m2eclipse you can generate eclipse project metadata using the following command:

$ ./mvnw eclipse:eclipse

The generated eclipse projects can be imported by selecting import existing projects from the file menu. [[contributing] == Contributing

Spring Cloud is released under the non-restrictive Apache 2.0 license, and follows a very standard Github development process, using Github tracker for issues and merging pull requests into master. If you want to contribute even something trivial please do not hesitate, but follow the guidelines below.

A.4 Sign the Contributor License Agreement

Before we accept a non-trivial patch or pull request we will need you to sign the contributor’s agreement. Signing the contributor’s agreement does not grant anyone commit rights to the main repository, but it does mean that we can accept your contributions, and you will get an author credit if we do. Active contributors might be asked to join the core team, and given the ability to merge pull requests.

A.5 Code Conventions and Housekeeping

None of these is essential for a pull request, but they will all help. They can also be added after the original pull request but before a merge.

  • Use the Spring Framework code format conventions. If you use Eclipse you can import formatter settings using the eclipse-code-formatter.xml file from the Spring Cloud Build project. If using IntelliJ, you can use the Eclipse Code Formatter Plugin to import the same file.
  • Make sure all new .java files to have a simple Javadoc class comment with at least an @author tag identifying you, and preferably at least a paragraph on what the class is for.
  • Add the ASF license header comment to all new .java files (copy from existing files in the project)
  • Add yourself as an @author to the .java files that you modify substantially (more than cosmetic changes).
  • Add some Javadocs and, if you change the namespace, some XSD doc elements.
  • A few unit tests would help a lot as well — someone has to do it.
  • If no-one else is using your branch, please rebase it against the current master (or other target branch in the main project).
  • When writing a commit message please follow these conventions, if you are fixing an existing issue please add Fixes gh-XXXX at the end of the commit message (where XXXX is the issue number).