By default, the RabbitMQ binder uses Spring Boot’s ConnectionFactory. Conseuqently, it supports all Spring Boot configuration options for RabbitMQ. (For reference, see 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. Only needed if you use a RabbitMQ cluster and wish to consume from the node that hosts the queue. See Queue Affinity and the LocalizedQueueConnectionFactory for more information.

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. Only needed if you use a RabbitMQ cluster and wish to consume from the node that hosts the queue. See Queue Affinity and the LocalizedQueueConnectionFactory for more information.

Default: empty.

spring.cloud.stream.rabbit.binder.compressionLevel

The compression level for compressed bindings. See java.util.zip.Deflater.

Default: 1 (BEST_LEVEL).

spring.cloud.stream.binder.connection-name-prefix

A connection name prefix used to name the connection(s) created by this binder. The name is this prefix followed by #n, where n increments each time a new connection is opened.

Default: none (Spring AMQP default).

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

However if the same set of properties needs to be applied to most bindings, to avoid repetition, Spring Cloud Stream supports setting values for all channels, in the format of spring.cloud.stream.rabbit.default.<property>=<value>.

Also, keep in mind that binding specific property will override its equivalent in the default.

acknowledgeMode

The acknowledge mode.

Default: AUTO.

anonymousGroupPrefix

When the binding has no group property, an anonymous, auto-delete queue is bound to the destination exchange. The default naming stragegy for such queues results in a queue named anonymous.<base64 representation of a UUID>. Set this property to change the prefix to something other than the default.

Default: anonymous..

autoBindDlq

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

Default: false.

bindingRoutingKey

The routing key with which to bind the queue to the exchange (if bindQueue is true). Can be multiple keys - see bindingRoutingKeyDelimiter. For partitioned destinations, -<instanceIndex> is appended to each key.

Default: #.

bindingRoutingKeyDelimiter

When this is not null, 'bindingRoutingKey' is considered to be a list of keys delimited by this value; often a comma is used.

Default: null.

bindQueue

Whether to declare the queue and bind it to the destination exchange. Set it to false if you have set up your own infrastructure and have previously created and bound the queue.

Default: true.

consumerTagPrefix

Used to create the consumer tag(s); will be appended by #n where n increments for each consumer created. Example: ${spring.application.name}-${spring.cloud.stream.bindings.input.group}-${spring.cloud.stream.instance-index}.

Default: none - the broker will generate random consumer tags.

containerType

Select the type of listener container to be used. See Choosing a Container in the Spring AMQP documentation for more information.

Default: simple

deadLetterQueueName

The name of the DLQ

Default: prefix+destination.dlq

deadLetterExchange

A DLX to assign to the queue. Relevant only if autoBindDlq is true.

Default: 'prefix+DLX'

deadLetterExchangeType

The type of the DLX to assign to the queue. Relevant only if autoBindDlq is true.

Default: 'direct'

deadLetterRoutingKey

A dead letter routing key to assign to the queue. Relevant only if autoBindDlq is true.

Default: destination

declareDlx

Whether to declare the dead letter exchange for the destination. Relevant only if autoBindDlq is true. Set to false if you have a pre-configured DLX.

Default: true.

declareExchange

Whether to declare the exchange for the destination.

Default: true.

delayedExchange

Whether to declare the exchange as a Delayed Message Exchange. Requires the delayed message exchange plugin on the broker. The x-delayed-type argument is set to the exchangeType.

Default: false.

dlqBindingArguments

Arguments applied when binding the dlq to the dead letter exchange; used with headers deadLetterExchangeType to specify headers to match on. For example …​dlqBindingArguments.x-match=any, …​dlqBindingArguments.someHeader=someValue.

Default: empty

dlqDeadLetterExchange

If a DLQ is declared, a DLX to assign to that queue.

Default: none

dlqDeadLetterRoutingKey

If a DLQ is declared, a dead letter routing key to assign to that queue.

Default: none

dlqExpires

How long before an unused dead letter queue is deleted (in milliseconds).

Default: no expiration

dlqLazy

Declare the dead letter queue with the x-queue-mode=lazy argument. See “Lazy Queues”. Consider using a policy instead of this setting, because using a policy allows changing the setting without deleting the queue.

Default: false.

dlqMaxLength

Maximum number of messages in the dead letter queue.

Default: no limit

dlqMaxLengthBytes

Maximum number of total bytes in the dead letter queue from all messages.

Default: no limit

dlqMaxPriority

Maximum priority of messages in the dead letter queue (0-255).

Default: none

dlqOverflowBehavior

Action to take when dlqMaxLength or dlqMaxLengthBytes is exceeded; currently drop-head or reject-publish but refer to the RabbitMQ documentation.

Default: none

dlqQuorum.deliveryLimit

When quorum.enabled=true, set a delivery limit after which the message is dropped or dead-lettered.

Default: none - broker default will apply.

dlqQuorum.enabled

When true, create a quorum dead letter queue instead of a classic queue.

Default: false

dlqQuorum.initialQuorumSize

When quorum.enabled=true, set the initial quorum size.

Default: none - broker default will apply.

dlqSingleActiveConsumer

Set to true to set the x-single-active-consumer queue property to true.

Default: false

dlqTtl

Default time to live to apply to the dead letter queue when declared (in milliseconds).

Default: no limit

durableSubscription

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

Default: true.

exchangeAutoDelete

If declareExchange is true, whether the exchange should be auto-deleted (that is, removed after the last queue is removed).

Default: true.

exchangeDurable

If declareExchange is true, whether the exchange should be durable (that is, it survives broker restart).

Default: true.

exchangeType

The exchange type: direct, fanout, headers or topic for non-partitioned destinations and direct, headers or topic for partitioned destinations.

Default: topic.

exclusive

Whether to create an exclusive consumer. Concurrency should be 1 when this is true. Often used when strict ordering is required but enabling a hot standby instance to take over after a failure. See recoveryInterval, which controls how often a standby instance attempts to consume. Consider using singleActiveConsumer instead when using RabbitMQ 3.8 or later.

Default: false.

expires

How long before an unused queue is deleted (in milliseconds).

Default: no expiration

failedDeclarationRetryInterval

The interval (in milliseconds) between attempts to consume from a queue if it is missing.

Default: 5000

frameMaxHeadroom

The number of bytes to reserve for other headers when adding the stack trace to a DLQ message header. All headers must fit within the frame_max size configured on the broker. Stack traces can be large; if the size plus this property exceeds frame_max then the stack trace will be truncated. A WARN log will be written; consider increasing the frame_max or reducing the stack trace by catching the exception and throwing one with a smaller stack trace.

Default: 20000

headerPatterns

Patterns for headers to be mapped from inbound messages.

Default: ['*'] (all headers).

lazy

Declare the queue with the x-queue-mode=lazy argument. See “Lazy Queues”. Consider using a policy instead of this setting, because using a policy allows changing the setting without deleting the queue.

Default: false.

maxConcurrency

The maximum number of consumers. Not supported when the containerType is direct.

Default: 1.

maxLength

The maximum number of messages in the queue.

Default: no limit

maxLengthBytes

The maximum number of total bytes in the queue from all messages.

Default: no limit

maxPriority

The maximum priority of messages in the queue (0-255).

Default: none

missingQueuesFatal

When the queue cannot be found, whether to treat the condition as fatal and stop the listener container. Defaults to false so that the container keeps trying to consume from the queue — for example, when using a cluster and the node hosting a non-HA queue is down.

Default: false

overflowBehavior

Action to take when maxLength or maxLengthBytes is exceeded; currently drop-head or reject-publish but refer to the RabbitMQ documentation.

Default: none

prefetch

Prefetch count.

Default: 1.

prefix

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

Default: "".

queueBindingArguments

Arguments applied when binding the queue to the exchange; used with headers exchangeType to specify headers to match on. For example …​queueBindingArguments.x-match=any, …​queueBindingArguments.someHeader=someValue.

Default: empty

queueDeclarationRetries

The number of times to retry consuming from a queue if it is missing. Relevant only when missingQueuesFatal is true. Otherwise, the container keeps retrying indefinitely. Not supported when the containerType is direct.

Default: 3

queueNameGroupOnly

When true, consume from a queue with a name equal to the group. Otherwise the queue name is destination.group. This is useful, for example, when using Spring Cloud Stream to consume from an existing RabbitMQ queue.

Default: false.

quorum.deliveryLimit

When quorum.enabled=true, set a delivery limit after which the message is dropped or dead-lettered.

Default: none - broker default will apply.

quorum.enabled

When true, create a quorum queue instead of a classic queue.

Default: false

quorum.initialQuorumSize

When quorum.enabled=true, set the initial quorum size.

Default: none - broker default will apply.

recoveryInterval

The interval between connection recovery attempts, in milliseconds.

Default: 5000.

requeueRejected

Whether delivery failures should be re-queued when retry is disabled or republishToDlq is false.

Default: false.

republishDeliveryMode

When republishToDlq is true, specifies the delivery mode of the republished message.

Default: DeliveryMode.PERSISTENT

republishToDlq

By default, messages that fail after retries are exhausted are rejected. If a dead-letter queue (DLQ) is configured, RabbitMQ routes the failed message (unchanged) to the DLQ. If set to true, the binder republishs failed messages to the DLQ with additional headers, including the exception message and stack trace from the cause of the final failure. Also see the frameMaxHeadroom property.

Default: true

singleActiveConsumer

Set to true to set the x-single-active-consumer queue property to true.

Default: false

transacted

Whether to use transacted channels.

Default: false.

ttl

Default time to live to apply to the queue when declared (in milliseconds).

Default: no limit

txSize

The number of deliveries between acks. Not supported when the containerType is direct.

Default: 1.

To set listener container properties that are not exposed as binder or binding properties, add a single bean of type ListenerContainerCustomizer to the application context. The binder and binding properties will be set and then the customizer will be called. The customizer (configure() method) is provided with the queue name as well as the consumer group as arguments.

From time to time, the RabbitMQ team add new features that are enabled by setting some argument when declaring, for example, a queue. Generally, such features are enabled in the binder by adding appropriate properties, but this may not be immediately available in a current version. Starting with version 3.0.1, you can now add DeclarableCustomizer bean(s) to the application context to modify a Declarable (Queue, Exchange or Binding) just before the declaration is performed. This allows you to add arguments that are not currently directly supported by the binder.

With the RabbitMQ binder, there are two types of batches handled by consumer bindings:

Batches Created by Producers

Consumer-side Batching

spring.cloud.stream.bindings.input-in-0.group=someGroup

spring.cloud.stream.bindings.input-in-0.consumer.batch-mode=true

spring.cloud.stream.rabbit.bindings.input-in-0.consumer.enable-batching=true
spring.cloud.stream.rabbit.bindings.input-in-0.consumer.batch-size=10
spring.cloud.stream.rabbit.bindings.input-in-0.consumer.receive-timeout=200

@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @Bean
    Consumer<List<Thing>> input() {
        return list -> {
            System.out.println("Received " + list.size());
            list.forEach(thing -> {
                System.out.println(thing);

                // ...

            });
        };
    }

    @Bean
    public ApplicationRunner runner(RabbitTemplate template) {
        return args -> {
            template.convertAndSend("input-in-0.someGroup", "{\"field\":\"value1\"}");
            template.convertAndSend("input-in-0.someGroup", "{\"field\":\"value2\"}");
        };
    }

    public static class Thing {

        private String field;

        public Thing() {
        }

        public Thing(String field) {
            this.field = field;
        }

        public String getField() {
            return this.field;
        }

        public void setField(String field) {
            this.field = field;
        }

        @Override
        public String toString() {
            return "Thing [field=" + this.field + "]";
        }

    }

}

Received 2
Thing [field=value1]
Thing [field=value2]

@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @Bean
    Consumer<Message<List<Thing>>> input() {
        return msg -> {
            List<Thing> things = msg.getPayload();
            System.out.println("Received " + things.size());
            @SuppressWarnings("unchecked")
            List<Map<String, Object>> headers =
                    (List<Map<String, Object>>) msg.getHeaders().get(AmqpInboundChannelAdapter.CONSOLIDATED_HEADERS);
            for (int i = 0; i < things.size(); i++) {
                System.out.println(things.get(i) + " myHeader=" + headers.get(i).get("myHeader"));

                // ...

            }
        };
    }

    @Bean
    public ApplicationRunner runner(RabbitTemplate template) {
        return args -> {
            template.convertAndSend("input-in-0.someGroup", "{\"field\":\"value1\"}", msg -> {
                msg.getMessageProperties().setHeader("myHeader", "headerValue1");
                return msg;
            });
            template.convertAndSend("input-in-0.someGroup", "{\"field\":\"value2\"}", msg -> {
                msg.getMessageProperties().setHeader("myHeader", "headerValue2");
                return msg;
            });
        };
    }

    public static class Thing {

        private String field;

        public Thing() {
        }

        public Thing(String field) {
            this.field = field;
        }

        public String getfield() {
            return this.field;
        }

        public void setfield(String field) {
            this.field = field;
        }

        @Override
        public String toString() {
            return "Thing [field=" + this.field + "]";
        }

    }

}

Received 2
Thing [field=value1] myHeader=headerValue1
Thing [field=value2] myHeader=headerValue2

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

However if the same set of properties needs to be applied to most bindings, to avoid repetition, Spring Cloud Stream supports setting values for all channels, in the format of spring.cloud.stream.rabbit.default.<property>=<value>.

Also, keep in mind that binding specific property will override its equivalent in the default.

autoBindDlq

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

Default: false.

batchingEnabled

Whether to enable message batching by producers. Messages are batched into one message according to the following properties (described in the next three entries in this list): 'batchSize', batchBufferLimit, and batchTimeout. See Batching for more information. Also see Receiving Batched Messages.

Default: false.

batchSize

The number of messages to buffer when batching is enabled.

Default: 100.

batchBufferLimit

The maximum buffer size when batching is enabled.

Default: 10000.

batchTimeout

The batch timeout when batching is enabled.

Default: 5000.

bindingRoutingKey

The routing key with which to bind the queue to the exchange (if bindQueue is true). Can be multiple keys - see bindingRoutingKeyDelimiter. For partitioned destinations, -n is appended to each key. Only applies if requiredGroups are provided and then only to those groups.

Default: #.

bindingRoutingKeyDelimiter

When this is not null, 'bindingRoutingKey' is considered to be a list of keys delimited by this value; often a comma is used. Only applies if requiredGroups are provided and then only to those groups.

Default: null.

bindQueue

Whether to declare the queue and bind it to the destination exchange. Set it to false if you have set up your own infrastructure and have previously created and bound the queue. Only applies if requiredGroups are provided and then only to those groups.

Default: true.

compress

Whether data should be compressed when sent.

Default: false.

confirmAckChannel

When errorChannelEnabled is true, a channel to which to send positive delivery acknowledgments (aka publisher confirms). If the channel does not exist, a DirectChannel is registered with this name. The connection factory must be configured to enable publisher confirms. Mutually exclusive with useConfirmHeader.

Default: nullChannel (acks are discarded).

deadLetterQueueName

The name of the DLQ Only applies if requiredGroups are provided and then only to those groups.

Default: prefix+destination.dlq

deadLetterExchange

A DLX to assign to the queue. Relevant only when autoBindDlq is true. Applies only when requiredGroups are provided and then only to those groups.

Default: 'prefix+DLX'

deadLetterExchangeType

The type of the DLX to assign to the queue. Relevant only if autoBindDlq is true. Applies only when requiredGroups are provided and then only to those groups.

Default: 'direct'

deadLetterRoutingKey

A dead letter routing key to assign to the queue. Relevant only when autoBindDlq is true. Applies only when requiredGroups are provided and then only to those groups.

Default: destination

declareDlx

Whether to declare the dead letter exchange for the destination. Relevant only if autoBindDlq is true. Set to false if you have a pre-configured DLX. Applies only when requiredGroups are provided and then only to those groups.

Default: true.

declareExchange

Whether to declare the exchange for the destination.

Default: true.

delayExpression

A SpEL expression to evaluate the delay to apply to the message (x-delay header). It has no effect if the exchange is not a delayed message exchange.

Default: No x-delay header is set.

delayedExchange

Whether to declare the exchange as a Delayed Message Exchange. Requires the delayed message exchange plugin on the broker. The x-delayed-type argument is set to the exchangeType.

Default: false.

deliveryMode

The delivery mode.

Default: PERSISTENT.

dlqBindingArguments

Arguments applied when binding the dlq to the dead letter exchange; used with headers deadLetterExchangeType to specify headers to match on. For example …​dlqBindingArguments.x-match=any, …​dlqBindingArguments.someHeader=someValue. Applies only when requiredGroups are provided and then only to those groups.

Default: empty

dlqDeadLetterExchange

When a DLQ is declared, a DLX to assign to that queue. Applies only if requiredGroups are provided and then only to those groups.

Default: none

dlqDeadLetterRoutingKey

When a DLQ is declared, a dead letter routing key to assign to that queue. Applies only when requiredGroups are provided and then only to those groups.

Default: none

dlqExpires

How long (in milliseconds) before an unused dead letter queue is deleted. Applies only when requiredGroups are provided and then only to those groups.

Default: no expiration

dlqLazy

Declare the dead letter queue with the x-queue-mode=lazy argument. See “Lazy Queues”. Consider using a policy instead of this setting, because using a policy allows changing the setting without deleting the queue. Applies only when requiredGroups are provided and then only to those groups.

dlqMaxLength

Maximum number of messages in the dead letter queue. Applies only if requiredGroups are provided and then only to those groups.

Default: no limit

dlqMaxLengthBytes

Maximum number of total bytes in the dead letter queue from all messages. Applies only when requiredGroups are provided and then only to those groups.

Default: no limit

dlqMaxPriority

Maximum priority of messages in the dead letter queue (0-255) Applies only when requiredGroups are provided and then only to those groups.

Default: none

dlqQuorum.deliveryLimit

When quorum.enabled=true, set a delivery limit after which the message is dropped or dead-lettered. Applies only when requiredGroups are provided and then only to those groups.

Default: none - broker default will apply.

dlqQuorum.enabled

When true, create a quorum dead letter queue instead of a classic queue. Applies only when requiredGroups are provided and then only to those groups.

Default: false

dlqQuorum.initialQuorumSize

When quorum.enabled=true, set the initial quorum size. Applies only when requiredGroups are provided and then only to those groups.

Default: none - broker default will apply.

dlqSingleActiveConsumer

Set to true to set the x-single-active-consumer queue property to true. Applies only when requiredGroups are provided and then only to those groups.

Default: false

dlqTtl

Default time (in milliseconds) to live to apply to the dead letter queue when declared. Applies only when requiredGroups are provided and then only to those groups.

Default: no limit

exchangeAutoDelete

If declareExchange is true, whether the exchange should be auto-delete (it is removed after the last queue is removed).

Default: true.

exchangeDurable

If declareExchange is true, whether the exchange should be durable (survives broker restart).

Default: true.

exchangeType

The exchange type: direct, fanout, headers or topic for non-partitioned destinations and direct, headers or topic for partitioned destinations.

Default: topic.

expires

How long (in milliseconds) before an unused queue is deleted. Applies only when requiredGroups are provided and then only to those groups.

Default: no expiration

headerPatterns

Patterns for headers to be mapped to outbound messages.

Default: ['*'] (all headers).

lazy

Declare the queue with the x-queue-mode=lazy argument. See “Lazy Queues”. Consider using a policy instead of this setting, because using a policy allows changing the setting without deleting the queue. Applies only when requiredGroups are provided and then only to those groups.

Default: false.

maxLength

Maximum number of messages in the queue. Applies only when requiredGroups are provided and then only to those groups.

Default: no limit

maxLengthBytes

Maximum number of total bytes in the queue from all messages. Only applies if requiredGroups are provided and then only to those groups.

Default: no limit

maxPriority

Maximum priority of messages in the queue (0-255). Only applies if requiredGroups are provided and then only to those groups.

Default: none

prefix

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

Default: "".

queueBindingArguments

Arguments applied when binding the queue to the exchange; used with headers exchangeType to specify headers to match on. For example …​queueBindingArguments.x-match=any, …​queueBindingArguments.someHeader=someValue. Applies only when requiredGroups are provided and then only to those groups.

Default: empty

queueNameGroupOnly

When true, consume from a queue with a name equal to the group. Otherwise the queue name is destination.group. This is useful, for example, when using Spring Cloud Stream to consume from an existing RabbitMQ queue. Applies only when requiredGroups are provided and then only to those groups.

Default: false.

quorum.deliveryLimit

When quorum.enabled=true, set a delivery limit after which the message is dropped or dead-lettered. Applies only when requiredGroups are provided and then only to those groups.

Default: none - broker default will apply.

quorum.enabled

When true, create a quorum queue instead of a classic queue. Applies only when requiredGroups are provided and then only to those groups.

Default: false

quorum.initialQuorumSize

When quorum.enabled=true, set the initial quorum size. Applies only when requiredGroups are provided and then only to those groups.

Default: none - broker default will apply.

routingKeyExpression

A SpEL expression to determine the routing key to use when publishing messages. For a fixed routing key, use routingKey.

Default: destination or destination-<partition> for partitioned destinations.

routingKey

A string defining a fixed routing key to use when publishing messages.

Default: see routingKeyExpression

singleActiveConsumer

Set to true to set the x-single-active-consumer queue property to true. Applies only when requiredGroups are provided and then only to those groups.

Default: false

transacted

Whether to use transacted channels.

Default: false.

ttl

Default time (in milliseconds) to live to apply to the queue when declared. Applies only when requiredGroups are provided and then only to those groups.

Default: no limit

useConfirmHeader

See Publisher Confirms. Mutually exclusive with confirmAckChannel.

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 (prior to 0.11), that do not natively support headers.

There are two mechanisms to get the result of publishing a message; in each case, the connection factory must have publisherConfirmType set ConfirmType.CORRELATED. The "legacy" mechanism is to set the confirmAckChannel to the bean name of a message channel from which you can retrieve the confirmations asynchronously; negative acks are sent to the error channel (if enabled) - see Error Channels.

The preferred mechanism, added in version 3.1 is to use a correlation data header and wait for the result via its Future<Confirm> property. This is particularly useful with a batch listener because you can send multiple messages before waiting for the result. To use this technique, set the useConfirmHeader property to true The following simple application is an example of using this technique:

As you can see, we send each message and then await for the publication results. If the messages can’t be routed, then correlation data is populated with the returned message before the future is completed.

You cannot set both useConfirmHeader and confirmAckChannel but you can still receive returned messages in the error channel when useConfirmHeader is true, but using the correlation header is more convenient.

The following configuration creates an exchange myDestination with queue myDestination.consumerGroup bound to a topic exchange with a wildcard routing key #:

This configuration creates a DLQ bound to a direct exchange (DLX) with a routing key of myDestination.consumerGroup. When messages are rejected, they are routed to the DLQ. After 5 seconds, the message expires and is routed to the original queue by using the queue name as the routing key, as shown in the following example:

Notice that the count property in the x-death header is a Long.

Pre-requisites:

• To compile, JDK 1.8 installed.

• To run tests, RabbitMQ server running on localhost:5672

The build uses the Maven wrapper so you don’t have to install a specific version of Maven. The main build command is

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

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

./mvnw clean package -Pdocs -DskipTests

The reference documentation can then be found in docs/target/contents/reference.

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.

Importing into eclipse with m2eclipse

Importing into eclipse without m2eclipse

$ ./mvnw eclipse:eclipse

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.

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).