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GH-1009: Producer properties for dynamic bindings

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Resolves https://github.com/spring-cloud/spring-cloud-stream/issues/1009

Provide a callback mechanism to set properties on dynamically created bindings.

Polishing - callback name.

Resolves #1009
Resolves #1132
This commit is contained in:
Gary Russell
2017-11-10 09:54:08 -05:00
committed by Oleg Zhurakousky
parent 73f0fc38a6
commit 83fa5f3858
6 changed files with 160 additions and 28 deletions
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31
spring-cloud-stream-core-docs/src/main/asciidoc/spring-cloud-stream-overview.adoc
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@@ -1282,7 +1282,7 @@ This is useful, for example, when the target destination needs to be determined
Applications can do so by using the `BinderAwareChannelResolver` bean, registered automatically by the `@EnableBinding` annotation.
The property 'spring.cloud.stream.dynamicDestinations' can be used for restricting the dynamic destination names to a set known beforehand (whitelisting).
If the property is not set, any destination can be bound dynamicaly.
If the property is not set, any destination can be bound dynamically.
The `BinderAwareChannelResolver` can be used directly as in the following example, in which a REST controller uses a path variable to decide the target channel.
@@ -1360,6 +1360,35 @@ public class SourceWithDynamicDestination {
}
----
The https://github.com/spring-cloud-stream-app-starters/router[Router Sink Application] uses this technique to create the destinations on-demand.
If the channel names are known in advance, you can configure the producer properties as with any other destination.
Alternatively, if you register a `NewBindingCallback<>` bean, it will be invoked just before the binding is created.
The callback takes the generic type of the extended producer properties used by the binder; it has one method:
[source, java]
----
void configure(String channelName, MessageChannel channel, ProducerProperties producerProperties,
T extendedProducerProperties);
----
The following is an example using the RabbitMQ binder:
[source, xml]
----
@Bean
public NewBindingCallback<RabbitProducerProperties> dynamicConfigurer() {
return (name, channel, props, extended) -> {
props.setRequiredGroups("bindThisQueue");
extended.setQueueNameGroupOnly(true);
extended.setAutoBindDlq(true);
extended.setDeadLetterQueueName("myDLQ");
};
}
----
NOTE: If you need to support dynamic destinations with multiple binder types, use `Object` for the generic type and cast the `extended` argument as needed.
[[contenttypemanagement]]
== Content Type and Transformation