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Polishing error-handling doc section

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This commit is contained in:
Oleg Zhurakousky
2018-04-02 10:44:39 -04:00
parent 819b3047d5
commit f5fb5b35a6
1 changed files with 6 additions and 2 deletions
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8
spring-cloud-stream-core-docs/src/main/asciidoc/spring-cloud-stream-overview.adoc
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@@ -675,7 +675,7 @@ the error back to the messaging system (re-queue, DLQ, and others).
There are two types of application-level error handling. Errors can be handled at each binding subscription or a global handler can handle all the binding subscription errors. Let's review the details.
.A Spring Cloud Stream Sink Application with Custom and Global Error Handlers
image::custom_vs_global_error_channels.png[width=300,scaledwidth="50%"]
image::custom_vs_global_error_channels.png[width=300,scaledwidth="75%",align="center"]
For each input binding, Spring Cloud Stream creates a dedicated error channel with the following semantics `<destinationName>.errors`.
@@ -695,7 +695,7 @@ public void handle(Person value)
throw new RuntimeException("BOOM!");
}
@StreamListener(Processor.INPUT + ".myGroup.errors") //channel name 'input.myGroup.errors'
@ServiceActivator(inputChannel = Processor.INPUT + ".myGroup.errors") //channel name 'input.myGroup.errors'
public void error(Message<?> message) {
System.out.println("Handling ERROR: " + message);
}
@@ -703,6 +703,10 @@ public void error(Message<?> message) {
In the preceeding example the destination name is `input.myGroup` and the dedicated error channel name is `input.myGroup.errors`.
NOTE: The use of @StreamListener annotation is intended specifically to define bindings that bridge internal channels and external destinations. Given that the destination
specific error channel does NOT have an associated external destination, such channel is a prerogative of Spring Integration (SI). This means that the handler
for such destination must be defined using one of the SI handler annotations (i.e., @ServiceActivator, @Transformer etc.).
NOTE: If `group` is not specified anonymous group is used (something like `input.anonymous.2K37rb06Q6m2r51-SPIDDQ`), which is not suitable for error
handling scenarious, since you don't know what it's going to be until the destination is created.