Spring Integration迁移问题

Question

I have this kind of chains at different places in my application:

<int:chain input-channel="updateAdministratorChannel">
    <int:filter expression="payload.isAdministatorPublished"/>
    <int:service-activator expression="..."/>
    <int:gateway request-channel="mergeEntityChannel"/>
    <int:logging-channel-adapter logger-name="..." expression="'...'"/>
</int:chain>

Everything was working fine with Spring Integration version 3.0.1.RELEASE. We decided to migrate to version 4.2.x and we have an issue with the filter : when the condition is false the system hangs (until it timeout i suppose). In the end i had to add a discard channel and modify my chains like so:

<int:chain input-channel="updateAdministratorChannel">
    <int:filter expression="payload.isAdministatorPublished" discard-channel="defaultDiscardChannel"/>
    <int:service-activator expression="..."/>
    <int:gateway request-channel="mergeEntityChannel"/>
    <int:logging-channel-adapter logger-name="..." expression="'...'"/>
</int:chain>

<int:header-value-router input-channel="defaultDiscardChannel" header-name="replyChannel"/>

I've read the Migration Guides but i don't see anything about that. Did i miss something ?

Spring version : 4.2.5.RELEASE
Spring Integration version : 4.2.6.RELEASE

Answer 1

Your concern isn't clear because the behavior is expected: when filter is used by default, a discarded message is just dropped.

Not sure what behavior you are expecting or what you are claiming is working in version 3.0.x , but what I guess by your config that you have a messaging gateway in the beginning you expect some reply from your <chain> . Of course this is not possible when you do nothing on the filter level.

What you do with the discard-channel is the correct solution.

Another option would be possible with the throw-exception-on-rejection="true" and an error-channel on the <gateway> to catch those discarded messages there and resend as a reply.

Note: Spring Integration 4.2 is out of support already. It is recommended to upgrade at least to the 4.3.x if can't to 5.0.x : https://spring.io/projects/spring-integration#learn