CODEWITHSUNDEEP
javaapache-camel
David
David

Reputation: 579

Apache Camel: place message back in original location after being processed

I've run into a strange obstacle using Apache Camel's file component. The gist of the problem is this: I'm using the file component to load in all messages from a directory. I then use a processor to perform some operation on the files loaded. If the process succeeds, then I move the file to a different location and delete the original file. If the process fails however, I leave the message in it's original directory. The code looks something like this:

from("fileLocation")
   .process(new MessageProcessor())
   .choice()
       .when(header("processPassed").isEqualTo(true))
          .to("file:newLocation")
   .otherwise()
       .to("fileLocation");

If the processor passes then everything works great. However, if the processor fails and I'm trying to return the message back to its original location, that doesn't work. Any idea on how to fix this?

Upvotes: 2

Views: 1127

Answers (2)

Petter Nordlander
Petter Nordlander

Reputation: 22279

Read the documentation, there is a moveFailed option that you can specify. It is a good thing to have the files placed in some error folder, and not the original location though. Then you will know where to look for bad files.

Update: Since it's a firm requirement that you need to leave the files in place, you need to setup a persistent idempotent repository.

This is mostly copied from docs, and will save the absolute file paths of the processed files into a file on disk - so that it will never process the same (filename) again.

<!-- this is our file based idempotent store configured to use the .filestore.dat as file -->
<bean id="fileStore" class="org.apache.camel.processor.idempotent.FileIdempotentRepository">
    <!-- the filename for the store -->
    <property name="fileStore" value="some/folder/.idempotentrepo/filestore.dat"/>
    <!-- the max filesize in bytes for the file.-->
    <property name="maxFileStoreSize" value="<some size>"/>
</bean>

<camelContext xmlns="http://camel.apache.org/schema/spring">
    <route>
        <from uri="file://some/folder/?idempotentRepository=#fileStore&amp;noop=true"/>
        <to uri="mock:result"/>
    </route>
</camelContext>

Upvotes: 1

Richard Miskin
Richard Miskin

Reputation: 1260

I think there are two problems affecting you. Firstly you cannot write the file back to the original location because Camel is processing it and second there is a risk that you'll repeatedly process the same file. To get around this you can use two options:

  1. preMove to use a working directory
  2. idempotent to prevent the same file be processed a second time.

Here is a slightly modified version of your code that I believe does what you require

    from("file:fileLocation?idempotent=true&preMove=working")
       .process(new MessageProcessor())
       .choice()
           .when(header("processPassed").isEqualTo(true))
              .to("file:newLocation")
       .otherwise()
           .to("file:fileLocation");

More details available in the File Endpoint documentation.

Upvotes: 2

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