[
https://issues.apache.org/jira/browse/NIFI-190?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15182160#comment-15182160
]
Joseph Gresock commented on NIFI-190:
-------------------------------------
FYI, we ended up having to augment our existing HoldFile processor with the
distributed map cache so that we could interact with RPGs at certain points in
our flow. It works quite well, and we have a property that lets us specify a
distributed map cache client service on HoldFile - that way if it's not set,
the cache is localized. This is all coded on an enclosed network, so I can't
easily port it over here, but the concept could still apply.
> HoldFile processor
> ------------------
>
> Key: NIFI-190
> URL: https://issues.apache.org/jira/browse/NIFI-190
> Project: Apache NiFi
> Issue Type: New Feature
> Components: Extensions
> Reporter: Joseph Gresock
> Assignee: Bryan Bende
> Priority: Minor
> Attachments: HoldFile_example.xml
>
>
> Our team has developed a processor for the following use case:
> * Format A needs to be sent to Endpoint A
> * Format B needs to be sent to Endpoint B, but should not proceed until A has
> reached Endpoint A. We most commonly have this restriction when Endpoint B
> requires some output of Endpoint A.
> The proposed HoldFile processor takes 2 types of flow files as input:
> * Files to be held
> * Signal files that can release corresponding held files, based on the value
> of a configurable "release" attribute
> Signal files are distinguished from held files by the presence of the
> "flow.file.release.value" attribute. The processor is configured with a
> "Release Signal Attribute". Held files with this attribute whose value
> matches a received signal value will be released.
> An example:
> HoldFile is configured with Release Signal Attribute = "myId". Its 'Hold'
> relationship routes back onto itself.
> 1. flowFile 1 { myId : "123" } enters HoldFile. It is routed to the 'Hold'
> relationship
> 2. flowFile 2 { flow.file.release.value : "123" } enters HoldFile. flowfile
> 1 is then routed to 'Release', and flow file 2 is removed from the session.
> Signal flow files will also copy their attributes to matching held files,
> unless otherwise indicated. This is what allows the output of Endpoint A to
> pass to Endpoint B, above.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
