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https://issues.apache.org/jira/browse/NIFI-5287?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16509558#comment-16509558
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ASF GitHub Bot commented on NIFI-5287:
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Github user ottobackwards commented on the issue:
https://github.com/apache/nifi/pull/2777
It may be overkill, that is true. But if you have to keep adding new
functions to account for different scenarios that isn't great either and may
suggest something like that would be good to have. Having a context or resolver
for this type of thing isn't that radical. Having a context sets the interface,
that is true, but the implementation can be any kind of
policy/strategy/composition you may require.
That being said, just a thought anyways.
> LookupRecord should supply flowfile attributes to the lookup service
> --------------------------------------------------------------------
>
> Key: NIFI-5287
> URL: https://issues.apache.org/jira/browse/NIFI-5287
> Project: Apache NiFi
> Issue Type: Improvement
> Reporter: Mike Thomsen
> Assignee: Mike Thomsen
> Priority: Major
>
> -LookupRecord should supply the flowfile attributes to the lookup service. It
> should be done as follows:-
> # -Provide a regular expression to choose which attributes are used.-
> # -The chosen attributes should be foundation of the coordinates map used
> for the lookup.-
> # -If a configured key collides with a flowfile attribute, it should
> override the flowfile attribute in the coordinate map.-
> Mark had the right idea:
>
> I would propose an alternative approach, which would be to add a new method
> to the interface that has a default implementation:
> {{default Optional<T> lookup(Map<String, Object> coordinates, Map<String,
> String> context) throws LookupFailureException \{ return lookup(coordinates);
> } }}
> Where {{context}} is used for the FlowFile attributes (I'm referring to it as
> {{context}} instead of {{attributes}} because there may well be a case where
> we want to provide some other value that is not specifically a FlowFile
> attribute). Here is why I am suggesting this:
> * It provides a clean interface that properly separates the data's
> coordinates from FlowFile attributes.
> * It prevents any collisions between FlowFile attribute names and
> coordinates.
> * It maintains backward compatibility, and we know that it won't change the
> behavior of existing services or processors/components using those services -
> even those that may have been implemented by others outside of the Apache
> realm.
> * If attributes are passed in by a Processor, those attributes will be
> ignored anyway unless the Controller Service is specifically updated to make
> use of those attributes, such as via Expression Language. In such a case, the
> Controller Service can simply be updated at that time to make use of the new
> method instead of the existing method.
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