NIFI-3600 Improve logging and relationship routing for failures in De…

[jdye64]

…leteHDFS

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[trixpan]

@jdye64 can you please solve the conflicts?

Cheers!

[jdye64]

@trixpan I tried talking it out but that didn't seem to solve the conflict?? Will try more forceful procedures when I get off the road and near a computer ;) thanks for taking a look at this!

[trixpan]

🤣

[jdye64]

@trixpan I fixed the conflicts by refactoring some code that had changed due to NIFI-3204 #1561

[trixpan]

Glad you managed to get the lines out of their conflict... 😀 will review

[trixpan]

From a first look the code seems ok but I have a quick question:

Do we truly need a permission denied relationship? It seems like a deviation from the general nature of failure relationships (generally they are nearly all encompassing).

Perhaps we could add the failure reason to an attribute and route to failure?

Reason I ask is that I like the strong similarity between the *HDFS, the *File and *S3 processors and I suspect this change would introduce change that will move some of them appart?

[jdye64]

My reasoning for adding the extra relationship was for end users to understand that certain directories or files had improper permissions and have a visible way to see that with the extra relationship. However your right we could just add something like a "error.code" and "error.message" attributes and route to failure. I would like the "error.code" for sure however since that would be easy to route against while error.message might contain different messages from the exceptions when dependency versions change

[trixpan]

Thisbis what I had in mind. What do you think about using numeric codes borrowed from HTTP (as I suspect WebHDFS does?).

Good thing about numbers is that as long they are on the hundreds and have no fractional points they are locale agnostic. As long...

[mattyb149]

Reviewer consensus (see the Jira case for details) is to exclude the hdfs.error.code for now, rather than possibly reporting an incorrect cause of an IOException. Once we can tell the difference, we can add that attribute back in. In that state, @bbende and I are a +1

Adding a unit test, removing the attribute, and merging to master. Thanks much!