NIFI-5292 Renamed ElasticSearch client service impl to show it is for…

[MikeThomsen]

… 5x.

NIFI-5292 Added 6.X ES Client.

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[MikeThomsen]

Looked over the transitive dependencies and HdrHistogram (license info; appears public domain), Spatial4J (ASL v2) and SnakeYaml (ASL, unknown copyright) appear to be the only two needed to be added to the NOTICE for the v6 version.

[MikeThomsen]

@markap14 can you review?

@joewitt can you review the L&N? I took a stab at updating the v6 client's NOTICE, but am not sure if it's right.

[markap14]

Hey @MikeThomsen when we discussed the renaming on the mailing list, I was under the impression that the Elasticsearch Client Service was new for 1.7.0. But it appears that it already has been released in 1.6.0. We need to avoid changing the names of components once they have been released because doing so would break users' flows. I think we need to keep the name nifi-elasticsearch-client-service and then we can use the name nifi-elasticsearch-client-service-6, etc. for the new one. Then we'd just document the old one to indicate that it was designed to work against Elasticsearch 5.x. Sorry for the confusion! We do need to ensure that we keep existing flows stable, though, and we only want to break a flow if there's no feasible way around it.

[MikeThomsen]

@markap14 Ok, that's fair. I think the general issue has to be addressed, but the easy route is obviously blocked. So what I'm going to do to try to head this is off is:

1. Rip out the changes to the 5x client and keep the 6x version.
2. Add some metadata to the 5x client service to help provide some visual cues in the UI.
3. See if there is a way to get the protocol compatibility range from the ES client API. I've seen debug info that suggests it looks for that and enforces it, so I'm hoping there's a client API which will let us sniff that and throw an error saying you need to change client services to keep w/ ES protocol compatibility.

[MikeThomsen]

@markap14 I cleaned it up and got most of what I suggested done. Couldn't figure out a good way to detect the protocol ranges, but this should do.

[MikeThomsen]

@zenfenan can you review? It's mostly copy pasta from the ES v5 client.

[mattyb149]

@MikeThomsen Did you close this due to inactivity, or did you move the changes into a different PR, or something else?

[MikeThomsen]

I don't even remember closing it, that's the weird part.

[mattyb149]

These should all be updated to 1.11.0-SNAPSHOT, that might be what's causing the non-cached Maven build failures in Travis.

[MikeThomsen]

Going to follow @markap14 's original guidance and close this as it would constitute a breaking change. Plus, we don't technically need this since the most recent changes to this bundle merged in preliminary support for ES 7