NIFI-5155: Add host address info to bulletins

[mattyb149]

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[zenfenan]

Hi.. When I started looking into this sometime back, I came across this: https://stackoverflow.com/questions/2381316/java-inetaddress-getlocalhost-returns-127-0-0-1-how-to-get-real-ip

In some cases (mostly a Debian thing), there are high possibilities of getting 127.0.0.1 eventhough there is an actual IP associated to the machine(s).

[mattyb149]

@zenfenan Good point. The reporting tasks haven't had this information available before, is this a "no-harm-no-foul" thing, and if not, how should it be handled?

[zenfenan]

I'm not entirely sure if this poses an immediate threat, but in the future when other extensions try to use the getNodeAddress() API, it might possibly be an issue, especially on the user experience perspective i.e. chances of the user getting confused when all the bulletins print 127.0.0.1 are there, IMO.

For the workaround, this feels like a good approach: https://stackoverflow.com/a/28346117

[mcgilman]

I'm not exactly sure why the Bulletin itself has a nodeAddress field. However, I can offer that the corresponding BulletinDTO contains a nodeAddress to help differentiate between which node in the cluster is reporting the message. This is populated when the responses are merged at the cluster coordinator. In standalone mode, there is only a single instance so this field does not need to be populated. This is also how component validationErrors work.

[zenfenan]

@mcgilman Are you saying regardless of the setNodeAddress API not setting anything, the cluster coordinator takes care of populating it ?

[mcgilman]

@zenfenan Correct. The cluster coordinator handles setting the node address for the bulletins that are returned through the REST API. However, those are not the same objects that are available in the SiteToSiteBulletinReportingTask. I wasn't considering this in my previous response.

[markap14]

@mattyb149 I think this makes sense but have a couple of thoughts on the PR:

• Probably should use the value set in NiFiProperties for the http/https hostname if it is populated. This would be more consistent with the value provided to the Cluster Coordinator and also is better for multi-homed environments.
• If not available, I would do the InetAddress.getLocalHost().getHostAddress() address only once and stash away that value in a final member variable rather than performing the lookup for each Bulletin that is created.

[mattyb149]

@markap14 How would we get at the value in NiFiProperties? They're not readily available from the FlowController (nor is the FlowController interface itself IIRC). Perhaps we call a static method on BulletinFactory?

Agreed about storing away getHostAddress(), that was a hasty copy-pasty :)

[github-actions]

We're marking this PR as stale due to lack of updates in the past few months. If after another couple of weeks the stale label has not been removed this PR will be closed. This stale marker and eventual auto close does not indicate a judgement of the PR just lack of reviewer bandwidth and helps us keep the PR queue more manageable. If you would like this PR re-opened you can do so and a committer can remove the stale tag. Or you can open a new PR. Try to help review other PRs to increase PR review bandwidth which in turn helps yours.