NIFI-13868: add pg-delete command to Nifi Toolkit

[grishick]

Summary

NIFI-13868

Adding pg-delete command to Nifi Toolkit. The command works the same way as deleting a process group via UI. If there are messages in PG queue, deletion will fail. I ported this change from Anetac's Nifi fork where I made it a while ago. We have been using this feature in production at Anetac for months now.

PR with the same feature for main branch: #9388
The change for support/nifi-1.x branch is larger than for main, because the support branch does not have changes for NIFI-12898

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[exceptionfactory]

Thanks for the contribution @grishick. The general implementation looks good, just one functional note on returning the deleted entity instead of void.

Also, please submit new features to the main branch first. Once that is approved and merged, then submitting a separate pull request for the support branch would be helpful if it is desirable to have this functionality on the support branch.

[grishick]

Thanks for the contribution @grishick. The general implementation looks good, just one functional note on returning the deleted entity instead of void.

Also, please submit new features to the main branch first. Once that is approved and merged, then submitting a separate pull request for the support branch would be helpful if it is desirable to have this functionality on the support branch.

Got it. Here is the PR for main branch: #9388

[pvillard31]

Thanks for the improvement. I'd recommend adding more details in the helper text for this command. For this command to be successful, three actions would need to be taken before:

• stop the processors in the process group (pg-stop)
• disable the controller services in the process group (pg-disable-services)
• empty all queues in the process group (we don't have a CLI command for that now, would certainly be a nice addition)

I didn't test the current PR but would be good to confirm that everything works fine especially when having nested process groups with controller services at multiple levels, etc.

[grishick]

Sounds good. I'll try to make the changes asap.