Feature/279 add snapshot modules

[JaymitP]

SUMMARY

Hi, thought I would implement the snapshot functionality since it was something I was looking for.
I saw in #279 that it was a module of interest as well and I am learning to create ansible modules.
I have of course included integration tests 😄
Do let me know if anything should be changed/improved.

Some caveats:

• A check mode could be added easily using listsnapshot (I could definitely do so)
• Merging both snapshot and clearsnapshot into a single module is possible by making use of a 'present/state' variable, but is messy.
• Nodetool requests for a snapshot to be created/removed, so although the command is run successfully, changes may not be made...

ISSUE TYPE

• Feature Pull Request

COMPONENT NAME

cassandra_snapshot
cassandra_clearsnapshot

[rhysmeister]

First two points...

• A check mode could be added easily using listsnapshot (I could definitely do so)
• Merging both snapshot and clearsnapshot into a single module is possible by making use of a 'present/state' variable, but is messy.

yes, definitely both of these. snapshot and clearsnapshot should be merged into a single module. It's not messy, I do a similar thing for elastic here...

https://github.com/ansible-collections/community.elastic/blob/master/plugins/modules/elastic_snapshot.py

• Nodetool requests for a snapshot to be created/removed, so although the command is run successfully, changes may not be made...

The alternative here is to request the action, and then continually poll for success, before confirming the action. That's probably a bit much. I would just assume it works, if rc == 0, and see how it goes. Perhaps make this clear in module documentation.

[JaymitP]

yes, definitely both of these. snapshot and clearsnapshot should be merged into a single module. It's not messy, I do a similar thing for elastic here...

https://github.com/ansible-collections/community.elastic/blob/master/plugins/modules/elastic_snapshot.py

Rather than messy, I mean more so confusing. Implementation wise it's fine, but it would make the module difficult to use.
snapshot can take tables, keyspace.tables and keyspaces as arguments. Whilst clearsnapshot can only take keyspaces...
Alebit it's still usable, just a tad annoying.

PS: Accidental git push, no need to approve workflow for now

[rhysmeister]

@JaymitP It's up to you what you want implement but you don't have to support everything the underlying cmds do. Perhaps instance & keyspace snapshots are enough for 99% of people? Even if not... you could push to v2 and keep things simpler for now.