Add method to RocksDB for backing up partitions

[wbarnha]

I have a specific use-case where I need to actively backup a RocksDB store. I've had success using rocksdb.BackupEngine with faust but it'd be much more usable if the code was integrated into faust.

I should note I've only had success with this using librocksdb-dev==6.11.4-3 on Ubuntu 22.04 and the python-rocksdb bindings from https://github.com/NightTsarina/python-rocksdb.

If you have interest in this, let me know because I really need this feature.

[wbarnha]

I'm satisfied with the changes I have now. If you have any other changes you'd like to see, let me know. I haven't done any testing for Aerospike, but it seems possible to backup a table from what's done in https://github.com/aerospike/aerospike-tools-backup/blob/fc348e6016cdfccc0e75a6b76621067e57d2a11c/test/integration/run_backup.py.

[wbarnha]

I forgot to test some last-minute changes earlier. I've tested everything and runs properly now.

[wbarnha]

Removed import of BackupEngine to pass lint check, should be good now...

[wbarnha]

I'm not sure where this should be added, but according to https://fauststream.slack.com/archives/C7FL9CB5E/p1594816114113200?thread_ts=1594815786.109000&cid=C7FL9CB5E, recoveries are automatically triggered when a table is accessed. After testing further, it seems that calling restore_backup is equally safe as calling it during initialization or in asynchronous tasks that startup upon app initialization. Still haven't tested periodically restoring backups while the app is initialized since I haven't needed to do that.

[wbarnha]

On further testing, it appears that the current release of https://github.com/faust-streaming/python-rocksdb is fine for accessing the backup functions in librocksdb-dev. For older versions that are released such as 5.8.8, I got errors along the lines of rocksdb.error.NotImplementedError. We may want to add a disclaimer that the backup options are only available in specific versions of librocksdb.

[codecov-commenter]

Codecov Report

Merging #304 (836751a) into master (a887571) will decrease coverage by 0.24%.
The diff coverage is 40.81%.

@@            Coverage Diff             @@
##           master     #304      +/-   ##
==========================================
- Coverage   94.66%   94.42%   -0.25%     
==========================================
  Files         100      100              
  Lines       10855    10903      +48     
  Branches     1520     1529       +9     
==========================================
+ Hits        10276    10295      +19     
- Misses        505      533      +28     
- Partials       74       75       +1     

Impacted Files	Coverage Δ
faust/stores/rocksdb.py	89.38% <36.11%> (-6.98%)	⬇️
faust/stores/aerospike.py	76.12% <50.00%> (-0.70%)	⬇️
faust/tables/objects.py	97.70% <50.00%> (-2.30%)	⬇️
faust/stores/memory.py	95.23% <60.00%> (-4.77%)	⬇️

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[wbarnha]

I'd like to squash a lot of these commits before merging... unless the maintainers have the option to automatically do that 😄