Extract common object store key builder helpers

[pcholakov]

This PR factors out the object store key construction logic into a few methods that are easier to follow and reuse.

Closes: #2389

[github-actions]

Test Results

  7 files  ±0    7 suites  ±0   4m 30s ⏱️ -9s
 47 tests ±0   46 ✅ ±0  1 💤 ±0  0 ❌ ±0 
182 runs  ±0  179 ✅ ±0  3 💤 ±0  0 ❌ ±0 

Results for commit 9d41368. ± Comparison against base commit 1ac1f70.

♻️ This comment has been updated with latest results.

[muhamadazmy]

Thank you so much @pcholakov for this PR. The changes looks good to me.
I think also it can be handy to use Path in place of String for paths. It can be very handy specially when using it with .child() method where u can chain paths naturally without the need to use format! string.

let prefix = Path::from("prefix");
let child1 = prefix.child("child1");
let deep = prefix.child("child2").child("deep");

[muhamadazmy]

I really recommend to create a wrapper type on top of String. For example struct PaddedSnapshotKey(String) or even better struct PaddedSnapshotKey{min_applied_lsn, snapshot_id} and then build string when it's needed

[pcholakov]

I like this a lot! 👍

[pcholakov]

The reason I've been avoiding Path/PathBuf even though they're a very logical fit, is to avoid dealing with OsStr conversions which add noise. The object_store::path::Path object takes a String but it doesn't have an equivalent to the join method of std::path::Path, hence all the format! string munging. Let me play around with thin a wrapper over object_store::path::Path that adds a simple join operation, and see how that turns out.

[muhamadazmy]

The join method for the object_store::path::Path is child. It acts in similar way to the std::Path::PathBuf::join

[pcholakov]

🤦‍♂️

[pcholakov]

Thank you for the suggestions @muhamadazmy, this is much better!