DPE 1073 DPE 1080: DEBUG verbosity for deferrals and early returns

[dragomirp]

Issue

• DPE-1073
• Low log verbosity when deferring events within the charm
• DPE-1080
• Warnings in unit tests

Solution

• Add debug log messages on event deferrals and early returns
• Clear up warnings

Context

• Added log messages within the charm, didn't touch or check library code deferrals
• Added a patch to a unit test that fails if dpkg is not present on the system
• Switch to tox ini to use allowlist_externals
• Enabled SIMULATE_CAN_CONNECT for relevant tests
• Adding unit test dependency to suppress the asyncio_mode warning config

Testing

• Increased a bit the unit test coverage

Release Notes

Increased log verbosity on deferrals

[codecov]

Codecov Report

Merging #49 (199a1e6) into main (0073d8f) will increase coverage by 1.29%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main      #49      +/-   ##
==========================================
+ Coverage   64.05%   65.35%   +1.29%     
==========================================
  Files           6        6              
  Lines         818      814       -4     
  Branches      121      115       -6     
==========================================
+ Hits          524      532       +8     
+ Misses        264      258       -6     
+ Partials       30       24       -6     

Impacted Files	Coverage Δ
src/charm.py	57.43% <ø> (+1.18%)	⬆️
src/relations/db.py	69.74% <ø> (+3.08%)	⬆️
src/relations/postgresql_provider.py	88.60% <ø> (+1.26%)	⬆️
src/cluster.py	68.00% <0.00%> (+0.21%)	⬆️

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[taurus-forever]

LGTM. Nice! Tnx!

BTW, how to deal with unhappy codecov?

[dragomirp]

@taurus-forever To not fail the codecov checks we must cover the specified amount (65%) of the new code and the overall code

[taurus-forever]

@taurus-forever To not fail the codecov checks we must cover the specified amount (65%) of the new code and the overall code

It doesn't match the warnings I see in https://github.com/canonical/postgresql-operator/pull/49/checks?check_run_id=10457437969
As for me codecov explicitly blame new debug lines... Which are hard to cover with unit tests (defer cases).
I hope I am wrong. @marceloneppel any comments? Should enforce such codecov requirements?

[marceloneppel]

@taurus-forever To not fail the codecov checks we must cover the specified amount (65%) of the new code and the overall code

It doesn't match the warnings I see in https://github.com/canonical/postgresql-operator/pull/49/checks?check_run_id=10457437969 As for me codecov explicitly blame new debug lines... Which are hard to cover with unit tests (defer cases). I hope I am wrong. @marceloneppel any comments? Should enforce such codecov requirements?

I think enforcing testing debug lines is not something that brings value to the code. We probably can use something like the .coveragerc file like the one from https://github.com/canonical/opensearch-operator/blob/56b9ed036d44f69a269217087093c55db89926c8/.coveragerc to avoid some lines to be verified in the coverage checks.

I thought on something like (I haven't tested it):

[report]
exclude_lines =
    # Don't complain about missing debug-only code:
    logger\.debug

[marceloneppel]

Amazing! Thanks for all those improvements @dragomirp!