Fix TLS flag

[marceloneppel]

Issue

• Jira issue: DPE-820
• A TLS flag was not set when the charm was not ready but is already related to the TLS certificates operator. This commonly happens when the charm is deployed in a bundle together with the TLS certificates operator.
• Also, another problem happened and was related to the charm sending a certificate signing request (CSR) with it's IP address as a DNS name instead of an IP address.

Solution

• Update the code to correctly set the TLS flag when the workload hasn't started yet, but already has a relation with the TLS certificates operator.

Context

• You can FOCUS on the following files when reviewing:

  • src/charm.py: has the change in the restart logic (to match the k8s charm) and also adds the missing change of the TLS flag (that is used internally by the charm to call the Patroni REST API using either HTTP or HTTPS).

  • tests/integration/test_tls.py: has the updates that Will made to improve the test (simulating what we have on a bundle deployment: no wait_for_idle).

• Other files and what has changed on them:

  • .github/workflows/ci.yaml: pinned the Juju Python library version due to https://bugs.launchpad.net/juju/+bug/1992833.

  • lib/charms/postgresql_k8s/v0/postgresql_tls.py: imported from the k8s charm (it contains the fix for the IP address issue) - it should be ignored in this PR and reviewed on Fix SANs list postgresql-k8s-operator#58 (every change there will be copied to this PR).

  • lib/charms/tls_certificates_interface/v1/tls_certificates.py: this is a patched version of the library that is used to solve the IP address issue. It was copied from https://github.com/canonical/opensearch-operator/blob/main/lib/charms/tls_certificates_interface/v1/tls_certificates.py (that patch will be pushed to the right repo in some weeks). Thanks @Mehdi-Bendriss!

Testing

• The integration test was improved and two new units tests were added.

Release Notes

• Fix TLS flag value change when the workload hasn't started yet.
• Fix IP address on certificate signing request.

Thanks @WRFitch for starting this fixes.

[codecov]

Codecov Report

Merging #44 (1bacda9) into main (4994516) will increase coverage by 1.60%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #44      +/-   ##
==========================================
+ Coverage   62.45%   64.05%   +1.60%     
==========================================
  Files           6        6              
  Lines         815      818       +3     
  Branches      122      121       -1     
==========================================
+ Hits          509      524      +15     
+ Misses        276      264      -12     
  Partials       30       30              

Impacted Files	Coverage Δ
src/charm.py	56.25% <100.00%> (+2.99%)	⬆️

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[Mehdi-Bendriss]

Very good work, Marcelo!

[MiaAltieri]

Looks great 2 minor comments

[marceloneppel]

Thanks for the reviews, @Mehdi-Bendriss and @MiaAltieri!