Smtp integration

[alithethird]

Overview

Add SMTP integration to 12 Factor apps.

Rationale

User story:
As a user, I need to email my clients for application notifications. I would need SMTP credentials to add email integration to my app so that I can send emails to my clients using the credentials.

Juju Events Changes

Observe smtp_data_available event.

Module Changes

Add 3 new classes to store SMTP credentials.

• SmtpParameters
• AuthType
• TransportSecurity

These classes are copied from smtp library to store smtp credentials correctly.

Add new attribute smtp_parameters to IntegrationsState class to store a SmtpParameters instance.

Add new function _init_smtp in PaasCharm class to handle smtp integration initialization.

Add a couple of unit tests for all frameworks.

Checklist

• The charm style guide was applied
• The contributing guide was applied
• The changes are compliant with ISD054 - Managing Charm Complexity
• The documentation is generated using src-docs
• The documentation for charmhub is updated
• The PR is tagged with appropriate label (urgent, trivial, complex)
• The changelog has been updated

[javierdelapuente]

I do not understand what we are doing in here?

[alithethird]

If we don't do this we have to check for it when generating environment variables from it. I think handling this in here is the cleanest way so we don't have to import this class into other places in the code.

[alithethird]

If we don't turn it into None, we either create a env variable with the value none or we check the auth_type to see if its not none then create the enb variable

[alithethird]

Had discussion with Greg about this. This is more like a property so I will make this a property and set it None when auth_type is string none

[github-actions]

Test results for commit acc491c

Test coverage for acc491c

Name                                          Stmts   Miss Branch BrPart  Cover   Missing
-----------------------------------------------------------------------------------------
src/paas_app_charmer/__init__.py                  2      0      0      0   100%
src/paas_app_charmer/django/__init__.py           2      0      0      0   100%
src/paas_app_charmer/django/charm.py              2      0      0      0   100%
src/paas_app_charmer/fastapi/__init__.py          2      0      0      0   100%
src/paas_app_charmer/fastapi/charm.py             2      0      0      0   100%
src/paas_app_charmer/flask/__init__.py            2      0      0      0   100%
src/paas_app_charmer/flask/charm.py               2      0      0      0   100%
src/paas_app_charmer/go/__init__.py               2      0      0      0   100%
src/paas_app_charmer/go/charm.py                  2      0      0      0   100%
src/paas_charm/__init__.py                       32     17      0      0    47%   13-14, 19-20, 26-27, 33-37, 43-44, 50-51, 57-58
src/paas_charm/_gunicorn/__init__.py              0      0      0      0   100%
src/paas_charm/_gunicorn/charm.py                42      0      6      0   100%
src/paas_charm/_gunicorn/webserver.py            90      4     16      1    95%   209, 221-227
src/paas_charm/_gunicorn/workload_config.py       8      0      0      0   100%
src/paas_charm/_gunicorn/wsgi_app.py             21      0      2      0   100%
src/paas_charm/app.py                           175      0     64      4    98%   115->exit, 172->178, 282->284, 284->287
src/paas_charm/charm.py                         309     40     64      5    87%   35-36, 43-44, 51-52, 60-61, 176-177, 199-200, 220-221, 271-272, 292-293, 339, 349-350, 352-353, 382-386, 456, 460, 554-555, 560, 565, 570, 580, 585, 590, 595, 600, 625, 660
src/paas_charm/charm_state.py                   210     14     30      5    92%   39-41, 48-50, 57-59, 66-68, 254, 357, 581, 598, 630-631
src/paas_charm/charm_utils.py                    23      0      0      0   100%
src/paas_charm/database_migration.py             35      0      2      0   100%
src/paas_charm/databases.py                      25      2      6      1    90%   89-90
src/paas_charm/django/__init__.py                 2      0      0      0   100%
src/paas_charm/django/charm.py                   50      4      8      2    90%   49, 124, 139-140
src/paas_charm/exceptions.py                      5      0      0      0   100%
src/paas_charm/fastapi/__init__.py                2      0      0      0   100%
src/paas_charm/fastapi/charm.py                  31      0      0      0   100%
src/paas_charm/flask/__init__.py                  2      0      0      0   100%
src/paas_charm/flask/charm.py                    26      0      0      0   100%
src/paas_charm/framework.py                      23      4     12      2    77%   36, 49-51
src/paas_charm/go/__init__.py                     2      0      0      0   100%
src/paas_charm/go/charm.py                       29      0      0      0   100%
src/paas_charm/observability.py                  24      3      4      1    86%   42->46, 73-77
src/paas_charm/rabbitmq.py                       78      2     22      5    93%   117->exit, 122->exit, 157->exit, 159-160, 181->175
src/paas_charm/secret_storage.py                 50      2     14      4    91%   55->54, 56->58, 86, 105
src/paas_charm/utils.py                          54      5     16      3    89%   94-95, 113, 117, 142
-----------------------------------------------------------------------------------------
TOTAL                                          1366     97    266     33    92%

Static code analysis report

Run started:2025-02-28 11:30:11.388870

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 2930
  Total lines skipped (#nosec): 1
  Total potential issues skipped due to specifically being disabled (e.g., #nosec BXXX): 2

Run metrics:
  Total issues (by severity):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
  Total issues (by confidence):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
Files skipped (0):