[FC-0099] feat: allow disabling auto-load policy based on settings

[BryanttV]

Description

This PR adds the possibility to disable the auto-load of policies by setting the CASBIN_AUTO_LOAD_POLICY_INTERVAL = -1.

When disabled, no policy is loaded, and auto-save is also disabled; therefore, permission validation will always return False.

Merge Checklist:

Check off if complete or not applicable:

• Version bumped
• Changelog record added
• Documentation updated (not only docstrings)
• Fixup commits are squashed away
• Unit tests added/updated
• Manual testing instructions provided
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[mariajgrimaldi]

Shouldn't this be also part of the internal checking?

[bmtcril]

We probably don't want to default to -1 either, and may want to check that the interval is > 0 since I don't know what will happen at 0 but it might result in a tight loop of database requests.

[BryanttV]

Thanks for your comments!

Finally, I implemented this code:

auto_load_policy_interval = getattr(settings, "CASBIN_AUTO_LOAD_POLICY_INTERVAL", 0)
if auto_load_policy_interval > 0:
    enforcer.start_auto_load_policy(auto_load_policy_interval)
    enforcer.enable_auto_save(True)
else:
    # Disable auto-save to prevent unnecessary database writes
    enforcer.enable_auto_save(False)

If CASBIN_AUTO_LOAD_POLICY_INTERVAL is not greater than 0, the following actions are performed:

• The auto-loading of the policy is disabled.
• Auto-save is also disabled.

What do you think? @bmtcril @mariajgrimaldi

[mariajgrimaldi]

Can we also make sure there are no SQL queries run in the background against the DB during this?

[BryanttV]

Yes, that's right! Thanks. I updated the unit test to check the queries.

[BryanttV]

I think we could bump to 0.8.0 with these latest changes. What do you think?

[bmtcril]

Changes make sense to me, thanks!

[rodmgwgu]

Code looks good, could you expand on which cases we would want to disable auto-load?

[bmtcril]

@rodmgwgu right now RBAC only works with the v2 libraries, so if a site isn't using that feature the auto reloading is an unnecessary burden on the database. This will just let sites that aren't using the feature have a way to get away from the extra unnecessary queries.