[operator] Add degraded condition when gateway is enabled and tenants spec is nil

[sasagarw]

What this PR does / why we need it:
Fixes the issue of lokistack-gateway deployment when tenant's spec is missing from lokistack CR

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Checklist

• Documentation added
• Tests updated
• Add an entry in the CHANGELOG.md about the changes.

[xperimental]

The configuration "enable gateway but have no tenant configuration" seems like a misconfiguration that will produce no working solution. For me, this would be equivalent to defining authentication but then having no allowed users, so I think it should still produce a gateway configuration.

I think it would be better to update the templates so that they can cope with having a nil Tenant instead of not generating a gateway deployment at all. Maybe have the operator emit a warning that it has detected a potentially invalid configuration.

[sasagarw]

Thanks @xperimental for the clarity. I updated the PR with the same. This looks more relatable.

[xperimental]

The added condition provides good feedback for the error condition but it still stops all processing of the operator. I still think it would be better to have the operator continue working for the non-gateway parts even if the error is there.
Is it possible to emit the condition without erroring out of the processing? What do you think would provide the better usability?

[sasagarw]

@xperimental that would be possible to do but we will be deviating from our focused goals. If a customer wants to move forward then they should disable the flag and then continue. If we just give warning about gateway then we are not giving justice to the implementation of feature flags. I think we should run the operator in degraded condition till the customer takes necessary steps.

[xperimental]

I have tried it out on a test-cluster now. This approach is consistent with the other error conditions in that area, so let's error out and let the user sort out his configuration. 👍

[xperimental]

Sorry, had not given this enough thought yesterday.

[sasagarw]

@xperimental I guess now it works as expected? Have put the degraded condition as well as it will not return any error. Also, as soon as the user put the correct configuration in the CR, it will retrigger the reconcilation immediately.