Improve logging of API failures

[legoktm]

Status

Ready for review

Description

Add more debug and error logging to make it easier to trace why things have failed.

Roughly, every failure branch should have an error-level log entry. In some cases where knowing additional context would be useful, a debug-level entry is also created with unredacted information.

Fixes #2206.

Test Plan

• visual review, specifically that no sensitive-looking info should appear in error level logs.

Checklist

If these changes modify code paths involving cryptography, the opening of files in VMs or network (via the RPC service) traffic, Qubes testing in the staging environment is required. For fine tuning of the graphical user interface, testing in any environment in Qubes is required. Please check as applicable:

• These changes should not need testing in Qubes

If these changes add or remove files other than client code, the AppArmor profile may need to be updated. Please check as applicable:

• No update to the AppArmor profile is required for these changes

If these changes modify the database schema, you should include a database migration. Please check as applicable:

• No database schema changes are needed

[cfm]

Very nice. And I quite like the guidelines you've articulated:

Roughly, every failure branch should have an error-level log entry. In some cases where knowing additional context would be useful, a debug-level entry is also created with unredacted information.