Previously we made a call to S3 to list objects for a letter, even
though we already had the precise key of the single object to hand.
This removes the one usage of "get_s3_bucket_objects" and uses the
filename directly in the call to remove the object.
Flake8 Bugbear checks for some extra things that aren’t code style
errors, but are likely to introduce bugs or unexpected behaviour. A
good example is having mutable default function arguments, which get
shared between every call to the function and therefore mutating a value
in one place can unexpectedly cause it to change in another.
This commit enables all the extra warnings provided by Flake8 Bugbear,
except for:
- the line length one (because we already lint for that separately)
- B903 Data class should either be immutable or use `__slots__` because
this seems to false-positive on some of our custom exceptions
- B902 Invalid first argument 'cls' used for instance method because
some SQLAlchemy decorators (eg `declared_attr`) make things that
aren’t formally class methods take a class not an instance as their
first argument
It disables:
- _B306: BaseException.message is removed in Python 3_ because I think
our exceptions have a custom structure that means the `.message`
attribute is still present
Matches the work done in other repos:
- https://github.com/alphagov/notifications-admin/pull/3172/files
this means that if the task is accidentally ran twice (eg we autoscale
notify-celery-worker-beat to 2), it won't send letters twice.
Additionally, update some function names and config variables to make
it clear that they are referring to letter jobs, rather than all letter
content
