A new table is created to track which path_id attachments are images,
and for those their metadata, and which thumbnails have been created.
Using path_id as the effective primary key lets us ignore if the
attachment is archived or not, saving some foreign key messes.
A new worker is added to observe events when rows are added to this
table, and to generate and store thumbnails for those images in
differing sizes and formats.
Actions like deleting realms may leave unreferenced uploads in the
attachment storage backend.
Fix these by walking the complete contents of the attachment storage
backend, and removing files which are no longer present in the
database. This may take quite some time, as it is necessarily O(n) in
the number of files uploaded to the system.
This function is oblivious to the existence of ArchivedAttachment, which
is incorrect. A file can be removed if and only if it is not referenced
by any Messages or ArchivedMessages.
This is a preparatory commit for using isort for sorting all of our
imports, merging changes to files where we can easily review the
changes as something we're happy with.
These are also files with relatively little active development, which
means we don't expect much merge conflict risk from these changes.
Previous cleanups (mostly the removals of Python __future__ imports)
were done in a way that introduced leading newlines. Delete leading
newlines from all files, except static/assets/zulip-emoji/NOTICE,
which is a verbatim copy of the Apache 2.0 license.
Signed-off-by: Anders Kaseorg <anders@zulipchat.com>
Using sys.exit in a management command makes it impossible
to unit test the code in question. The correct approach to do the same
thing in Django management commands is to raise CommandError.
Followup of b570c0dafa
This commit adds the capability to keep track and remove uploaded
files. Unclaimed attachments are files that have been uploaded to the
server but are not referred in any messages. A management command to
remove old unclaimed files after a week is also included.
Tests for getting the file referred in messages are also included.