Create a MetadataSyncJob

[sssoleileraaa]

Description

Move api calls to sync the client with the server into and ApiJob and ensure that it is called precisely every five minutes or immediately when the user clicks refresh.

Background

The client syncs with the server every five minutes by calling sync_api, which makes the following api calls:

• get_sources
• get_submissions (for each source)
• get_all_replies

Whenever sync_api returns successfully, the client then downloads and decrypts any new message or reply.

[sssoleileraaa]

Note: There could be jobs in the queue for downloading and decrypting that are not finished when the next sync happens on the 5-minute mark or when the user clicks the refresh button. This is okay because jobs will only be added for new submissions or replies.

[sssoleileraaa]

The following issue will be affected or resolved when metadata sync is moved to the queue: #462

[sssoleileraaa]

Right now a user can click the refresh link when the queue is paused (while the "retry" error message is showing). Once refresh/metadata sync is moved to the queue, a pause should either disable the refresh icon or resume the queue.

[eloquence]

Per #489 (comment) this also will help us resolve other issues, so we've agreed to prioritize it in the 10/23-11/6 sprint period, and I've added it to the alpha milestone.

[kushaldas]

I will pick up this one.

[redshiftzero]

There could be jobs in the queue for downloading and decrypting that are not finished when the next sync happens on the 5-minute mark or when the user clicks the refresh button. This is okay because jobs will only be added for new submissions or replies.

since for a given document A its is_downloaded field is only going to be updated once its download job is completed, if the download job is in the queued state when the second sync occurs, the second sync will add another job for document A. For now this is OK but I think we need to add a mechanism to deduplicate queue jobs in the future - this would also handle the situation in #116 (to be fair that could be avoided with a pending status in the FileWidget to prevent the user from triggering the download again).