Use native threading module in job_manager

[m3nu]

Some cleanup after adding the new jobs scheduler:

• Keep jobs_manager with main app
• Rename job_scheduler to jobs_manager to match main JobsManager class
• Remove if DEBUG statements. Should use logger.debug instead.
• Use native threading.Thread class instead of Qt QThreadpool
• Remove extra mutex, semaphore, etc.
• Combine borg.jobs_manager.Job with borg.borg_job

This is a big cleanup. I probably removed too many things. Please let me know if something is broken now or if anything should be put back.

@bastiencyr: Also, my apologies, if this changes much of your earlier PR. I just felt some things could be solved in a simpler way. I still envy the general idea and I'm happy I took the time to understand it in details.

Fixes #1094, fixes #1091, maybe fixes #1095

[m3nu]

So the test are still passing. If I broke anything, we should consider adding a test for that. 😇

[bastiencyr]

@bastiencyr: Also, my apologies, if this changes much of your earlier PR. I just felt some things could be solved in a simpler way. I still envy the general idea and I'm happy I took the time to understand it in details.

I have to admit that Im a little be disappointed but it was necessary 😢😢
Some things was useless like all my prints everywhere, the timeout and some functions like load_from_db. But some important things has been removed (mutex, getters).

[m3nu]

Thanks for understanding. My goal is also to help future coders understand it. The main idea of using one queue and worker per repo/site is still there and it was brilliant!

I can put the mutex stuff back. What is it needed for and can we add a test to test for the problem?

[bastiencyr]

* Combine `borg.jobs_manager.Job` with `borg.borg_job`

Its not a good idea. The Job class add an abstraction (interface) and separate jobs manager from jobs itself. By doing this, it becomes difficult to know what jobs managers need (for example a repo_id function, a site_id property...). It will be difficult for another dev to rewrite the jobs manager if needed.

[m3nu]

Its not a good idea. The Job class add an abstraction (interface) and separate jobs manager from jobs itself.

OK. Undoing again. Also looking at locks real quick.

[m3nu]

Put back your JobInterface, so it's all in one place.

And added some locks and checks to avoid dupe jobs.

Please help improve, so we get a good PR.

[bastiencyr]

Sorry @m3nu , I have an hackathon this week end so basically more than 20 hours of code 😅
I will tried to help the evening but if it can wait a little, its better 🙄

[m3nu]

No worries. All the best for the hackathon! I value your opinion and feedback, so will just keep it open here.

[bastiencyr]

Hello @m3nu I look at this today !

[bastiencyr]

Is there something else you need @m3nu ?
I let some comments