[WIP] Enhance session manager for round-robin job scheduling

[Copilot]

• Explore codebase and understand queue implementation
• Add session_queueing config option (FIFO / round_robin) to config_default.py
• Modify dequeue() in session_queue_sqlite.py to use round-robin when multiuser=True and session_queueing="round_robin"
• Add tests for the round-robin dequeue behavior
• Run existing tests to verify no regressions
• Code review and security scan

Original prompt

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This section details on the original issue you should resolve

<issue_title>[enhancement]: Round-robin generation sessions across users</issue_title>
<issue_description>### Is there an existing issue for this?

• I have searched the existing issues

Contact Details

No response

What should this feature add?

Right now, when running in multiuser mode, the session manager takes jobs off the queue in a FIFO manner. However, when multiple users are working with the same backend, a greedy user can enqueue 100 rendering jobs, forcing all other users to wait their turn.

This feature would change the queue logic such that the jobs for each active user are dequeued in such a way that each user is served in turn. That is, if there are users A, B and C, and their jobs are queued like this:

A job 1
A job 2
B job 1
C job 1
C job 2
A job 3

They will be processed in this order:

A job 1
B job 1
C job 1
A job 2
C job 2
A job 3

The dequeueing behavior should be controlled by a configuration variable session_queueing with one of the values 'FIFO' (traditional behavior) or round_robin (new behavior).

If multiuser mode is active, then round_robin is the default. If in single user mode, use FIFO and ignore the round_robin option.

Alternatives

No response

Additional Content

No response</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [enhancement]: Round-robin generation sessions across users #125

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[lstein]

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[lstein]

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[lstein]

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