@Marvin Consider a deployed flow that processes a single file, identified by its date. I might trigger that flow many times, for many files, each with a different date. These flows are queued and processed 1 by 1, as I set a concurrency limit of 1. How can I make sure that the flows processing the newest files are processed first, independently of when they were added to the queue? Can I set a priority to a flow, to allow it to "jump the queue"?

Prefect provides a feature called work queues where you can configure priority for flow run submission. When there are concurrency limits and not all flow runs can be executed, priority is used to determine which queues receive precedence to submit runs for execution. Flow run submissions proceed from the highest priority to the lowest. The documentation does not directly offer a way to dynamically prioritize flow runs based on attributes such as file dates, but configuring priorities in work queues can help you manage the order of execution to some extent. For more information on work queues and priority, you can refer to the Prefect Work Queues documentation. It seems that Prefect doesn't provide an out-of-the-box feature to dynamically prioritize flow runs based on custom criteria (like file dates). You may need to implement a custom logic to sort and schedule your flows or use work queues with priorities set according to your needs. Remember to set up the priorities carefully so the newest files are assigned a higher priority to ensure they are processed first.

@Marvin how do I explicitely assign a flow to a queue?

To assign a flow to a specific work queue in Prefect, you would typically configure this as part of your deployment workflows or agent setup. Unfortunately, the provided documents do not directly indicate how to explicitly assign a flow run to a work queue. However, the usual process involves configuring your flow deployments to target a specific queue, and setting up an agent to pull work from that queue. The queues are then prioritized based on the priority you set when creating the queue. You need to define work queues with distinct properties (like priority) for your flows. Then during deployment or runtime, you specify which queue the flow should utilize. The agent responsible for executing the flow runs polls these queues according to their priority. For further guidance on how to assign flows to work queues using Prefect, please consult Prefect's Work Queues documentation, or the source code where such functionality might be implemented, which may give insight into how flow runs are submitted for execution agent.py on GitHub. If the official documentation doesn't provide enough specifics, consider reaching out to the community forums or official support for a more detailed walkthrough. It's quite typical that such nuanced configurations are buried under layers of doc pages or require some nuanced understanding of how to stitch together different pieces of the system.