Hi guys, I'm looking to build a

class MyFlowRunner(prefect.engine.flow_runner.FlowRunner)

(or subclassing another component - open to suggestions!) inside a custom package

my-prefect

to send some HTTP requests before a

Flow

starts, and after it ends. My questions are: • where would be the best way for me to implement such a functionality? along with the considerations: • keep the Prefect API to be as pure as possible • allow the implementation of the

MyFlowRunner

(or some other custom component) to be uncoupled, i.e. if a project upgrades

my-prefect

, the flow configuration doesn't have to change at all Would appreciate comments/suggestions/discussions from whoever are interested/have had experience doing so!

Hey @haven, could you give me some clue to what those HTTP requests are such that they can’t be done inside the Flow?

The HTTP requests I'm trying to make is a metadata submission sort of request. The idea is to allow thousands of applications/flows to have such submission without modifying all these applications manually.

Ok I think we can subclass the

Flow

class instead. Will try to make an example.

That's awesome!

Ok so I talked to the team and the best way to do this is actually with a state handler attached to the Flow. If you use a state handler, you can run code whenever the code Flow goes from a scheduled to running state. In that state handler you could send you queries. And then just attach the state handler to the flow level. This will be a lot easier than subclassing the FlowRunner or FLow.

Ah that sounds neat. Let me try that out! Thanks @Kevin Kho!