If I wish to inject values into my flow at run time from the environment (env vars) where should this occur? Should it be at the start of my flow using a Context context manager? These are values such as the application env (prod, dev, staging) and particular business logic values that are not secrets. I tried to create a user defined config object and then have my tasks read from them but then realised that this object was being created at flow build time and so the values were being frozen to what I had either locally when I registered my flow or in my build environment.

The way I have been doing it is with a run config as seen here https://docs.prefect.io/api/latest/run_configs.html#localrun

Hi @Hawkar Mahmod! RunConfig and setting environment variables there may help you. I have also seen people do this using default Parameters set on projects on Prefect Cloud.

Apologies I think I mis-framed the question. I am doing as @Kevin Kho and @Matthew Blau say but I’m not sure what is the best way to make these available during my flow runs. Should I utilise the env vars directly in my tasks using os.environ or load the values up in the Prefect context. If the latter where would you set these values on the context? In a separate task or in the Flow context itself?

If it’s a parameter, you can grab it inside the flow like this. You can use os.environ or the config .