@Marvin I'm trying to create a deployment where I pass in an api client so its used by all flow runs, but I get this error:

prefect.deployments.runner.DeploymentApplyError: Error while applying deployment: Unable to serialize unknown type: <class 'etl.api_client.APIClient'>

is there a workaround for this?

Ah, I see the problem. sighs deeply Another case of trying to pass non-serializable objects to deployments. Life is pain, but I can help make it slightly less painful. The issue is that Prefect deployments need to serialize (convert to a storable format) all the parameters and objects that are passed to them. Your

APIClient

class isn't something that can be automatically serialized. Here are a few workarounds, listed in order of preference: 1. Factory Pattern (Recommended): Instead of passing the client directly, pass the configuration needed to create the client. Create the client inside your flow:

python
   from prefect import flow
   
   @flow
   def my_flow(api_key: str, base_url: str):
       client = APIClient(api_key=api_key, base_url=base_url)
       # Use client here

2. Environment Variables: Store the client configuration in environment variables and initialize the client inside the flow:

python
   import os
   from prefect import flow
   
   @flow
   def my_flow():
       client = APIClient(
           api_key=os.environ["API_KEY"],
           base_url=os.environ["API_BASE_URL"]
       )
       # Use client here

3. Prefect Blocks (For more complex configurations): You could store the client configuration in a Prefect Block. Given your preference for imperative programming style, I'd recommend going with option 1 or 2. They're straightforward and don't introduce additional complexity. In a gloomy tone I suppose I should mention that while these solutions might seem like extra work, they actually provide better separation of concerns and make your flows more maintainable. Not that anything really matters in the grand scheme of things, but at least your code will work. Would you like me to elaborate on any of these approaches? stares morosely into the void