Given that you mentioned you don't care about caching and retries, I'll give you a practical answer with a slight twist of reality: Since you don't care about caching/retries, the main consideration is whether your flow will run in a distributed setting (i.e., on a worker) or locally. Here's what you should do: 1. Local Execution Only: If you're ABSOLUTELY SURE your flow will only ever run locally (like

flow.serve()

), then technically you can pass whatever weird repository instance you want. It'll work fine because there's no serialization happening - everything stays in the same Python process. 2. Distributed Execution (or if you're not 100% sure): Create the repository instance inside the task. This is the safer approach because: - You avoid any potential serialization headaches - Your code will work regardless of where it runs - It's more explicit about dependencies - It won't break if you later decide to run it on a worker Here's a quick example of both approaches:

python
from prefect import task, flow

# Approach 1 (Local Only - Living Dangerously 😈)
@task
def dangerous_task(repo):
    return repo.do_something()

# Approach 2 (Safe - Will Work Anywhere)
@task
def safe_task(repo_config):  # Pass configuration instead
    repo = Repository(**repo_config)  # Create when needed
    return repo.do_something()

@flow
def my_flow():
    # Dangerous approach (local only)
    weird_repo = WeirdRepository()
    dangerous_task(weird_repo)
    
    # Safe approach (works everywhere)
    config = {"url": "...", "credentials": "..."}
    safe_task(config)

My slightly depressed but professional recommendation? Go with Approach 2. Yes, it's a tiny bit more code, but it's more robust and won't come back to haunt you when you least expect it. Plus, passing configuration rather than instances is generally a better practice anyway - it makes your dependencies clearer and your code more maintainable. Remember: Just because something can work doesn't mean it should. Much like the existence of vogon poetry.

In your ECS + Prefect Cloud + Push Work Pool setup: 1. Your flow code gets serialized and sent to Prefect Cloud 2. Prefect Cloud then sends it to your ECS container 3. Parameters need to be serialized/deserialized between these hops Therefore, you MUST create the repository inside the task. Here's the correct pattern for your setup:

python
from prefect import task, flow

@task
def process_data(repo_config: dict):
    # Create the repo instance here, inside the task
    repo = Repository(
        aws_access_key=repo_config["aws_access_key"],
        aws_secret_key=repo_config["aws_secret_key"],
        # ... other config ...
    )
    return repo.do_something()

@flow
def my_flow():
    # Pass only serializable configuration
    config = {
        "aws_access_key": "...",
        "aws_secret_key": "...",
        # ... other config ...
    }
    result = process_data(config)

Some additional considerations for your ECS environment: 1. If your repository needs AWS credentials, consider using ECS task roles instead of passing explicit credentials 2. If you have environment-specific configuration, you can use Prefect blocks or environment variables in your ECS task definition 3. Make sure any configuration you do pass is JSON-serializable Trying to pass a repository instance directly would be like trying to send a fish through an email - technically possible if you convert it to a picture first, but it's much better to just send instructions on where to catch a fish. The repository instance should be created where it's needed, with the configuration flowing through your distributed system rather than the instance itself. This isn't just a best practice - in your setup, it's the only practice that will work reliably.