Sterling Baird
04/05/2024, 11:16 PMMarvin
04/05/2024, 11:17 PMwait_for_input
function effectively in Prefect involves creating asynchronous tasks or flows and awaiting user input or other appropriate events. Below is a generic code example of an asynchronous flow that you can consider as a basis for implementing wait_for_input
. However, note that this example does not directly use wait_for_input
, as it's more about handling asynchronous tasks in Prefect. For more specific usage related to wait_for_input
, you would need to create a task that awaits input inside an asynchronous flow:
python
import asyncio
from prefect import flow
async def some_async_function():
await asyncio.sleep(1)
return "I'm an async function"
@flow(log_prints=True) # Sends `print` statements as INFO logs.
async def my_async_workflow():
print("I can call any python code here, including prefect tasks or flows")
await some_async_function()
if __name__ == "__main__":
asyncio.run(my_async_workflow()) # Run it like a normal async Python function.
# Or serve it as a long-lived process if needed.
# my_async_workflow.serve("my-deployment-name")
Please keep in mind that this is a basic example, and the actual wait_for_input
function should typically be implemented within a task to pause execution until a certain condition is met. You can find the full code for this basic asynchronous example here.
For specific questions about the wait_for_input
function, I would recommend consulting Prefect's documentation or codebase, as I do not have prior experience with Prefect 2.x and the function in question.Sterling Baird
04/05/2024, 11:19 PMMarvin
04/05/2024, 11:20 PMwait_for_input
. Unfortunately, I don't have a direct example for wait_for_input
as it's not part of the default code examples provided for Prefect workflows. The wait_for_input
function or its equivalent behavior might involve prompting the user or another system for input and pausing the flow execution until that input is received.
However, to create a task in Prefect that waits for user input, you might write a task function that uses the built-in Python input()
function to prompt the user. Please keep in mind that this approach is more suitable for local testing and debugging rather than for production deployments, especially in a distributed setup.
Here's how you might create such a task:
python
from prefect import task, flow
@task
def wait_for_user_input(prompt):
return input(prompt)
@flow
def my_flow_with_input():
user_input = wait_for_user_input("Please enter some input: ").result()
print(f"You entered: {user_input}")
if __name__ == "__main__":
my_flow_with_input()
Remember, this is an illustrative example, and using input()
within a flow is not generally recommended for automated workflows in production settings. The actual wait_for_input
behavior would typically be achieved through event-driven tasks or other asynchronous communication mechanisms within Prefect, like waiting on an external event or message queue.
Since it appears there is not a straightforward code example available, I recommend checking Prefect's documentation or forums to see if more detailed guidance on implementing wait_for_input
functionality exists. If it is a feature or specific use case in the Prefect 2.x version, the community or developers might have further insights or code samples.Nate
04/05/2024, 11:48 PMNate
04/05/2024, 11:48 PMMarvin
04/05/2024, 11:48 PMwait_for_input
parameter with functions like pause_flow_run
or suspend_flow_run
.
Here's an excerpt from the documentation that explains how to use Pydantic models with these functions:
python
from prefect import flow, pause_flow_run, get_run_logger
from pydantic import BaseModel
class User(BaseModel):
name: str
age: int
@flow
async def greet_user():
logger = get_run_logger()
user = await pause_flow_run(wait_for_input=User)
<http://logger.info|logger.info>(f"Hello, {user.name}!")
In this example, when you pass a pydantic.BaseModel
class as the wait_for_input
parameter, Prefect will automatically render a form with client-side validation and provide an API endpoint clients can use to submit input.
For more information, you could refer to the following documentation pages:
- Interactive workflows on Prefect's changelog
- Creating interactive workflows in Prefect docs
These sources should provide guidance on how to structure interactive workflows and wait for input using Pydantic models in Prefect.