@Marvin I have this flow:

@task
def task_1(number:int):
    print(number)
    return number*2

@flow
def flow_1():
    result_v1 = task_1.submit(1).result()
    result_v2 = task_1(1)

Which is the difference in the two ways of calling the task called "task_1"?

It seems like your code snippet got cut off. However, from what I can see, you're trying to use the

submit

method to run a task within a flow. Let's make sure you have the correct syntax and understanding of how to use Prefect's imperative API in version 3.x. Here's a basic example that demonstrates how to use the

submit

method with tasks in an imperative style:

python
from prefect import flow, task

@task
def task_1(number: int):
    print(number)

@flow
def flow_1():
    future = task_1.submit(1)
    result = future.result()
    return result

### Key Points: 1.

@task

Decorator: This is used to define a task that can be executed within a flow. 2.

submit

Method: This is used to run the task asynchronously and returns a

Future

object. 3.

result

Method: This is used to retrieve the result of the task once it has completed. ### Assumptions: - This example assumes you're using Prefect 3.x, which has a slightly different API compared to 2.x. - The

submit

method is used to run tasks imperatively, which is what you seem to prefer. If you have any specific issues or parts of your flow that you need help with, feel free to provide more details or the rest of the code!

@Marvin Which is the difference for this in Prefect 2.x and 3.x

The differences between using the

submit

method and direct calls in Prefect 2.x and 3.x are primarily around the API's evolution and how tasks are executed within flows. Here's a summary based on the available documentation: ### Prefect 2.x: - Submit Method: In Prefect 2.x, the

submit

method is used to run tasks asynchronously. It creates a new task run in the backing API and submits the task to the flow's task runner. The method is synchronous in the sense that it blocks only during the submission process, after which the flow execution continues. - Direct Call: Directly calling a task executes it synchronously within the flow. This means the flow will wait for the task to complete before moving to the next step. ### Prefect 3.x: - Submit Method: The

submit

method in Prefect 3.x serves a similar purpose but is part of a more refined API. It allows for asynchronous task execution, returning a

PrefectFuture

object that can be used to manage task dependencies and retrieve results once the task is complete. - Direct Call: As in 2.x, a direct call to a task in 3.x executes it synchronously. This is straightforward and suitable for tasks that do not require concurrency. ### General Differences: - API Evolution: Prefect 3.x has a more streamlined and consistent API, focusing on improving usability and performance. - Concurrency Management: The

submit

method in both versions is designed for asynchronous execution, but 3.x offers more robust handling of task dependencies and futures. For more details on these methods, you can refer to the Prefect documentation: - Prefect 2.x Task Runners - Prefect 3.x Task API If you have specific scenarios or additional questions about using Prefect in your environment, feel free to ask!