@Marvin what is the proper way to create a flow that runs concurrent tasks using .map()

To create a flow that runs concurrent tasks using

.map()

in Prefect 3.x, you can follow these steps: 1. Define Your Tasks: Create tasks that you want to run concurrently. In Prefect, tasks are defined using the

@task

decorator. 2. Use Task Runners: Prefect uses task runners to manage concurrent execution. The default task runner is

ThreadPoolTaskRunner

, which runs tasks concurrently within a thread pool. For more advanced parallel execution, you can use

DaskTaskRunner

or

RayTaskRunner

. 3. Map Tasks: Use the

map

method to apply a task across a collection of inputs, enabling concurrent execution. This is similar to Python's built-in

map

function but designed for concurrent execution in Prefect. Here is a basic example:

python
from prefect import flow, task
from prefect.task_runners import ThreadPoolTaskRunner

@task
def my_task(x):
    return x * x

@flow(task_runner=ThreadPoolTaskRunner())
def my_flow(data):
    results = my_task.map(data)
    return results

# Run the flow with a list of inputs
my_flow([1, 2, 3, 4, 5])

In this example,

my_task

will be executed concurrently across the list

[1, 2, 3, 4, 5]

. You can adjust the concurrency level by configuring the task runner. For more details, you can refer to the Prefect Task Runners documentation.