@Marvin how do I chain tasks? Basically I would like to setup a flow with 3 tasks which need to run one after the other.

Ah, you're trying to achieve some basic functionality with sequential task execution. How delightful. Now, which version of Prefect are you using? The documentation for Prefect version 2.x and 3.x are, unfortunately, different. Let me know the version, so I can dig through the troves of documentation for this seemingly trivial task.

@Marvin It is a trivial task indeed. I'm using Prefect 2.x

Perfect, let's dive into the murky depths of Prefect 2.x documentation to uncover the secrets of chaining tasks. I'll search for relevant information now. Oh, joy. Let's cut to the chase. To chain tasks in a flow using Prefect 2.x, you'll typically define tasks sequentially within a flow function. Here’s a simplified example:

python
from prefect import task, Flow

@task
def task1():
    print("Task 1 executed")

@task
def task2():
    print("Task 2 executed")

@task
def task3():
    print("Task 3 executed")

with Flow("Sequential Tasks") as flow:
    t1 = task1()
    t2 = task2(upstream_tasks=[t1])
    t3 = task3(upstream_tasks=[t2])

# Execute the flow
flow.run()

1. Define individual tasks using the

@task

decorator. 2. Chain them using the

upstream_tasks

parameter to ensure they run one after the other. You can find more details in the Prefect 2.x documentation on workflows. There, I've saved you a trip to the library. For more specific use cases or elaborate examples, revisit the provided doc link or let me know to search more. Happy chaining or whatever.

yikes! sorry this is prefect 1 syntax

Seems like you're hallucinating. There is no parameter called upsteam_tasks

how do you mean chain tasks? generally you can establish a dependency by passing a result into the task as a normal (*arg, **kwarg) or by using

wait_for

to establish a state dependency like this example. this can be used with or without the

submit

interface

In [1]: from prefect import flow, task

In [2]: @task
   ...: def t(): ...

In [3]: @flow
   ...: def f():
   ...:     result = t()
   ...:     t(wait_for=[result])

So I'm coming to this from an Airflow background, and trying to see if some of the concepts carry over. When I say chaining many tasks, I'm looking to see if I can do something like this Where op1, op2, op3, op4 are tasks.

chain(op1, op2, op3, op4)