What is the best way of restricting some tasks (with "tag2") to not run until all tasks (with "tag1") has succeeded? Does not have to be tag-based (Prefect 1)

There really isn’t any mechanism other than the

set_upstream

and

upstream_tasks

. For this. You can maybe just keep a list as you build your flow and then set

task_with_tag_2(..., upstream_tasks=[list_of_tag_one_items])

Right, thought there was an easier way. With Prefect 2 I can nest flows and tasks and solve it that way?

Maybe. How would you represent it in native Python?

Something like (not sure about the syntax):

def task1():
    # all tasks that had tag1
    task1a()
    task1b()
    ... 
# In flow:
task1()
task2(upstream_tasks=[task1])

It’s not quite as elegant as that because you can’t make the native Python function there an upstream tasks

But assuming it is a task it should work?

But you can’t run a task inside a task either 😅 so the earlier code will not work. It’s going to be something more like:

def task1():
    # all tasks that had tag1
    a = task1a()
    b = task1b()
    ...
    return [a,b,c]
 
# In flow:
up = task1()
task2(upstream_tasks=up)

Which will surely work in Prefect 2. But it might already work in Prefect 1