Dependencies between tasks

Tasks can depend on other tasks. This is useful when you want to run a task only if another task has run successfully, or if you want to run cleanup tasks.

from quickie import task

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

@task(before=[task1])
def task2():
    print("Task 2")

@task(after=[task2], cleanup=["cleanup"])
def task3():
    print("Task 3")

@task
def cleanup():
    print("Cleanup")

The tasks are executed in the following order:

1. Before tasks

2. The task itself

3. After tasks

4. Cleanup tasks

If a task fails, the cleanup tasks will still run. And if one of the cleanup tasks fails, the rest of the cleanup tasks will still run.

Tasks ran as a dependency will not inherit the arguments from the tasks that depend on them. If you need to pass arguments quickie.partial_task() can be used to create a task with predefined arguments. You can also override get_before, get_after, and get_cleanup methods to dynamically set the dependencies.

from quickie import task, partial_task, Task

@task
def task1(*args, **kwargs):
    print(f"{args=}, {kwargs=}")

@task(after=[partial_task(task1, "arg1", kwarg="value")])
def task2():
    print("Task 2")

class MyTask(Task):
    def get_before(self, *args, **kwargs):
        # Args and kwargs are forwarded to task1
        yield partial_task(task1, *args, **kwargs)

    def run(self, *arg, **kwargs):
        print("My task")