@Marvin How to use tags dynamically for flows in Prefect 3?

To use tags dynamically for flows in Prefect 3, you can utilize the

tags

context manager from the

prefect

module. Here's a concise example:

python
from prefect import flow, tags
from prefect.events.schemas import DeploymentTrigger

TAG_NAME = "foobar"

@flow
def upstream():
    pass

@flow
def downstream():
    pass

if __name__ == "__main__":
    with tags(TAG_NAME):
        upstream()
        upstream()
        upstream()
    
    downstream.serve(
        name="downstream-of-tagged-upstream",
        triggers=[
            DeploymentTrigger(
                expect={"prefect.flow-run.Completed"},
                match_related=[
                    {
                        "prefect.resource.role": "tag",
                        "prefect.resource.id": f"prefect.tag.{TAG_NAME}",
                    },
                    {
                        "prefect.resource.role": "flow",
                        "prefect.resource.name": "upstream",
                    }
                ],
                threshold=3,
            )
        ]
    )

In this example, the

tags

context manager is used to apply a dynamic tag (

TAG_NAME

) to multiple runs of the

upstream

flow. The

downstream

flow is configured to trigger based on the completion of these tagged

upstream

runs. For more details, you can view the full example here.

@Marvin How to apply dynamic tags to task?

To apply dynamic tags to tasks in Prefect 3, you can use the

@task

decorator with the

tags

parameter. Here's a simple example:

python
from prefect import task, flow

@task(tags=["dynamic-tag"])
def my_task():
    print("Task is running with dynamic tags!")

@flow
def my_flow():
    my_task()

my_flow()

In this example, the

my_task

function is decorated with

@task

and assigned a dynamic tag using the

tags

parameter. You can modify the

tags

list based on your requirements to apply different tags. For more details on the

@task

decorator and its parameters, you can refer to the Prefect documentation.