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<@ULVA73B9P> Is it possible to run different tasks...
# marvin-in-the-wild
d
@Marvin Is it possible to run different tasks on different infrastructure within a flow?
m
Yes, it is possible to run different tasks on different infrastructure within a flow in Prefect. To achieve this, you can use different task runners for your tasks. Flow configurations use infrastructure blocks, whereas task configurations use task runners. Prefect supports various task runners such as 
RayTaskRunner
and 
DaskTaskRunner
amongst others. This allows you to run tasks independently and on different infrastructure. Here is an example of using 
EcsTaskRunner
(this feature might still be under discussion) to run tasks on AWS ECS:
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python 
from prefect import flow, task
from prefect.task_runners import EcsTaskRunner

@task
def process_file(path, memory_size):
    # Your file processing logic goes here
    pass

@flow(task_runner=EcsTaskRunner())
def my_weekly_huge_files_job():
    files_on_s3 = get_list_of_huge_files()
    for path, file_size in files_on_s3:
        if file_size > xxx:
            process_file.submit(path, memory_size='4gb')
        else:
            process_file.submit(path, memory_size='1gb')
For more information, you can refer to: - Task Runners Documentation - Deployments and Infrastructure - Discussions on GitHub for task runners: EcsTaskRunner Discussion Keep these links handy for further details.
d
@Marvin Is it possible to run tasks with different work-pools within a flow?
m
Yes, it is possible to run tasks with different work-pools within a flow in Prefect. Work Pools serve as a bridge between the orchestration layer and the infrastructure for flow runs. They facilitate dynamic infrastructure provisioning and configuration. Here are some key points: 1. Configuration: You can set up different work pools and associate flow or task runs with specific work pools. 2. Definition: Define deployments differently when using work-pool-based execution and use the 
deploy
method for configuration. 3. Advantages: - Dynamic and flexible infrastructure management. - Prioritize or limit flow runs using work queues. - Can be used to run workflows remotely without needing a cloud-provider account, especially using Prefect Managed work pools. Here's an excerpt to better illustrate the concept: Example Configuration:
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yaml
definitions:
    work_pools:
        ecs_work_pool: &ecs_work_pool
            name: "ecs-work-pool"
            work_queue_name: "default"
            job_variables:
                image: "ecs-image"

        another_pool: &another_pool
            name: "another-work-pool"
            work_queue_name: "default"
            job_variables:
                image: "second-image"

deployments:
- name: example-deployment
  version: 1.0
  schedule: {}
  entrypoint: "flow.py:example_flow"
  parameters: {}
  work_pool: *ecs_work_pool
Running Tasks:
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python
from prefect import flow, task
from prefect.deployments import deploy_flow

@task
def process_data():
    pass

@flow
def example_flow():
    process_data.with_options(work_pool_name="another-work-pool")()

deploy_flow(example_flow)
The documentation and issues related to work pools can be found here: - Prefect Work Pools Documentation - Example Github Discussions on Work Pools For more in-depth instructions or examples, please refer to the provided links.
d
@Marvin Prefect 2.19 doesn't have work_pool_name in with_options method for a task.
m
You are correct that Prefect 2.19 does not support specifying 
work_pool_name
directly in the 
with_options
method for a task. However, you can still assign tasks to different infrastructures by coupling work pools with different flow configurations or using different task runners within the same flow. Here is how you can leverage this functionality: Work Pools Setup 1. Create Work Pools: Use the Prefect CLI to create and configure multiple work pools.
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shell
    prefect work-pool create my-work-pool-1 --type prefect:process
    prefect work-pool create my-work-pool-2 --type prefect:process
2. Configure Flows with Work Pools: Assign different work pools to different deployments or flow runs.
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yaml
    deployments:
    - name: flow-deployment-1
      version: 1.0
      entrypoint: "flow.py:flow_one"
      work_pool: 'my-work-pool-1'
    
    - name: flow-deployment-2
      version: 1.0
      entrypoint: "flow.py:flow_two"
      work_pool: 'my-work-pool-2'
3. Run Different Tasks in Separate Work Pools: Create flows that internally manage which work pool to use based on task requirements.
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python
    from prefect import flow, task
    
    @task
    def process_small_task():
        pass
    
    @task
    def process_big_task():
        pass
    
    @flow
    def my_flow():
        if condition_for_small_task():
            process_small_task()  # This would be part of an appropriate work pool
        else:
            process_big_task()  # This would be part of a different work pool
    
    my_flow()
For more detailed information, you may check the Prefect Work Pools Documentation as well as related GitHub Issues. If you seek the most up-to-date features or functionality, consider upgrading to the latest version of Prefect. Be sure to refer to the Release Notes for the latest version.
d
@Marvin How to trigger deployment by its name inside another flow run (deployment uses another work pool)?
m
To trigger a deployment by its name inside another flow run (where the deployment uses a different work pool), you can use the 
run_deployment
utility in Prefect. Here’s how you can achieve this: Example:
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python
from prefect import flow
from prefect.deployments import run_deployment

@flow
def trigger_another_deployment():
    deployment_id = "other_flow/deployment_name"
    deployment_result = run_deployment(deployment=deployment_id)
    return deployment_result

@flow
def main_flow():
    print("Before triggering another deployment")
    trigger_another_deployment()
    print("After triggering another deployment")

if __name__ == "__main__":
    main_flow()
Here’s a step-by-step explanation: 1. Define the Main Flow: This is your primary flow that will trigger another deployment. 2. Use 
run_deployment
Utility: Within the main flow, use 
run_deployment
and provide the deployment_id (in the format 
flow_name/deployment_name
) to trigger the desired deployment. 3. Execute the Main Flow: Run the main flow, and it will trigger the specified deployment as part of its execution. Make sure the deployment you are triggering is correctly defined and uses the intended work pool. References: - Deployment related concepts: Prefect Deployment Documentation - Example Code You can configure and run these deployments using the Prefect CLI or the Prefect UI to ensure the deployments and work pools are set up correctly.
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