@Marvin can docker-worker create container only when flow is triggered?

Yes, a Docker worker can be configured to create a container only when a flow is triggered. In Prefect 3.x, you can create a deployment from your flow code, and this deployment can be configured to run in a Docker container. The Docker worker will handle starting the container when the flow is triggered. Here's a brief overview of the process: 1. Create a Deployment: You can create a deployment from your flow code by using the

.deploy

method. This process includes building a Docker image with your flow code and optionally pushing it to a Docker registry. 2. Run the Worker: The worker is responsible for executing the flow within a Docker container. You can start a worker for your deployment, which will listen for flow runs and create containers as needed. For more detailed instructions, you can refer to the Prefect documentation on Docker infrastructure examples. If you have any specific configurations or further questions, feel free to ask!

@Marvin can you tell me how to parametrize .deploy to achive that?

To configure the

.deploy

method to create a Docker container only when a flow is triggered, you can use several parameters to customize your deployment. Here's a concise guide on how to achieve this: 1. Specify the Docker Image: You can specify the Docker image using the

image

argument. If you don't specify an image, you must define where to pull the flow code from at runtime using the

from_source

method. 2. Pass Parameters: Use the

parameters

argument to pass a dictionary of key-value pairs to your flow. 3. Job Variables: Use the

job_variables

parameter to override default infrastructure settings for a deployment. This includes settings like

image_pull_policy

and

image

. Here's a basic example of how you might set up the

.deploy

method:

python
from prefect import flow

@flow
def my_flow():
    # Your flow logic here
    pass

my_flow.deploy(
    name="my-flow-deployment",
    image="my-docker-image:latest",
    parameters={"param1": "value1", "param2": "value2"},
    job_variables={
        "image_pull_policy": "IfNotPresent"
    }
)

For more detailed information, you can refer to the Prefect documentation on Docker deployments.