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<@ULVA73B9P> If I am using prefect.yaml in Prefect...
# ask-marvin
k
@Marvin If I am using prefect.yaml in Prefect 3.x for prefect docker worker, show me an illustrative example of what my main () function looks like in my ETL python script.
m
To create an ETL script using Prefect 3.x with a Docker worker, you need to set up a Docker work pool and worker. Here's a basic idea of how your main function might look in your ETL Python script: First, make sure you have Docker installed and running on your machine, and that you've set up a Docker work pool using the following command:
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prefect work-pool create --type docker my-docker-pool
Then start the worker in another terminal with:
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prefect worker start --pool my-docker-pool
Now, in your ETL script, your main function could look like this:
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python
from prefect import task, flow

@task
def extract_data():
    # Logic to extract data
    pass

@task
def transform_data(data):
    # Logic to transform data
    pass

@task
def load_data(transformed_data):
    # Logic to load data
    pass

@flow
def etl_flow():
    data = extract_data()
    transformed_data = transform_data(data)
    load_data(transformed_data)

def main():
    # Execute the flow
    etl_flow()

if __name__ == "__main__":
    main()
This example illustrates basic ETL using Prefect 3.x. You define tasks for each of the ETL steps and organize them within a flow. The 
main()
function then triggers the execution of the flow. For a detailed guide on deploying a flow to Docker work pool and starting workers, you can refer to the Prefect documentation on Docker deployment.
k
@Marvin How would I execute a deployment from a prefect.yaml file in a python script
m
To execute a deployment defined in a 
prefect.yaml
file from a Python script using Prefect 3.x, you'll first need to ensure that the environment is set up correctly with Prefect and that your deployment is configured in your 
prefect.yaml
file. Here's a general approach to invoke the deployment from a Python script: 1. Ensure Prefect is properly configured: Verify that your Prefect server or Prefect Cloud API is correctly set up, as this is essential to execute deployments. 2. Use Prefect CLI to Set Up: First, ensure that you have initialized your deployment configuration with Prefect CLI:
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bash
   prefect init
3. Execute Deployment in Python: Although typically deployments are triggered through the CLI, in Python you would normally interact with the Prefect API to trigger flows or manage tasks directly. Here's an example of how you might structure your Python code to execute your flow or interact with Prefect:
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python
from prefect import Flow
from prefect.deployments import Deployment
from prefect.client import get_client
import anyio

async def run_deployment(deployment_name: str):
    async with get_client() as client:
        deployment = await client.read_deployment_by_name(deployment_name)
        flow_run = await client.create_flow_run_from_deployment(deployment=deployment.id)
        state = await client.get_run_state(flow_run.id)
        print(f"Flow run {flow_run.id} is {state}")

def main():
    # Make sure you provide the correct deployment name
    deployment_name = "your-flow-name/your-deployment-name"
    anyio.run(run_deployment, deployment_name)

if __name__ == "__main__":
    main()
Make sure that when you set up your 
prefect.yaml
, it should define the flow and necessary configurations like schedules, storage, infrastructure, etc. For more information on how to define a deployment using the 
prefect.yaml
file and executing it, you can look into the Prefect documentation on defining deployments with YAML. Remember, this example assumes that the Prefect server or Prefect Cloud is properly set up and that you have access to it according to your PREFECT_API_URL setting.
k
@Marvin I already have a prefect.yaml file, do i still need to initialize it?
@Marvin I already have a prefect.yaml file, do i still need to initialize it?
m
No, if you already have a 
prefect.yaml
file, you don't need to initialize it again with 
prefect init
. The 
prefect init
command is typically used to create a new 
prefect.yaml
file when you're starting a new project. Since you already have this file, you can proceed with using it to configure and manage your deployments as needed. Just make sure that the 
prefect.yaml
file contains all the necessary settings for your deployment workflows. If any updates or changes are required, you can manually update the file or use the Prefect CLI to modify specific configurations.
k
@Marvin, This code:
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if __name__ == "__main__":
    # main()
    run_ream_get_app_list_landing_etl.deploy(
        name="ream-get-app-list-landing-etl-image-deployment",
        work_pool_name="test_pool",
        image="10.10.4.100:5000/ream_get_app_list_landing:latest",
        push=True
    )
Gets the following error, what's wrong?
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Exception has occurred: DeploymentApplyError
Block not found.
httpx.HTTPStatusError: Client error '404 Not Found' for url '<http://10.10.4.100:4200/api/deployments/>'
For more information check: <https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/404>

During handling of the above exception, another exception occurred:

prefect.exceptions.PrefectHTTPStatusError: Client error '404 Not Found' for url '<http://10.10.4.100:4200/api/deployments/>'
Response: {'detail': 'Block not found.'}
For more information check: <https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/404>
m
Your message was too long by 24 tokens - please shorten it and try again. For reference, here's your message at the allowed limit:
, This code:
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if __name__ == "__main__":
    # main()
    run_ream_get_app_list_landing_etl.deploy(
        name="ream-get-app-list-landing-etl-image-deployment",
        work_pool_name="test_pool",
        image="10.10.4.100:5000/ream_get_app_list_landing:latest",
        push=True
    )
Gets the following error, what's wrong? ```Exception has occurred: DeploymentApplyError Block not found. httpx.HTTPStatusError: Client error '404 Not Found' for url 'http://10.10.4.100:4200/api/deployments/' For more information check: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/404 During handling of the above exception, another exception occurred: prefect.exceptions.PrefectHTTPStatusError: Client error '404 Not Found' for url 'http://10.10.4.100:4200/api/deployments/' Response: {'detail': 'Block not found.'} For more information check: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/404 The above exception was the direct cause of the following exception: File "/home/myusername/development/marketing/src/etl/landing/ream/ream_get_app_list_landing_etl_prefect.py", line 236, in <module> run_ream
The error you're encountering, 
DeploymentApplyError: Block not found
, typically indicates that there is a misconfiguration or missing configuration related to deployment specifications, blocks, or infrastructure within your Prefect setup. Here's a guide to help troubleshoot this error: 1. Check API Configuration: Ensure that the PREFECT_API_URL is set correctly. The error message indicates it is trying to access the API at 
<http://10.10.4.100:4200/api/deployments/>
. Verify that your Prefect server is running and accessible at this address. 2. Block Configuration: A "block" in Prefect terminology refers to infrastructure or configuration blocks like storage, Docker infrastructure, etc. Make sure that any referenced block (like work pools or task blocks) is defined and correctly configured within your Prefect Cloud or server. 3. Deployment Registration: Ensure that you've registered your deployment properly. Use the Prefect CLI to register and verify deployments:
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bash
   prefect deployment register --file <your-python-file.py>
This command ensures that your deployment is registered with the Prefect API. 4. Correct usage of 
deploy
method: It looks like you are using the 
deploy
method incorrectly. Normally, 
deploy
is used as part of setting up a Prefect deployment via the Prefect CLI or an intermediate API layer, not directly within Python script code blocks like a function call. 5. Dependency Issues: Ensure all Prefect dependencies and version requirements are met on your local setup, especially focusing on the Prefect 3.x series. If you've verified these steps and the error still persists, there might be a deeper issue with your deployment setup. If needed, you can refer to the Prefect documentation on deployment definitions to ensure all configurations are correct.
k
@Marvin there is no "prefect deployment register" command . Im on prefect 3.s
m
It seems there is a bit of confusion regarding how to register deployments in Prefect 3.x. The concept of "registering" a deployment as in earlier Prefect versions has evolved. To deploy a flow using a 
prefect.yaml
file in Prefect 3.x, you typically should be using Prefect CLI commands that deal with deployments. Since Prefect 3.x focuses on flexibility through infrastructure blocks and custom YAML configurations, here's what you can do: 1. Ensure Prefect Server/Cloud Connection: Make sure your connection to Prefect Cloud or self-hosted Prefect server is correctly configured. Check that the API URL (
PREFECT_API_URL
) is accessible. 2. Create and Apply Deployment Files: If you have a deployment configured in a 
prefect.yaml
file, you should ensure it is applied and referenced correctly in your script. 3. Deploy Using 
prefect.yaml
: To use the deployment described in your YAML file: - Use the Prefect CLI or Prefect API to create a deployment from the 
prefect.yaml
file, ensuring that all blocks like storage, infrastructure, and any other settings are correctly referenced and available. 4. Run Deployments Programmatically: Prefect 3.x does allow execution programmatically, but you should verify that any blocks or configurations mentioned are properly defined in your Prefect infrastructure. This also includes ensuring that the 
image
, 
work_pool_name
, and any other blocks in your YAML are correctly set up. Unfortunately, I couldn't find an existing GitHub issue regarding 
DeploymentApplyError: Block not found
for Prefect 3.x. If you're consistently facing this issue and the above steps don't resolve it, consider reaching out on the Prefect community forums or checking for updates in the Prefect documentation related to deployments.
k
How do I create a work pool in a python script?
@Marvin How do I create a work pool in a python script?
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