@Marvin When running a deploy script that references a flow which includes a custom block I'm receiving the following error. The blocks are registered in Prefect Cloud. They're saved in a "blocks" folder in my working directory and imported like this: from blocks.keap import Keap from blocks.postgresql import PostgreSQL What am I doing wrong? File "C:\Users\Alexander.Ford\Dev\data-pipeline\venv\Lib\site-packages\prefect\utilities\importtools.py", line 164, in load_script_as_module raise ScriptError(user_exc=exc, path=path) from exc prefect.exceptions.ScriptError: Script at 'C:\\Users\\ALEXAN~1.FOR\\AppData\\Local\\Temp\\tmp0efqm10e\\data-pipeline-main\\flows\\keap\\keap_contact_sync.py' encountered an exception: ImportError("cannot import name 'Keap' from 'prefect.blocks.system' (C:\\Users\\Alexander.Ford\\Dev\\data-pipeline\\venv\\Lib\\site-packages\\prefect\\blocks\\system.py)")

It looks like there might be an issue with how you're importing and using custom blocks within your Prefect workflow scripts. Based on the logs you shared, Prefect is unable to import

Keap

from

prefect.blocks.system

, likely because it's not part of the standard Prefect blocks, but rather a custom one that you defined. To work with custom blocks in Prefect, remember to follow these guidelines: 1. The blocks need to be registered in Prefect Cloud, which you've already done. 2. You need to ensure the blocks are available in your environment, either by installing a package that provides them or by having the proper script in your local folder. From the Prefect documentation, it seems that you may use the following methods to import and load blocks that are registered in Prefect Cloud:

python
from prefect import flow
# Replace 'DbtCloudCredentials' and 'MY_BLOCK_NAME' with the appropriate block and name
from your_module_name import YourBlockName

@flow
def my_flow():
    my_block = YourBlockName.load("MY_BLOCK_NAME")
    # ... your flow logic here

Here's a link with a relevant section from the Prefect documentation that should help you Blocks Catalog and Registering blocks for use in the Prefect UI. Looking at the Github issue, I couldn't find a directly related issue, but here's an example of someone having trouble with module imports during deployment, which might offer some insights: ModuleNotFoundError when simultaneously running deployed flows using custom image. Make sure your script paths are correct and that the custom block files are accessible from within your project's environment. This might also involve ensuring any init.py files are set up correctly to allow imports from within your blocks folder. If you're still having trouble, I'd recommend verifying the registration of your custom blocks and making sure the Python environment where you're running your flows has access to these block definitions.

how do I import a custom block properly?

To properly import and use a custom block in Prefect, you should follow these steps: 1. Make sure you have registered your custom block with Prefect Cloud or your self-hosted Prefect server. This can be done via the Prefect CLI using commands like

prefect block register --module your_module_name

or

prefect block register --file your_block.py

. 2. Once registered, you can use the

load

method to import the block within your flow. The block will be identified by its name in the Prefect Cloud or server. Here's a generic code snippet on how to import and load a registered block in your flow:

python
from prefect import flow

@flow
def my_flow():
    # Replace 'YourBlockClass' and 'MY_BLOCK_NAME' with your actual block class and name
    from your_package.blocks import YourBlockClass
    my_block = YourBlockClass.load("MY_BLOCK_NAME")
    # Your flow logic

Remember to replace

your_package.blocks

with the actual Python module path where your custom block classes are defined and

YourBlockClass

,

MY_BLOCK_NAME

with the actual class name of your block and the name of the block instance you have registered in Prefect Cloud. Please take a look at these resources for detailed guidance: - Using blocks in Prefect: Concepts - Blocks - Blocks Catalog example: Prefect-dbt Blocks Catalog If you experience an import error, make sure that the module and class names are correct and that the custom blocks are accessible within your Python environment. I was unable to find a directly related GitHub issue regarding a custom block import error, but I recommend you keep an eye on the issues tracker should anything similar come up or to open a new issue if needed: - PrefectHQ GitHub Issues: Prefect Issues