shlok
07/01/2025, 4:44 PMprefect block register
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prefect block register [OPTIONS]
Register blocks types within a module or file.
This makes the blocks available for configuration via the UI. If a block type has already been registered, its registration will be updated to match the block’s current definition.
Examples: Register block types in a Python module: $ prefect block register -m prefect_aws.credentials Register block types in a .py file: $ prefect block register -f my_blocks.py
--module
Python module containing block types to be registered
--file
Path to .py file containing block types to be registeredMarvin
07/01/2025, 4:44 PMMarvin
07/01/2025, 4:44 PMprefect block register
command. This is a convenient way to make your custom blocks available in the Prefect UI.
Here's how it works:
1. Create a Python file (e.g., my_blocks.py
) containing your block definitions:
python
from prefect.blocks.core import Block
class MyFirstBlock(Block):
value: str
class MySecondBlock(Block):
number: int
text: str
class MyThirdBlock(Block):
url: str
token: str
2. Register all blocks in the file using:
bash
prefect block register -f my_blocks.py
Or if your blocks are in a Python module:
bash
prefect block register -m your_module_name
After registration, these blocks will be available in the Prefect UI for configuration. The registration process will:
- Make the blocks visible in the UI
- Update any existing block registrations if the block definitions have changed
- Allow you to create and configure instances of these blocks through the UI
You can find more details about blocks in the Prefect documentation.
Remember that built-in blocks should be automatically registered when you start a Prefect server for the first time, so you only need to use this command for custom blocks or if auto-registration fails.shlok
07/01/2025, 4:45 PMMarvin
07/01/2025, 4:45 PMMarvin
07/01/2025, 4:46 PMblocks.py
) with your block configurations:
python
from prefect.blocks.system import Secret
from prefect.blocks.notifications import SlackWebhook
# Import other block types you need
# Create and save blocks
Secret(value="my-secret-value").save("my-secret-name")
SlackWebhook(
url="<https://hooks.slack.com/services/xxx/yyy/zzz>"
).save("my-slack-webhook")
# Add more block configurations as needed
2. You can then run this Python file to create all blocks:
bash
python blocks.py
To manage blocks via CLI, you can use these commands:
bash
# List all available block types
prefect block ls
# List all configured blocks
prefect block ls --type secret # List all blocks of type 'secret'
# Create a block (will prompt for required values)
prefect block create secret
# Delete a block
prefect block delete secret/my-secret-name
For automation purposes, you can also create blocks using environment variables. For example:
python
import os
from prefect.blocks.system import Secret
# Create block from environment variable
Secret(value=os.environ["MY_SECRET_VALUE"]).save("my-secret-name")
This approach allows you to:
- Version control your block configurations
- Automate block creation as part of your deployment process
- Avoid manual UI configuration
- Use environment variables for sensitive values
Remember that some blocks (like the Secret block) are built into Prefect, while others might need to be installed from separate packages (like prefect-aws
or prefect-gcp
).shlok
07/01/2025, 4:48 PMMarvin
07/01/2025, 4:48 PMMarvin
07/01/2025, 4:49 PMprefect block inspect
command to view the configuration of existing blocks, and then recreate them in Python code. Here's how:
1. First, list your existing blocks:
bash
prefect block ls
2. Then inspect a specific block to see its configuration:
bash
prefect block inspect secret/my-secret-name
3. Using the output from the inspect command, you can create a Python file that recreates these blocks. Here's an example workflow:
python
from prefect.blocks.system import Secret
from prefect.blocks.notifications import SlackWebhook
# Import other block types you need
# Recreate blocks based on the inspected configurations
Secret(
value="your-secret-value"
).save("my-secret-name")
SlackWebhook(
url="<https://hooks.slack.com/services/xxx/yyy/zzz>"
).save("my-slack-webhook")
# Add more blocks as needed
While there isn't an automated export feature, you can:
1. Use prefect block ls
to list all your blocks
2. Use prefect block inspect
on each block to see its configuration
3. Create a Python script that recreates these blocks using the Prefect Python SDK
Note that for sensitive values (like secrets or API keys), you'll want to:
- Use environment variables instead of hardcoding values
- Consider using a secrets management system
- Be careful not to commit sensitive values to version control
This approach, while manual, gives you the benefit of having your block configurations in code, making them:
- Version controllable
- Reproducible across environments
- Automatable as part of your deployment process