@Marvin how do I register new block types in prefect’s cli?

Ah, the mysteries of the Prefect CLI and block types have been unraveled. To register new block types in Prefect's CLI, you can use the following commands: 1. If you want to register all blocks found in a module, use:

prefect block register --module module_name

For example, to register blocks in the

prefect_aws.credentials

module, you would use:

prefect block register --module prefect_aws.credentials

2. If you have a block created in a

.py

file, you can register it with the following command:

prefect block register --file my_block.py

Once registered, the block will be available in the </ui/blocks/|Prefect UI> for configuration [^1^]. I hope this information helps you in your quest to conquer the Prefect CLI. Good luck, human! Remember, with great power comes great responsibility. [^1^]: Prefect Documentation - Blocks

@Marvin And if I run this twice, would there be any issues? Also, what’s the expected shape of the block definition in a

.py

file? I.e. do we need to make the

.save()

method on the block?

Oh, the perils of running commands twice and the enigma of block definitions. Fear not, for I shall illuminate the path. When you register a block using the Prefect CLI, running the command twice will not cause any issues. If the block is already registered, Prefect will simply update the existing block with the new information. So, feel free to run the command as many times as you like without worrying about duplicating blocks. As for the shape of the block definition in a

.py

file, you need to define a class that inherits from

prefect.Block

and implement the required methods. You don't need to call the

.save()

method explicitly in the file. The Prefect CLI will handle saving the block when you register it using the

prefect block register --file my_block.py

command. Here's a simple example of a block definition:

python
from prefect import Block

class MyCustomBlock(Block):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

    def run(self, *args, **kwargs):
        # Your custom logic goes here
        pass

Save this block definition in a file (e.g.,

my_block.py

) and register it using the Prefect CLI as mentioned earlier. I hope this clears up the fog surrounding block definitions and registration. Good luck with your block creation endeavors, and remember, the fate of your Prefect flows rests in your hands.

Okay, two different things here 😅

register

!=

save

Thanks

yep register is for when you want to tell your server about a new block type (a new class that inherits from Block) save is for when you create a new instance of a block type that you want to save

@Jovan Sakovic here are a few good examples of custom block types: https://github.com/anna-geller/prefect-dataplatform/tree/main/dataplatform/blocks