Developing custom actions#

Creating a new action type#

  • If you haven’t yet, take a decision where to store your action definitions.
    It could be one directory or multiple.
    Make sure this directory is listed among the action class directories.

  • Give your new action type a good name.
    It’s recommended to be recognizable and unique.

  • Create a file called <your-new-type-name>.py in your action definitions directory with the following backbone:

    from grana import ActionBase, ArgsBase

class Args(ArgsBase):
    """Here goes the arguments description"""

class Action(ActionBase):
    args: Args

    async def run(self):
        """Here goes your logic"""

About action arguments#

Each action class has an args field, which is:

  • Annotated with a python dataclass (typically a subclass of grana.ArgsBase).

  • Populated for the instance by the workflow, based on the loaded information.

Subclasses of grana.ArgsBase are automatically dataclasses.
Raw arguments data is transformed into dataclass instances according to intuitive logic.

Action methods#

Tip

Grana leverages python asyncio functionality to implement tasks concurrency, so be sure you module does not use long-running synchronous calls.

async run()#

Main entry for any action. Return value is ignored.

say(message: str)#

Sends a text to the display.

yield_outcome(key: str, value: Any)#

Registers an outcome with the given value under the specified key.

skip()#

Terminates execution and sets the status to SKIPPED.

fail(message: str = '')#

Terminates execution with an optional message and sets the status to FAILURE.