Hello World Metaflow Card

This repository is an example hello world card.

You can install this card via :

pip install metaflow-card

How to use a helloworld card

@card(type='helloworld',options={"attribute":"html"})
@step
def train(self):
    ...
    ...
    self.html = some_html() # set some html to the self attribute

How to implement custom card module

The core namespace package name is metaflow_extensions. Any new custom MetaflowCard should be present inside a folder with the following directory structure:

some_random_dir/ # the name of this dir doesn't matter
├ setup.py
├ metaflow_extensions/ # namespace package name 
│  └ organizationA/ # NO __init__.py file as it is a namespace package. 
│      └ plugins/ # NO __init__.py file
│        └ cards/ # NO __init__.py file # This is a namespace package. 
│           └ my_card_module/  # Name of card_module
│               └ __init__.py. # This is the __init__.py is required to recoginize `my_card_module` as a package
│               └ somerandomfile.py. # Some file as a part of the package. 
.

The __init__.py of the metaflow_extensions.organizationA.plugins.cards.my_card_module, requires a CARDS attribute which needs to be a list of objects inheriting MetaflowCard class. For example, the below __init__.py file exposes a MetaflowCard of type "y_card2".

from metaflow.cards import MetaflowCard

class YCard(MetaflowCard):
    type = "y_card2"

    ALLOW_USER_COMPONENTS = True

    def __init__(self, options={}, components=[], graph=None):
        self._components = components

    def render(self, task):
        return "I am Y card %s" % '\n'.join([comp for comp in self._components])

CARDS = [YCard]

Having this metaflow_extensions module present in the python path of your flow will make the cards usable within the flow.