Airflow has a simple plugin manager built-in that can integrate external
features to its core by simply dropping files in your
The python modules in the
plugins folder get imported,
and hooks, operators, macros, executors and web views
get integrated to Airflow’s main collections and become available for use.
Airflow offers a generic toolbox for working with data. Different organizations have different stacks and different needs. Using Airflow plugins can be a way for companies to customize their Airflow installation to reflect their ecosystem.
Plugins can be used as an easy way to write, share and activate new sets of features.
There’s also a need for a set of more complex applications to interact with different flavors of data and metadata.
- A set of tools to parse Hive logs and expose Hive metadata (CPU /IO / phases/ skew /...)
- An anomaly detection framework, allowing people to collect metrics, set thresholds and alerts
- An auditing tool, helping understand who accesses what
- A config-driven SLA monitoring tool, allowing you to set monitored tables and at what time they should land, alert people, and expose visualizations of outages
Why build on top of Airflow?¶
Airflow has many components that can be reused when building an application:
- A web server you can use to render your views
- A metadata database to store your models
- Access to your databases, and knowledge of how to connect to them
- An array of workers that your application can push workload to
- Airflow is deployed, you can just piggy back on it’s deployment logistics
- Basic charting capabilities, underlying libraries and abstractions
To create a plugin you will need to derive the
airflow.plugins_manager.AirflowPlugin class and reference the objects
you want to plug into Airflow. Here’s what the class you need to derive
class AirflowPlugin(object): # The name of your plugin (str) name = None # A list of class(es) derived from BaseOperator operators =  # A list of class(es) derived from BaseHook hooks =  # A list of class(es) derived from BaseExecutor executors =  # A list of references to inject into the macros namespace macros =  # A list of objects created from a class derived # from flask_admin.BaseView admin_views =  # A list of Blueprint object created from flask.Blueprint flask_blueprints =  # A list of menu links (flask_admin.base.MenuLink) menu_links = 
The code below defines a plugin that injects a set of dummy object definitions in Airflow.
# This is the class you derive to create a plugin from airflow.plugins_manager import AirflowPlugin from flask import Blueprint from flask_admin import BaseView, expose from flask_admin.base import MenuLink # Importing base classes that we need to derive from airflow.hooks.base_hook import BaseHook from airflow.models import BaseOperator from airflow.executors.base_executor import BaseExecutor # Will show up under airflow.hooks.test_plugin.PluginHook class PluginHook(BaseHook): pass # Will show up under airflow.operators.test_plugin.PluginOperator class PluginOperator(BaseOperator): pass # Will show up under airflow.executors.test_plugin.PluginExecutor class PluginExecutor(BaseExecutor): pass # Will show up under airflow.macros.test_plugin.plugin_macro def plugin_macro(): pass # Creating a flask admin BaseView class TestView(BaseView): @expose('/') def test(self): # in this example, put your test_plugin/test.html template at airflow/plugins/templates/test_plugin/test.html return self.render("test_plugin/test.html", content="Hello galaxy!") v = TestView(category="Test Plugin", name="Test View") # Creating a flask blueprint to intergrate the templates and static folder bp = Blueprint( "test_plugin", __name__, template_folder='templates', # registers airflow/plugins/templates as a Jinja template folder static_folder='static', static_url_path='/static/test_plugin') ml = MenuLink( category='Test Plugin', name='Test Menu Link', url='http://pythonhosted.org/airflow/') # Defining the plugin class class AirflowTestPlugin(AirflowPlugin): name = "test_plugin" operators = [PluginOperator] hooks = [PluginHook] executors = [PluginExecutor] macros = [plugin_macro] admin_views = [v] flask_blueprints = [bp] menu_links = [ml]