Add sample python package

Author: ericdaat

README.md

@@ -6,6 +6,9 @@ A sample data stack running on Docker, that contains the following services:
 - [Metabase](https://metabase.com/) (with its Postgres database)
 - [MariaDB](https://mariadb.org/) (as main database)
 
+There is also a python package containing an example module, used by the
+example Airflow DAG.
+
 Run it with:
 
 ``` text

airflow-dags/example.py

@@ -2,10 +2,13 @@
 Code that goes along with the Airflow located at:
 http://airflow.readthedocs.org/en/latest/tutorial.html
 """
-from airflow import DAG
-from airflow.operators.bash_operator import BashOperator
 from datetime import datetime, timedelta
 
+from airflow import DAG
+from airflow.operators import BashOperator, PythonOperator
+
+from python_package.example_module import some_function
+
 
 default_args = {
     "owner": "airflow",
@@ -44,5 +47,12 @@
     dag=dag,
 )
 
+t4 = PythonOperator(
+    task_id="python_code",
+    python_callable=some_function,
+    dag=dag
+)
+
 t2.set_upstream(t1)
 t3.set_upstream(t1)
+t4.set_upstream(t1)

docker-compose.yml

@@ -44,10 +44,14 @@ services:
           - LOAD_EX=n
           - EXECUTOR=Local
           - POSTGRES_HOST=airflow-postgres
+          - PYTHONPATH=${PYTHONPATH}:/opt
       volumes:
+          # Airflow DAGS
           - ./airflow-dags:/usr/local/airflow/dags
           # Uncomment to include custom plugins
           # - ./airflow-plugins:/usr/local/airflow/plugins
+          # Python packages
+          - ./python_package:/opt/python_package/
       ports:
           - "8080:8080"
       command: webserver

python_package/__init__.py

@@ -0,0 +1,2 @@
+def some_function():
+    return "Hello, world!"