Dynamic DAG Creation Not working as expected in Apache airflow - python-3.x

Question

I was trying to understand how dynamic dags are created in Apache airflow as I need this to create dynamic dags in my project.
Below is the link iam following:Dynamic DAG creation in Apache airflow
Below is the code block for creating a sample hello world dynamic DAGS.(Dynamic DAGs creation based on input parameters).
from datetime import datetime
from airflow import DAG
from airflow.operators.python_operator import PythonOperator
def create_dag(dag_id,
schedule,
dag_number,
default_args):
def hello_world_py(*args):
print('Hello World')
print('This is DAG: {}'.format(str(dag_number)))
dag = DAG(dag_id,
schedule_interval=schedule,
default_args=default_args)
with dag:
t1 = PythonOperator(
task_id='hello_world',
python_callable=hello_world_py,
dag_number=dag_number)
return dag
# build a dag for each number in range(10)
for n in range(1, 10):
dag_id = 'hello_world_{}'.format(str(n))
default_args = {'owner': 'airflow',
'start_date': datetime(2018, 1, 1)
}
schedule = '#daily'
dag_number = n
globals()[dag_id] = create_dag(dag_id,
schedule,
dag_number,
default_args)
The expectation is to create 9 such DAGs.But what I could see is that once i compile the above code block with python3 code_sample.py,it creates 9 DAGs however the code embeded in the DAG is entire sample code.
But to my understanding the created DAGs should have only the below code block which is available inside create_dag method in the above sample code block.
Expected DAG code:
from datetime import datetime
from airflow import DAG
from airflow.operators.python_operator import PythonOperator
def hello_world_py(*args):
print('Hello World')
print('This is DAG: {}'.format(str(dag_number)))
dag = DAG(dag_id,
schedule_interval=schedule,
default_args=default_args)
with dag:
t1 = PythonOperator(
task_id='hello_world',
python_callable=hello_world_py,
dag_number=dag_number)
Actual DAG code:
from datetime import datetime
from airflow import DAG
from airflow.operators.python_operator import PythonOperator
def create_dag(dag_id,
schedule,
dag_number,
default_args):
def hello_world_py(*args):
print('Hello World')
print('This is DAG: {}'.format(str(dag_number)))
dag = DAG(dag_id,
schedule_interval=schedule,
default_args=default_args)
with dag:
t1 = PythonOperator(
task_id='hello_world',
python_callable=hello_world_py,
dag_number=dag_number)
return dag
# build a dag for each number in range(10)
for n in range(1, 10):
dag_id = 'hello_world_{}'.format(str(n))
default_args = {'owner': 'airflow',
'start_date': datetime(2018, 1, 1)
}
schedule = '#daily'
dag_number = n
globals()[dag_id] = create_dag(dag_id,
schedule,
dag_number,
default_args)
Let me know what is creating the above problem

Answer 1

The code that you see in Airflow UI when clicking on "Code" tab is simply the whole .py file source code. See how this function is implemented:
https://github.com/apache/airflow/blob/master/airflow/www/views.py#L437