I’m relatively new to using Airflow, and I’m encountering a problem with setting default values for DAG run conf. I’ve been reading documentation and forums to find a solution that works for me, but I haven’t been successful so far.
To provide some context, I have a DAG with a number of tasks, and each task requires a specific set of parameters to be passed in the DAG run conf. However, these parameters are the same for every task, and I want to be able to set default values for them. This way, I can avoid duplicating and hardcoding these parameters for each task, which would be very time-consuming and error-prone.
Here’s what I’ve tried so far in my DAG file:
“`python
default_args = {
‘start_date’: datetime(2021, 8, 1),
’email_on_failure’: False,
‘catchup_by_default’: False,
‘provide_context’: True,
‘default_view’: ‘tree’,
‘default_dates’: [datetime(2021, 8, 1), datetime(2021, 8, 2)],
‘params’: {
‘param1’: ‘default_value_1’,
‘param2’: ‘default_value_2’,
‘param3’: ‘default_value_3’
}
}
dag = DAG(
‘my_dag’,
catchup=False,
default_args=default_args,
schedule_interval=’0 0 * * *’
)
“`
However, when I try to run this DAG, I get an error message saying that the `params` attribute is not a valid DAG argument. I’ve also tried using the `default_args` parameter for the operator tasks in my DAG, but this didn’t seem to work either. Can anyone help me figure out why this is happening and how I can set default values for my DAG run conf?
Airflow: how to set default values for dag_run.conf
The solution to your problem might be to use the DAG default_args parameter to define default values for your DAG. You can define default parameters for your DAG in the default_args property. One way to do this would be to instantiate a Python dictionary at the start of your DAG file, fill it with the desired default values, and then pass it to the DAG parameters.
For example, you could define default arguments for your DAG like this:
“` python
default_args = {
‘owner’: ‘airflow’,
‘depends_on_past’: False,
‘start_date’: days_ago(2),
’email’: [‘[email protected]’],
’email_on_failure’: False,
’email_on_retry’: False,
‘retries’: 1,
‘retry_delay’: timedelta(minutes=5),
}
“`
By using this method, you can effectively set default values for any argument used in your DAG.
Hello there! I came across your question on how to set default values for DAG run configurations in Airflow, and I would like to help you out with your coding problem.
Firstly, it is essential to understand that setting default values for DAG run configurations can be approached in different ways, depending on your specific use case. One way to achieve this is by using the `default_args` dictionary in your DAG definition to pass in default values for various settings in your DAG. For example, you can set default values for the `start_date`, `end_date`, `owner`, `depends_on_past`, and `retries` parameters, among others.
Another approach to set default values for DAG run configurations is by using the `Variable` object in Airflow to store and retrieve default values for your DAGs. This approach is especially useful for storing default values that are used across several DAGs, as it facilitates centralized configuration management.
To use the `Variable` object to set default values, you will need to create a Python module that holds the default configuration dictionaries, where each dictionary holds the default values for a particular set of DAG parameters. You can then use these default dictionaries in your DAG definition to set the corresponding default values. For instance, you can set default values for the `email_on_failure`, `email_on_retry`, and `email`, among others, by passing the `default_args` parameter to your DAG definition as follows:
“`
from datetime import datetime, timedelta
from airflow import DAG
from airflow.models import Variable
default_dag_args = Variable.get(“default_dag_args”, deserialize_json=True)
default_args = default_dag_args[“default_args”]
dag = DAG(
“my_dag”,
default_args=default_args,
schedule_interval=timedelta(days=1),
)
“`
In conclusion, there are various ways to set default values for DAG run configurations in Airflow, depending on your specific use case. You can use the `default_args` dictionary in your DAG definition or the `Variable` object to store and retrieve default configuration dictionaries. Whichever approach you choose, be sure to test your DAGs thoroughly to ensure that the default values are being applied as expected. Best of luck with your coding!