dinigo opened a new issue #20857:
URL: https://github.com/apache/airflow/issues/20857
### Apache Airflow version
2.2.3 (latest released)
### What happened
I'm working on an operator that receives a lot of params, by convention with
the rest of the developers one of the named params is called `output`. However
when you add this param to the `templated_fields` airflow Fails with the
mentioned Exception
It seems like a reasonable name for a param. I've given a look at the
`airflow.utils.dag_cycle_tester` but I couln't find the reason why this is
raising the exception
```
Traceback (most recent call last):
File
"/home/airflow/.local/lib/python3.9/site-packages/airflow/models/dagbag.py",
line 402, in _process_modules
self.bag_dag(dag=dag, root_dag=dag)
File
"/home/airflow/.local/lib/python3.9/site-packages/airflow/models/dagbag.py",
line 426, in bag_dag
self._bag_dag(dag=dag, root_dag=root_dag, recursive=True)
File
"/home/airflow/.local/lib/python3.9/site-packages/airflow/models/dagbag.py",
line 434, in _bag_dag
check_cycle(dag) # throws if a task cycle is found
File
"/home/airflow/.local/lib/python3.9/site-packages/airflow/utils/dag_cycle_tester.py",
line 76, in check_cycle
child_to_check = _check_adjacent_tasks(current_task_id, task)
File
"/home/airflow/.local/lib/python3.9/site-packages/airflow/utils/dag_cycle_tester.py",
line 62, in _check_adjacent_tasks
raise AirflowDagCycleException(msg)
airflow.exceptions.AirflowDagCycleException: Cycle detected in DAG. Faulty
task: test_template_output_task
```
### What you expected to happen
Should be able to template this `output` param
### How to reproduce
Simply try the following
```python
from datetime import datetime
from airflow import DAG
from airflow.models import BaseOperator
class TemplateOutputOperator(BaseOperator):
template_fields = ['output']
def __init__(self, output: str = None, *args, **kwargs):
super(TemplateOutputOperator, self).__init__(*args, **kwargs)
with DAG(
dag_id='test_template_output',
start_date=datetime(2021, 10, 22),
schedule_interval='@daily',
catchup=False,
doc_md=__doc__,
) as dag:
TemplateOutputOperator(task_id='test_template_output_task')
```
Should generate
### Operating System
Official docker image
### Versions of Apache Airflow Providers
Default ones
### Deployment
Docker-Compose
### Deployment details
Here's my docker-compose and Dockerfile
```Dockerfile
FROM apache/airflow:2.2.3-python3.8
USER root
RUN apt-get update && apt-get install git -y
USER airflow
COPY requirements.txt .
RUN set -ex && pip install --user --requirement requirements.txt
```
```yaml
version: '3.9'
services:
airflow:
build: .
secrets:
- gcp_credentials.json
environment:
AIRFLOW__WEBSERVER__NAVBAR_COLOR: orange
AIRFLOW__WEBSERVER__EXPOSE_CONFIG: True
AIRFLOW__CORE__LOAD_DEFAULT_CONNECTIONS: False
GOOGLE_APPLICATION_CREDENTIALS: /run/secrets/gcp_credentials.json
command: standalone
volumes:
# mounts dags folder
- ./dags:/opt/airflow/dags
ports:
- "8080:8080"
```
### Anything else
_No response_
### Are you willing to submit PR?
- [ ] Yes I am willing to submit a PR!
### Code of Conduct
- [X] I agree to follow this project's [Code of
Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)
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