[GitHub] [airflow] chronitis commented on issue #5231: [AIRFLOW-4456] Add BranchOperator

[GitBox <gi...@apache.org>]

chronitis commented on issue #5231: [AIRFLOW-4456] Add BranchOperator
URL: https://github.com/apache/airflow/pull/5231#issuecomment-489062169
 
 
   I take the comment that this logic shouldn't be duplicated between this operator and `BranchPythonOperator` - I'll look at a better way of avoiding duplication.
   
   The reason for not subclassing `BranchPythonOperator` was that creating a bound reference to the method in `__init__` seems to cause issues with templating:
   
   ```python
   class MyBranch(BranchPythonOperator):
       template_fields = ('myvar', )
       def __init__(self, myvar, **kwargs):
          self.myvar = myvar
          super().__init__(python_callable=self.choose_branch)
   
       def choose_branch(self):
           # for reasons I'm not totally clear on, but I'm guessing the reference to `self` before `super()`
           # has returned creates a closure, any {{ templates }} in `self.myvar` here don't get evaluated
           return self.myvar
   ```
   
   Less importantly, it seems a bit inelegant to need to pass a reference to the method like this.

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services