[GitHub] [airflow] dstandish commented on issue #19096: Sets in parameters cause "TypeError: Object of type set is not JSON serializable"

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

dstandish commented on issue #19096:
URL: https://github.com/apache/airflow/issues/19096#issuecomment-953232043


   Taking a look at this.  But first wanted to establish a workaround.  And this seems to work:
   
   ```python
   from datetime import datetime
   from typing import Any
   
   from airflow.models import DAG, BaseOperator
   
   
   dag = DAG("paramtest",
             start_date=datetime(2021, 1, 1),
             schedule_interval="@daily", catchup=False, user_defined_macros={'set': lambda x: set(x)})
   
   
   @dag.task(params={"a": [1, 2, 3], "b": [3, 4, 5]})
   def intersect(intersection):
       print(intersection)
   
   
   intersect("{{ set(params.a).intersection(params.b).pop() }}")
   ```
   
   Notice that you need to add `set` as a macro, because builtins are not available in jinja.  But this allows you to use those same set  operations in a template. 


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