Airflow’s GrpcOperator supports passing template variables in the data field. However, the protobuf-generated message object that needs to go into the data field is evaluated at parse time, which breaks the templates.

For example, in the task below, I want to send a request to a gRPC server that has the DAG run’s date ds in its message body:

task_grpc = GrpcOperator(
    dag=dag,
    task_id="task_grpc",
    grpc_conn_id="grpc_default",
    stub_class=CustomGrpcServiceStub,
    call_func="CustomGrpcServiceFunction",
    response_callback=CustomGrpcService_callback,
    streaming=False,
    data = {"request": proto_pb2.CustomGrpcServiceRequest(request_date="{{ ds }}")}
)

This will fail, as the request_date is always rendered as "{ ds }". Is there a workaround to achieve templated fields in the protobuf message objects?

I tried to write a user-defined macro as suggested in https://github.com/apache/airflow/discussions/36661, but that does not change the outcome.