Info about the parameter "conf" when triggering a DAG

[AmarEL]

Description

The information and examples about the optional JSON conf when triggering a dag from UI or by CLI needs to be included in the documentation.

Use case / motivation

I would like to have some reference in Docs since conf is not even mentioned as a parameter in the create_dagrun method in the specification of parameters. I would like to have too some examples of how to use conf in a DAG definition code since there is no section for that yet and some people, like me, would be missing this information about how to access this parameter.

    @provide_session
    def create_dagrun(self,
                      run_id,
                      state,
                      execution_date=None,
                      start_date=None,
                      external_trigger=False,
                      conf=None,
                      session=None):
        """
        Creates a dag run from this dag including the tasks associated with this dag.
        Returns the dag run.
        :param run_id: defines the run id for this dag run
        :type run_id: str
        :param execution_date: the execution date of this dag run
        :type execution_date: datetime.datetime
        :param state: the state of the dag run
        :type state: airflow.utils.state.State
        :param start_date: the date this dag run should be evaluated
        :type start_date: datetime
        :param external_trigger: whether this dag run is externally triggered
        :type external_trigger: bool
        :param session: database session
        :type session: sqlalchemy.orm.session.Session
        """

Related Issues

#7312

[boring-cyborg]

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[mik-laj]

I added a tip in Web UI.
https://github.com/apache/airflow/commits/master?after=b4b84a1933d055a2803b80b990482a7257a203ff+69
What else should we do?

[AmarEL]

That works!
But I think that adding the param conf and its type in the create_dagrun docstring would be more complete, because the create_dagrun method doesn't have this param in the docstring.

[kaxil]

Related issue I had created: #9238 (comment) -will add some more docs for 1.10.11