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**Description**

Airflow 1.10 support providing a run_id to TriggerDagRunOperator using [DagRunOrder](https://github.com/apache/airflow/blob/v1-10-stable/airflow/operators/dagrun_operator.py#L30-L33) object that will be returned after calling [TriggerDagRunOperator#python_callable](https://github.com/apache/airflow/blob/v1-10-stable/airflow/operators/dagrun_operator.py#L88-L95). With https://github.com/apache/airflow/pull/6317 (Airflow 2.0), this behavior changed and one could not provide run_id anymore to the triggered dag, which is very odd to say the least.

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**Use case / motivation**

I want to be able to provide run_id for the TriggerDagRunOperator. In my case, I use the TriggerDagRunOperator to trigger 30K dag_run daily and will be so annoying to see them having unidentifiable run_id.

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After discussing with @ashb
**Suggested fixes can be**
 * provide a templated run_id as a parameter to TriggerDagRunOperator.
 * restore the old behavior of Airflow 1.10, where DagRunOrder holds the run_id and dag_run_conf of the triggered dag
 * create a new sub-class of TriggerDagRunOperator to fully customize it

**Are you willing to submit a PR?**

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**Related Issues**

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airflow/operators/trigger_dagrun.py
"""
    Triggers a DAG run for a specified ``dag_id``
    :param trigger_dag_id: the dag_id to trigger (templated)
    :type trigger_dag_id: str
    :param conf: Configuration for the DAG run
    :type conf: dict
    :param execution_date: Execution date for the dag (templated)
    :type execution_date: str or datetime.datetime
    :param reset_dag_run: Whether or not clear existing dag run if already exists.
        This is useful when backfill or rerun an existing dag run.
        When reset_dag_run=False and dag run exists, DagRunAlreadyExists will be raised.
        When reset_dag_run=True and dag run exists, existing dag run will be cleared to rerun.
    :type reset_dag_run: bool
    :param wait_for_completion: Whether or not wait for dag run completion. (default: False)
    :type wait_for_completion: bool
    :param poke_interval: Poke interval to check dag run status when wait_for_completion=True.
        (default: 60)
    :type poke_interval: int
    :param allowed_states: list of allowed states, default is ``['success']``
    :type allowed_states: list
    :param failed_states: list of failed or dis-allowed states, default is ``None``
    :type failed_states: list
    """
    template_fields = ("trigger_dag_id", "execution_date", "conf")
    template_fields_renderers = {"conf": "py"}
    ui_color = "#ffefeb"
    @property
    def operator_extra_links(self):