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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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tests/operators/test_trigger_dagrun.py
#
#
#
import pathlib
import tempfile
from datetime import datetime
from unittest import TestCase
import pytest
from airflow.exceptions import AirflowException, DagRunAlreadyExists
from airflow.models import DAG, DagBag, DagModel, DagRun, Log, TaskInstance
from airflow.models.serialized_dag import SerializedDagModel
from airflow.operators.trigger_dagrun import TriggerDagRunOperator
from airflow.utils import timezone
from airflow.utils.session import create_session
from airflow.utils.state import State
DEFAULT_DATE = datetime(2019, 1, 1, tzinfo=timezone.utc)
TEST_DAG_ID = "testdag"
TRIGGERED_DAG_ID = "triggerdag"
DAG_SCRIPT = (
    "from datetime import datetime\n\n"
    "from airflow.models import DAG\n"
    "from airflow.operators.dummy import DummyOperator\n\n"
    "dag = DAG(\n"
    'dag_id="{dag_id}", \n'
    'default_args={{"start_date": datetime(2019, 1, 1)}}, \n'
    "schedule_interval=None,\n"
    ")\n"
    'task = DummyOperator(task_id="test", dag=dag)'
).format(dag_id=TRIGGERED_DAG_ID)
class TestDagRunOperator(TestCase):