**Description**


It would be great if the metrics we publish in Airflow change to include TAGs for "variable" parts of those (such as dag_id, task_id, pool name) rather than being part of the metrics.

See here: https://airflow.apache.org/docs/1.10.12/metrics.html, https://airflow.readthedocs.io/en/latest/logging-monitoring/metrics.html  - those variable parts should be tags.

We might consider to change those metrics by default in 2.0 and possibly introduce a backport in 1.10.13 to allow people to migrate.


**Use case / motivation**

Having the variable parts of the metrics makes it really difficult to aggregate the metrics. Seems that statsd python library does not support tags, but there are possible solutions by installing extensions:

https://stackoverflow.com/questions/49852654/sending-statsd-metrics-with-tags-from-python-client

**Related Issues**

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"""
        DagRuns with one successful and one future root task -> SUCCESS
        Noted: the DagRun state could be still in running state during CI.
        """
        clear_db_dags()
        dag_id = "test_dagrun_states_root_future"
        dag = self.dagbag.get_dag(dag_id)
        dag.sync_to_db()
        self.scheduler_job = SchedulerJob(num_runs=1, executor=self.null_exec, subdir=dag.fileloc)
        self.scheduler_job.run()
        first_run = DagRun.find(dag_id=dag_id, execution_date=DEFAULT_DATE)[0]
        ti_ids = [(ti.task_id, ti.state) for ti in first_run.get_task_instances()]
        assert ti_ids == [("current", State.SUCCESS)]
        assert first_run.state in [State.SUCCESS, State.RUNNING]
    def test_dagrun_deadlock_ignore_depends_on_past_advance_ex_date(self):