**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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"""
        Tests that adding State.failed_states and State.success_states work as expected.
        """
        dag = DAG(dag_id="test_dagrun_states", start_date=DEFAULT_DATE)
        dag_task_success = EmptyOperator(task_id="dummy", dag=dag)
        dag_task_failed = EmptyOperator(task_id="dummy2", dag=dag)
        initial_task_states = {
            dag_task_success.task_id: TaskInstanceState.SUCCESS,
            dag_task_failed.task_id: TaskInstanceState.FAILED,
        }
        dag_run = self.create_dag_run(dag=dag, task_states=initial_task_states, session=session)
        ti_success = dag_run.get_task_instance(dag_task_success.task_id)
        ti_failed = dag_run.get_task_instance(dag_task_failed.task_id)
        assert ti_success.state in State.success_states
        assert ti_failed.state in State.failed_states
@pytest.mark.parametrize(
    ("run_type", "expected_tis"),
    [
        pytest.param(DagRunType.MANUAL, 1, id="manual"),
        pytest.param(DagRunType.BACKFILL_JOB, 3, id="backfill"),
    ],
)
@mock.patch.object(Stats, "incr")
def test_verify_integrity_task_start_and_end_date(Stats_incr, session, run_type, expected_tis):