**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**

<!-- Is there currently another issue associated with this? -->

"""
        Run a scheduler until any dag run reaches a terminal state, or the scheduler becomes "idle".
        This needs a DagRun to be pre-created (it can be in running or queued state) as no more will be
        created as we turn off creating new DagRuns via setting USE_JOB_SCHEDULE to false
        Note: This doesn't currently account for tasks that go into retry -- the scheduler would be detected
        as idle in that circumstance
        """
        
        
        
        
        def spy_on_return(orig, result):