**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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def setup_method(self):
        dictConfig(DEFAULT_LOGGING_CONFIG)
        clear_db_runs()
        clear_db_serialized_dags()
        clear_db_dags()
        clear_db_callbacks()
    def teardown_class(self):
        clear_db_runs()
        clear_db_serialized_dags()
        clear_db_dags()
        clear_db_callbacks()
    def run_processor_manager_one_loop(self, manager, parent_pipe):
        if not manager._async_mode:
            parent_pipe.send(DagParsingSignal.AGENT_RUN_ONCE)
        results = []
        while True:
            manager._run_parsing_loop()
            while parent_pipe.poll(timeout=0.01):
                obj = parent_pipe.recv()
                if not isinstance(obj, DagParsingStat):
                    results.append(obj)
                elif obj.done:
                    return results
            raise RuntimeError("Shouldn't get here - nothing to read, but manager not finished!")
    @conf_vars({("core", "load_examples"): "False"})
    def test_remove_file_clears_import_error(self, tmpdir):