**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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"""
        Retrieve the last processing time of a specific path.
        :param file_path: the path to the file that was processed
        :return: the runtime (in seconds) of the process of the last run, or
            None if the file was never processed.
        """
        stat = self._file_stats.get(file_path)
        return stat.last_duration.total_seconds() if stat and stat.last_duration else None
    def get_last_dag_count(self, file_path) -> int | None:
        """
        Retrieve the total DAG count at a specific path.
        :param file_path: the path to the file that was processed
        :return: the number of dags loaded from that file, or None if the file
            was never processed.
        """
        stat = self._file_stats.get(file_path)
        return stat.num_dags if stat else None
    def get_last_error_count(self, file_path) -> int | None:
        """
        Retrieve the total number of errors from processing a specific path.
        :param file_path: the path to the file that was processed
        :return: the number of import errors from processing, or None if the file
            was never processed.
        """
        stat = self._file_stats.get(file_path)
        return stat.import_errors if stat else None
    def get_last_finish_time(self, file_path) -> datetime | None: