**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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"""Get DataDog StatsD logger."""
        from datadog import DogStatsd
        dogstatsd = DogStatsd(
            host=conf.get("metrics", "statsd_host"),
            port=conf.getint("metrics", "statsd_port"),
            namespace=conf.get("metrics", "statsd_prefix"),
            constant_tags=cls.get_constant_tags(),
        )
        dogstatsd_allow_list = conf.get("metrics", "statsd_allow_list", fallback=None)
        allow_list_validator = AllowListValidator(dogstatsd_allow_list)
        datadog_metrics_tags = conf.get("metrics", "statsd_datadog_metrics_tags", fallback=True)
        return SafeDogStatsdLogger(dogstatsd, allow_list_validator, datadog_metrics_tags)
    @classmethod
    def get_constant_tags(cls):
        """Get constant DataDog tags to add to all stats."""
        tags = []
        tags_in_string = conf.get("metrics", "statsd_datadog_tags", fallback=None)
        if tags_in_string is None or tags_in_string == "":
            return tags
        else:
            for key_value in tags_in_string.split(","):
                tags.append(key_value)
            return tags
if TYPE_CHECKING:
    Stats: StatsLogger
else:
    class Stats(metaclass=_Stats):
        """Empty class for Stats - we use metaclass to inject the right one."""