**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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task_instance,
                        )
                        session.query(TI).filter(
                            TI.dag_id == dag_id, TI.state == TaskInstanceState.SCHEDULED
                        ).update({TI.state: TaskInstanceState.FAILED}, synchronize_session="fetch")
                        continue
                    task_concurrency_limit: int | None = None
                    if serialized_dag.has_task(task_instance.task_id):
                        task_concurrency_limit = serialized_dag.get_task(
                            task_instance.task_id
                        ).max_active_tis_per_dag
                    if task_concurrency_limit is not None:
                        current_task_concurrency = task_concurrency_map[
                            (task_instance.dag_id, task_instance.task_id)
                        ]
                        if current_task_concurrency >= task_concurrency_limit:
                            self.log.info(
                                "Not executing %s since the task concurrency for"
                                " this task has been reached.",
                                task_instance,
                            )
                            starved_tasks.add((task_instance.dag_id, task_instance.task_id))
                            continue
                executable_tis.append(task_instance)
                open_slots -= task_instance.pool_slots
                dag_active_tasks_map[dag_id] += 1
                task_concurrency_map[(task_instance.dag_id, task_instance.task_id)] += 1
                pool_stats["open"] = open_slots
            is_done = executable_tis or len(task_instances_to_examine) < max_tis