Related to
[`internal#1139`](https://github.com/coder/internal/issues/1139)
This implements some prometheus metrics for records being removed from
the database. Currently we're tracking the following fields being
removed from the DB by this. They're viewable in the
`/api/v2/debug/metrics` endpoint.
* `expired_api_keys`
* `aibridge_records`
* `connection_logs`
* `duration`
```
# HELP coderd_dbpurge_iteration_duration_seconds Duration of each dbpurge iteration in seconds.
# TYPE coderd_dbpurge_iteration_duration_seconds histogram
coderd_dbpurge_iteration_duration_seconds_bucket{success="true",le="1"} 1
coderd_dbpurge_iteration_duration_seconds_bucket{success="true",le="5"} 1
coderd_dbpurge_iteration_duration_seconds_bucket{success="true",le="10"} 1
coderd_dbpurge_iteration_duration_seconds_bucket{success="true",le="30"} 1
coderd_dbpurge_iteration_duration_seconds_bucket{success="true",le="60"} 1
coderd_dbpurge_iteration_duration_seconds_bucket{success="true",le="300"} 1
coderd_dbpurge_iteration_duration_seconds_bucket{success="true",le="600"} 1
coderd_dbpurge_iteration_duration_seconds_bucket{success="true",le="+Inf"} 1
coderd_dbpurge_iteration_duration_seconds_sum{success="true"} 0.014787814
coderd_dbpurge_iteration_duration_seconds_count{success="true"} 1
# HELP coderd_dbpurge_records_purged_total Total number of records purged by type.
# TYPE coderd_dbpurge_records_purged_total counter
coderd_dbpurge_records_purged_total{record_type="aibridge_records"} 0
coderd_dbpurge_records_purged_total{record_type="audit_logs"} 0
coderd_dbpurge_records_purged_total{record_type="connection_logs"} 0
coderd_dbpurge_records_purged_total{record_type="expired_api_keys"} 0
coderd_dbpurge_records_purged_total{record_type="workspace_agent_logs"} 0
```
| Position | Pull-request |
| -------- | ------------ |
| ✅ | [feat: add prometheus observability metrics for
`dbpurge`](https://github.com/coder/coder/pull/21074) |
| | [feat: add rbac specificity for
`dbpurge`](https://github.com/coder/coder/pull/21088) |
Jake Howell
00793cc0b5