A resource tag is a key-value label that gives a metric a dimension beyond its name. Metrics can share a name while differing in tag values; each unique combination of values identifies a separate data series. This makes related measurements easier to query and aggregate. section 10.3.3
HTTP request counts
Counters named `http_requests` can carry `method`, `path`, and `status` tags. Aggregate by `method` to count requests using a particular HTTP method, or combine `path` and `status` to count responses for a particular route and status code. section 10.3.3
Choose dimensions with low cardinality: a user ID is a poor tag value because each user has a distinct ID. Quarkus uses dimensions in many built-in metrics, and business metrics can use them where they help answer a query. section 10.3.3
A Micrometer `@Counted` annotation on a method produces counters with `class`, `method`, `exception`, and `result` dimensions. Call the method at least once before looking for its counter at `/q/metrics`: registration is lazy when the owning bean is first instantiated. section 10.3.6
method_counted_total{
class="org.acme.inventory.service.GraphQLInventoryService",
exception="none",
method="register",
result="success"} 1.0
The Prometheus output shows one counted-method series with its tag values and count. section 10.3.6
