NewMetric associates prometheus.Collector based on Metric.Type.

NewPrometheus generates a new set of metrics with a certain subsystem name.

Metric is a definition for the name, description, type, ID, and prometheus.Collector type (i.e.

Prometheus contains the metrics gathered by the instance and its path.

PrometheusPushGateway contains the configuration for pushing to a Prometheus pushgateway (optional).

RequestCounterURLLabelMappingFn is a function which can be supplied to the middleware to control the cardinality of the request counter's "url" label, which might be required in some contexts.