Imports go.opentelemetry.io/otel/api/metric go.opentelemetry.io/otel/sdk/metric/controller/push go.opentelemetry.io/contrib/exporters/metric/cortex go.opentelemetry.io/otel/sdk/resource go.opentelemetry.io/otel/label go.opentelemetry.io/contrib/exporters/metric/cortex/utils Standard library imports context fmt math/rand time