@spinajs/telemetry-common

The metric abstraction shared by @spinajs/telemetry and by packages that must publish metrics without taking on the HTTP stack.

@spinajs/telemetry depends on @spinajs/http, @spinajs/log, @spinajs/validation and @spinajs/configuration — it serves /metrics, /health and the telemetry JSON api. A package that only wants to record a metric, such as @spinajs/orm publishing connection-pool gauges, must not drag any of that underneath itself.

So this package holds exactly the part that needs nothing but @spinajs/di and prom-client:

• Metrics — a @Singleton() wrapper over a PRIVATE prom-client Registry, with the declarative defineMetrics( prefix, defs ) factory and an async Prometheus text renderer,
• MetricDef / MetricType / AnyMetric / MetricMap,
• the prom-client metric types, re-exported so consumers need no direct prom-client dependency.

@spinajs/telemetry re-exports all of it, so import { Metrics } from '@spinajs/telemetry' keeps working and both packages share ONE Metrics class identity — which matters, because DI resolves the singleton by that identity and a second copy would mean a second, separate registry.

Same pattern as @spinajs/configuration-common and @spinajs/log-common.