observability

type AppMetrics interface {
	// IncCacheHits increments the cache hits counter for the given repository.
	IncCacheHits(repository string)

	// IncCacheMisses increments the cache misses counter for the given repository.
	IncCacheMisses(repository string)

	// IncCoalescedRequests increments the counter of requests served by coalescing
	// onto an in-flight upstream fetch, for the given repository.
	IncCoalescedRequests(repository string)

	// IncCacheEntryMissing increments the counter of serve-time cache misses for
	// the given repository: a fetch that stored or coalesced successfully but
	// found its entry gone when it went to serve it, and had to re-fetch.
	IncCacheEntryMissing(repository string)

	// IncNonCacheableRequests increments the non-cacheable requests counter for the given reason.
	IncNonCacheableRequests(reason string)

	// IncCacheEvictions increments the cache-evictions counter for the given reason
	// (ttl, size, reject). Reason distinguishes sliding-TTL expiration from
	// size-driven LFU eviction from admission-policy rejection.
	IncCacheEvictions(reason string)

	// ObserveFetchDuration records the end-to-end duration of a cacheable fetch,
	// labelled by result (hit, miss, coalesce, bypass).
	ObserveFetchDuration(result string, seconds float64)

	// IncErrors increments the error counter for the given type (upstream, cache, internal).
	IncErrors(errorType string)
}

type CacheCollector struct {
	// contains filtered or unexported fields
}

type MockAppMetrics struct {
	// contains filtered or unexported fields
}

type NullAppMetrics struct{}

type PrometheusAppMetrics struct {
	// contains filtered or unexported fields
}

type PrometheusManager struct {
	// contains filtered or unexported fields
}