Consolidate rate limiter metrics

Signed-off-by: Arve Knudsen <[email protected]>

Author: aknuds1

pkg/storage/bucket/gcs/rate_limiter.go

@@ -45,7 +45,7 @@ type rateLimiter struct {
 
 // newRateLimiter creates a new rate limiter with exponential doubling.
 // The rate starts at initialQPS (capped by maxQPS) and doubles every rampPeriod until it reaches maxQPS.
-// The operation parameter is used to differentiate metrics (e.g., "upload" or "read").
+// The mode parameter configures whether to rate limit uploads or reads.
 // If reg is nil, no metrics will be registered.
 func newRateLimiter(maxQPS int, rampPeriod time.Duration, mode rateLimiterMode, reg prometheus.Registerer) *rateLimiter {
 	var initialQPS int
@@ -71,17 +71,21 @@ func newRateLimiter(maxQPS int, rampPeriod time.Duration, mode rateLimiterMode,
 	}
 
 	if reg != nil {
+		constLabels := prometheus.Labels{"operation": operation}
 		rl.rateLimitedSeconds = promauto.With(reg).NewCounter(prometheus.CounterOpts{
-			Name: "cortex_gcs_" + operation + "_rate_limited_seconds_total",
-			Help: "Total seconds spent waiting due to GCS " + operation + " rate limiting.",
+			Name:        "cortex_gcs_rate_limited_seconds_total",
+			Help:        "Total seconds spent waiting due to GCS rate limiting.",
+			ConstLabels: constLabels,
 		})
 		rl.currentQPSGauge = promauto.With(reg).NewGauge(prometheus.GaugeOpts{
-			Name: "cortex_gcs_" + operation + "_current_qps",
-			Help: "Current queries per second limit for GCS " + operation + "s.",
+			Name:        "cortex_gcs_current_qps",
+			Help:        "Current queries per second limit for GCS operations.",
+			ConstLabels: constLabels,
 		})
 		rl.requestsTotal = promauto.With(reg).NewCounterVec(prometheus.CounterOpts{
-			Name: "cortex_gcs_" + operation + "_requests_total",
-			Help: "Total GCS " + operation + " requests, labeled by whether they were allowed immediately or rate limited.",
+			Name:        "cortex_gcs_requests_total",
+			Help:        "Total GCS requests, labeled by whether they were allowed immediately or rate limited.",
+			ConstLabels: constLabels,
 		}, []string{"allowed"})
 		rl.currentQPSGauge.Set(float64(startQPS))
 	}