Fix metrics to not tie them to loglevel (#149)

* Remove /health and /metrics req logging; closes #127

* Move metrics to metrics package

* Prometheus for index and car lookups; closes #126

* Cleanup metrics; closes #128

* Report latency histograms regardless of log level

Previously the latency histograms were tied to verbosity level which meant
that they were not published unless using v=5. This makes the metrics always visible.

http-range.go

@@ -32,6 +32,30 @@ func (r *readCloserWrapper) ReadAt(p []byte, off int64) (n int, err error) {
 	startedAt := time.Now()
 	defer func() {
 		took := time.Since(startedAt)
+		var isIndex, isCar bool
+
+		// Metrics want to always report
+		// if has suffix .index, then it's an index file
+		if strings.HasSuffix(r.name, ".index") {
+			isIndex = true
+			// get the index name, which is the part before the .index suffix, after the last .
+			indexName := strings.TrimSuffix(r.name, ".index")
+			// split the index name by . and get the last part
+			byDot := strings.Split(indexName, ".")
+			if len(byDot) > 0 {
+				indexName = byDot[len(byDot)-1]
+			}
+			// TODO: distinguish between remote and local index reads
+			metrics.IndexLookupHistogram.WithLabelValues(indexName).Observe(float64(took.Seconds()))
+		}
+		// if has suffix .car, then it's a car file
+		if strings.HasSuffix(r.name, ".car") || r.isSplitCar {
+			isCar = true
+			carName := filepath.Base(r.name)
+			// TODO: distinguish between remote and local index reads
+			metrics.CarLookupHistogram.WithLabelValues(carName).Observe(float64(took.Seconds()))
+		}
+
 		if klog.V(5).Enabled() {
 			var icon string
 			if r.isRemote {
@@ -41,31 +65,19 @@ func (r *readCloserWrapper) ReadAt(p []byte, off int64) (n int, err error) {
 				// add disk icon
 				icon = "💾 "
 			}
+
 			prefix := icon + "[READ-UNKNOWN]"
-			// if has suffix .index, then it's an index file
-			if strings.HasSuffix(r.name, ".index") {
+			if isIndex {
 				prefix = icon + azureBG("[READ-INDEX]")
-				// get the index name, which is the part before the .index suffix, after the last .
-				indexName := strings.TrimSuffix(r.name, ".index")
-				// split the index name by . and get the last part
-				byDot := strings.Split(indexName, ".")
-				if len(byDot) > 0 {
-					indexName = byDot[len(byDot)-1]
-				}
-				// TODO: distinguish between remote and local index reads
-				metrics.IndexLookupHistogram.WithLabelValues(indexName).Observe(float64(took.Seconds()))
-			}
-			// if has suffix .car, then it's a car file
-			if strings.HasSuffix(r.name, ".car") || r.isSplitCar {
+			} else if isCar {
+
 				if r.isSplitCar {
 					prefix = icon + azureBG("[READ-SPLIT-CAR]")
 				} else {
 					prefix = icon + purpleBG("[READ-CAR]")
 				}
-				carName := filepath.Base(r.name)
-				// TODO: distinguish between remote and local index reads
-				metrics.CarLookupHistogram.WithLabelValues(carName).Observe(float64(took.Seconds()))
 			}
+
 			klog.V(5).Infof(prefix+" %s:%d+%d (%s)\n", (r.name), off, len(p), took)
 		}
 	}()