filer: adds basic metrics pushing to Prometheus gateway

weed/server/metrics.go

@@ -0,0 +1,27 @@
+package weed_server
+
+import "github.com/prometheus/client_golang/prometheus"
+
+var (
+	filerRequestCounter = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "SeaweedFS",
+			Subsystem: "filer",
+			Name:      "request_total",
+			Help:      "Counter of filer requests.",
+		}, []string{"type"})
+
+	filerRequestHistogram = prometheus.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: "SeaweedFS",
+			Subsystem: "filer",
+			Name:      "request_seconds",
+			Help:      "Bucketed histogram of filer request processing time.",
+			Buckets:   prometheus.ExponentialBuckets(0.0005, 2, 18),
+		}, []string{"type"})
+)
+
+func init() {
+	prometheus.MustRegister(filerRequestCounter)
+	prometheus.MustRegister(filerRequestHistogram)
+}