Adding Prometheus metrics, refactoring code

app/Prometheus/utils.go

@@ -0,0 +1,49 @@
+// Package prometheus provides useful functions to initialize and populate metrics
+package prometheus
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// Metrics structure for storing counter
+type Metrics struct {
+	ClientHTTPReqs  *prometheus.CounterVec
+	BackendHTTPReqs *prometheus.CounterVec
+}
+
+var (
+	//HTTPCounter Metrics
+	HTTPCounter = InitializeHTTPReqCounter(Reg)
+	Reg         = prometheus.NewRegistry()
+)
+
+// IncrementClientCounterVec increments the counter with method label provided.
+func IncrementClientCounterVec(m string) {
+	HTTPCounter.ClientHTTPReqs.WithLabelValues(m).Inc()
+	return
+}
+
+// IncrementBackendCounterVec increments the counter with method label provided.
+func IncrementBackendCounterVec(m string) {
+	HTTPCounter.BackendHTTPReqs.WithLabelValues(m).Inc()
+	return
+}
+
+// InitializeHTTPReqCounter inits the httpReqs counter that will be exported.
+func InitializeHTTPReqCounter(reg prometheus.Registerer) *Metrics {
+	HTTPCounters := &Metrics{
+		ClientHTTPReqs: prometheus.NewCounterVec(prometheus.CounterOpts{
+			Name: "client_http_requests_total",
+			Help: "How many HTTP requests processed, partitioned by HTTP method.",
+		},
+			[]string{"method"},
+		),
+		BackendHTTPReqs: prometheus.NewCounterVec(prometheus.CounterOpts{
+			Name: "backend_http_requests_total",
+			Help: "How many HTTP requests sent to backend, partitioned by HTTP method.",
+		},
+			[]string{"method"},
+		),
+	}
+	return HTTPCounters
+}