Metrics package unit tests

Issue: COSI-65

pkg/metrics/metrics_test.go

@@ -0,0 +1,175 @@
+package metrics_test
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/scality/cosi-driver/pkg/constants"
+	"github.com/scality/cosi-driver/pkg/metrics"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+func TestGRPCFactorySuite(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Metrics Test Suite")
+}
+
+var _ = Describe("Metrics Server", func() {
+	var (
+		server      *http.Server
+		listener    net.Listener
+		registry    *prometheus.Registry
+		grpcMetrics *prometheus.CounterVec
+	)
+
+	BeforeEach(func() {
+		// Create a fresh registry
+		registry = prometheus.NewRegistry()
+
+		// Create and register gRPC metrics with the fresh registry
+		grpcMetrics = prometheus.NewCounterVec(
+			prometheus.CounterOpts{
+				Name: "grpc_server_started_total",
+				Help: "Total number of RPCs started on the server.",
+			},
+			[]string{"grpc_method", "grpc_service", "grpc_type"},
+		)
+		Expect(registry.Register(grpcMetrics)).To(Succeed())
+
+		// Increment gRPC metrics to simulate usage
+		grpcMetrics.WithLabelValues("DriverGetInfo", "cosi.v1alpha1.Identity", "unary").Add(5)
+		grpcMetrics.WithLabelValues("DriverCreateBucket", "cosi.v1alpha1.Provisioner", "unary").Add(4)
+		grpcMetrics.WithLabelValues("DriverDeleteBucket", "cosi.v1alpha1.Provisioner", "unary").Add(3)
+		grpcMetrics.WithLabelValues("DriverGrantBucketAccess", "cosi.v1alpha1.Provisioner", "unary").Add(2)
+		grpcMetrics.WithLabelValues("DriverRevokeBucketAccess", "cosi.v1alpha1.Provisioner", "unary").Add(1)
+
+		// Increment the cosi_requests_total counter
+		Expect(registry.Register(metrics.RequestsTotal)).To(Succeed())
+		metrics.RequestsTotal.With(prometheus.Labels{"method": "GET", "status": "200"}).Inc()
+
+		// Wrap the Prometheus handler with the fresh registry
+		mux := http.NewServeMux()
+		mux.Handle(constants.MetricsPath, promhttp.HandlerFor(registry, promhttp.HandlerOpts{}))
+
+		// Create and start the metrics server
+		var err error
+		server = &http.Server{Handler: mux}
+		listener, err = net.Listen("tcp", "127.0.0.1:0")
+		Expect(err).NotTo(HaveOccurred())
+
+		go func() {
+			err := server.Serve(listener)
+			if err != nil && err != http.ErrServerClosed {
+				panic(err)
+			}
+		}()
+
+		// Wait for the server to start
+		time.Sleep(100 * time.Millisecond)
+	})
+
+	AfterEach(func() {
+		// Shutdown the server if it is still running
+		if server != nil {
+			err := server.Close()
+			if err != nil && !strings.Contains(err.Error(), "use of closed network connection") {
+				Expect(err).NotTo(HaveOccurred())
+			}
+		}
+
+		// Close the listener if it's still open
+		if listener != nil {
+			err := listener.Close()
+			if err != nil && !strings.Contains(err.Error(), "use of closed network connection") {
+				Expect(err).NotTo(HaveOccurred())
+			}
+		}
+	})
+
+	It("should expose gRPC metrics on the Prometheus endpoint", func() {
+		addr := listener.Addr().String()
+		resp, err := http.Get(fmt.Sprintf("http://%s%s", addr, constants.MetricsPath))
+		Expect(err).NotTo(HaveOccurred())
+		Expect(resp.StatusCode).To(Equal(http.StatusOK))
+
+		// Read and validate metrics
+		body, err := io.ReadAll(resp.Body)
+		Expect(err).NotTo(HaveOccurred())
+		Expect(resp.Body.Close()).To(Succeed())
+		metricsOutput := string(body)
+
+		Expect(metricsOutput).To(ContainSubstring(`grpc_server_started_total{grpc_method="DriverGetInfo",grpc_service="cosi.v1alpha1.Identity",grpc_type="unary"} 5`))
+		Expect(metricsOutput).To(ContainSubstring(`grpc_server_started_total{grpc_method="DriverCreateBucket",grpc_service="cosi.v1alpha1.Provisioner",grpc_type="unary"} 4`))
+		Expect(metricsOutput).To(ContainSubstring(`grpc_server_started_total{grpc_method="DriverDeleteBucket",grpc_service="cosi.v1alpha1.Provisioner",grpc_type="unary"} 3`))
+		Expect(metricsOutput).To(ContainSubstring(`grpc_server_started_total{grpc_method="DriverGrantBucketAccess",grpc_service="cosi.v1alpha1.Provisioner",grpc_type="unary"} 2`))
+		Expect(metricsOutput).To(ContainSubstring(`grpc_server_started_total{grpc_method="DriverRevokeBucketAccess",grpc_service="cosi.v1alpha1.Provisioner",grpc_type="unary"} 1`))
+		Expect(metricsOutput).To(ContainSubstring(`cosi_requests_total{method="GET",status="200"} 1`))
+	})
+
+	It("should gracefully shutdown the server", func() {
+		Expect(server.Close()).To(Succeed())
+	})
+
+	It("should handle invalid metric labels gracefully", func() {
+		Expect(func() {
+			grpcMetrics.WithLabelValues("InvalidMethod", "InvalidService", "InvalidType").Inc()
+		}).NotTo(Panic())
+	})
+
+	It("should return 404 for invalid metrics paths", func() {
+		addr := listener.Addr().String()
+		resp, err := http.Get(fmt.Sprintf("http://%s/invalid-path", addr))
+		Expect(err).NotTo(HaveOccurred())
+		Expect(resp.StatusCode).To(Equal(http.StatusNotFound))
+		Expect(resp.Body.Close()).To(Succeed())
+	})
+
+	It("should handle multiple concurrent requests", func() {
+		addr := listener.Addr().String()
+		const numRequests = 10
+		done := make(chan bool, numRequests)
+
+		for i := 0; i < numRequests; i++ {
+			go func() {
+				resp, err := http.Get(fmt.Sprintf("http://%s%s", addr, constants.MetricsPath))
+				Expect(err).NotTo(HaveOccurred())
+				Expect(resp.StatusCode).To(Equal(http.StatusOK))
+				Expect(resp.Body.Close()).To(Succeed())
+				done <- true
+			}()
+		}
+
+		for i := 0; i < numRequests; i++ {
+			<-done
+		}
+	})
+
+	It("should expose additional custom metrics", func() {
+		customCounter := prometheus.NewCounter(prometheus.CounterOpts{
+			Name: "custom_metric_total",
+			Help: "A custom metric for testing purposes.",
+		})
+		Expect(registry.Register(customCounter)).To(Succeed())
+		customCounter.Add(42)
+
+		addr := listener.Addr().String()
+		resp, err := http.Get(fmt.Sprintf("http://%s%s", addr, constants.MetricsPath))
+		Expect(err).NotTo(HaveOccurred())
+		Expect(resp.StatusCode).To(Equal(http.StatusOK))
+
+		// Validate custom metrics
+		body, err := io.ReadAll(resp.Body)
+		Expect(err).NotTo(HaveOccurred())
+		Expect(resp.Body.Close()).To(Succeed())
+		Expect(string(body)).To(ContainSubstring(`custom_metric_total 42`))
+	})
+})