Make Prometheus trait compatible with Knative Serving

pkg/trait/prometheus.go

@@ -121,10 +121,17 @@ func (t *prometheusTrait) Apply(e *Environment) (err error) {
 	options := []string{strconv.Itoa(t.Port), path.Join(prometheusJmxExporterConfigMountPath, prometheusJmxExporterConfigFileName)}
 	container.Args = append(container.Args, "-javaagent:dependencies/io.prometheus.jmx.jmx_prometheus_javaagent-0.3.1.jar="+strings.Join(options, ":"))
 
-	// Add the container port
+	// Configure the Prometheus container port
 	containerPort := t.getContainerPort()
-	container.Ports = append(container.Ports, *containerPort)
-	condition.Message = fmt.Sprintf("%s(%s/%d)", container.Name, containerPort.Name, containerPort.ContainerPort)
+	controller, err := e.DetermineControllerStrategy(t.Ctx, t.Client)
+	if err != nil {
+		return err
+	}
+	// Skip declaring the Prometheus port when Knative is enabled, as only one container port is supported
+	if controller != ControllerStrategyKnativeService {
+		container.Ports = append(container.Ports, *containerPort)
+	}
+	condition.Message = fmt.Sprintf("%s(%d)", container.Name, containerPort.ContainerPort)
 
 	// Retrieve the service or create a new one if the service trait is enabled
 	serviceEnabled := false
@@ -135,14 +142,18 @@ func (t *prometheusTrait) Apply(e *Environment) (err error) {
 			serviceEnabled = serviceTrait.isEnabled()
 		}
 		if serviceEnabled {
-			// add a new service if not already created
+			// Add a new service if not already created
 			service = getServiceFor(e)
+			// Override the service name if none exists.
+			// This is required for Knative Serving, that checks no standard eponymous service exist
+			service.Name = service.Name + "-prometheus"
 			e.Resources.Add(service)
 		}
+	} else {
+		serviceEnabled = true
 	}
 
 	// Add the service port and service monitor resource
-	// A better strategy may be needed when the Knative profile is active
 	if serviceEnabled {
 		servicePort := t.getServicePort()
 		service.Spec.Ports = append(service.Spec.Ports, *servicePort)
@@ -168,7 +179,6 @@ func (t *prometheusTrait) Apply(e *Environment) (err error) {
 
 func (t *prometheusTrait) getContainerPort() *corev1.ContainerPort {
 	containerPort := corev1.ContainerPort{
-		Name:          prometheusPortName,
 		ContainerPort: int32(t.Port),
 		Protocol:      corev1.ProtocolTCP,
 	}
@@ -177,10 +187,11 @@ func (t *prometheusTrait) getContainerPort() *corev1.ContainerPort {
 
 func (t *prometheusTrait) getServicePort() *corev1.ServicePort {
 	servicePort := corev1.ServicePort{
-		Name:       prometheusPortName,
-		Port:       int32(t.Port),
-		Protocol:   corev1.ProtocolTCP,
-		TargetPort: intstr.FromString(prometheusPortName),
+		Name:     prometheusPortName,
+		Port:     int32(t.Port),
+		Protocol: corev1.ProtocolTCP,
+		// Avoid relying on named port, as Knative enforces specific values used for content negotiation
+		TargetPort: intstr.FromInt(t.Port),
 	}
 	return &servicePort
 }

pkg/trait/prometheus_test.go

@@ -68,12 +68,11 @@ func TestApplyNominalPrometheusTraitDoesSucceed(t *testing.T) {
 
 	ports := container.Ports
 	assert.Len(t, ports, 1)
-	assert.Equal(t, "prometheus", ports[0].Name)
 	assert.Equal(t, int32(9779), ports[0].ContainerPort)
 	assert.Equal(t, corev1.ProtocolTCP, ports[0].Protocol)
 
 	service := environment.Resources.GetService(func(service *corev1.Service) bool {
-		return service.Name == "integration-name"
+		return service.Name == "integration-name-prometheus"
 	})
 	assert.NotNil(t, service)
 	assert.Len(t, service.Spec.Ports, 1)
@@ -103,7 +102,7 @@ func TestApplyPrometheusTraitWithoutContainerDoesNotSucceed(t *testing.T) {
 	assert.Equal(t, corev1.ConditionFalse, condition.Status)
 }
 
-func TestApplyPrometheusTraitWithServiceDoesNotSucceed(t *testing.T) {
+func TestApplyPrometheusTraitWithServiceDoesSucceed(t *testing.T) {
 	trait, environment := createNominalPrometheusTest()
 	environment.Resources = kubernetes.NewCollection(
 		&appsv1.Deployment{
@@ -146,8 +145,8 @@ func TestApplyPrometheusTraitWithServiceDoesNotSucceed(t *testing.T) {
 
 	assert.Len(t, environment.Integration.Status.Conditions, 1)
 	condition := environment.Integration.Status.Conditions[0]
-	assert.Equal(t, v1.IntegrationConditionServiceNotAvailableReason, condition.Reason)
-	assert.Equal(t, corev1.ConditionFalse, condition.Status)
+	assert.Equal(t, v1.IntegrationConditionPrometheusAvailableReason, condition.Reason)
+	assert.Equal(t, corev1.ConditionTrue, condition.Status)
 }
 
 func TestPrometheusTraitGetServiceMonitor(t *testing.T) {