Feature: support multi hosts in vs (#5430)

* Update controller_utils.go

add GetAnnotations() to support multi hosts

* Update istio.go

add env ANNOTATION_ISTIO_HOST_SEPARATOR to support multi hosts

* Update seldondeployment_controller.go

Update controller to support multi hosts

* Update seldondeployment_explainers.go

Update explianer to support multi hosts

* Update istio.go

Remove seperator defination

* Update controller_utils.go

Rename GetAnnotation to HostsFromAnnotation, and remove the redundant logic

* Update seldondeployment_explainers.go

* Update seldondeployment_controller.go

* Update operator/controllers/seldondeployment_controller.go

* add test and trimp whitespaces

---------

Co-authored-by: Rafal Skolasinski <r.j.skolasinski@gmail.com>

Author: ooooona

operator/controllers/seldondeployment_controller.go

@@ -262,7 +262,7 @@ func createIstioResources(mlDep *machinelearningv1.SeldonDeployment,
 			Namespace: namespace,
 		},
 		Spec: istio_networking.VirtualService{
-			Hosts:    []string{utils2.GetAnnotation(mlDep, ANNOTATION_ISTIO_HOST, "*")},
+			Hosts:    utils2.HostsFromAnnotation(mlDep, ANNOTATION_ISTIO_HOST, "*"),
 			Gateways: []string{utils2.GetAnnotation(mlDep, ANNOTATION_ISTIO_GATEWAY, istio_gateway)},
 			Http: []*istio_networking.HTTPRoute{
 				{

operator/controllers/seldondeployment_explainers.go

@@ -328,7 +328,7 @@ func createExplainerIstioResources(pSvcName string, p *machinelearningv1.Predict
 			Namespace: namespace,
 		},
 		Spec: istio_networking.VirtualService{
-			Hosts:    []string{utils2.GetAnnotation(mlDep, ANNOTATION_ISTIO_HOST, "*")},
+			Hosts:    utils2.HostsFromAnnotation(mlDep, ANNOTATION_ISTIO_HOST, "*"),
 			Gateways: []string{utils2.GetAnnotation(mlDep, ANNOTATION_ISTIO_GATEWAY, istio_gateway)},
 			Http: []*istio_networking.HTTPRoute{
 				{
@@ -349,7 +349,7 @@ func createExplainerIstioResources(pSvcName string, p *machinelearningv1.Predict
 			Namespace: namespace,
 		},
 		Spec: istio_networking.VirtualService{
-			Hosts:    []string{utils2.GetAnnotation(mlDep, ANNOTATION_ISTIO_HOST, "*")},
+			Hosts:    utils2.HostsFromAnnotation(mlDep, ANNOTATION_ISTIO_HOST, "*"),
 			Gateways: []string{utils2.GetAnnotation(mlDep, ANNOTATION_ISTIO_GATEWAY, istio_gateway)},
 			Http: []*istio_networking.HTTPRoute{
 				{

operator/controllers/utils/controller_utils.go

@@ -51,6 +51,20 @@ func GetAnnotation(mlDep *machinelearningv1.SeldonDeployment, annotationKey stri
 	}
 }
 
+// Get an annotation array for hosts from the Seldon Deployment given by annotationKey or return the array with fallback.
+func HostsFromAnnotation(mlDep *machinelearningv1.SeldonDeployment, annotationKey string, fallback string) []string {
+	annotation := GetAnnotation(mlDep, annotationKey, fallback)
+	if strings.Contains(annotation, ",") {
+		hosts := strings.Split(annotation, ",")
+		for i, host := range hosts {
+			hosts[i] = strings.TrimSpace(host)
+		}
+		return hosts
+	} else {
+		return []string{strings.TrimSpace(annotation)}
+	}
+}
+
 // get annotations that start with seldon.io/engine
 func GetEngineEnvAnnotations(mlDep *machinelearningv1.SeldonDeployment) []corev1.EnvVar {
 

operator/controllers/utils/controller_utils_test.go

@@ -1,12 +1,16 @@
 package utils
 
 import (
+	"testing"
+
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/ginkgo/extensions/table"
 	. "github.com/onsi/gomega"
 	machinelearningv1 "github.com/seldonio/seldon-core/operator/apis/machinelearning.seldon.io/v1"
 )
 
+const HOST_ANNOTATION = "host-annotation"
+
 var _ = Describe("Controller utils", func() {
 	DescribeTable(
 		"isEmptyExplainer",
@@ -23,3 +27,68 @@ var _ = Describe("Controller utils", func() {
 		),
 	)
 })
+
+func TestHostsFromAnnotation(t *testing.T) {
+	var key = HOST_ANNOTATION
+	var fallback = "*"
+
+	tests := []struct {
+		name  string
+		mldep *machinelearningv1.SeldonDeployment
+		want  []string
+	}{
+		{
+			name: "No host",
+			mldep: &machinelearningv1.SeldonDeployment{
+				Spec: machinelearningv1.SeldonDeploymentSpec{
+					Annotations: map[string]string{},
+				},
+			},
+			want: []string{fallback},
+		},
+		{
+			name: "Single host",
+			mldep: &machinelearningv1.SeldonDeployment{
+				Spec: machinelearningv1.SeldonDeploymentSpec{
+					Annotations: map[string]string{
+						key: "prod.svc.cluster.local",
+					},
+				},
+			},
+			want: []string{"prod.svc.cluster.local"},
+		},
+		{
+			name: "Multiple hosts",
+			mldep: &machinelearningv1.SeldonDeployment{
+				Spec: machinelearningv1.SeldonDeploymentSpec{
+					Annotations: map[string]string{
+						key: "prod.svc.cluster.local,dev.svc.cluster.local",
+					},
+				},
+			},
+			want: []string{"prod.svc.cluster.local", "dev.svc.cluster.local"},
+		},
+		{
+			name: "Multiple hosts with space",
+			mldep: &machinelearningv1.SeldonDeployment{
+				Spec: machinelearningv1.SeldonDeploymentSpec{
+					Annotations: map[string]string{
+						key: "prod.svc.cluster.local, dev.svc.cluster.local",
+					},
+				},
+			},
+			want: []string{"prod.svc.cluster.local", "dev.svc.cluster.local"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			hosts := HostsFromAnnotation(tt.mldep, key, fallback)
+			for i, host := range hosts {
+				if host != tt.want[i] {
+					t.Errorf("got: %v; want %v", host, tt.want[i])
+				}
+			}
+		})
+	}
+}