Failover strategy implementation

deploy/crds/ohmyglb.absa.oss_gslbs_crd.yaml

@@ -165,7 +165,15 @@ spec:
                   type: array
               type: object
             strategy:
-              type: string
+              properties:
+                primaryGeoTag:
+                  type: string
+                type:
+                  type: string
+              required:
+              - primaryGeoTag
+              - type
+              type: object
           required:
           - ingress
           - strategy

deploy/crds/ohmyglb.absa.oss_v1beta1_gslb_cr.yaml

@@ -27,4 +27,5 @@ spec:
               serviceName: frontend-podinfo # Gslb should reflect Healthy status and create associated DNS records
               servicePort: http
             path: /
-  strategy: roundRobin # Use a round robin load balancing strategy, when deciding which downstream clusters to route clients too
+  strategy:
+    type: roundRobin # Use a round robin load balancing strategy, when deciding which downstream clusters to route clients too

deploy/crds/ohmyglb.absa.oss_v1beta1_gslb_cr_failover.yaml

@@ -0,0 +1,18 @@
+apiVersion: ohmyglb.absa.oss/v1beta1
+kind: Gslb
+metadata:
+  name: test-gslb
+  namespace: test-gslb
+spec:
+  ingress:
+    rules:
+      - host: failover.cloud.example.com
+        http:
+          paths:
+          - backend:
+              serviceName: frontend-podinfo # Gslb should reflect Healthy status and create associated DNS records
+              servicePort: http
+            path: /
+  strategy:
+    type: failover
+    primaryGeoTag: eu

pkg/apis/ohmyglb/v1beta1/gslb_types.go

@@ -8,14 +8,19 @@ import (
 // EDIT THIS FILE!  THIS IS SCAFFOLDING FOR YOU TO OWN!
 // NOTE: json tags are required.  Any new fields you add must have json tags for the fields to be serialized.
 
+type Strategy struct {
+	Type          string `json:"type"`
+	PrimaryGeoTag string `json:"primaryGeoTag"`
+}
+
 // GslbSpec defines the desired state of Gslb
 // +k8s:openapi-gen=true
 type GslbSpec struct {
 	// INSERT ADDITIONAL SPEC FIELDS - desired state of cluster
 	// Important: Run "operator-sdk generate k8s" to regenerate code after modifying this file
 	// Add custom validation using kubebuilder tags: https://book-v1.book.kubebuilder.io/beyond_basics/generating_crd.html
 	Ingress  v1beta1.IngressSpec `json:"ingress"`
-	Strategy string              `json:"strategy"`
+	Strategy Strategy            `json:"strategy"`
 }
 
 // GslbStatus defines the observed state of Gslb

pkg/controller/gslb/dnsupdate.go

@@ -157,9 +157,26 @@ func (r *ReconcileGslb) gslbDNSEndpoint(gslb *ohmyglbv1beta1.Gslb) (*externaldns
 			return nil, err
 		}
 		if len(externalTargets) > 0 {
-			switch gslb.Spec.Strategy {
+			switch gslb.Spec.Strategy.Type {
 			case "roundRobin":
 				finalTargets = append(finalTargets, externalTargets...)
+			case "failover":
+				clusterGeoTag := os.Getenv("CLUSTER_GEO_TAG")
+				// If cluster is Primary
+				if gslb.Spec.Strategy.PrimaryGeoTag == clusterGeoTag {
+					// If cluster is Primary and Healthy return only own targets
+					// If cluster is Primary and Unhealthy return Secondary external targets
+					if health != "Healthy" {
+						finalTargets = externalTargets
+					}
+				} else {
+					// If cluster is Secondary and Primary external cluster is Healthy
+					// then return Primary external targets.
+					// Return own targets by default.
+					if len(externalTargets) > 0 {
+						finalTargets = externalTargets
+					}
+				}
 			}
 		}
 

pkg/controller/gslb/gslb_controller_test.go

@@ -389,6 +389,118 @@ func TestGslbController(t *testing.T) {
 			t.Errorf("got:\n %s unexpected heartbeat records,\n\n want:\n %s", got, want)
 		}
 	})
+
+	t.Run("Returns own records using Failover strategy when Primary", func(t *testing.T) {
+		err := os.Setenv("OVERRIDE_WITH_FAKE_EXT_DNS", "true")
+		if err != nil {
+			t.Fatalf("Can't setup env var: (%v)", err)
+		}
+		err = os.Setenv("CLUSTER_GEO_TAG", "eu")
+		if err != nil {
+			t.Fatalf("Can't setup env var: (%v)", err)
+		}
+
+		// Enable failover strategy
+		gslb.Spec.Strategy.Type = "failover"
+		gslb.Spec.Strategy.PrimaryGeoTag = "eu"
+		err = cl.Update(context.TODO(), gslb)
+		if err != nil {
+			t.Fatalf("Can't update gslb: (%v)", err)
+		}
+
+		reconcileAndUpdateGslb(t, r, req, cl, gslb)
+
+		dnsEndpoint := &externaldns.DNSEndpoint{}
+		err = cl.Get(context.TODO(), req.NamespacedName, dnsEndpoint)
+		if err != nil {
+			t.Fatalf("Failed to get expected DNSEndpoint: (%v)", err)
+		}
+
+		got := dnsEndpoint.Spec.Endpoints
+
+		want := []*externaldns.Endpoint{
+			{
+				DNSName:    "localtargets.app3.cloud.example.com",
+				RecordTTL:  30,
+				RecordType: "A",
+				Targets:    externaldns.Targets{"10.0.0.1", "10.0.0.2", "10.0.0.3"},
+			},
+			{
+				DNSName:    "app3.cloud.example.com",
+				RecordTTL:  30,
+				RecordType: "A",
+				Targets:    externaldns.Targets{"10.0.0.1", "10.0.0.2", "10.0.0.3"},
+			},
+		}
+
+		prettyGot := prettyPrint(got)
+		prettyWant := prettyPrint(want)
+
+		if !reflect.DeepEqual(got, want) {
+			t.Errorf("got:\n %s DNSEndpoint,\n\n want:\n %s", prettyGot, prettyWant)
+		}
+
+		err = os.Setenv("OVERRIDE_WITH_FAKE_EXT_DNS", "false")
+		if err != nil {
+			t.Fatalf("Can't setup env var: (%v)", err)
+		}
+	})
+
+	t.Run("Returns external records using Failover strategy when Secondary", func(t *testing.T) {
+		err := os.Setenv("OVERRIDE_WITH_FAKE_EXT_DNS", "true")
+		if err != nil {
+			t.Fatalf("Can't setup env var: (%v)", err)
+		}
+		err = os.Setenv("CLUSTER_GEO_TAG", "za")
+		if err != nil {
+			t.Fatalf("Can't setup env var: (%v)", err)
+		}
+
+		// Enable failover strategy
+		gslb.Spec.Strategy.Type = "failover"
+		gslb.Spec.Strategy.PrimaryGeoTag = "eu"
+		err = cl.Update(context.TODO(), gslb)
+		if err != nil {
+			t.Fatalf("Can't update gslb: (%v)", err)
+		}
+
+		reconcileAndUpdateGslb(t, r, req, cl, gslb)
+
+		dnsEndpoint := &externaldns.DNSEndpoint{}
+		err = cl.Get(context.TODO(), req.NamespacedName, dnsEndpoint)
+		if err != nil {
+			t.Fatalf("Failed to get expected DNSEndpoint: (%v)", err)
+		}
+
+		got := dnsEndpoint.Spec.Endpoints
+
+		want := []*externaldns.Endpoint{
+			{
+				DNSName:    "localtargets.app3.cloud.example.com",
+				RecordTTL:  30,
+				RecordType: "A",
+				Targets:    externaldns.Targets{"10.0.0.1", "10.0.0.2", "10.0.0.3"},
+			},
+			{
+				DNSName:    "app3.cloud.example.com",
+				RecordTTL:  30,
+				RecordType: "A",
+				Targets:    externaldns.Targets{"10.1.0.1", "10.1.0.2", "10.1.0.3"},
+			},
+		}
+
+		prettyGot := prettyPrint(got)
+		prettyWant := prettyPrint(want)
+
+		if !reflect.DeepEqual(got, want) {
+			t.Errorf("got:\n %s DNSEndpoint,\n\n want:\n %s", prettyGot, prettyWant)
+		}
+
+		err = os.Setenv("OVERRIDE_WITH_FAKE_EXT_DNS", "false")
+		if err != nil {
+			t.Fatalf("Can't setup env var: (%v)", err)
+		}
+	})
 }
 
 func reconcileAndUpdateGslb(t *testing.T,