feat: handle panic exceptions about istio objects (#14)

* feat: handle panic exceptions about istio objects

* feat: lint

steps.go

@@ -59,10 +59,14 @@ func MigrationWorkflow(
 
 	utils.LogInfo("2.1 Updating Istio destination rules")
 	var temporalDestinationRule = currentDestinationRule
-	delete(temporalDestinationRule.Spec.Subsets[0].Labels, changingLabelKey)
-	_, err = istioClient.NetworkingV1alpha3().DestinationRules(namespace).Update(context.TODO(), temporalDestinationRule, metav1.UpdateOptions{})
-	utils.Check(err)
-	utils.LogSuccess("2.1 Istio destination rules updated")
+	if len(temporalDestinationRule.Spec.Subsets) > 0 {
+		delete(temporalDestinationRule.Spec.Subsets[0].Labels, changingLabelKey)
+		_, err = istioClient.NetworkingV1alpha3().DestinationRules(namespace).Update(context.TODO(), temporalDestinationRule, metav1.UpdateOptions{})
+		utils.Check(err)
+		utils.LogSuccess("2.1 Istio destination rules updated")
+	} else {
+		utils.LogSuccess("2.1 No Istio destination rules found")
+	}
 
 	utils.LogInfo("2.2 Keda")
 	keda.PauseScaledObject(crdClient, clientset, deploymentName, namespace)
@@ -178,21 +182,29 @@ func AddLabelToIstioDestinatonRulesSelector(
 	utils.LogInfo("====== Additionnal step ====================================")
 	utils.LogInfo("9. Add the label as a selector in istio destination rules...")
 	currentDestinationRule, err := istioClient.NetworkingV1alpha3().DestinationRules(namespace).Get(context.TODO(), applicationName, v1.GetOptions{})
-	utils.Check(err)
 
-	var futureDestinationRule = currentDestinationRule
-	if removeLabel {
-		// Update the value of the label
-		delete(futureDestinationRule.Spec.Subsets[0].Labels, changingLabelKey)
+	if strings.HasSuffix(err.Error(), "not found") {
+		utils.LogSuccess("9. Not Istio rules configured")
+		utils.LogInfo("============================================================")
 	} else {
-		futureDestinationRule.Spec.Subsets[0].Labels[changingLabelKey] = changingLabelValue
-		// If the string is empty, remove the label (see deployment)
-	}
+		fmt.Println(currentDestinationRule)
+		fmt.Println(err)
+		utils.Check(err)
+
+		var futureDestinationRule = currentDestinationRule
+		if removeLabel {
+			// Update the value of the label
+			delete(futureDestinationRule.Spec.Subsets[0].Labels, changingLabelKey)
+		} else {
+			futureDestinationRule.Spec.Subsets[0].Labels[changingLabelKey] = changingLabelValue
+			// If the string is empty, remove the label (see deployment)
+		}
 
-	// Update the service in the cluster
-	_, updateDestinationRuleError := istioClient.NetworkingV1alpha3().DestinationRules(namespace).Update(context.TODO(), futureDestinationRule, metav1.UpdateOptions{})
-	utils.Check(updateDestinationRuleError)
+		// Update the service in the cluster
+		_, updateDestinationRuleError := istioClient.NetworkingV1alpha3().DestinationRules(namespace).Update(context.TODO(), futureDestinationRule, metav1.UpdateOptions{})
+		utils.Check(updateDestinationRuleError)
 
-	utils.LogSuccess("9. Istio destination rules configured")
-	utils.LogInfo("============================================================")
+		utils.LogSuccess("9. Istio destination rules configured")
+		utils.LogInfo("============================================================")
+	}
 }

summary.go

@@ -79,45 +79,44 @@ func resourcesAnalyze(
 		namespace,
 		podLabels,
 	)
-	for _, a := range services {
-		resources = append(resources, a)
-	}
+
+	resources = append(resources, services...)
+
 	// Native HPA
 	hpa := native.NativeHPAResourceAnalyze(
 		clientset,
 		namespace,
 		deploymentName,
 	)
-	for _, a := range hpa {
-		resources = append(resources, a)
-	}
+
+	resources = append(resources, hpa...)
+
 	// Istio Authorization Policies
 	authorizationPolicies := authorizationPolicy.IstioAuthorizationPolicyResourceAnalyze(
 		istioClient,
 		namespace,
 		podLabels,
 	)
-	for _, a := range authorizationPolicies {
-		resources = append(resources, a)
-	}
+
+	resources = append(resources, authorizationPolicies...)
+
 	// Destination rules
 	destinationRules := authorizationPolicy.IstioDestinationRuleResourceAnalyze(
 		istioClient,
 		namespace,
 		podLabels,
 	)
-	for _, a := range destinationRules {
-		resources = append(resources, a)
-	}
+
+	resources = append(resources, destinationRules...)
+
 	// Keda — ScaledObject
 	scaledobjects := keda.KedaScaledObjectResourceAnalyze(
 		crdClient,
 		namespace,
 		deploymentName,
 	)
-	for _, a := range scaledobjects {
-		resources = append(resources, a)
-	}
+
+	resources = append(resources, scaledobjects...)
 
 	if len(podLabels) == 1 && podLabels[changingLabelKey] != "" {
 		utils.LogError(fmt.Sprintf("The label \"%s\" can not be edited because it's the only one in the matching set for the deployment", changingLabelKey))
@@ -129,7 +128,7 @@ func resourcesAnalyze(
 		os.Exit(1)
 	}
 
-	utils.LogSuccess("Resources analyzed (" + strconv.FormatFloat(time.Now().Sub(startTime).Seconds(), 'f', 2, 64) + "s)")
+	utils.LogSuccess("Resources analyzed (" + strconv.FormatFloat(time.Since(startTime).Seconds(), 'f', 2, 64) + "s)")
 
 	webapp.StartWebServer(
 		deploymentName,

summary/webapp/router.go

@@ -1,6 +1,7 @@
 package webapp
 
 import (
+	"fmt"
 	"net/http"
 	"strings"
 	"text/template"
@@ -53,10 +54,20 @@ func StartWebServer(
 			NativeResources:     filter(resources, func(r resource.Resource) bool { return r.Category == "Native" }),
 			PodLabels:           podLabels,
 		}
-		ViewRenderer.Template(w, http.StatusOK, tpls, data)
+		err := ViewRenderer.Template(w, http.StatusOK, tpls, data)
+		utils.Check(err)
 	})
 
 	utils.LogInfo("View resumed here: http://localhost:8080")
-	utils.OpenURL("http://localhost:8080")
-	go http.ListenAndServe(":8080", nil)
+	err := utils.OpenURL("http://localhost:8080")
+	utils.Check(err)
+
+	httpServerError := make(chan error, 1)
+	go func() {
+		httpServerError <- http.ListenAndServe(":8080", nil)
+	}()
+
+	if err := <-httpServerError; err != nil {
+		fmt.Println(err)
+	}
 }