[Feat] Add nodePort and loadbalancerIPAddress as optional fields in WG gateway template

deployments/liqo/templates/liqo-wireguard-gateway-server-template.yaml

@@ -32,10 +32,12 @@ spec:
           selector:
             {{- include "liqo.labelsTemplate" (merge (dict "isService" true) $templateConfig) | nindent 12 }}
           type: "{{"{{ .Spec.Endpoint.ServiceType }}"}}"
+          ?loadBalancerIP: "{{"{{ .Spec.Endpoint.LoadBalancerIP }}"}}"
           ports:
           - port: "{{"{{ .Spec.Endpoint.Port }}"}}"
             protocol: UDP
             targetPort: "{{"{{ .Spec.Endpoint.Port }}"}}"
+            ?nodePort: "{{"{{ .Spec.Endpoint.NodePort }}"}}"
           {{- if .Values.networking.gatewayTemplates.server.service.allocateLoadBalancerNodePorts }}
           allocateLoadBalancerNodePorts: {{ .Values.networking.gatewayTemplates.server.service.allocateLoadBalancerNodePorts }}
           {{- end }}
@@ -81,8 +83,8 @@ spec:
                 {{- if .Values.requirements.kernel.disabled }}
                 - --disable-kernel-version-check
                 {{- end }}
-                volumeMounts: 
-                - name: ipc 
+                volumeMounts:
+                - name: ipc
                   mountPath: /ipc
                 {{- if .Values.metrics.enabled }}
                 ports:
@@ -135,7 +137,7 @@ spec:
                   privileged: true
                   {{ end }}
                 volumeMounts:
-                - name: ipc 
+                - name: ipc
                   mountPath: /ipc
                 - name: wireguard-config
                   mountPath: /etc/wireguard/keys
@@ -156,8 +158,8 @@ spec:
                 - --metrics-address=:8084
                 {{- end }}
                 - --health-probe-bind-address=:8085
-                volumeMounts: 
-                - name: ipc 
+                volumeMounts:
+                - name: ipc
                   mountPath: /ipc
                 {{- if .Values.metrics.enabled }}
                 ports:
@@ -184,6 +186,6 @@ spec:
               - name: wireguard-config
                 secret:
                   secretName: "{{"{{ .SecretName }}"}}"
-              - name: ipc 
-                emptyDir: {} 
+              - name: ipc
+                emptyDir: {}
 {{- end }}

pkg/liqo-controller-manager/networking/external-network/utils/template.go

@@ -16,11 +16,20 @@ package utils
 
 import (
 	"bytes"
+	"fmt"
 	"reflect"
+	"regexp"
 	"strconv"
+	"strings"
 	"text/template"
 )
 
+var variableRegex = regexp.MustCompile(`{{\s*(.\S+)\s*}}`)
+
+type renderOptions struct {
+	skipIfEmpty bool
+}
+
 // RenderTemplate renders a template.
 func RenderTemplate(obj, data interface{}, forceString bool) (interface{}, error) {
 	// if the object is a string, render the template
@@ -48,12 +57,16 @@ func RenderTemplate(obj, data interface{}, forceString bool) (interface{}, error
 	// if the object is a map, render the template for each value
 	if reflect.TypeOf(obj).Kind() == reflect.Map {
 		for k, v := range obj.(map[string]interface{}) {
-			res, err := RenderTemplate(v, data, forceString || isLabelsOrAnnotations(obj))
+			useKey, useValue, options := preProcessOptional(k, v, obj)
+
+			res, err := RenderTemplate(useValue, data, forceString || isLabelsOrAnnotations(obj))
 			if err != nil {
 				return obj, err
 			}
 
-			obj.(map[string]interface{})[k] = res
+			if !(reflect.ValueOf(res).IsZero() && options.skipIfEmpty) {
+				obj.(map[string]interface{})[useKey] = res
+			}
 		}
 
 		return obj, nil
@@ -73,6 +86,10 @@ func RenderTemplate(obj, data interface{}, forceString bool) (interface{}, error
 		return obj, nil
 	}
 
+	if forceString {
+		return fmt.Sprintf("%v", obj), nil
+	}
+
 	return obj, nil
 }
 
@@ -87,3 +104,33 @@ func isLabelsOrAnnotations(obj interface{}) bool {
 
 	return false
 }
+
+// getVariableFromValue given a field value returns the first matched gotmpl variable.
+func getVariableFromValue(value string) (string, bool) {
+	// Look for variables in the value
+	matches := variableRegex.FindStringSubmatch(value)
+
+	// If a variable is found, than get only the first one
+	if len(matches) > 1 {
+		return matches[1], true
+	}
+
+	return "", false
+}
+
+// preProcessOptional preprocesses the template so that a field is rendered only if it has been provided.
+func preProcessOptional(key string, value, obj interface{}) (newKey string, newValue interface{}, options renderOptions) {
+	newKey = key
+	newValue = value
+	if strings.HasPrefix(key, "?") && reflect.TypeOf(key).Kind() == reflect.String {
+		if variable, match := getVariableFromValue(value.(string)); match {
+			newKey = key[1:]
+			newValue = fmt.Sprintf("{{if %s}}%s{{end}}", variable, value)
+			options.skipIfEmpty = true
+			// Delete the field with the condition option
+			delete(obj.(map[string]interface{}), key)
+		}
+	}
+
+	return
+}

pkg/liqo-controller-manager/networking/external-network/utils/template_test.go

@@ -0,0 +1,216 @@
+// Copyright 2019-2024 The Liqo Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+package utils_test
+
+import (
+	"fmt"
+	"testing"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+
+	"github.com/liqotech/liqo/pkg/liqo-controller-manager/networking/external-network/utils"
+)
+
+type sampleDataStructure struct {
+	Number         int
+	Value          string
+	OptionalString *string
+	OptionalNumber *int
+}
+
+type nestedSampleDataStructure struct {
+	Number         int
+	Value          string
+	OptionalString *string
+	OptionalNumber *int
+	Nested         sampleDataStructure
+}
+
+type testDataStructure struct {
+	Name      string
+	Namespace string
+	Spec      nestedSampleDataStructure
+}
+
+type templateTestCase struct {
+	template    any
+	expectedRes any
+	data        testDataStructure
+}
+
+var optionalNumber = 10
+var optionalString = "Mr. Jack!"
+var nestedOptionalString = "optionalVal"
+
+var _ = DescribeTable("Templating tests", func(testCase templateTestCase) {
+	res, err := utils.RenderTemplate(testCase.template, testCase.data, false)
+
+	Expect(err).NotTo(HaveOccurred())
+	Expect(testCase.expectedRes).To(Equal(res), "Unexpected result returned")
+},
+	Entry("Simple case", templateTestCase{
+		template: map[string]any{
+			"Name":      "{{ .Name }}",
+			"Namespace": "{{ .Namespace }}",
+		},
+		expectedRes: map[string]any{
+			"Name":      "hello",
+			"Namespace": "world!",
+		},
+		data: testDataStructure{
+			Name:      "hello",
+			Namespace: "world!",
+		},
+	}),
+	Entry("Labels and annotations should force string", templateTestCase{
+		template: map[string]any{
+			"labels": map[string]any{
+				"hello": "{{ .Namespace }}",
+				"test":  4,
+			},
+			"annotations": map[string]any{
+				"hello": "{{ .Name }}",
+				"test":  5,
+			},
+		},
+		expectedRes: map[string]any{
+			"labels": map[string]any{
+				"hello": "world!",
+				"test":  "4",
+			},
+			"annotations": map[string]any{
+				"hello": "hello",
+				"test":  "5",
+			},
+		},
+		data: testDataStructure{
+			Name:      "hello",
+			Namespace: "world!",
+		},
+	}),
+	Entry("Nested variables", templateTestCase{
+		template: map[string]any{
+			"Name": "{{ .Name }}",
+			"Nested": map[string]any{
+				"NestedVal": map[string]any{
+					"Value":  "{{ .Spec.Nested.Value }}",
+					"Number": "{{ .Spec.Nested.Number }}",
+				},
+				"ListVal": []any{
+					map[string]any{
+						"Another": "{{ .Spec.Value }}",
+					},
+					map[string]any{
+						"Number": "{{ .Spec.Number }}",
+					},
+				},
+			},
+		},
+		expectedRes: map[string]any{
+			"Name": "hello",
+			"Nested": map[string]any{
+				"NestedVal": map[string]any{
+					"Value":  "world!",
+					"Number": 1924,
+				},
+				"ListVal": []any{
+					map[string]any{
+						"Another": "value",
+					},
+					map[string]any{
+						"Number": 10,
+					},
+				},
+			},
+		},
+		data: testDataStructure{
+			Name: "hello",
+			Spec: nestedSampleDataStructure{
+				Value:  "value",
+				Number: 10,
+				Nested: sampleDataStructure{
+					Value:  "world!",
+					Number: 1924,
+				},
+			},
+		},
+	}),
+	Entry("Optional fields", templateTestCase{
+		template: map[string]any{
+			"Name":         "{{ .Name }}",
+			"?NotOptional": "This should be kept as is",
+			"Nested": map[string]any{
+				"NestedVal": map[string]any{
+					"Value":           "{{ .Spec.Nested.Value }}",
+					"?Optional":       "Some text plus variable {{ .Spec.Nested.OptionalString }}",
+					"?OptionalNumber": "{{ .Spec.Nested.OptionalNumber }}",
+				},
+				"ListVal": []any{
+					map[string]any{
+						"Another": "{{ .Spec.Value }}",
+						"?Hey":    "{{ .Spec.OptionalString }}",
+					},
+					map[string]any{
+						"number":                        "{{ .Spec.Number }}",
+						"?anotherNumber":                "{{ .Spec.OptionalNumber }}",
+						"?optionalDifferentThanPointer": "{{ .Spec.Value }}",
+					},
+				},
+			},
+		},
+		expectedRes: map[string]any{
+			"Name":         "hello",
+			"?NotOptional": "This should be kept as is",
+			"Nested": map[string]any{
+				"NestedVal": map[string]any{
+					"Value":          "world!",
+					"Optional":       fmt.Sprintf("Some text plus variable %s", nestedOptionalString),
+					"OptionalNumber": optionalNumber,
+				},
+				"ListVal": []any{
+					map[string]any{
+						"Another": "value",
+						"Hey":     optionalString,
+					},
+					map[string]any{
+						"number":                       42,
+						"optionalDifferentThanPointer": "value",
+					},
+				},
+			},
+		},
+		data: testDataStructure{
+			Name: "hello",
+			Spec: nestedSampleDataStructure{
+				Value:          "value",
+				Number:         42,
+				OptionalString: &optionalString,
+				Nested: sampleDataStructure{
+					Value:          "world!",
+					Number:         1924,
+					OptionalNumber: &optionalNumber,
+					OptionalString: &nestedOptionalString,
+				},
+			},
+		},
+	}),
+)
+
+func TestLocal(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "External network utils test suite")
+}

pkg/liqoctl/network/cluster.go

@@ -301,8 +301,11 @@ func (c *Cluster) checkTemplateServerServiceNodePort(template *unstructured.Unst
 
 	_, err = maps.GetNestedField(port, "nodePort")
 	if err != nil {
-		return fmt.Errorf("unable to get spec.template.spec.service.spec.ports[0].nodePort int the server template, " +
-			"since you specified the flag \"--server-service-nodeport\" you need to add the \"nodePort\" field in the template")
+		// If the field is missing, it might be optional (represented by leading ?). If not, raise an error
+		if _, errOptional := maps.GetNestedField(port, "?nodePort"); errOptional != nil {
+			return fmt.Errorf("unable to get spec.template.spec.service.spec.ports[0].nodePort int the server template, " +
+				"since you specified the flag \"--server-service-nodeport\" you need to add the \"nodePort\" field in the template")
+		}
 	}
 
 	return nil
@@ -312,11 +315,14 @@ func (c *Cluster) checkTemplateServerServiceLoadBalancer(template *unstructured.
 		return nil
 	}
 
-	path := "spec.template.spec.service.spec.loadBalancerIP"
-	_, err := maps.GetNestedField(template.Object, path)
+	servicePath := "spec.template.spec.service.spec"
+	_, err := maps.GetNestedField(template.Object, fmt.Sprintf("%s.loadBalancerIP", servicePath))
 	if err != nil {
-		return fmt.Errorf("unable to get %s of the server template, "+
-			"since you specified the flag \"--server-service-loadbalancerip\" you need to add the \"loadBalancerIP\" field in the template", path)
+		// If the field is missing, it might be optional (represented by leading ?). If not, raise an error
+		if _, errOptional := maps.GetNestedField(template.Object, fmt.Sprintf("%s.?loadBalancerIP", servicePath)); errOptional != nil {
+			return fmt.Errorf("unable to get %s of the server template, "+
+				"since you specified the flag \"--server-service-loadbalancerip\" you need to add the \"loadBalancerIP\" field in the template", servicePath)
+		}
 	}
 	return nil
 }