Plumb in filtering on ingress class name

main.go

@@ -104,6 +104,7 @@ func main() {
 		Namespace:                      cfg.Namespace,
 		AnnotationFilter:               cfg.AnnotationFilter,
 		LabelFilter:                    cfg.LabelFilter,
+		IngressClassNameFilter:         cfg.IngressClassNameFilter,
 		FQDNTemplate:                   cfg.FQDNTemplate,
 		CombineFQDNAndAnnotation:       cfg.CombineFQDNAndAnnotation,
 		IgnoreHostnameAnnotation:       cfg.IgnoreHostnameAnnotation,

pkg/apis/externaldns/types.go

@@ -53,6 +53,7 @@ type Config struct {
 	Namespace                         string
 	AnnotationFilter                  string
 	LabelFilter                       string
+	IngressClassNameFilter            []string
 	FQDNTemplate                      string
 	CombineFQDNAndAnnotation          bool
 	IgnoreHostnameAnnotation          bool
@@ -186,6 +187,7 @@ var defaultConfig = &Config{
 	Namespace:                   "",
 	AnnotationFilter:            "",
 	LabelFilter:                 "",
+	IngressClassNameFilter:      nil,
 	FQDNTemplate:                "",
 	CombineFQDNAndAnnotation:    false,
 	IgnoreHostnameAnnotation:    false,
@@ -362,6 +364,7 @@ func (cfg *Config) ParseFlags(args []string) error {
 	app.Flag("namespace", "Limit sources of endpoints to a specific namespace (default: all namespaces)").Default(defaultConfig.Namespace).StringVar(&cfg.Namespace)
 	app.Flag("annotation-filter", "Filter sources managed by external-dns via annotation using label selector semantics (default: all sources)").Default(defaultConfig.AnnotationFilter).StringVar(&cfg.AnnotationFilter)
 	app.Flag("label-filter", "Filter sources managed by external-dns via label selector when listing all resources; currently only supported by source CRD").Default(defaultConfig.LabelFilter).StringVar(&cfg.LabelFilter)
+	app.Flag("ingress-class-filter", "Filter ingresses to just these ingress class(es)").StringsVar(&cfg.IngressClassNameFilter)
 	app.Flag("fqdn-template", "A templated string that's used to generate DNS names from sources that don't define a hostname themselves, or to add a hostname suffix when paired with the fake source (optional). Accepts comma separated list for multiple global FQDN.").Default(defaultConfig.FQDNTemplate).StringVar(&cfg.FQDNTemplate)
 	app.Flag("combine-fqdn-annotation", "Combine FQDN template and Annotations instead of overwriting").BoolVar(&cfg.CombineFQDNAndAnnotation)
 	app.Flag("ignore-hostname-annotation", "Ignore hostname annotation when generating DNS names, valid only when using fqdn-template is set (optional, default: false)").BoolVar(&cfg.IgnoreHostnameAnnotation)

source/ingress.go

@@ -54,6 +54,7 @@ type ingressSource struct {
 	client                   kubernetes.Interface
 	namespace                string
 	annotationFilter         string
+	ingressClassNameFilter   []string
 	fqdnTemplate             *template.Template
 	combineFQDNAnnotation    bool
 	ignoreHostnameAnnotation bool
@@ -63,7 +64,7 @@ type ingressSource struct {
 }
 
 // NewIngressSource creates a new ingressSource with the given config.
-func NewIngressSource(kubeClient kubernetes.Interface, namespace, annotationFilter string, fqdnTemplate string, combineFqdnAnnotation bool, ignoreHostnameAnnotation bool, ignoreIngressTLSSpec bool, ignoreIngressRulesSpec bool) (Source, error) {
+func NewIngressSource(kubeClient kubernetes.Interface, namespace, annotationFilter string, fqdnTemplate string, combineFqdnAnnotation bool, ignoreHostnameAnnotation bool, ignoreIngressTLSSpec bool, ignoreIngressRulesSpec bool, ingressClassNameFilter []string) (Source, error) {
 	tmpl, err := parseTemplate(fqdnTemplate)
 	if err != nil {
 		return nil, err
@@ -94,6 +95,7 @@ func NewIngressSource(kubeClient kubernetes.Interface, namespace, annotationFilt
 		client:                   kubeClient,
 		namespace:                namespace,
 		annotationFilter:         annotationFilter,
+		ingressClassNameFilter:   ingressClassNameFilter,
 		fqdnTemplate:             tmpl,
 		combineFQDNAnnotation:    combineFqdnAnnotation,
 		ignoreHostnameAnnotation: ignoreHostnameAnnotation,
@@ -116,6 +118,11 @@ func (sc *ingressSource) Endpoints(ctx context.Context) ([]*endpoint.Endpoint, e
 		return nil, err
 	}
 
+        ingresses, err = sc.filterByIngressClass(ingresses)
+	if err != nil {
+		return nil, err
+	}
+
 	endpoints := []*endpoint.Endpoint{}
 
 	for _, ing := range ingresses {
@@ -210,6 +217,29 @@ func (sc *ingressSource) filterByAnnotations(ingresses []*networkv1.Ingress) ([]
 	return filteredList, nil
 }
 
+// filterByIngressClass filters a list of ingresses based on a required ingress
+// class
+func (sc *ingressSource) filterByIngressClass(ingresses []*v1beta1.Ingress) ([]*v1beta1.Ingress, error) {
+	// if no class is specified then there's nothing to do
+	if sc.ingressClassNameFilter == nil {
+		return ingresses, nil
+	}
+
+	filteredList := []*v1beta1.Ingress{}
+
+	for _, ingress := range ingresses {
+		for _, nameFilter := range sc.ingressClassNameFilter {
+			// include ingress if its annotations match the selector
+			if ingress.Spec.IngressClassName != nil && nameFilter == *ingress.Spec.IngressClassName {
+				filteredList = append(filteredList, ingress)
+				break
+			}
+		}
+	}
+
+	return filteredList, nil
+}
+
 func (sc *ingressSource) setResourceLabel(ingress *networkv1.Ingress, endpoints []*endpoint.Endpoint) {
 	for _, ep := range endpoints {
 		ep.Labels[endpoint.ResourceLabelKey] = fmt.Sprintf("ingress/%s/%s", ingress.Namespace, ingress.Name)

source/store.go

@@ -43,6 +43,7 @@ type Config struct {
 	Namespace                      string
 	AnnotationFilter               string
 	LabelFilter                    string
+	IngressClassNameFilter         []string
 	FQDNTemplate                   string
 	CombineFQDNAndAnnotation       bool
 	IgnoreHostnameAnnotation       bool
@@ -189,7 +190,7 @@ func BuildWithConfig(source string, p ClientGenerator, cfg *Config) (Source, err
 		if err != nil {
 			return nil, err
 		}
-		return NewIngressSource(client, cfg.Namespace, cfg.AnnotationFilter, cfg.FQDNTemplate, cfg.CombineFQDNAndAnnotation, cfg.IgnoreHostnameAnnotation, cfg.IgnoreIngressTLSSpec, cfg.IgnoreIngressRulesSpec)
+		return NewIngressSource(client, cfg.Namespace, cfg.AnnotationFilter, cfg.FQDNTemplate, cfg.CombineFQDNAndAnnotation, cfg.IgnoreHostnameAnnotation, cfg.IgnoreIngressTLSSpec, cfg.IgnoreIngressRulesSpec, cfg.IngressClassNameFilter)
 	case "pod":
 		client, err := p.KubeClient()
 		if err != nil {