feat: Add support for ingress and service annotations (#100)

* add support for ingress/service annotations

* update example values

* update annotation examples

* update example annotations

* add plan cleanup function

* add some tests

* refactor and add tests

* update `isEndpointMatching` function to assume `match-subdomain` false by default

* cleanup

* update limitations

* update requirements

* update readme

* update readme

* update readme

* update readme

* update readme

* update readme

README.md

@@ -7,26 +7,24 @@
 
 [ExternalDNS](https://github.com/kubernetes-sigs/external-dns) is a Kubernetes add-on for automatically managing DNS records for Kubernetes ingresses and services by using different DNS providers. This webhook provider allows you to automate DNS records from your Kubernetes clusters into your MikroTik router.
 
-Supported DNS record types:
+Supported DNS record types: `A`, `AAAA`, `CNAME`, `MX`, `NS`, `SRV`, `TXT`
 
-- A
-- AAAA
-- CNAME
-- MX
-- NS
-- SRV
-- TXT
+For examples of creating DNS records either via CRDs or via Ingress/Service annotations, check out the [`example/` directory](./example/).
 
 ## 🎯 Requirements
 
-- ExternalDNS >= v0.14.0
-- Mikrotik RouterOS (tested on 7.14.3 stable)
+> [!Note]
+> `v0.15.0` of ExternalDNS added support for `providerSpecific` annotations in Ingress/Service objects for webhook providers.
+>
+> While older versions of ExternalDNS may work, but support for this feature will not be present.
+
+- ExternalDNS >= `v0.15.0`
+- Mikrotik RouterOS (tested on `7.16` stable)
 
 ## 🚫 Limitations
 
 - Currently, `DNSEndpoints` with multiple `targets` are *technically* not supported. Only one record will be created with the first target from the list, but eDNS will keep trying to update your DNS record in RouterOS, constantly sending `PUT` requests.
 - The `Disabled` option on DNS records is currently ignored
-- Support for `providerSpecific` annotations on `Ingress` objects is not **yet** supported.
 
 ## ⚙️ Configuration Options
 

example/ingress/sample.yaml

@@ -41,7 +41,9 @@ metadata:
   annotations:
     external-dns.alpha.kubernetes.io/hostname: "example.com"
     external-dns.alpha.kubernetes.io/ttl: "60"
-    external-dns.alpha.kubernetes.io/webhook-comment: "This is a comment"
+    external-dns.alpha.kubernetes.io/webhook-comment: "This is a static DNS record created via ingress annotations!"
+    external-dns.alpha.kubernetes.io/webhook-address-list: "4.5.6.7"
+    external-dns.alpha.kubernetes.io/webhook-match-subdomain: "false"
 spec:
   rules:
     - host: example.com

example/records/complex-record.yaml

@@ -1,5 +1,4 @@
 ---
----
 apiVersion: externaldns.k8s.io/v1alpha1
 kind: DNSEndpoint
 metadata:

example/service/service.yaml

@@ -26,8 +26,10 @@ metadata:
   name: test
   annotations:
     external-dns.alpha.kubernetes.io/hostname: nginx2.example.com
-    external-dns.alpha.kubernetes.io/ttl: "600"
-    external-dns.alpha.kubernetes.io/webhook-comment: "This is a comment"
+    external-dns.alpha.kubernetes.io/ttl: "1800"
+    external-dns.alpha.kubernetes.io/webhook-comment: "This is a static DNS record created via service annotations!"
+    external-dns.alpha.kubernetes.io/webhook-address-list: "6.7.8.9"
+    external-dns.alpha.kubernetes.io/webhook-match-subdomain: "true"
 spec:
   ports:
     - port: 80

example/values.yaml

@@ -2,12 +2,15 @@
 fullnameOverride: external-dns-mikrotik
 
 logLevel: debug
-policy: sync
-sources: ["ingress", "service"]
+logFormat: text
 interval: 1s
+sources: ["ingress", "service", "crd"]
+registry: txt
 txtOwnerId: default
 txtPrefix: k8s.
 domainFilters: ["example.com"]
+excludeDomains: []
+policy: sync
 
 provider:
   name: webhook
@@ -57,23 +60,10 @@ provider:
 
 extraArgs:
   - --ignore-ingress-tls-spec
-  - --source=crd
-  - --crd-source-apiversion=externaldns.k8s.io/v1alpha1
-  - --crd-source-kind=DNSEndpoint
   - --managed-record-types=A
   - --managed-record-types=AAAA
   - --managed-record-types=CNAME
   - --managed-record-types=TXT
   - --managed-record-types=MX
   - --managed-record-types=SRV
   - --managed-record-types=NS
-
-rbac:
-  create: true
-  additionalPermissions:
-    - apiGroups: ["externaldns.k8s.io"]
-      resources: ["dnsendpoints"]
-      verbs: ["get", "watch", "list"]
-    - apiGroups: ["externaldns.k8s.io"]
-      resources: ["dnsendpoints/status"]
-      verbs: ["*"]

internal/mikrotik/provider.go

@@ -66,6 +66,8 @@ func (p *MikrotikProvider) Records(ctx context.Context) ([]*endpoint.Endpoint, e
 
 // ApplyChanges applies a given set of changes in the DNS provider.
 func (p *MikrotikProvider) ApplyChanges(ctx context.Context, changes *plan.Changes) error {
+	changes = cleanupChanges(changes)
+
 	for _, endpoint := range append(changes.UpdateOld, changes.Delete...) {
 		if err := p.client.DeleteDNSRecord(endpoint); err != nil {
 			return err
@@ -85,3 +87,91 @@ func (p *MikrotikProvider) ApplyChanges(ctx context.Context, changes *plan.Chang
 func (p *MikrotikProvider) GetDomainFilter() endpoint.DomainFilterInterface {
 	return p.domainFilter
 }
+
+// ================================================================================================
+// UTILS
+// ================================================================================================
+func getProviderSpecific(ep *endpoint.Endpoint, ps string) string {
+	value, valueExists := ep.GetProviderSpecificProperty(ps)
+	if !valueExists {
+		value, _ = ep.GetProviderSpecificProperty(fmt.Sprintf("webhook/%s", ps))
+	}
+	return value
+}
+
+func isEndpointMatching(a *endpoint.Endpoint, b *endpoint.Endpoint) bool {
+	if a.DNSName != b.DNSName || a.Targets[0] != b.Targets[0] || a.RecordTTL != b.RecordTTL {
+		return false
+	}
+
+	aComment := getProviderSpecific(a, "comment")
+	bComment := getProviderSpecific(b, "comment")
+	if aComment != bComment {
+		return false
+	}
+
+	aMatchSubdomain := getProviderSpecific(a, "match-subdomain")
+	if aMatchSubdomain == "" {
+		aMatchSubdomain = "false"
+	}
+	bMatchSubdomain := getProviderSpecific(b, "match-subdomain")
+	if bMatchSubdomain == "" {
+		bMatchSubdomain = "false"
+	}
+	if aMatchSubdomain != bMatchSubdomain {
+		return false
+	}
+
+	aAddressList := getProviderSpecific(a, "address-list")
+	bAddressList := getProviderSpecific(b, "address-list")
+	if aAddressList != bAddressList {
+		return false
+	}
+
+	aRegexp := getProviderSpecific(a, "regexp")
+	bRegexp := getProviderSpecific(b, "regexp")
+	return aRegexp == bRegexp
+}
+
+func contains(haystack []*endpoint.Endpoint, needle *endpoint.Endpoint) bool {
+	for _, v := range haystack {
+		if isEndpointMatching(needle, v) {
+			return true
+		}
+	}
+	return false
+}
+
+func cleanupChanges(changes *plan.Changes) *plan.Changes {
+	// Initialize new plan -> we don't really need to worry about Create or Delete changes.
+	// Only updates are sketchy
+	newChanges := &plan.Changes{
+		Create:    changes.Create,
+		Delete:    changes.Delete,
+		UpdateOld: []*endpoint.Endpoint{},
+		UpdateNew: []*endpoint.Endpoint{},
+	}
+
+	duplicates := []*endpoint.Endpoint{}
+
+	for _, old := range changes.UpdateOld {
+		for _, new := range changes.UpdateNew {
+			if isEndpointMatching(old, new) {
+				duplicates = append(duplicates, old)
+			}
+		}
+	}
+
+	for _, old := range changes.UpdateOld {
+		if !contains(duplicates, old) {
+			newChanges.UpdateOld = append(newChanges.UpdateOld, old)
+		}
+	}
+	for _, new := range changes.UpdateNew {
+		if !contains(duplicates, new) {
+			newChanges.UpdateNew = append(newChanges.UpdateNew, new)
+		}
+	}
+
+	return newChanges
+}