Use the External DNS webhook server implementation

This enables us to drop our own server implementation.

README.md

@@ -22,6 +22,8 @@ The application arguments are as follows:
 - `tidydns-endpoint` Tidy DNS server addr
 - `zone-update-interval` The time-duration between updating the zone information
 - `log-level` Application logging level (debug, info, warn, error)
+- `read-timeout` Read timeout in duration format (default: 5s)
+- `write-timeout` Write timeout in duration format (default: 10s)
 
 This application is strictly meant to run in a container as a sidecar to
 External-DNS inside a Kubernetes environment. Refer to the External-DNS

cmd/webhook/main.go

@@ -28,11 +28,14 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"go.opentelemetry.io/otel/exporters/prometheus"
 	"go.opentelemetry.io/otel/sdk/metric"
+	"sigs.k8s.io/external-dns/provider/webhook/api"
 )
 
 func main() {
 	tidyEndpoint := flag.String("tidydns-endpoint", "", "DNS server address")
 	logLevel := flag.String("log-level", "", "logging level (debug, info, warn, err)")
+	readTimeout := flag.Duration("read-timeout", (5 * time.Second), "Read timeout in duration format (default: 5s)")
+	writeTimeout := flag.Duration("write-timeout", (10 * time.Second), "Write timeout in duration format (default: 10s)")
 
 	zoneArgDescription := "The intercval at which to update zone information format 00h00m00s e.g. 1h32m"
 	zoneUpdateIntervalArg := flag.String("zone-update-interval", "10m", zoneArgDescription)
@@ -96,15 +99,8 @@ func main() {
 		panic(err.Error())
 	}
 
-	// Use the provider to make a webhook containing all the callable endpoints
-	webhook := newWebhook(provider)
-
 	// Start webserver to service requests from External-DNS
-	go func() {
-		if err = serveWebhook(webhook, "127.0.0.1:8888"); err != nil {
-			panic(err.Error())
-		}
-	}()
+	go api.StartHTTPApi(provider, nil, *readTimeout, *writeTimeout, "127.0.0.1:8888")
 
 	metricsHandler := promhttp.Handler()
 

cmd/webhook/provider.go

@@ -53,7 +53,7 @@ func newProvider(tidy tidydns.TidyDNSClient, zoneProvider ZoneProvider) (*tidyPr
 }
 
 // Get list of zones from Tidy and return a domain filter based on them.
-func (p *tidyProvider) GetDomainFilter() endpoint.DomainFilter {
+func (p *tidyProvider) GetDomainFilter() endpoint.DomainFilterInterface {
 	// Make list of all zone names
 	zoneNames := []string{}
 	for _, zone := range p.zoneProvider.getZones() {

cmd/webhook/server.go

@@ -24,22 +24,6 @@ import (
 
 type Samples []metrics.Sample
 
-func serveWebhook(wh webhook, addr string) error {
-	slog.Debug("start webhook server on " + addr)
-	mux := http.NewServeMux()
-	mux.HandleFunc("GET /", wh.negociate)
-	mux.HandleFunc("GET /records", wh.getRecords)
-	mux.HandleFunc("POST /adjustendpoints", wh.adjustEndpoints)
-	mux.HandleFunc("POST /records", wh.applyChanges)
-
-	server := http.Server{
-		Addr:    addr,
-		Handler: mux,
-	}
-
-	return server.ListenAndServe()
-}
-
 func serveExposed(addr string, metricsHandler http.Handler) error {
 	slog.Debug("start webhook server on " + addr)
 	mux := http.NewServeMux()

vendor/modules.txt

@@ -246,6 +246,7 @@ k8s.io/utils/strings/slices
 sigs.k8s.io/external-dns/endpoint
 sigs.k8s.io/external-dns/plan
 sigs.k8s.io/external-dns/provider
+sigs.k8s.io/external-dns/provider/webhook/api
 # sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd
 ## explicit; go 1.18
 sigs.k8s.io/json