Merge pull request #31 from rackerlabs/fix/srv-record-creation

fix: correct SRV record creation and RFC 2782 trailing dot handling

Author: nicholaskuechler

README.md

@@ -201,6 +201,14 @@ docker build -t external-dns-rackspace-webhook .
 3. **Permission Denied**: Check that your API key has DNS management permissions
 4. **TTL Too Low**: The webhook enforces a minimum TTL of 300 seconds
 
+### external-dns Compatibility (SRV Records)
+
+SRV record support requires external-dns v0.21.0 or later:
+
+- **Versions prior to 0.21** do not include SRV in the TXT registry's `getSupportedTypes()`. This prevents the registry from matching `srv-` prefixed TXT ownership records to their SRV data records, causing all SRV records to appear unowned. external-dns will not update or delete them.
+
+- **Version 0.21.0** fixes the ownership matching but introduces contradictory SRV validation in the CRD source. The CRD validator rejects targets with a trailing dot, while `ValidateSRVRecord` requires one per RFC 2782. This makes it impossible to create SRV records via DNSEndpoint CRDs. See [kubernetes-sigs/external-dns#6357](https://github.com/kubernetes-sigs/external-dns/issues/6357) and the fix in [PR #6383](https://github.com/kubernetes-sigs/external-dns/pull/6383).
+
 ### Debug Mode
 
 Enable debug logging by setting `LOG_LEVEL` in your values file:

internal/handlers/handler.go

@@ -3,6 +3,7 @@ package handlers
 import (
 	"encoding/json"
 	"net/http"
+	"strings"
 
 	"github.com/charmbracelet/log"
 	"github.com/labstack/echo/v4"
@@ -37,11 +38,10 @@ func (h *Handler) HandleGetRecords(c echo.Context) error {
 	return c.JSON(http.StatusOK, endpoints)
 }
 
-// HandleAdjustEndpoints returns endpoints unchanged. Rackspace does not
-// require any provider-specific canonicalization. Transforming endpoints
-// here (adding trailing dots, modifying TTL, stripping TXT quotes) caused
-// mismatches with what Records() returns and with the TXT registry's
-// internal representation, leading to constant update churn.
+// HandleAdjustEndpoints normalises provider-specific endpoint details.
+// For SRV records, RFC 2782 requires the target host to be an absolute
+// FQDN (trailing dot).  Sources that omit the dot would be rejected by
+// external-dns's ValidateSRVRecord, so we append it here as a safety net.
 func (h *Handler) HandleAdjustEndpoints(c echo.Context) error {
 	defer c.Request().Body.Close()
 	var endpoints []*endpoint.Endpoint
@@ -50,6 +50,17 @@ func (h *Handler) HandleAdjustEndpoints(c echo.Context) error {
 		return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
 	}
 
+	for _, ep := range endpoints {
+		if ep.RecordType == "SRV" {
+			for i, target := range ep.Targets {
+				parts := strings.SplitN(target, " ", 4)
+				if len(parts) == 4 && !strings.HasSuffix(parts[3], ".") {
+					ep.Targets[i] = parts[0] + " " + parts[1] + " " + parts[2] + " " + parts[3] + "."
+				}
+			}
+		}
+	}
+
 	log.Info("POST /adjustendpoints", "count", len(endpoints))
 	return c.JSON(http.StatusOK, endpoints)
 }

internal/providers/consistency_test.go

@@ -57,23 +57,23 @@ func TestConvertRecordToEndpoint_SRVFormat(t *testing.T) {
 				Name: "_mongodb._tcp.myrs.example.com", Type: "SRV",
 				Data: "0 27017 node1.example.com", TTL: 300, Priority: 10,
 			},
-			wantTarget: "10 0 27017 node1.example.com",
+			wantTarget: "10 0 27017 node1.example.com.",
 		},
 		{
 			name: "zero priority",
 			record: records.RecordList{
 				Name: "_sip._tcp.svc.example.com", Type: "SRV",
 				Data: "5 5060 sip.example.com", TTL: 300, Priority: 0,
 			},
-			wantTarget: "0 5 5060 sip.example.com",
+			wantTarget: "0 5 5060 sip.example.com.",
 		},
 		{
 			name: "high priority value",
 			record: records.RecordList{
 				Name: "_http._tcp.web.example.com", Type: "SRV",
 				Data: "1 443 web.example.com", TTL: 300, Priority: 100,
 			},
-			wantTarget: "100 1 443 web.example.com",
+			wantTarget: "100 1 443 web.example.com.",
 		},
 	}
 

internal/providers/provider_test.go

@@ -2,7 +2,9 @@ package providers
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
+	"io"
 	"net/http"
 	"testing"
 	"time"
@@ -282,7 +284,7 @@ func TestRackspaceProvider_createRecord(t *testing.T) {
 			endpoint: &endpoint.Endpoint{
 				DNSName:    "_sip._tcp.example.com",
 				RecordType: "SRV",
-				Targets:    []string{"1 5 5060 _sip._tcp.example.com."},
+				Targets:    []string{"1 5 5060 sipserver.example.com"},
 				RecordTTL:  endpoint.TTL(3600),
 				Labels:     map[string]string{},
 			},
@@ -331,6 +333,28 @@ func TestRackspaceProvider_createRecord(t *testing.T) {
 				th.TestMethod(t, r, "POST")
 				th.TestHeader(t, r, "X-Auth-Token", "cbc36478b0bd8e67e89469c7749d4127")
 
+				if !tt.wantErr {
+					body, _ := io.ReadAll(r.Body)
+					var payload map[string]interface{}
+					if err := json.Unmarshal(body, &payload); err != nil {
+						t.Fatalf("failed to parse request body: %v", err)
+					}
+					recs, _ := payload["records"].([]interface{})
+					if len(recs) > 0 {
+						rec := recs[0].(map[string]interface{})
+						if data, ok := rec["data"].(string); ok {
+							if data != "5 5060 sipserver.example.com" {
+								t.Errorf("SRV data = %q, want %q", data, "5 5060 sipserver.example.com")
+							}
+						}
+						if priority, ok := rec["priority"].(float64); ok {
+							if priority != 1 {
+								t.Errorf("SRV priority = %v, want 1", priority)
+							}
+						}
+					}
+				}
+
 				w.Header().Add("Content-Type", "application/json")
 				w.WriteHeader(http.StatusCreated)
 				fmt.Fprint(w, `{

internal/providers/providers.go

@@ -244,6 +244,14 @@ func convertRecordToEndpoint(record records.RecordList, domainName string) *endp
 	// target" format that external-dns expects.
 	if record.Type == "SRV" {
 		data = fmt.Sprintf("%d %s", record.Priority, record.Data)
+		// Ensure the target host ends with a dot (RFC 2782) so that the
+		// value returned here matches what adjustEndpoints produces for
+		// the desired endpoints.  Without this trailing dot external-dns
+		// ≥ 0.21 rejects the record as invalid.
+		parts := strings.SplitN(data, " ", 4)
+		if len(parts) == 4 && !strings.HasSuffix(parts[3], ".") {
+			data = parts[0] + " " + parts[1] + " " + parts[2] + " " + parts[3] + "."
+		}
 	}
 
 	return &endpoint.Endpoint{
@@ -288,7 +296,7 @@ func (p *RackspaceProvider) createRecord(ctx context.Context, ep *endpoint.Endpo
 				return err
 			}
 			createOpts.Priority = uint(priority)
-			createOpts.Data = fmt.Sprintf("%s %s %s", parts[1], parts[2], fqdn)
+			createOpts.Data = fmt.Sprintf("%s %s %s", parts[1], parts[2], strings.TrimSuffix(parts[3], "."))
 		}
 
 		if _, err := p.getClient(ctx).CreateRecord(ctx, domain.ID, createOpts); err != nil {