fix: read delegation from public NS (#12)

Author: intel352

internal/drivers/delegation.go

@@ -5,6 +5,7 @@ package drivers
 import (
 	"context"
 	"fmt"
+	"net"
 	"sort"
 	"strings"
 
@@ -28,12 +29,13 @@ type HoverDelegationClient interface {
 // [ns1.hover.com, ns2.hover.com]; restore-from-stash is deferred to
 // v0.3.0 because interfaces.ResourceRef has no state channel.
 type DelegationDriver struct {
-	client HoverDelegationClient
+	client     HoverDelegationClient
+	nsResolver func(context.Context, string) ([]string, error)
 }
 
 // NewDelegationDriver returns a DelegationDriver bound to a real *hover.Client.
 func NewDelegationDriver(c *hover.Client) *DelegationDriver {
-	return &DelegationDriver{client: c}
+	return &DelegationDriver{client: c, nsResolver: lookupPublicNameservers}
 }
 
 // NewDelegationDriverWithClient returns a DelegationDriver bound to an
@@ -42,6 +44,12 @@ func NewDelegationDriverWithClient(c HoverDelegationClient) *DelegationDriver {
 	return &DelegationDriver{client: c}
 }
 
+// NewDelegationDriverWithClientAndResolver returns a DelegationDriver bound
+// to an injected client and public-NS resolver; used by tests.
+func NewDelegationDriverWithClientAndResolver(c HoverDelegationClient, resolver func(context.Context, string) ([]string, error)) *DelegationDriver {
+	return &DelegationDriver{client: c, nsResolver: resolver}
+}
+
 func (d *DelegationDriver) Type() string { return "infra.dns_delegation" }
 
 func (d *DelegationDriver) SensitiveKeys() []string { return nil }
@@ -105,11 +113,15 @@ func parseDelegationSpec(spec interfaces.ResourceSpec) (dnsDelegationSpec, error
 func nameserversToAny(ns []string) []any {
 	out := make([]any, len(ns))
 	for i, s := range ns {
-		out[i] = s
+		out[i] = normalizeNameserverHost(s)
 	}
 	return out
 }
 
+func normalizeNameserverHost(host string) string {
+	return strings.TrimSuffix(strings.TrimSpace(host), ".")
+}
+
 // delegationOutput builds the ResourceOutput for a Create/Update result.
 // v0.2.0 ships without previous_nameservers (no state channel in
 // interfaces.ResourceRef; v0.3.0 follow-up).
@@ -154,13 +166,34 @@ func (d *DelegationDriver) Read(ctx context.Context, ref interfaces.ResourceRef)
 	if domain == "" {
 		domain = ref.Name
 	}
+	if d.nsResolver != nil {
+		if ns, err := d.nsResolver(ctx, domain); err == nil && len(ns) > 0 {
+			return delegationOutput(ref.Name, domain, ns), nil
+		}
+	}
 	dom, err := d.client.GetDomainDelegation(ctx, domain)
 	if err != nil {
 		return nil, fmt.Errorf("dns_delegation read %q: %w", ref.Name, err)
 	}
 	return delegationOutput(ref.Name, domain, dom.Nameservers), nil
 }
 
+func lookupPublicNameservers(ctx context.Context, domain string) ([]string, error) {
+	resolver := net.DefaultResolver
+	records, err := resolver.LookupNS(ctx, domain)
+	if err != nil {
+		return nil, err
+	}
+	out := make([]string, 0, len(records))
+	for _, record := range records {
+		host := normalizeNameserverHost(record.Host)
+		if host != "" {
+			out = append(out, host)
+		}
+	}
+	return out, nil
+}
+
 // Update replaces the registrar nameservers. Rejects in-place domain
 // renames (those must route through Diff → NeedsReplace → Delete-then-Create).
 func (d *DelegationDriver) Update(ctx context.Context, ref interfaces.ResourceRef, spec interfaces.ResourceSpec) (*interfaces.ResourceOutput, error) {

internal/drivers/delegation_test.go

@@ -13,11 +13,13 @@ import (
 type fakeDelegationClient struct {
 	getResult *hover.DomainDelegation
 	getErr    error
+	getCalls  int
 	setErr    error
 	lastSetNS []string
 }
 
 func (f *fakeDelegationClient) GetDomainDelegation(_ context.Context, _ string) (*hover.DomainDelegation, error) {
+	f.getCalls++
 	return f.getResult, f.getErr
 }
 
@@ -140,6 +142,28 @@ func TestDelegationDriver_Read_HappyPath(t *testing.T) {
 	}
 }
 
+func TestDelegationDriver_Read_UsesPublicNSBeforeHoverLogin(t *testing.T) {
+	fc := &fakeDelegationClient{getErr: errors.New("hover login should not be needed")}
+	d := NewDelegationDriverWithClientAndResolver(fc, func(_ context.Context, domain string) ([]string, error) {
+		if domain != "example.com" {
+			t.Fatalf("resolver domain = %q, want example.com", domain)
+		}
+		return []string{"ns1.digitalocean.com.", "ns2.digitalocean.com.", "ns3.digitalocean.com."}, nil
+	})
+
+	out, err := d.Read(context.Background(), interfaces.ResourceRef{Name: "example.com", ProviderID: "example.com"})
+	if err != nil {
+		t.Fatalf("Read: %v", err)
+	}
+	if fc.getCalls != 0 {
+		t.Fatalf("GetDomainDelegation called %d times; public NS should avoid Hover login", fc.getCalls)
+	}
+	ns, _ := out.Outputs["nameservers"].([]any)
+	if len(ns) != 3 || ns[0] != "ns1.digitalocean.com" {
+		t.Fatalf("nameservers = %#v", ns)
+	}
+}
+
 func TestDelegationDriver_Read_PropagatesError(t *testing.T) {
 	fc := &fakeDelegationClient{getErr: errors.New("API down")}
 	d := NewDelegationDriverWithClient(fc)