zones: add ResolvePublicAddresses() ScanOption to prevent early LookupIP calls

Signed-off-by: Alejandro Mery <amery@jpi.io>

pkg/zones/options.go

@@ -12,7 +12,22 @@ import (
 type ScanOption func(*Zones, *ScanOptions) error
 
 // ScanOptions contains flags used by the initial scan
-type ScanOptions struct{}
+type ScanOptions struct {
+	// DontResolvePublicAddresses indicates we shouldn't
+	// pre-populate Machine.PublicAddresses during the
+	// initial scan
+	DontResolvePublicAddresses bool
+}
+
+// ResolvePublicAddresses instructs the scanner to use
+// the DNS resolver to get PublicAddresses of nodes.
+// Default is true
+func ResolvePublicAddresses(resolve bool) ScanOption {
+	return func(m *Zones, opt *ScanOptions) error {
+		opt.DontResolvePublicAddresses = !resolve
+		return nil
+	}
+}
 
 // WithLookuper specifies what resolver.Lookuper to use to
 // find public addresses