plugin/secondary: parse catalog zones after transfer (#8209)

plugin/file/file.go

@@ -24,6 +24,7 @@ type (
 		Next plugin.Handler
 		Zones
 		Xfer *transfer.Transfer
+		TransferInFunc
 
 		Fall fall.F
 	}
@@ -71,7 +72,9 @@ func (f File) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (i
 			log.Infof("Notify from %s for %s: checking transfer", state.IP(), zone)
 			ok, err := z.shouldTransfer()
 			if ok {
-				z.TransferIn(f.Xfer)
+				if err := f.transferIn(z, f.Xfer); err != nil {
+					log.Warningf("Notify from %s for %s: transfer failed: %s", state.IP(), zone, err)
+				}
 			} else {
 				log.Infof("Notify from %s for %s: no SOA serial increase seen", state.IP(), zone)
 			}
@@ -131,6 +134,13 @@ func (f File) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (i
 // Name implements the Handler interface.
 func (f File) Name() string { return "file" }
 
+func (f File) transferIn(z *Zone, t *transfer.Transfer) error {
+	if f.TransferInFunc != nil {
+		return f.TransferInFunc(z, t)
+	}
+	return z.TransferIn(t)
+}
+
 type serialErr struct {
 	err    string
 	zone   string

plugin/file/secondary.go

@@ -9,8 +9,17 @@ import (
 	"github.com/miekg/dns"
 )
 
+// TransferInFunc transfers zone data into z.
+type TransferInFunc func(z *Zone, t *transfer.Transfer) error
+
 // TransferIn retrieves the zone from the masters, parses it and sets it live.
 func (z *Zone) TransferIn(t *transfer.Transfer) error {
+	return z.TransferInWithRecords(t, nil)
+}
+
+// TransferInWithRecords retrieves the zone from the masters, calls validate
+// with the transferred records, and sets the zone live if validation succeeds.
+func (z *Zone) TransferInWithRecords(t *transfer.Transfer, validate func([]dns.RR) error) error {
 	if len(z.TransferFrom) == 0 {
 		return nil
 	}
@@ -22,6 +31,7 @@ func (z *Zone) TransferIn(t *transfer.Transfer) error {
 		Err error
 		tr  string
 	)
+	var transferred []dns.RR
 
 Transfer:
 	for _, tr = range z.TransferFrom {
@@ -32,6 +42,7 @@ Transfer:
 			Err = err
 			continue Transfer
 		}
+		var records []dns.RR
 		for env := range c {
 			if env.Error != nil {
 				log.Errorf("Failed to transfer `%s' from %q: %v", z.origin, tr, env.Error)
@@ -44,14 +55,23 @@ Transfer:
 					Err = err
 					continue Transfer
 				}
+				if validate != nil {
+					records = append(records, rr)
+				}
 			}
 		}
+		transferred = records
 		Err = nil
 		break
 	}
 	if Err != nil {
 		return Err
 	}
+	if validate != nil {
+		if err := validate(transferred); err != nil {
+			return err
+		}
+	}
 
 	z.setData(z1.Apex, z1.Tree)
 	log.Infof("Transferred: %s from %s", z.origin, tr)
@@ -114,6 +134,11 @@ func less(a, b uint32) bool {
 // server) it will retry every retry interval. If the zone failed to transfer before the expire, the zone
 // will be marked expired.
 func (z *Zone) Update(updateShutdown chan bool, t *transfer.Transfer) error {
+	return z.UpdateWithTransfer(updateShutdown, t, (*Zone).TransferIn)
+}
+
+// UpdateWithTransfer updates the secondary zone using transferIn for zone transfers.
+func (z *Zone) UpdateWithTransfer(updateShutdown chan bool, t *transfer.Transfer, transferIn TransferInFunc) error {
 	// If we don't have a SOA, we don't have a zone, wait for it to appear.
 	for z.getSOA() == nil {
 		if waitOrShutdown(updateShutdown, time.Second) {
@@ -162,7 +187,7 @@ Restart:
 			}
 
 			if ok {
-				if err := z.TransferIn(t); err != nil {
+				if err := transferIn(z, t); err != nil {
 					// transfer failed, leave retryActive true
 					break
 				}
@@ -188,7 +213,7 @@ Restart:
 			}
 
 			if ok {
-				if err := z.TransferIn(t); err != nil {
+				if err := transferIn(z, t); err != nil {
 					// transfer failed
 					retryActive = true
 					break