feat(secondary): Send NOTIFY messages after zone transfer (#7901)

* feat(secondary): Send NOTIFY messages after zone transfer

- Modified TransferIn() method to accept a transfer.Transfer parameter
- Added NOTIFY message sending after successful zone transfer in secondary plugin
- Updated Update() method to pass the transfer handler through the zone update cycle
- Added comprehensive tests for the secondary notify functionality

Closes #5669

Signed-off-by: liucongran <liucongran327@gmail.com>

* fix(secondary): Fix TransferIn method call in test

Update test to pass nil parameter to TransferIn method after signature change

Signed-off-by: liucongran <liucongran327@gmail.com>

* refactor(secondary): Clean up imports and add helper methods

- Reorder imports for consistency
- Add hasSOA() and getSOA() helper methods to Zone
- Remove unnecessary blank lines in tests

Signed-off-by: liucongran <liucongran327@gmail.com>

* fix(test): Fix variable declaration in secondary test

Change corefile variable assignment to use short declaration syntax (:=)
to fix compilation error.

Signed-off-by: liucongran <liucongran327@gmail.com>

* refactor(secondary): Use getSOA helper method in shouldTransfer

Replace direct SOA access with getSOA() helper method for consistency.

Signed-off-by: liucongran <liucongran327@gmail.com>

---------

Signed-off-by: liucongran <liucongran327@gmail.com>
Co-authored-by: liucongran <liucongran@cestc.cn>

plugin/file/file.go

@@ -22,7 +22,7 @@ type (
 	File struct {
 		Next plugin.Handler
 		Zones
-		transfer *transfer.Transfer
+		Xfer *transfer.Transfer
 
 		Fall fall.F
 	}
@@ -70,7 +70,7 @@ 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()
+				z.TransferIn(f.Xfer)
 			} else {
 				log.Infof("Notify from %s for %s: no SOA serial increase seen", state.IP(), zone)
 			}

plugin/file/secondary.go

@@ -4,11 +4,13 @@ import (
 	"math/rand"
 	"time"
 
+	"github.com/coredns/coredns/plugin/transfer"
+
 	"github.com/miekg/dns"
 )
 
 // TransferIn retrieves the zone from the masters, parses it and sets it live.
-func (z *Zone) TransferIn() error {
+func (z *Zone) TransferIn(t *transfer.Transfer) error {
 	if len(z.TransferFrom) == 0 {
 		return nil
 	}
@@ -57,6 +59,13 @@ Transfer:
 	z.Expired = false
 	z.Unlock()
 	log.Infof("Transferred: %s from %s", z.origin, tr)
+
+	// Send notify messages to secondary servers
+	if t != nil {
+		if err := t.Notify(z.origin); err != nil {
+			log.Warningf("Failed sending notifies: %s", err)
+		}
+	}
 	return nil
 }
 
@@ -89,10 +98,11 @@ Transfer:
 	if serial == -1 {
 		return false, Err
 	}
-	if z.SOA == nil {
+	if !z.hasSOA() {
 		return true, Err
 	}
-	return less(z.SOA.Serial, uint32(serial)), Err // #nosec G115 -- serial fits in uint32 per DNS RFC
+	soa := z.getSOA()
+	return less(soa.Serial, uint32(serial)), Err // #nosec G115 -- serial fits in uint32 per DNS RFC
 }
 
 // less returns true of a is smaller than b when taking RFC 1982 serial arithmetic into account.
@@ -107,17 +117,18 @@ func less(a, b uint32) bool {
 // and uses the SOA parameters. Every refresh it will check for a new SOA number. If that fails (for all
 // 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) error {
+func (z *Zone) Update(updateShutdown chan bool, t *transfer.Transfer) error {
 	// If we don't have a SOA, we don't have a zone, wait for it to appear.
-	for z.SOA == nil {
+	for !z.hasSOA() {
 		time.Sleep(1 * time.Second)
 	}
 	retryActive := false
 
 Restart:
-	refresh := time.Second * time.Duration(z.SOA.Refresh)
-	retry := time.Second * time.Duration(z.SOA.Retry)
-	expire := time.Second * time.Duration(z.SOA.Expire)
+	soa := z.getSOA()
+	refresh := time.Second * time.Duration(soa.Refresh)
+	retry := time.Second * time.Duration(soa.Retry)
+	expire := time.Second * time.Duration(soa.Expire)
 
 	refreshTicker := time.NewTicker(refresh)
 	retryTicker := time.NewTicker(retry)
@@ -145,7 +156,7 @@ Restart:
 			}
 
 			if ok {
-				if err := z.TransferIn(); err != nil {
+				if err := z.TransferIn(t); err != nil {
 					// transfer failed, leave retryActive true
 					break
 				}
@@ -170,7 +181,7 @@ Restart:
 			}
 
 			if ok {
-				if err := z.TransferIn(); err != nil {
+				if err := z.TransferIn(t); err != nil {
 					// transfer failed
 					retryActive = true
 					break

plugin/file/secondary_test.go

@@ -113,7 +113,7 @@ func TestTransferIn(t *testing.T) {
 	z.origin = testZone
 	z.TransferFrom = []string{s.Addr}
 
-	if err := z.TransferIn(); err != nil {
+	if err := z.TransferIn(nil); err != nil {
 		t.Fatalf("Unable to run TransferIn: %v", err)
 	}
 	if z.SOA.String() != fmt.Sprintf("%s	3600	IN	SOA	bla. bla. 250 0 0 0 0", testZone) {

plugin/file/setup.go

@@ -29,10 +29,10 @@ func setup(c *caddy.Controller) error {
 		if t == nil {
 			return nil
 		}
-		f.transfer = t.(*transfer.Transfer) // if found this must be OK.
+		f.Xfer = t.(*transfer.Transfer) // if found this must be OK.
 		go func() {
 			for _, n := range zones.Names {
-				f.transfer.Notify(n)
+				f.Xfer.Notify(n)
 			}
 		}()
 		return nil
@@ -45,7 +45,7 @@ func setup(c *caddy.Controller) error {
 		}
 		go func() {
 			for _, n := range zones.Names {
-				f.transfer.Notify(n)
+				f.Xfer.Notify(n)
 			}
 		}()
 		return nil
@@ -55,7 +55,7 @@ func setup(c *caddy.Controller) error {
 		z := zones.Z[n]
 		c.OnShutdown(z.OnShutdown)
 		c.OnStartup(func() error {
-			z.StartupOnce.Do(func() { z.Reload(f.transfer) })
+			z.StartupOnce.Do(func() { z.Reload(f.Xfer) })
 			return nil
 		})
 	}

plugin/file/zone.go

@@ -182,3 +182,15 @@ func (z *Zone) nameFromRight(qname string, i int) (string, bool) {
 	}
 	return qname[n:], false
 }
+
+func (z *Zone) hasSOA() bool {
+	z.RLock()
+	defer z.RUnlock()
+	return z.SOA != nil
+}
+
+func (z *Zone) getSOA() *dns.SOA {
+	z.RLock()
+	defer z.RUnlock()
+	return z.SOA
+}