From 8cf8be277810d52e472537470eaf04037ab3f2c4 Mon Sep 17 00:00:00 2001
From: matst80 <mats.tornberg@gmail.com>
Date: Sat, 9 Nov 2024 19:16:01 +0100
Subject: [PATCH] more sync stuff

---
 synced-pool.go | 69 ++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 64 insertions(+), 5 deletions(-)

diff --git a/synced-pool.go b/synced-pool.go
index e6b53a6..15ffb67 100644
--- a/synced-pool.go
+++ b/synced-pool.go
@@ -49,7 +49,7 @@ func NewK8sDiscovery(client *kubernetes.Clientset) *K8sDiscovery {
 
 type Quorum interface {
 	Negotiate(knownHosts []string) ([]string, error)
-	ElectOwner(CartId) error
+	OwnerChanged(CartId, host string) error
 }
 
 type RemoteHost struct {
@@ -119,6 +119,8 @@ func NewSyncedPool(local *GrainLocalPool, hostname string, d Discovery) (*Synced
 const (
 	RemoteNegotiate    = uint16(3)
 	RemoteGrainChanged = uint16(4)
+	AckChange          = uint16(5)
+	AckError           = uint16(6)
 )
 
 func (p *SyncedPool) handleConnection(conn net.Conn) {
@@ -162,9 +164,38 @@ func (p *SyncedPool) handleConnection(conn net.Conn) {
 			// remote grain changed
 			log.Printf("Remote grain changed\n")
 			for err == nil {
-				id := make([]byte, 16)
-				_, err = conn.Read(id)
-				log.Printf("Remote grain %s changed\n", id)
+				idAndHost := make([]byte, packet.DataLength)
+				_, err = conn.Read(idAndHost)
+				log.Printf("Remote grain %s changed\n", idAndHost)
+				if err != nil {
+					break
+				}
+				idAndHostParts := strings.Split(string(idAndHost), ";")
+				if len(idAndHostParts) != 2 {
+					log.Printf("Invalid remote grain change message\n")
+					break
+				}
+				found := false
+				for _, r := range p.remotes {
+					if r.Host == string(idAndHostParts[1]) {
+						found = true
+						log.Printf("Remote grain %s changed to %s\n", idAndHostParts[0], idAndHostParts[1])
+						p.remoteIndex[ToCartId(idAndHostParts[0])] = r.Pool
+					}
+				}
+
+				if !found {
+					log.Printf("Remote host %s not found\n", idAndHostParts[1])
+					SendPacket(conn, AckError, func(w io.Writer) error {
+						w.Write([]byte("remote host not found"))
+						return nil
+					})
+				} else {
+					SendPacket(conn, AckChange, func(w io.Writer) error {
+						w.Write([]byte("ok"))
+						return nil
+					})
+				}
 			}
 		}
 	}
@@ -203,7 +234,31 @@ func (p *SyncedPool) Negotiate(knownHosts []string) ([]string, error) {
 	return ret, nil
 }
 
-func (p *SyncedPool) ListChanged(ids []CartId) error {
+func (r *RemoteHost) ConfirmChange(id CartId, host string) error {
+	SendPacket(r.connection, RemoteGrainChanged, func(w io.Writer) error {
+
+		w.Write([]byte(fmt.Sprintf("%s;%s", id, host)))
+		return nil
+	})
+	t, _, err := ReceivePacket(r.connection)
+	if err != nil {
+		return err
+	}
+	if t != AckChange {
+		return fmt.Errorf("unexpected message type %d", t)
+	}
+	return nil
+}
+
+func (p *SyncedPool) OwnerChanged(id CartId, host string) error {
+	for _, r := range p.remotes {
+		err := r.ConfirmChange(id, host)
+
+		if err != nil {
+			log.Printf("Error confirming change: %v\n", err)
+			return err
+		}
+	}
 	return nil
 }
 
@@ -241,6 +296,10 @@ func (p *SyncedPool) Process(id CartId, messages ...Message) ([]byte, error) {
 			return remoteGrain.Process(id, messages...)
 		}
 	}
+	err := p.OwnerChanged(id, p.Hostname)
+	if err != nil {
+		return nil, err
+	}
 	return p.local.Process(id, messages...)
 }