update

pkg/actor/grain_pool.go

@@ -19,8 +19,13 @@ type GrainPool[V any] interface {
 	OwnerHost(id uint64) (Host[V], bool)
 	Hostname() string
 	TakeOwnership(id uint64)
-	HandleOwnershipChange(host string, ids []uint64) error
-	HandleRemoteExpiry(host string, ids []uint64) error
+	// HandleOwnershipChange processes a remote first-touch ownership
+	// claim. lastChanges is the parallel []int64 of UnixNano stamps from
+	// the announcer; -1 entries fall back to the pre-arbitration
+	// "always accept remote" behaviour so mixed-version rollouts
+	// remain safe.
+	HandleOwnershipChange(host string, ids []uint64, lastChanges []int64) error
+	HandleRemoteExpiry(host string, ids []uint64, lastChanges []int64) error
 	Negotiate(otherHosts []string)
 	GetLocalIds() []uint64
 	IsHealthy() bool
@@ -32,7 +37,13 @@ type GrainPool[V any] interface {
 
 // Host abstracts a remote node capable of proxying cart requests.
 type Host[V any] interface {
-	AnnounceExpiry(ids []uint64)
+	// AnnounceExpiry broadcasts per-id eviction decisions. lastChanges is
+	// a parallel []int64 of UnixNano stamps taken at the moment the
+	// grain was dropped from the local cache; it is informational on
+	// this path (the receiver just removes the id from its remoteOwners
+	// map) but kept in the wire signature for symmetry with
+	// AnnounceOwnership.
+	AnnounceExpiry(ids []uint64, lastChanges []int64)
 	Negotiate(otherHosts []string) ([]string, error)
 	Name() string
 	Proxy(id uint64, w http.ResponseWriter, r *http.Request, customBody io.Reader) (bool, error)
@@ -42,5 +53,14 @@ type Host[V any] interface {
 	Close() error
 	Ping() bool
 	IsHealthy() bool
-	AnnounceOwnership(ownerHost string, ids []uint64)
+	// AnnounceOwnership broadcasts a first-touch ownership claim.
+	// lastChanges is a parallel []int64 of UnixNano stamps of the
+	// announcing pod's local grain's GetLastChange() at the moment of
+	// broadcast; receivers use it as the first-spawn-wins oracle for
+	// concurrent cold-cache first-touch (smaller stamp = older spawn =
+	// owns the grain; on equal stamps the lexicographically smaller
+	// hostname wins). A stamp of -1 means "no local grain to back this
+	// id" — receivers treat that as legacy/no-arbitration and accept
+	// the remote claim as before.
+	AnnounceOwnership(ownerHost string, ids []uint64, lastChanges []int64)
 }