issue 1840/S6: emit through the same EventSink as the upgrade parts, so one connection serves both

modules/pacman/cmd/pacman-tools/keeper.go

@@ -77,10 +77,6 @@ type Store interface {
 	Watch(key string, handle func(stdio.StateChange) error) error
 }
 
-// Emitter emits one event with its body; id is the event's id, the bus's dedup id, so emitting it again after a
-// failure the bus did not report is dropped.
-type Emitter func(event string, body any, id string) error
-
 // Clock is the time as the keeper sees it.
 type Clock interface {
 	Now() time.Time
@@ -154,7 +150,9 @@ type Keeper struct {
 	Config  KeeperConfig
 	Machine *Machine
 	State   func(name string) Store
-	Emit    Emitter
+	// Events emits the keeper's events; package.changed carries the id `installed.<node>.<revision>`, the bus's
+	// dedup id, so the same change said twice is dropped.
+	Events  EventSink
 	Clock   Clock
 	Watcher Watcher
 	// Locked says pacman's lock is held now: a released lock followed at once by another transaction is read
@@ -334,7 +332,8 @@ func (k *Keeper) refreshInstalled(at time.Time) *PackageChanged {
 		return nil
 	}
 	ev := &PackageChanged{Node: k.Node, At: at.UTC(), Added: c.Added, Removed: c.Removed, Changed: c.Changed}
-	if err := k.Emit(EventPackageChanged, *ev, fmt.Sprintf("%s.%s.%d", StateInstalled, k.Node, rev)); err != nil {
+	id := fmt.Sprintf("%s.%s.%d", StateInstalled, k.Node, rev)
+	if err := k.Events.Emit(EventPackageChanged, *ev, stdio.EmitOptions{MessageID: id}); err != nil {
 		k.logf("[pacman] keeper: emitting %s for installed.%s at revision %d: %v", EventPackageChanged, k.Node, rev, err)
 	}
 	return ev
@@ -521,8 +520,6 @@ func runKeeper(ctx context.Context, account process.Account, k *Keeper) error {
 		k.Node = account.Node
 	}
 	k.State = func(name string) Store { return processStore{conn.State(name)} }
-	k.Emit = func(event string, body any, id string) error {
-		return conn.Emit(event, body, stdio.EmitOptions{MessageID: id})
-	}
+	k.Events = conn
 	return k.Run(ctx)
 }

modules/pacman/cmd/pacman-tools/keeper_test.go

@@ -202,9 +202,13 @@ type emittedEvent struct {
 	id   string
 }
 
-func (e *emitted) Emit(name string, body any, id string) error {
+func (e *emitted) Emit(name string, body any, opts ...stdio.EmitOptions) error {
 	e.mu.Lock()
 	defer e.mu.Unlock()
+	id := ""
+	for _, o := range opts {
+		id = o.MessageID
+	}
 	e.events = append(e.events, emittedEvent{name, body, id})
 	return nil
 }
@@ -318,7 +322,7 @@ func newTestKeeper(db *pacmanDB) (*Keeper, *fakeStates, *emitted, *fakeClock, fa
 	states, ev, clock := &fakeStates{}, &emitted{}, &fakeClock{now: t0}
 	w := fakeWatcher{make(chan Signal)}
 	m := machine(db.runner(), 1000)
-	k := &Keeper{Node: "node-a", Machine: m, State: states.State, Emit: ev.Emit, Clock: clock, Watcher: w,
+	k := &Keeper{Node: "node-a", Machine: m, State: states.State, Events: ev, Clock: clock, Watcher: w,
 		Logf: func(string, ...any) {}}
 	return k, states, ev, clock, w
 }