Report what an adopted node holds, its firewall and what is reachable, and speak unasked when that changes (hq ADR 0100)

internal/link/run.go

@@ -70,15 +70,21 @@ type Announce func(string)
 type Roused <-chan struct{}
 
 func Hold(ctx context.Context, m Membership, apply Applier, say Announce, timeout time.Duration) error {
-	return HoldRoused(ctx, m, apply, say, timeout, nil)
+	return HoldRoused(ctx, m, apply, say, timeout, nil, nil)
 }
 
-// HoldRoused is Hold, told when the machine has reason to think its link is stale.
+// Outbox carries reports the node has to say without having been sent anything — what a
+// reconcile found changed on an adopted node (novox/hq ADR 0100). Published while the link is up;
+// a report made while it is down waits in the channel for the next one. Nil is allowed.
+type Outbox <-chan Report
+
+// HoldRoused is Hold, told when the machine has reason to think its link is stale, and handed
+// reports to publish between deliveries.
 func HoldRoused(ctx context.Context, m Membership, apply Applier, say Announce,
-	timeout time.Duration, roused Roused) error {
+	timeout time.Duration, roused Roused, outbox Outbox) error {
 
 	return holdWith(ctx, func(ctx context.Context) error {
-		return Run(ctx, m, apply, say, timeout)
+		return Run(ctx, m, apply, say, timeout, outbox)
 	}, say, roused)
 }
 
@@ -171,7 +177,8 @@ func holdWith(ctx context.Context, run attempt, say Announce, roused Roused) err
 //
 // Outbound only, and nothing listens on this machine. Returns when the link ends, for any reason;
 // Hold is what decides whether to open it again.
-func Run(ctx context.Context, m Membership, apply Applier, say Announce, timeout time.Duration) error {
+func Run(ctx context.Context, m Membership, apply Applier, say Announce, timeout time.Duration,
+	outbox Outbox) error {
 	if say == nil {
 		say = func(string) {}
 	}
@@ -254,6 +261,10 @@ func Run(ctx context.Context, m Membership, apply Applier, say Announce, timeout
 			return nil
 		case <-beat.C:
 			publishAlive(ctx, channel, m, say, timeout)
+		case report := <-outbox:
+			// Said without having been asked: a reconcile found what an adopted node holds, or
+			// its firewall, changed since it last said.
+			publishReport(ctx, channel, m, report, say, timeout)
 		case reason := <-closed:
 			return fmt.Errorf("the link closed: %v", reason)
 		case delivery, ok := <-deliveries: