The view reads directly and makes no consumer: a consumer's deliver subject publishes anywhere

Review of the view (research 036): granted CONSUMER.CREATE on the bucket's stream, the view made a
push consumer delivering to mesh.mod.mesh-issues.event.opened, and a module subscribed there
received the bucket's entry as the tracker's event — measured on 2.11.17. The server does not hold a
deliver subject to its creator's permissions, so a consumer grant is a publish to any subject.

The view now binds and reads directly, nothing else: STREAM.INFO, DIRECT.GET by key, and the batch
DIRECT.GET (multi_last) that lists every key's newest value into its inbox. No watch: the page
re-reads the key a tracker event names (every event carries the number). The live test lists with
the batch, follows a moved event to the re-read, and is refused the consumer and the watch with
nothing reaching the event subject; the mutation (CONSUMER.CREATE back) fails three tests.

The credential says how to read, and that the step making it work is the next `bus upgrade` while
a new bus build waits, not a push.

cmd/mesh-controller/bus_view.go

@@ -68,6 +68,7 @@ func busViewCredential(ctx context.Context, args []string) error {
 		InboxPrefix string   `json:"inbox_prefix"`
 		Hears       []string `json:"hears"`
 		Reads       string   `json:"reads"`
+		HowToRead   string   `json:"how_to_read"`
 	}{
 		WebSocket: websocket, URL: "nats://" + where.Address, Fingerprint: where.Fingerprint,
 		User: broker.ViewUser, Password: password,
@@ -75,6 +76,10 @@ func busViewCredential(ctx context.Context, args []string) error {
 		// `_INBOX.view.>` and no wider (design 25 §4), and a client's default inbox is not under it.
 		InboxPrefix: "_INBOX." + broker.ViewUser,
 		Hears:       broker.ViewHears, Reads: broker.ViewBucket,
+		HowToRead: "direct reads only, no watch (a consumer is refused): list with a request to $JS.API.DIRECT.GET.KV_" +
+			broker.ViewBucket + ` carrying {"multi_last":["$KV.` + broker.ViewBucket + `.>"]}, answered until a 204 status; ` +
+			"read one key with $JS.API.DIRECT.GET.KV_" + broker.ViewBucket + ".$KV." + broker.ViewBucket + ".<number> " +
+			"(nats.js: kvm.open(bucket, {allow_direct: true}), never create); re-read the key an event's number names",
 	})
 	if err != nil {
 		return err
@@ -83,8 +88,9 @@ func busViewCredential(ctx context.Context, args []string) error {
 	fmt.Printf("issued the view, which hears %s and reads the bucket %s, and nothing else\n",
 		strings.Join(broker.ViewHears, ", "), broker.ViewBucket)
 	fmt.Println("  this is the only time the credential is printed; the mesh keeps a hash")
-	fmt.Println("  it works once the bus has been told, which is the next push to the machine holding mesh-broker;")
-	fmt.Println("  the WebSocket listener it connects through is the bus module's, live there after the bus step a person starts (`bus upgrade`)")
+	fmt.Println("  it works once the bus has been told, which is the next push to the machine holding mesh-broker —")
+	fmt.Println("  and while a new build of the bus module waits for that machine, the next `bus upgrade` a person starts,")
+	fmt.Println("  which is also what brings the WebSocket listener it connects through")
 	fmt.Println()
 	fmt.Println(string(held))
 	return nil