A node is given how it hears its declarations as it enrols

The node's declaration consumer was asserted only when the control plane
started, so the first machine of a mesh, enrolling after the control
plane was up, joined and then heard nothing: its host retried 'consumer
not found' for ever (novox/hq issue 146).

internal/link/bus_nats.go

@@ -9,12 +9,13 @@ import (
 // the streams and the controller's consumers are asserted by Raise, before anything is served.
 func ConnectNats(js *broker.JetStream, enroller Enroller, listener Listener) *Server {
 	return &Server{
-		inbound:  Nats(js),
-		bus:      OverNATS{JS: js.Context(), Conn: js.Conn()},
-		js:       js,
-		enroller: enroller,
-		listener: listener,
-		log:      newLog(),
+		inbound:   Nats(js),
+		bus:       OverNATS{JS: js.Context(), Conn: js.Conn()},
+		js:        js,
+		consumers: js,
+		enroller:  enroller,
+		listener:  listener,
+		log:       newLog(),
 	}
 }
 

internal/link/enrol_consumer_test.go

@@ -0,0 +1,51 @@
+package link
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"log"
+	"testing"
+	"time"
+
+	"github.com/novox/mesh-controller/internal/broker"
+)
+
+type ensured struct{ consumers []broker.Consumer }
+
+func (e *ensured) EnsureConsumer(c broker.Consumer) error {
+	e.consumers = append(e.consumers, c)
+	return nil
+}
+
+type acceptsAs string
+
+func (n acceptsAs) Enrol(context.Context, EnrolRequest) (EnrolReply, error) {
+	return EnrolReply{Accepted: true, Node: string(n)}, nil
+}
+
+type anEnrolment struct{ body []byte }
+
+func (m anEnrolment) Kind() string                         { return "enrol" }
+func (m anEnrolment) Body() []byte                         { return m.body }
+func (m anEnrolment) Redelivered() bool                    { return false }
+func (m anEnrolment) HeldFor() time.Duration               { return 0 }
+func (m anEnrolment) Answer(context.Context, []byte) error { return nil }
+func (m anEnrolment) Took() error                          { return nil }
+func (m anEnrolment) Hold(time.Duration) error             { return nil }
+func (m anEnrolment) Drop() error                          { return nil }
+
+// **A node that enrols can hear its declarations at once** (novox/hq 04-ISSUES/146): its consumer is
+// made as it enrols, not only when the control plane next starts — the first machine of a mesh
+// enrols after the control plane is up, and heard nothing.
+func TestAnEnrolledNodeIsGivenHowItHearsItsDeclarations(t *testing.T) {
+	made := &ensured{}
+	s := &Server{enroller: acceptsAs("anchor"), consumers: made, log: log.New(io.Discard, "", 0)}
+	body, _ := json.Marshal(EnrolRequest{Node: "anchor"})
+	s.enrolling(context.Background(), anEnrolment{body: body})
+
+	want := broker.NodeConsumer("anchor")
+	if len(made.consumers) != 1 || made.consumers[0].Name != want.Name || made.consumers[0].Stream != want.Stream {
+		t.Fatalf("the enrolled node was given %v, want its own declaration consumer %v", made.consumers, want)
+	}
+}

internal/link/serve.go

@@ -73,6 +73,8 @@ type Server struct {
 	inbound Inbound
 	bus     Bus
 	js      *broker.JetStream
+	// consumers makes a node's declaration consumer as it enrols; the bus connection, or a stand-in.
+	consumers interface{ EnsureConsumer(broker.Consumer) error }
 
 	enroller Enroller
 	listener Listener
@@ -383,6 +385,7 @@ func (s *Server) enrolling(ctx context.Context, m Control) {
 		default:
 			reply = accepted
 			s.log.Printf("enrolled %s", accepted.Node)
+			s.hearsItsDeclarations(accepted.Node)
 		}
 	}
 
@@ -402,6 +405,24 @@ func (s *Server) enrolling(ctx context.Context, m Control) {
 	_ = m.Took()
 }
 
+// hearsItsDeclarations makes the consumer a node reads its declarations through, as it enrols and
+// before it is answered.
+//
+// **Created at enrolment, as the consumer's own doc has always said** (novox/hq 04-ISSUES/146). It
+// was asserted only when the control plane started, so the first machine of a mesh — which enrols
+// after the control plane is already up — joined and then heard nothing, its host retrying "consumer
+// not found" for ever. Failing here is said and does not unspend the token: the next start of the
+// control plane asserts it again.
+func (s *Server) hearsItsDeclarations(node string) {
+	if s.consumers == nil {
+		return
+	}
+	if err := s.consumers.EnsureConsumer(broker.NodeConsumer(node)); err != nil {
+		s.log.Printf("%s enrolled, and how it hears its declarations could not be made — it will hear "+
+			"nothing until the control plane next starts: %v", node, err)
+	}
+}
+
 // wasBuilt keeps what a builder said, whichever way it went.
 //
 // This is for results nobody was waiting for. A build asked for with `build` is answered directly