Compose where a declaration was sent: secrets, credentials, acceptances, the hub's peers, adoption, assignments and the bus's user list (issue 1945, B2, B6)

Each act that changed what a node runs now writes that node's compositions, and its wants follow by the assigner's
rules; a bus upgrade composes the bus's machines and answers the want the operator writes, since the assigner never
moves the bus (ADR 0539 clauses 5, 7 and 15). A node-engine may ask its own backup holder before a data module moves.

internal/broker/composed.go

@@ -96,3 +96,20 @@ func ComposedReads(node string) ([]string, error) {
 	}
 	return append(readGrants(bucket, ""), readGrants(delivery.AssignerWantsBucket, "want."+node+".>")...), nil
 }
+
+// VerbsTheNodeAgentAsks are the seat verbs a node's node-engine calls of its own machine while it applies a want (ADR
+// 0539 clause 16, ADR 0429 §14): its backup holder backs a data module up before it moves, and says when it was. Asked
+// of its own machine only, `mesh.seat.<seat>.tool.<verb>.<node>`.
+var VerbsTheNodeAgentAsks = []SeatVerb{{Seat: "node-backup", Verb: "now"}, {Seat: "node-backup", Verb: "backed-up"}}
+
+// NodeAgentAsks are the subjects of VerbsTheNodeAgentAsks for one node.
+func NodeAgentAsks(node string) ([]string, error) {
+	if !safeSubject.MatchString(node) {
+		return nil, fmt.Errorf("%q cannot be part of a subject: a permission is a subject pattern, and this would widen it", node)
+	}
+	var out []string
+	for _, v := range VerbsTheNodeAgentAsks {
+		out = append(out, "mesh.seat."+v.Seat+".tool."+v.Verb+"."+node)
+	}
+	return out, nil
+}

internal/broker/composed_test.go

@@ -47,3 +47,25 @@ func TestANodeReadsOnlyItsOwnCompositions(t *testing.T) {
 		t.Errorf("a node name with a wildcard was granted")
 	}
 }
+
+// 1945 (for issue 1944): a node-engine asks its own machine's backup holder to back a data module up before it moves
+// and when it last was, and no other machine's.
+func TestANodeAgentAsksItsOwnBackupHolder(t *testing.T) {
+	asks, err := NodeAgentAsks("ace")
+	if err != nil || strings.Join(asks, " ") != "mesh.seat.node-backup.tool.now.ace mesh.seat.node-backup.tool.backed-up.ace" {
+		t.Errorf("NodeAgentAsks(ace) = %v, %v", asks, err)
+	}
+	p, err := PermissionsFor(Principal{Kind: KindNode, Node: "ace", PasswordHash: "x"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	all := strings.Join(p.Publish, " ")
+	for _, want := range append(asks, "$JS.API.DIRECT.GET.KV_composed-ace.>") {
+		if !strings.Contains(all, want) {
+			t.Errorf("a node-engine of ace may not publish %s", want)
+		}
+	}
+	if strings.Contains(all, "node-backup.tool.now.*") || strings.Contains(all, "KV_composed-g14") {
+		t.Errorf("a node-engine of ace reaches another machine: %v", p.Publish)
+	}
+}

internal/broker/nats.go

@@ -865,6 +865,12 @@ func PermissionsFor(p Principal) (Permissions, error) {
 			return Permissions{}, err
 		}
 		pub = append(pub, composedReads...)
+		// And its own machine's backup holder, before a data module moves (ADR 0539 clause 16).
+		backups, err := NodeAgentAsks(p.Node)
+		if err != nil {
+			return Permissions{}, err
+		}
+		pub = append(pub, backups...)
 		// And, while the vault serves it, the vault's move-in in its own name and nobody else's (issue 676): the
 		// values sealed to this machine, which only it opens, handed in sealed to the vault's key for the call.
 		if p.MovesIntoTheVault {

internal/broker/testdata/composed.conf

@@ -38,7 +38,7 @@ accounts {
         subscribe: { allow: ["_INBOX.enrol.one.>"] }
       } }
       { user: "node.one", password: "$2a$11$nnnnnnnnnnnnnnnnnnnnnn", permissions: {
-        publish: { allow: ["$JS.ACK.NODES.one.>", "$JS.API.CONSUMER.CREATE.KV_composed-one.>", "$JS.API.CONSUMER.CREATE.KV_mesh-delivery-assigner_wants.*.$KV.mesh-delivery-assigner_wants.want.one.>", "$JS.API.CONSUMER.CREATE.KV_node-engine_have.*.$KV.node-engine_have.one.>", "$JS.API.CONSUMER.CREATE.OBJ_declaration-files-one.*.$O.declaration-files-one.C.*", "$JS.API.CONSUMER.DELETE.KV_composed-one.>", "$JS.API.CONSUMER.DELETE.KV_mesh-delivery-assigner_wants.>", "$JS.API.CONSUMER.DELETE.KV_node-engine_have.>", "$JS.API.CONSUMER.DELETE.OBJ_declaration-files-one.*", "$JS.API.CONSUMER.INFO.NODES.one", "$JS.API.DIRECT.GET.KV_composed-one.>", "$JS.API.DIRECT.GET.KV_mesh-delivery-assigner_wants.$KV.mesh-delivery-assigner_wants.want.one.>", "$JS.API.DIRECT.GET.KV_node-engine_have.$KV.node-engine_have.one.>", "$JS.API.DIRECT.GET.OBJ_declaration-files-one.$O.declaration-files-one.M.*", "$JS.API.STREAM.INFO.KV_composed-one", "$JS.API.STREAM.INFO.KV_mesh-delivery-assigner_wants", "$JS.API.STREAM.INFO.KV_node-engine_have", "$JS.FC.KV_composed-one.>", "$JS.FC.KV_mesh-delivery-assigner_wants.>", "$JS.FC.KV_node-engine_have.>", "$JS.FC.OBJ_declaration-files-one.>", "$KV.node-engine_have.one.>", "$SRV.PING.node-tools.one", "mesh.control.one.>"] }
+        publish: { allow: ["$JS.ACK.NODES.one.>", "$JS.API.CONSUMER.CREATE.KV_composed-one.>", "$JS.API.CONSUMER.CREATE.KV_mesh-delivery-assigner_wants.*.$KV.mesh-delivery-assigner_wants.want.one.>", "$JS.API.CONSUMER.CREATE.KV_node-engine_have.*.$KV.node-engine_have.one.>", "$JS.API.CONSUMER.CREATE.OBJ_declaration-files-one.*.$O.declaration-files-one.C.*", "$JS.API.CONSUMER.DELETE.KV_composed-one.>", "$JS.API.CONSUMER.DELETE.KV_mesh-delivery-assigner_wants.>", "$JS.API.CONSUMER.DELETE.KV_node-engine_have.>", "$JS.API.CONSUMER.DELETE.OBJ_declaration-files-one.*", "$JS.API.CONSUMER.INFO.NODES.one", "$JS.API.DIRECT.GET.KV_composed-one.>", "$JS.API.DIRECT.GET.KV_mesh-delivery-assigner_wants.$KV.mesh-delivery-assigner_wants.want.one.>", "$JS.API.DIRECT.GET.KV_node-engine_have.$KV.node-engine_have.one.>", "$JS.API.DIRECT.GET.OBJ_declaration-files-one.$O.declaration-files-one.M.*", "$JS.API.STREAM.INFO.KV_composed-one", "$JS.API.STREAM.INFO.KV_mesh-delivery-assigner_wants", "$JS.API.STREAM.INFO.KV_node-engine_have", "$JS.FC.KV_composed-one.>", "$JS.FC.KV_mesh-delivery-assigner_wants.>", "$JS.FC.KV_node-engine_have.>", "$JS.FC.OBJ_declaration-files-one.>", "$KV.node-engine_have.one.>", "$SRV.PING.node-tools.one", "mesh.control.one.>", "mesh.seat.node-backup.call.backed-up.one.node~one", "mesh.seat.node-backup.call.now.one.node~one", "mesh.seat.node-backup.tool.backed-up.one", "mesh.seat.node-backup.tool.now.one"] }
         subscribe: { allow: ["_DELIVER.one", "_DELIVER.one.>", "_INBOX.node.one.>", "mesh.node.one.ask.hand-over", "mesh.node.one.ask.judge-directories", "mesh.node.one.ask.move-secret", "mesh.node.one.ask.report", "mesh.node.one.ask.setuid-search", "mesh.node.one.declare"] }
         allow_responses: { max: 1, ttl: "1m" }
       } }