Merge pull request 'A route composes its internal-network alias too, not only its public name' (#60) from feat/route-carries-internal-alias into main

internal/catalogue/declaration.go

@@ -911,7 +911,7 @@ func (r Resolution) contributions(settings SettingsBy, grants []Grant,
 			if err != nil {
 				return nil, fmt.Errorf("%s contributing to %s: %w", m.Module, to, err)
 			}
-			composeName(values, r.PublicDomain)
+			composeName(values, r.PublicDomain, r.At)
 			out[to] = append(out[to], Contribution{From: m.Module, Values: values})
 		}
 		// Several contributions to one requirement (ADR 0094's sibling for `contributes`): an
@@ -925,7 +925,7 @@ func (r Resolution) contributions(settings SettingsBy, grants []Grant,
 				if err != nil {
 					return nil, fmt.Errorf("%s contributing %s to %s: %w", m.Module, local, to, err)
 				}
-				composeName(values, r.PublicDomain)
+				composeName(values, r.PublicDomain, r.At)
 				out[to] = append(out[to], Contribution{From: m.Module, Values: values})
 			}
 		}
@@ -933,23 +933,31 @@ func (r Resolution) contributions(settings SettingsBy, grants []Grant,
 	return out, nil
 }
 
-// composeName joins a contribution's label with a node's public domain, in place (novox/hq ADR
+// composeName joins a contribution's label with a node's public domain, and separately with its
-// 0056).
+// private one, in place (novox/hq ADR 0056).
 //
-// **The whole of what the mesh does with a route's name: join two given strings.** A contribution
+// **The whole of what the mesh does with a route's name: join two given strings — twice.** A
-// carries a `label` — the subdomain its operator chose — and the node carries its public domain;
+// contribution carries a `label` — the subdomain its operator chose — and the node carries its
-// the granted name is `<label>.<public-domain>` and the mesh interprets neither half. It runs on
+// public domain and its own private-network address; the granted names are `<label>.<public-domain>`
-// any contribution carrying a label, not only a route's, because the mesh does not know what a
+// and `<label>.<internal-domain>`, and the mesh interprets none of the halves. It runs on any
+// contribution carrying a label, not only a route's, because the mesh does not know what a
 // provision means — a name it can compose from parts it was given is the point, whatever the
 // provision is called.
 //
+// **The internal name is not a security boundary.** A predecessor proxy that answered both a
+// public and a private-network hostname for the same route did so as a convenience — reaching a
+// service over the VPN without a public TLS round trip — not as an access control, and composing
+// the same alias here restores that convenience rather than adding one. A route with no internal
+// domain to compose against (a node not on the private network) gets no internal name, the same as
+// it gets no public one with no public domain.
+//
 // **Additive, so an unmigrated catalogue still works.** A contribution that already carries a full
 // `name` and no `label` is left exactly as it is: the catalogue can migrate module by module while
 // the running mesh keeps serving the full names it has. And a labelled contribution on a node with
 // no public domain composes nothing — there is nothing to join it to — which reads downstream as a
 // route that named no host, the same as it would have before this existed.
-func composeName(values map[string]any, publicDomain string) {
+func composeName(values map[string]any, publicDomain, internalDomain string) {
-	if values == nil || publicDomain == "" {
+	if values == nil {
 		return
 	}
 	if _, already := values["name"]; already {
@@ -962,14 +970,25 @@ func composeName(values map[string]any, publicDomain string) {
 	if !ok || strings.TrimSpace(label) == "" {
 		return
 	}
-	if strings.TrimSpace(label) == "@" {
+	trimmed := strings.TrimSpace(label)
-		// The apex: a module served at the bare public domain, no subdomain — the zone-file
+	if trimmed == "@" {
-		// convention `@`. Composes to the domain itself, so a node's own site is a label like any
+		// The apex: a module served at the bare domain, no subdomain — the zone-file convention
-		// other rather than the one route that must still carry a full name.
+		// `@`. Composes to the domain itself, so a node's own site is a label like any other rather
+		// than the one route that must still carry a full name.
+		if publicDomain != "" {
 			values["name"] = publicDomain
+		}
+		if internalDomain != "" {
+			values["internal-name"] = internalDomain
+		}
 		return
 	}
-	values["name"] = strings.TrimSpace(label) + "." + publicDomain
+	if publicDomain != "" {
+		values["name"] = trimmed + "." + publicDomain
+	}
+	if internalDomain != "" {
+		values["internal-name"] = trimmed + "." + internalDomain
+	}
 }
 
 // receivedFile is the file a provider is given its consumers' contributions in.

internal/catalogue/routing_test.go

@@ -132,6 +132,72 @@ func TestALabelWithNoPublicDomainComposesNothing(t *testing.T) {
 	}
 }
 
+// withPrivateAddress is a workstation on the private network, at the given internal name — the
+// same fact a route's own consumers already receive as `${bound:...:at}`.
+func withPrivateAddress(at string) Node {
+	n := workstation()
+	n.At = at
+	return n
+}
+
+func TestALabelComposesWithTheNodesPrivateAddressToo(t *testing.T) {
+	// A predecessor proxy answered a route on both a public and a private-network hostname for the
+	// same convenience the mesh restores here: reaching a service over the VPN without a public TLS
+	// round trip. Composed independently of the public name, from the node's own `At`.
+	got, err := Resolve(shelf(proxy(), labelled("board", "git", 8080)),
+		[]string{"board"}, withPrivateAddress("anchor.internal"), World{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	given := received(t, mustDeclare(t, got))
+	if given[0].Values["internal-name"] != "git.anchor.internal" {
+		t.Fatalf("the label did not compose with the private address: %v", given[0].Values)
+	}
+}
+
+func TestThePublicAndInternalNamesComposeIndependently(t *testing.T) {
+	// A node with both a public domain and a private address gets both names from one label; a
+	// node with only one of the two gets only the matching one — neither composition depends on
+	// the other being possible.
+	both := withPrivateAddress("anchor.internal")
+	both.PublicDomain = "example.tld"
+	got, err := Resolve(shelf(proxy(), labelled("board", "git", 8080)),
+		[]string{"board"}, both, World{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	given := received(t, mustDeclare(t, got))
+	if given[0].Values["name"] != "git.example.tld" {
+		t.Fatalf("the public name did not compose alongside the internal one: %v", given[0].Values)
+	}
+	if given[0].Values["internal-name"] != "git.anchor.internal" {
+		t.Fatalf("the internal name did not compose alongside the public one: %v", given[0].Values)
+	}
+
+	publicOnly, err := Resolve(shelf(proxy(), labelled("board", "git", 8080)),
+		[]string{"board"}, withDomain("example.tld"), World{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	givenPublicOnly := received(t, mustDeclare(t, publicOnly))
+	if _, has := givenPublicOnly[0].Values["internal-name"]; has {
+		t.Fatalf("an internal name was composed with no private address to compose it from: %v",
+			givenPublicOnly[0].Values)
+	}
+}
+
+func TestTheApexLabelComposesToTheBarePrivateAddress(t *testing.T) {
+	got, err := Resolve(shelf(proxy(), labelled("board", "@", 4000)),
+		[]string{"board"}, withPrivateAddress("anchor.internal"), World{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	given := received(t, mustDeclare(t, got))
+	if given[0].Values["internal-name"] != "anchor.internal" {
+		t.Fatalf("the apex label did not compose to the bare private address: %v", given[0].Values)
+	}
+}
+
 func TestARoutedNameResolvesToTheServingNode(t *testing.T) {
 	// novox/hq ADR 0066 propagate: a granted route name is published into internal resolution,
 	// mapped to the node that serves it, alongside the `<node>.internal` names — so every