internal/catalogue/declaration.go

@@ -1098,7 +1098,7 @@ 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, r.At, reaches)
+			composeName(values, r.PublicDomain, r.At, reaches, endpointPorts(m))
 			out[to] = append(out[to], Contribution{From: m.Module, Values: values})
 		}
 		// Several contributions to one requirement (ADR 0094's sibling for `contributes`): an
@@ -1116,7 +1116,7 @@ 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, r.At, reaches)
+				composeName(values, r.PublicDomain, r.At, reaches, endpointPorts(m))
 				out[to] = append(out[to], Contribution{From: m.Module, Values: values})
 			}
 		}
@@ -1147,7 +1147,8 @@ func (r Resolution) contributions(settings SettingsBy, grants []Grant,
 // 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, internalDomain string, reaches map[int]string) {
+func composeName(values map[string]any, publicDomain, internalDomain string, reaches map[int]string,
+	ports map[string]int) {
 	if values == nil {
 		return
 	}
@@ -1164,7 +1165,7 @@ func composeName(values map[string]any, publicDomain, internalDomain string, rea
 	// Nothing said is both names, as before. That is what keeps every mesh already running identical
 	// until an assignment speaks.
 	wantPublic, wantInternal := true, true
-	if port, ok := asPort(values["port"]); ok {
+	if port, ok := endpointPortOf(values, ports); ok {
 		if reach, said := reaches[port]; said {
 			wantPublic, wantInternal = WantsPublicName(reach), WantsInternalName(reach)
 		}
@@ -1794,3 +1795,28 @@ func prepared(from map[string]any) map[string]any {
 	delete(step, "reload-on")
 	return step
 }
+
+// endpointPortOf is the port the endpoint a route serves listens on: looked up by the name the route
+// gives, or read from the port it repeats (novox/hq ADR 0138).
+//
+// `ports` maps this module's endpoint names to their ports, computed once per module rather than
+// re-scanned per contribution.
+func endpointPortOf(values map[string]any, ports map[string]int) (int, bool) {
+	if name, ok := values[RouteEndpoint].(string); ok {
+		if port, found := ports[strings.TrimSpace(name)]; found {
+			return port, true
+		}
+	}
+	return asPort(values["port"])
+}
+
+// endpointPorts is a module's endpoint names against the ports they listen on.
+func endpointPorts(m Manifest) map[string]int {
+	out := map[string]int{}
+	for _, l := range m.Listens {
+		if name := strings.TrimSpace(l.Name); name != "" {
+			out[name] = l.Port
+		}
+	}
+	return out
+}

internal/catalogue/endpoint_test.go

@@ -0,0 +1,141 @@
+package catalogue
+
+import (
+	"strings"
+	"testing"
+)
+
+// aMediaServer is the shape one port number per key cannot express: two endpoints of different kinds.
+// A web surface a proxy serves under a subdomain, and a protocol port clients dial directly because
+// the client expects that number.
+func aMediaServer() Manifest {
+	return Manifest{
+		Module: "media",
+		Listens: []Listening{
+			{Name: "web", Port: 80, From: FromMesh, Why: "the app, behind the proxy"},
+			{Name: "stream", Port: 32400, From: FromEverywhere, Fixed: true,
+				Why: "the client dials this number; the protocol chose it"},
+		},
+		Contributes: map[string]map[string]any{
+			"route": {"label": "media", RouteEndpoint: "web"},
+		},
+	}
+}
+
+// **A route names the endpoint it serves.** A route and a listen both carried a port and nothing said
+// they were the same thing; now one of them says so.
+func TestARouteNamesTheEndpointItServes(t *testing.T) {
+	m := aMediaServer()
+	if port, ok := EndpointPort(m, "web"); !ok || port != 80 {
+		t.Fatalf("the web endpoint resolves to %d (%v), want 80", port, ok)
+	}
+	if port, ok := EndpointPort(m, "stream"); !ok || port != 32400 {
+		t.Fatalf("the stream endpoint resolves to %d (%v), want 32400", port, ok)
+	}
+	if _, ok := EndpointPort(m, "absent"); ok {
+		t.Fatal("an endpoint the module does not declare resolved to a port")
+	}
+}
+
+// And the routed set is read through the name, so the endpoint the proxy serves is known without a
+// reader joining two numbers.
+func TestTheRoutedEndpointIsFoundByName(t *testing.T) {
+	routed := RoutedPorts(aMediaServer())
+	if !routed[80] {
+		t.Fatalf("the routed endpoint was not found by name: %v", routed)
+	}
+	// And the directly-dialled one is not routed, which is what lets its reach govern its port.
+	if routed[32400] {
+		t.Fatalf("the endpoint clients dial directly reads as routed: %v", routed)
+	}
+}
+
+// **Two endpoints of different shapes, configured as themselves.** The web endpoint's reach asks for
+// names and leaves its port to the proxy; the stream endpoint's reach governs its port, because
+// clients dial it and there is no name.
+func TestTwoEndpointsOfDifferentShapesAreConfiguredSeparately(t *testing.T) {
+	m := aMediaServer()
+	settings := SettingsBy{"media": {{From: "node anchor", Values: map[string]any{
+		ReachSetting: map[string]any{"80": ReachBoth, "32400": ReachPublic},
+	}}}}
+
+	r := Resolution{Node: "anchor", Modules: []Manifest{m},
+		PublicDomain: "example.test", At: "anchor.internal"}
+	rules, err := r.Rules(Rendering{Settings: settings})
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, rule := range rules {
+		switch rule.Port {
+		case 80:
+			if rule.From != FromMesh {
+				t.Fatalf("the routed endpoint's port opened to %q; the proxy is how it is reached",
+					rule.From)
+			}
+		case 32400:
+			if rule.From != FromEverywhere {
+				t.Fatalf("the directly-dialled endpoint's port is %q, want anywhere", rule.From)
+			}
+		}
+	}
+
+	// And the routed one carries both names, asked for by the same statement.
+	given, err := r.contributions(settings, nil, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var public, internal string
+	for _, c := range given["route"] {
+		public, _ = c.Values["name"].(string)
+		internal, _ = c.Values["internal-name"].(string)
+	}
+	if public != "media.example.test" || internal != "media.anchor.internal" {
+		t.Fatalf("names are %q and %q, want both", public, internal)
+	}
+}
+
+// A route naming an endpoint the module does not declare reaches nothing, and is refused where it is
+// written rather than resolving to no port and serving nothing.
+func TestARouteNamingAnEndpointTheModuleLacksIsRefused(t *testing.T) {
+	m := aMediaServer()
+	m.Contributes["route"][RouteEndpoint] = "absent"
+	got := strings.Join(RouteProblems(m), "\n")
+	if !strings.Contains(got, "does not declare") {
+		t.Fatalf("a route naming an absent endpoint was accepted:\n%s", got)
+	}
+}
+
+// **Two endpoints called the same would make an assignment configure whichever was read last.** The
+// point of a name is that it identifies one thing.
+func TestTwoEndpointsWithOneNameAreRefused(t *testing.T) {
+	m := Manifest{Module: "twice", Listens: []Listening{
+		{Name: "web", Port: 80, From: FromMesh},
+		{Name: "web", Port: 8080, From: FromMesh},
+	}}
+	got := strings.Join(endpointNameProblems(m), "\n")
+	if !strings.Contains(got, "could mean either") {
+		t.Fatalf("two endpoints with one name were accepted:\n%s", got)
+	}
+}
+
+// A name that is not a name is refused where it is written: it ends up in something a person types.
+func TestAnEndpointNameIsHeldToItsShape(t *testing.T) {
+	for _, wrong := range []string{"Web", "web port", "3000", "-web", "web_surface"} {
+		m := Manifest{Module: "odd", Listens: []Listening{{Name: wrong, Port: 80, From: FromMesh}}}
+		if got := strings.Join(endpointNameProblems(m), "\n"); !strings.Contains(got, "a name is lowercase") {
+			t.Fatalf("%q was accepted as an endpoint name:\n%s", wrong, got)
+		}
+	}
+}
+
+// **Every endpoint in the catalogue is unnamed today, and must stay valid.** The word ships one
+// release before anything uses it.
+func TestAnUnnamedEndpointIsStillValid(t *testing.T) {
+	m := Manifest{Module: "ordinary", Listens: []Listening{{Port: 443, From: FromEverywhere}}}
+	if got := endpointNameProblems(m); len(got) != 0 {
+		t.Fatalf("an unnamed endpoint was refused: %v", got)
+	}
+	if got := RouteProblems(m); len(got) != 0 {
+		t.Fatalf("a module with no route was refused: %v", got)
+	}
+}

internal/catalogue/filtering.go

@@ -752,6 +752,15 @@ var reaches = []string{ReachMachine, ReachInternal, ReachPublic, ReachBoth}
 func RoutedPorts(m Manifest) map[int]bool {
 	out := map[int]bool{}
 	note := func(values map[string]any) {
+		// **The endpoint it serves, by name where it says one.** A route repeating a port number is
+		// the older shape and still read: 35 of the catalogue's 36 route entries name a port their
+		// module declares a listen on (novox/hq ADR 0138).
+		if name, ok := values[RouteEndpoint].(string); ok {
+			if port, found := EndpointPort(m, name); found {
+				out[port] = true
+				return
+			}
+		}
 		if port, ok := asPort(values["port"]); ok {
 			out[port] = true
 		}
@@ -852,3 +861,38 @@ func Reaches(m Manifest, layers []Layer) (map[int]string, error) {
 	}
 	return out, nil
 }
+
+// RouteEndpoint is the key a route contribution names the endpoint it serves with, instead of
+// repeating that endpoint's port (novox/hq ADR 0138).
+//
+// **A route and a listen both carried a port, and nothing said they were the same thing.** They
+// always were — a route serves one of the module's own endpoints — but a reader had to join two
+// numbers, and an assignment configuring "the web endpoint" had to know which number that was. A
+// route that names the endpoint says what it means, and the mesh looks the port up.
+const RouteEndpoint = "endpoint"
+
+// RouteProblems holds a module's route contributions to naming an endpoint it actually has.
+//
+// A route naming an endpoint the module does not declare reaches nothing, and is refused where it is
+// written rather than resolving to no port and serving nothing — the fault this repository names most
+// often, a declaration that reads as though it did something.
+func RouteProblems(m Manifest) []string {
+	var problems []string
+	check := func(where string, values map[string]any) {
+		name, ok := values[RouteEndpoint].(string)
+		if !ok || strings.TrimSpace(name) == "" {
+			return
+		}
+		if _, found := EndpointPort(m, name); !found {
+			problems = append(problems, fmt.Sprintf(
+				"%s routes %s to the endpoint %q, which it does not declare", m.Module, where, name))
+		}
+	}
+	if values, ok := m.Contributes["route"]; ok {
+		check("a name", values)
+	}
+	for local, values := range m.ContributesMany["route"] {
+		check(local, values)
+	}
+	return problems
+}

internal/catalogue/manifest.go

@@ -657,8 +657,23 @@ const (
 // on is a fact, and it should be written once.
 const ArtifactStoreProvision = "artifact-store"
 
-// Listening is one port a module accepts connections on.
+// Listening is one endpoint a module serves: a port it accepts connections on, and what may be said
+// about that port from outside the module.
 type Listening struct {
+	// Name is what this endpoint is called, so an assignment and a route can refer to it as one thing
+	// (novox/hq ADR 0138).
+	//
+	// **Because a port number is not a name.** Three facts have to be said about an endpoint when a
+	// module is assigned — which machine port it lands on, the subdomain a proxy serves it under, and
+	// how far it reaches — and they were said in three places keyed by the port. A module with two
+	// endpoints of different shapes, a web surface behind a proxy and a protocol port clients dial
+	// directly, cannot be configured that way without a reader joining numbers by hand.
+	//
+	// The module's to choose, like the route's label: it names its own parts. Lowercase, and unique
+	// within the module, so a reference to it is unambiguous. Empty is allowed and means an endpoint
+	// nothing refers to by name, which is every endpoint in the catalogue until they are named.
+	Name string `json:"name,omitempty"`
+
 	Port int `json:"port"`
 	// Protocol is "tcp" or "udp". Absent means tcp, which is what almost everything is — and a
 	// field that had to be written every time would be written wrongly some of the time.
@@ -1265,6 +1280,8 @@ func ParseManifest(raw []byte) (Manifest, error) {
 				"%s listens on %d over %q, which is tcp or udp", m.Module, l.Port, p))
 		}
 	}
+	problems = append(problems, endpointNameProblems(m)...)
+	problems = append(problems, RouteProblems(m)...)
 	for _, port := range m.Guards {
 		if port < 1 || port > 65535 {
 			problems = append(problems, fmt.Sprintf(
@@ -1689,3 +1706,53 @@ func (m Manifest) undeclaredMounts() []string {
 	}
 	return problems
 }
+
+// endpointName is what an endpoint may be called: lowercase letters, digits and dashes, starting
+// with a letter. The same shape a label has, because both end up in something a person types.
+var endpointName = regexp.MustCompile(`^[a-z][a-z0-9-]*$`)
+
+// endpointNameProblems holds a module's endpoint names to being usable as references (novox/hq ADR
+// 0138).
+//
+// **Unique, because the point of a name is that it identifies one thing.** Two endpoints called the
+// same would make an assignment that configures one silently configure whichever the mesh read last
+// — the shape of fault this repository keeps finding, where a declaration appears to say something
+// and says something else.
+func endpointNameProblems(m Manifest) []string {
+	var problems []string
+	seen := map[string]int{}
+	for _, l := range m.Listens {
+		name := strings.TrimSpace(l.Name)
+		if name == "" {
+			continue
+		}
+		if !endpointName.MatchString(name) {
+			problems = append(problems, fmt.Sprintf(
+				"%s calls the endpoint on port %d %q; a name is lowercase letters, digits and "+
+					"dashes, starting with a letter", m.Module, l.Port, l.Name))
+			continue
+		}
+		if before, already := seen[name]; already {
+			problems = append(problems, fmt.Sprintf(
+				"%s calls both port %d and port %d %q, so anything naming that endpoint could mean "+
+					"either", m.Module, before, l.Port, name))
+			continue
+		}
+		seen[name] = l.Port
+	}
+	return problems
+}
+
+// EndpointPort is the port of the endpoint a module calls this, and whether it has one.
+func EndpointPort(m Manifest, name string) (int, bool) {
+	want := strings.TrimSpace(name)
+	if want == "" {
+		return 0, false
+	}
+	for _, l := range m.Listens {
+		if strings.TrimSpace(l.Name) == want {
+			return l.Port, true
+		}
+	}
+	return 0, false
+}