Merge pull request 'A route that names an endpoint still carries that endpoint's port' (#141) from fix/an-endpoint-named-by-a-route-still-carries-its-port into main

internal/catalogue/declaration.go

@@ -1102,6 +1102,7 @@ func (r Resolution) contributions(settings SettingsBy, grants []Grant,
 			if err != nil {
 				return nil, fmt.Errorf("%s contributing to %s: %w", m.Module, to, err)
 			}
+			portOfEndpoint(values, endpointPorts(m))
 			composeName(values, r.PublicDomain, r.At, reaches, endpointPorts(m), blocks)
 			out[to] = append(out[to], Contribution{From: m.Module, Values: values})
 		}
@@ -1124,6 +1125,7 @@ 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)
 				}
+				portOfEndpoint(values, endpointPorts(m))
 				composeName(values, r.PublicDomain, r.At, reaches, endpointPorts(m), blocks)
 				out[to] = append(out[to], Contribution{From: m.Module, Values: values})
 			}
@@ -1837,3 +1839,32 @@ func endpointPorts(m Manifest) map[string]int {
 	}
 	return out
 }
+
+// portOfEndpoint fills in the port of the endpoint a contribution names, in place.
+//
+// **A contribution that names an endpoint must still carry that endpoint's port**, because everything
+// downstream reads the port: the provider is told where to reach the consumer, and the machine-side
+// redirection that turns a declared port into the number the machine published is keyed on it
+// (atMachinePort). A route that named only its endpoint left the proxy with no port at all, and a
+// proxy with no port has nothing to dial.
+//
+// Found before it shipped and after the catalogue had already been changed to name endpoints — the
+// manifests were merged and the mesh had not yet picked them up, so nothing was broken yet. The
+// declared port, not the machine one: the redirection happens later and is keyed on the declared
+// number, so filling in the machine port here would be redirected a second time or not at all.
+func portOfEndpoint(values map[string]any, ports map[string]int) {
+	if values == nil {
+		return
+	}
+	if _, already := values["port"]; already {
+		// A route that says both is its own answer; the older shape repeated the port and is still read.
+		return
+	}
+	name, ok := values[RouteEndpoint].(string)
+	if !ok {
+		return
+	}
+	if port, found := ports[strings.TrimSpace(name)]; found {
+		values["port"] = port
+	}
+}

internal/catalogue/endpoint_test.go

@@ -145,3 +145,61 @@ func TestAnUnnamedEndpointIsStillValid(t *testing.T) {
 		t.Fatalf("a module with no route was refused: %v", got)
 	}
 }
+
+// **A route that names an endpoint still carries that endpoint's port.**
+//
+// Everything downstream reads the port: the provider is told where to reach the consumer, and the
+// redirection that turns a declared port into the number the machine published is keyed on it. A route
+// naming only its endpoint left the proxy with no port, and a proxy with no port has nothing to dial.
+//
+// Caught after the catalogue had already been changed to name endpoints, and before the mesh picked
+// those manifests up — which is the only reason nothing broke.
+func TestARouteNamingAnEndpointStillCarriesItsPort(t *testing.T) {
+	m := aMediaServer()
+	r := Resolution{Node: "anchor", Modules: []Manifest{m},
+		PublicDomain: "example.test", At: "anchor.internal"}
+	given, err := r.contributions(nil, nil, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var saw bool
+	for _, c := range given["route"] {
+		saw = true
+		port, ok := asPort(c.Values["port"])
+		if !ok {
+			t.Fatalf("the route carries no port, so the proxy has nothing to dial: %v", c.Values)
+		}
+		if port != 80 {
+			t.Fatalf("the route carries port %d, want the web endpoint's 80", port)
+		}
+	}
+	if !saw {
+		t.Fatal("the module contributed no route")
+	}
+}
+
+// And the declared port, not the machine one: the redirection to where the machine published it
+// happens later and is keyed on the declared number, so filling the machine port in here would be
+// redirected twice or not at all.
+func TestTheEndpointsDeclaredPortIsFilledInNotTheMachineOne(t *testing.T) {
+	m := aMediaServer()
+	values := map[string]any{RouteEndpoint: "web", "label": "media"}
+	portOfEndpoint(values, endpointPorts(m))
+	if got, _ := asPort(values["port"]); got != 80 {
+		t.Fatalf("filled in port %d, want the declared 80", got)
+	}
+	// Then the ordinary redirection puts it where the machine published it.
+	moved := atMachinePort(values, m.Module, map[string]map[int]int{"media": {80: 20009}})
+	if got, _ := asPort(moved["port"]); got != 20009 {
+		t.Fatalf("after redirection the port is %d, want the machine's 20009", got)
+	}
+}
+
+// A route that repeats a port keeps it, because that is the older shape and still read.
+func TestARouteThatRepeatsItsPortKeepsIt(t *testing.T) {
+	values := map[string]any{RouteEndpoint: "web", "port": 8080}
+	portOfEndpoint(values, map[string]int{"web": 80})
+	if got, _ := asPort(values["port"]); got != 8080 {
+		t.Fatalf("the port it stated was overwritten with %d", got)
+	}
+}