Merge pull request 'An assignment configures an endpoint as one thing' (#139) from feat/an-assignment-configures-an-endpoint into main

internal/catalogue/declaration.go

@@ -1098,7 +1098,11 @@ 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, endpointPorts(m))
+			blocks, err := Endpoints(m, settings[m.Module])
+			if err != nil {
+				return nil, fmt.Errorf("%s contributing to %s: %w", m.Module, to, err)
+			}
+			composeName(values, r.PublicDomain, r.At, reaches, endpointPorts(m), blocks)
 			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 +1120,11 @@ 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, endpointPorts(m))
+				blocks, err := Endpoints(m, settings[m.Module])
+				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, endpointPorts(m), blocks)
 				out[to] = append(out[to], Contribution{From: m.Module, Values: values})
 			}
 		}
@@ -1148,10 +1156,19 @@ func (r Resolution) contributions(settings SettingsBy, grants []Grant,
 // 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,
-	ports map[string]int) {
+	ports map[string]int, blocks map[string]Endpoint) {
 	if values == nil {
 		return
 	}
+	// **The subdomain an assignment gave this endpoint**, before the name is joined (novox/hq ADR
+	// 0138). The module contributes a label because it names its own parts; an assignment may say a
+	// different one, because where a thing lives under a domain is the operator's to choose and used
+	// to require editing the module to change.
+	if name, ok := values[RouteEndpoint].(string); ok {
+		if ep, said := blocks[strings.TrimSpace(name)]; said && ep.Label != "" {
+			values["label"] = ep.Label
+		}
+	}
 	// **How far the endpoint this route serves reaches decides which names exist** (novox/hq ADR
 	// 0138). Both were composed whenever the node had both domains, so every routed module got a
 	// public name and an internal one whether anybody wanted them or not — and a certificate for

internal/catalogue/endpoint_test.go

@@ -19,6 +19,12 @@ func aMediaServer() Manifest {
 		Contributes: map[string]map[string]any{
 			"route": {"label": "media", RouteEndpoint: "web"},
 		},
+		// Both endpoints are published by its container, which is what lets a machine port be given
+		// for either: the mesh moves a port the module publishes, never one it merely listens on.
+		Resources: []map[string]any{
+			{"id": "server", "type": "container", "name": "media",
+				"ports": []any{"80", "32400"}},
+		},
 	}
 }
 

internal/catalogue/endpoints_setting_test.go

@@ -0,0 +1,140 @@
+package catalogue
+
+import (
+	"strings"
+	"testing"
+)
+
+func configured(block map[string]any) SettingsBy {
+	return SettingsBy{"media": {{From: "node anchor",
+		Values: map[string]any{EndpointsSetting: block}}}}
+}
+
+// **One block per endpoint, saying all three things.** The machine port, the subdomain and the reach
+// were `ports`, the route's label and `reach`, each keyed by a port number, so configuring a module
+// with two endpoints of different shapes meant knowing which number was which.
+func TestAnEndpointsBlockSaysPortLabelAndReach(t *testing.T) {
+	m := aMediaServer()
+	// stream's reach NARROWS what the manifest says — the manifest has it from anywhere, the
+	// assignment says internal. Chosen deliberately: a reach that agrees with the manifest proves
+	// nothing about whether the block was read at all.
+	settings := configured(map[string]any{
+		"web":    map[string]any{"port": 20009, "label": "cinema", "reach": ReachBoth},
+		"stream": map[string]any{"reach": ReachInternal},
+	})
+
+	// The machine port, where the mapping is read.
+	given, err := GivenPorts(m, settings["media"])
+	if err != nil {
+		t.Fatal(err)
+	}
+	if given[80] != 20009 {
+		t.Fatalf("the web endpoint is on machine port %d, want 20009: %v", given[80], given)
+	}
+
+	// The reach, where the filter reads it.
+	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 {
+		if rule.Port == 32400 && rule.From != FromMesh {
+			t.Fatalf("the directly-dialled endpoint is %q; the assignment narrowed it to the private "+
+				"network and the manifest's 'anywhere' should not win", rule.From)
+		}
+		if rule.Port == 80 && rule.From != FromMesh {
+			t.Fatalf("the routed endpoint's port opened to %q; the proxy is how it is reached", rule.From)
+		}
+	}
+
+	// And the subdomain, where the name is composed — the assignment's, not the module's.
+	nodes, err := r.contributions(settings, nil, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, c := range nodes["route"] {
+		if got, _ := c.Values["name"].(string); got != "cinema.example.test" {
+			t.Fatalf("the public name is %q, want the label the assignment gave", got)
+		}
+		if got, _ := c.Values["internal-name"].(string); got != "cinema.anchor.internal" {
+			t.Fatalf("the internal name is %q, want the label the assignment gave", got)
+		}
+	}
+}
+
+// A block that says only a reach leaves the port to the mesh and the label to the module, which is the
+// ordinary case and must not require writing the other two.
+func TestABlockMaySayOnlyAReach(t *testing.T) {
+	m := aMediaServer()
+	settings := configured(map[string]any{"web": map[string]any{"reach": ReachInternal}})
+	r := Resolution{Node: "anchor", Modules: []Manifest{m},
+		PublicDomain: "example.test", At: "anchor.internal"}
+	nodes, err := r.contributions(settings, nil, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, c := range nodes["route"] {
+		if got, _ := c.Values["name"].(string); got != "" {
+			t.Fatalf("an internal endpoint composed the public name %q", got)
+		}
+		// The module's own label, untouched.
+		if got, _ := c.Values["internal-name"].(string); got != "media.anchor.internal" {
+			t.Fatalf("the internal name is %q, want the module's own label", got)
+		}
+	}
+}
+
+// An endpoint the module does not declare reaches nothing, and the refusal says what it does declare.
+func TestConfiguringAnEndpointTheModuleLacksIsRefused(t *testing.T) {
+	_, err := Endpoints(aMediaServer(), configured(map[string]any{
+		"admin": map[string]any{"reach": ReachInternal}})["media"])
+	if err == nil || !strings.Contains(err.Error(), "does not declare") {
+		t.Fatalf("configuring an absent endpoint was accepted: %v", err)
+	}
+	if err != nil && !strings.Contains(err.Error(), "stream") {
+		t.Fatalf("the refusal does not name what the module declares: %v", err)
+	}
+}
+
+func TestAReachInABlockIsHeldToTheFourValues(t *testing.T) {
+	_, err := Endpoints(aMediaServer(), configured(map[string]any{
+		"web": map[string]any{"reach": "mesh"}})["media"])
+	if err == nil || !strings.Contains(err.Error(), "a reach is") {
+		t.Fatalf("a filter word was accepted as a reach: %v", err)
+	}
+}
+
+// **Two places giving one endpoint a machine port is the confusion this key exists to end.**
+func TestAnEndpointGivenAPortTwiceIsRefused(t *testing.T) {
+	m := aMediaServer()
+	_, err := GivenPorts(m, []Layer{{From: "node anchor", Values: map[string]any{
+		EndpointsSetting: map[string]any{"web": map[string]any{"port": 20009}},
+		PortsSetting:     map[string]any{"80": 30000},
+	}}})
+	if err == nil || !strings.Contains(err.Error(), "published once") {
+		t.Fatalf("an endpoint given two machine ports was accepted: %v", err)
+	}
+}
+
+// And the same for its reach, said once here and once through the older key.
+func TestAnEndpointWhoseReachIsAlsoExposedIsRefused(t *testing.T) {
+	_, err := Endpoints(aMediaServer(), []Layer{{From: "node anchor", Values: map[string]any{
+		EndpointsSetting: map[string]any{"web": map[string]any{"reach": ReachInternal}},
+		ExposeSetting:    map[string]any{"80": FromEverywhere},
+	}}})
+	if err == nil || !strings.Contains(err.Error(), "same thing in different words") {
+		t.Fatalf("a reach said two ways was accepted: %v", err)
+	}
+}
+
+// A module whose endpoints are unnamed cannot be configured this way, and is told so rather than
+// having a block silently reach nothing — which is every module in the catalogue today.
+func TestAModuleWithNoNamedEndpointsIsToldSo(t *testing.T) {
+	m := Manifest{Module: "media", Listens: []Listening{{Port: 80, From: FromMesh}}}
+	_, err := Endpoints(m, configured(map[string]any{"web": map[string]any{"reach": ReachBoth}})["media"])
+	if err == nil || !strings.Contains(err.Error(), "no endpoints by name") {
+		t.Fatalf("a module with no named endpoints accepted a block: %v", err)
+	}
+}

internal/catalogue/filtering.go

@@ -536,6 +536,21 @@ const MeshWideLayer = "the mesh"
 // two mappings share a number, it is an entry one of them writes over the other's, and the reader
 // that finds the survivor disagrees with the reader that recomputes it.
 func GivenPorts(m Manifest, layers []Layer) (map[int]int, error) {
+	// An endpoint's own block may put it on a machine port, which is the same thing `ports` says about
+	// the number rather than about the endpoint (novox/hq ADR 0138). Collected first and then let the
+	// older key be read, which refuses a port said twice.
+	byName, err := Endpoints(m, layers)
+	if err != nil {
+		return nil, err
+	}
+	named := map[int]int{}
+	for name, ep := range byName {
+		if ep.Port == 0 {
+			continue
+		}
+		named[endpointPorts(m)[name]] = ep.Port
+	}
+
 	// Every name a setting may use, and the mapping it names.
 	names := map[int][]publishing{}
 	for _, p := range publishedPorts(m) {
@@ -634,6 +649,17 @@ func GivenPorts(m Manifest, layers []Layer) (map[int]int, error) {
 			out[key], by[key] = at, port
 		}
 	}
+	// And what the endpoints' own blocks put them on. Refused rather than merged where both keys name
+	// one endpoint: two places giving a port is the confusion this key exists to end.
+	for wanted, at := range named {
+		if was, twice := out[wanted]; twice && was != at {
+			return nil, fmt.Errorf(
+				"%s puts its port %d on %d through %s and on %d through %s — one endpoint, two "+
+					"machine ports, and it is published once. Keep the endpoint's own block",
+				m.Module, wanted, at, EndpointsSetting, was, PortsSetting)
+		}
+		out[wanted] = at
+	}
 	if len(out) == 0 {
 		return nil, nil
 	}
@@ -821,6 +847,20 @@ func Reaches(m Manifest, layers []Layer) (map[int]string, error) {
 	}
 
 	out := map[int]string{}
+	// What an endpoint's own block says, which is the same statement in the shape that names the
+	// endpoint rather than its port (novox/hq ADR 0138). Read first so the older key, which says less,
+	// cannot quietly win over the newer one that says more.
+	blocks, err := Endpoints(m, layers)
+	if err != nil {
+		return nil, err
+	}
+	declared := endpointPorts(m)
+	for name, ep := range blocks {
+		if ep.Reach == "" {
+			continue
+		}
+		out[declared[name]] = ep.Reach
+	}
 	for _, layer := range layers {
 		raw, ok := layer.Values[ReachSetting]
 		if !ok {
@@ -896,3 +936,123 @@ func RouteProblems(m Manifest) []string {
 	}
 	return problems
 }
+
+// EndpointsSetting is the settings key that configures a module's endpoints by name, per node
+// (novox/hq ADR 0138):
+//
+//	{"endpoints": {"web":    {"port": 20009, "label": "media", "reach": "both"},
+//	               "stream": {"reach": "public"}}}
+//
+// **One block per endpoint, instead of three keys joined by a number.** Which machine port it lands
+// on, the subdomain a proxy serves it under, and how far it reaches are the three things an operator
+// says when a module is assigned, and they were said in `ports`, in the route's label and in `reach`,
+// each keyed by the port. A module with two endpoints of different shapes — a web surface behind the
+// proxy and a protocol port clients dial directly — could only be configured by a reader who knew
+// which number was which.
+//
+// Every field is optional. A block that says only a reach leaves the port to the mesh and the label to
+// the module, which is the ordinary case.
+const EndpointsSetting = "endpoints"
+
+// Endpoint is what an assignment says about one of a module's endpoints.
+type Endpoint struct {
+	// Port is the machine-side port it is published on. Zero means the mesh assigns one, which it
+	// does anyway — a fixed port is the module's claim and is honoured without being said here.
+	Port int
+	// Label is the subdomain a proxy serves it under, overriding the one the module contributes.
+	Label string
+	// Reach is how far it reaches: machine, internal, public or both.
+	Reach string
+}
+
+// Endpoints reads a module's per-node endpoint configuration, by endpoint name.
+//
+// It refuses a name the module does not declare — the setting would reach nothing — and a reach that
+// is not one of the four. It also refuses an endpoint whose port or reach is said twice, once here and
+// once through the older key: two places saying the same thing is what this key exists to end, and
+// letting both stand would mean the mesh followed whichever it read last.
+func Endpoints(m Manifest, layers []Layer) (map[string]Endpoint, error) {
+	declared := endpointPorts(m)
+	exposed, err := Exposure(m, layers)
+	if err != nil {
+		return nil, err
+	}
+
+	out := map[string]Endpoint{}
+	for _, layer := range layers {
+		raw, ok := layer.Values[EndpointsSetting]
+		if !ok {
+			continue
+		}
+		blocks, ok := raw.(map[string]any)
+		if !ok {
+			return nil, fmt.Errorf("%s: %s is a { endpoint: { … } } map, and %q set it to something else",
+				m.Module, EndpointsSetting, layer.From)
+		}
+		for name, body := range blocks {
+			port, known := declared[name]
+			if !known {
+				return nil, fmt.Errorf(
+					"%s configures the endpoint %q, which it does not declare — the setting reaches "+
+						"nothing. It declares %s", m.Module, name, spokenEndpoints(m))
+			}
+			values, ok := body.(map[string]any)
+			if !ok {
+				return nil, fmt.Errorf("%s: the endpoint %q is configured with something that is not a "+
+					"block of settings", m.Module, name)
+			}
+			ep := out[name]
+			if reach, said := values["reach"]; said {
+				text, ok := reach.(string)
+				if !ok || !slices.Contains(reaches, text) {
+					return nil, fmt.Errorf("%s says the endpoint %q reaches %v; a reach is %s",
+						m.Module, name, reach, strings.Join(reaches, ", "))
+				}
+				if _, also := exposed[port]; also {
+					return nil, fmt.Errorf(
+						"%s says how far %q reaches and also exposes port %d. They say the same thing "+
+							"in different words; keep the endpoint's own block",
+						m.Module, name, port)
+				}
+				ep.Reach = text
+			}
+			if at, said := values["port"]; said {
+				machine, ok := asPort(at)
+				if !ok {
+					return nil, fmt.Errorf("%s puts the endpoint %q on %v, which is not a port",
+						m.Module, name, at)
+				}
+				ep.Port = machine
+			}
+			if label, said := values["label"]; said {
+				text, ok := label.(string)
+				if !ok || strings.TrimSpace(text) == "" {
+					return nil, fmt.Errorf("%s gives the endpoint %q a label that is not a name: %v",
+						m.Module, name, label)
+				}
+				ep.Label = strings.TrimSpace(text)
+			}
+			out[name] = ep
+		}
+	}
+	if len(out) == 0 {
+		return nil, nil
+	}
+	return out, nil
+}
+
+// spokenEndpoints is what a module's endpoints are called, as a refusal lists them — so a reader who
+// named one wrongly is one edit from right, and a module that has named none is told so.
+func spokenEndpoints(m Manifest) string {
+	names := make([]string, 0, len(m.Listens))
+	for _, l := range m.Listens {
+		if name := strings.TrimSpace(l.Name); name != "" {
+			names = append(names, name)
+		}
+	}
+	if len(names) == 0 {
+		return "no endpoints by name"
+	}
+	sort.Strings(names)
+	return strings.Join(names, ", ")
+}

internal/catalogue/settings.go

@@ -192,6 +192,11 @@ func UnusedSettings(m Manifest, layers []Layer) []string {
 			if key == ReachSetting && len(m.Listens) > 0 {
 				continue
 			}
+			// `endpoints` configures a module's endpoints by name — the machine port, the subdomain and
+			// the reach as one block each (novox/hq ADR 0138). Validated in Endpoints, so not stray.
+			if key == EndpointsSetting && len(m.Listens) > 0 {
+				continue
+			}
 			unused = append(unused, fmt.Sprintf(
 				"%s sets %q, and %s has no file or contribution to merge it into",
 				layer.From, key, m.Module))