Merge pull request 'A module is told the name it is served under (hq 122)' (#149) from fix/122-a-module-is-told-its-own-name into main

internal/catalogue/bound_into_files.go

@@ -70,6 +70,27 @@ func knownFor(m Manifest, needs []Needed, node string) map[string]map[string]str
 	return out
 }
 
+// withOwnNames adds a module's own composed names to what it may name from one binding:
+// `${bound:<provision>:name}` and `:internal-name`, and for several contributions to one requirement
+// `:name-<local>` / `:internal-name-<local>`. Set over anything the provider serves under those keys:
+// what the module is called is the mesh's statement, not the provider's.
+func withOwnNames(values map[string]string, own map[string]any) {
+	for _, key := range []string{"name", "internal-name"} {
+		if v, ok := own[key].(string); ok {
+			values[key] = v
+		}
+	}
+	many, _ := own["names"].(map[string]any)
+	for local, raw := range many {
+		names, _ := raw.(map[string]any)
+		for _, key := range []string{"name", "internal-name"} {
+			if v, ok := names[key].(string); ok {
+				values[key+"-"+local] = v
+			}
+		}
+	}
+}
+
 // plainly renders a served value as a program would expect to read it.
 func plainly(value any) string {
 	switch v := value.(type) {

internal/catalogue/declaration.go

@@ -574,7 +574,11 @@ func (r Resolution) compose(with Rendering, owner map[string]string) ([]map[stri
 				}
 				found = here
 			}
-			file, err := boundFile(*found, m.Binds[to], ConsumerIdentity(r.Node, IdentitySource(m.Slug, m.Module)))
+			own, err := r.ownNames(m, to, with.Settings[m.Module])
+			if err != nil {
+				return nil, err
+			}
+			file, err := boundFile(*found, m.Binds[to], ConsumerIdentity(r.Node, IdentitySource(m.Slug, m.Module)), own)
 			if err != nil {
 				return nil, err
 			}
@@ -635,6 +639,35 @@ func (r Resolution) compose(with Rendering, owner map[string]string) ([]map[stri
 		}
 		// And what its bindings say, for the half of a connection that is not secret.
 		known := knownFor(m, r.Needs, r.Node)
+		// A requirement answered on this same machine is not in r.Needs — its binding file is
+		// written from `here` (above) — and so `${bound:…}` could not name it, though the file
+		// beside it said the same facts. Filled from the same answer, so the two cannot disagree.
+		for _, want := range m.Wants() {
+			if _, has := known[want]; has {
+				continue
+			}
+			answered, err := here(r, want, with)
+			if err != nil {
+				return nil, err
+			}
+			if answered == nil {
+				continue
+			}
+			local := *answered
+			local.For = m.Module
+			for provision, values := range knownFor(m, []Needed{local}, r.Node) {
+				known[provision] = values
+			}
+		}
+		// And what the module is called through each requirement it contributes to (novox/hq
+		// 04-ISSUES/122) — the same composition its binding file carries.
+		for provision, values := range known {
+			own, err := r.ownNames(m, provision, with.Settings[m.Module])
+			if err != nil {
+				return nil, err
+			}
+			withOwnNames(values, own)
+		}
 		// And where this node places the directories the module declared without a path
 		// (novox/hq ADR 0112) — resolved once per module, named by ${dir:…} from any resource.
 		dirs := dirsFor(m, with)
@@ -1087,21 +1120,11 @@ func (r Resolution) contributions(settings SettingsBy, grants []Grant,
 			// Settings reach a contribution the same way they reach a file. A route's hostname is
 			// exactly the kind of thing that differs between one mesh and the next, and a module
 			// that could not have it set would have to be edited to be reused.
-			values, err := settle(m.Contributes[to], settings[m.Module], nil,
+			values, err := r.composed(m, to, m.Contributes[to], settings[m.Module],
 				m.Module+" contributing to "+to)
 			if err != nil {
-				return nil, fmt.Errorf("%s contributing to %s: %w", m.Module, to, err)
+				return nil, err
 			}
-			reaches, err := Reaches(m, settings[m.Module])
-			if err != nil {
-				return nil, fmt.Errorf("%s contributing to %s: %w", m.Module, to, err)
-			}
-			blocks, err := Endpoints(m, settings[m.Module])
-			if err != nil {
-				return nil, fmt.Errorf("%s contributing to %s: %w", m.Module, to, err)
-			}
-			portOfEndpoint(values, endpointPorts(m))
-			composeName(values, r.PublicDomain, servingAt(r, to), 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
@@ -1110,24 +1133,90 @@ func (r Resolution) contributions(settings SettingsBy, grants []Grant,
 		// name always reaches the provider from here.
 		for _, to := range sortedKeys(m.ContributesMany) {
 			for _, local := range sortedKeys(m.ContributesMany[to]) {
-				values, err := settle(m.ContributesMany[to][local], settings[m.Module], nil,
+				values, err := r.composed(m, to, m.ContributesMany[to][local], settings[m.Module],
 					m.Module+" contributing "+local+" to "+to)
 				if err != nil {
-					return nil, fmt.Errorf("%s contributing %s to %s: %w", m.Module, local, to, err)
+					return nil, err
 				}
-				reaches, err := Reaches(m, settings[m.Module])
+				out[to] = append(out[to], Contribution{From: m.Module, Values: values})
-				if err != nil {
-					return nil, fmt.Errorf("%s contributing %s to %s: %w", m.Module, local, to, err)
 			}
-				blocks, err := Endpoints(m, settings[m.Module])
+		}
+	}
+	return out, nil
+}
+
+// composed is one contribution as its provider receives it: settled with this node's settings, its
+// endpoint's port filled in, and its names composed from the label.
+//
+// **One function, because two readers must agree.** The provider is told the names in its received
+// file; the contributing module is told the same names in its own binding (novox/hq 04-ISSUES/122).
+// Composing them twice, in two places, is how the proxy would come to serve one name while the
+// module wrote another into its configuration.
+func (r Resolution) composed(m Manifest, to string, raw map[string]any, layers []Layer, what string) (
+	map[string]any, error) {
+	values, err := settle(raw, layers, nil, what)
 	if err != nil {
-					return nil, fmt.Errorf("%s contributing %s to %s: %w", m.Module, local, to, err)
+		return nil, fmt.Errorf("%s: %w", what, err)
+	}
+	reaches, err := Reaches(m, layers)
+	if err != nil {
+		return nil, fmt.Errorf("%s: %w", what, err)
+	}
+	blocks, err := Endpoints(m, layers)
+	if err != nil {
+		return nil, fmt.Errorf("%s: %w", what, err)
 	}
 	portOfEndpoint(values, endpointPorts(m))
 	composeName(values, r.PublicDomain, servingAt(r, to), reaches, endpointPorts(m), blocks)
-				out[to] = append(out[to], Contribution{From: m.Module, Values: values})
+	return values, nil
+}
+
+// ownNames is what a module is known by through what it contributes to one requirement — the names
+// the mesh composed for it, and nothing else of the contribution.
+//
+// **The half a module could not learn** (novox/hq 04-ISSUES/122). A module contributes a label, the
+// mesh joins it with this node's domains, and the provider serves the result — and the module itself
+// was never told. Software that must know its own address (a login redirect, a canonical URL, an
+// issuer) had it written into the manifest as a literal, which is a domain in a definition and wrong
+// on every other machine. `${bound:<requirement>:name}` is the answer, from the same composition the
+// provider receives.
+//
+// Several contributions to one requirement are keyed by their local name under `names`.
+func (r Resolution) ownNames(m Manifest, to string, layers []Layer) (map[string]any, error) {
+	pick := func(values map[string]any) map[string]any {
+		names := map[string]any{}
+		for _, key := range []string{"name", "internal-name"} {
+			if v, ok := values[key].(string); ok && v != "" {
+				names[key] = v
 			}
 		}
+		return names
+	}
+	out := map[string]any{}
+	if raw, ok := m.Contributes[to]; ok {
+		values, err := r.composed(m, to, raw, layers, m.Module+" contributing to "+to)
+		if err != nil {
+			return nil, err
+		}
+		for k, v := range pick(values) {
+			out[k] = v
+		}
+	}
+	if locals := m.ContributesMany[to]; len(locals) > 0 {
+		many := map[string]any{}
+		for _, local := range sortedKeys(locals) {
+			values, err := r.composed(m, to, locals[local], layers,
+				m.Module+" contributing "+local+" to "+to)
+			if err != nil {
+				return nil, err
+			}
+			if names := pick(values); len(names) > 0 {
+				many[local] = names
+			}
+		}
+		if len(many) > 0 {
+			out["names"] = many
+		}
 	}
 	return out, nil
 }
@@ -1346,14 +1435,14 @@ func sortedKeys[V any](m map[string]V) []string {
 // Where it is and what the providing module said about using it. **No credential**, and the file
 // says so rather than leaving a reader to wonder whether one was meant to be there — a missing
 // field looks like a bug, and a stated absence looks like a boundary.
-func boundFile(n Needed, path, as string) (map[string]any, error) {
+func boundFile(n Needed, path, as string, own map[string]any) (map[string]any, error) {
 	// A record has no machine and no address. Saying so is the difference between a reader
 	// concluding "somewhere with no address" and concluding the mesh failed to fill something in.
 	where := any(n.At)
 	if n.ByRecord {
 		where = "a record in this mesh, not a machine"
 	}
-	body, err := json.MarshalIndent(map[string]any{
+	doc := map[string]any{
 		"binding":   1,
 		"provision": n.Name,
 		"from":      n.From,
@@ -1369,7 +1458,14 @@ func boundFile(n Needed, path, as string) (map[string]any, error) {
 		"generated": "by the mesh — do not edit; replaced whenever this changes. " +
 			"The credential is not here: it is sealed, in the file this module's manifest " +
 			"names under `secrets`",
-	}, "", "  ")
+	}
+	// **What this module is called through what it contributes here** (novox/hq 04-ISSUES/122):
+	// `name`, `internal-name`, or `names` by local name — composed exactly as the provider receives
+	// them. Absent when the module contributes nothing named, rather than written empty.
+	for key, value := range own {
+		doc[key] = value
+	}
+	body, err := json.MarshalIndent(doc, "", "  ")
 	if err != nil {
 		return nil, err
 	}

internal/catalogue/own_name_test.go

@@ -0,0 +1,130 @@
+package catalogue
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+)
+
+// A module that must know its own address — a login redirect, a canonical URL, an issuer — had it
+// written into its manifest as a literal (novox/hq 04-ISSUES/122): a domain in a definition, wrong on
+// every other machine. It is told instead, from the same composition the provider receives.
+
+// selfAware contributes a labelled route, binds the requirement, and writes its own name into a file.
+func selfAware(label string) Manifest {
+	m := labelled("board", label, 8080)
+	m.Requires = []string{"reverse-proxy"}
+	m.Binds = map[string]string{"reverse-proxy": "/var/lib/board/route.json"}
+	m.Resources = []map[string]any{
+		{"id": "conf", "type": "file", "path": "/var/lib/board/app.conf",
+			"content": "root = https://${bound:reverse-proxy:name}/\ninternal = ${bound:reverse-proxy:internal-name}\n"},
+	}
+	return m
+}
+
+// servingProxy is proxy() as the catalogue's route providers are declared: the provision scoped to
+// the mesh, serving nothing a consumer must know (route-adapter, route-proxy: `"serves": {"route": {}}`).
+func servingProxy() Manifest {
+	p := proxy()
+	p.Provides = []Offer{{Name: "reverse-proxy", Scope: ScopeMesh}}
+	p.Serves = map[string]map[string]any{"reverse-proxy": {}}
+	return p
+}
+
+// nodeProxy is the same provider scoped to its node, whose answer on the same machine comes from
+// `here` rather than from the mesh's needs — the other path a binding is written by.
+func nodeProxy() Manifest {
+	p := proxy()
+	p.Serves = map[string]map[string]any{"reverse-proxy": {"scheme": "http"}}
+	return p
+}
+
+// onBoth is a node with a public domain and a private-network address, so both names compose.
+func onBoth(domain string) Node {
+	n := withDomain(domain)
+	n.At = "anchor.internal"
+	return n
+}
+
+func fileAt(t *testing.T, out []map[string]any, path string) string {
+	t.Helper()
+	for _, r := range out {
+		if r["path"] == path {
+			return r["content"].(string)
+		}
+	}
+	t.Fatalf("nothing was declared at %s", path)
+	return ""
+}
+
+func TestAModuleIsToldTheNameItsProviderServes(t *testing.T) {
+	got, err := Resolve(shelf(servingProxy(), selfAware("git")), []string{"traefik", "board"},
+		onBoth("example.tld"), World{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	out := mustDeclare(t, got)
+	served := received(t, out)[0].Values
+
+	var binding map[string]any
+	if err := json.Unmarshal([]byte(fileAt(t, out, "/var/lib/board/route.json")), &binding); err != nil {
+		t.Fatal(err)
+	}
+	if binding["name"] != served["name"] || binding["name"] != "git.example.tld" {
+		t.Fatalf("the module was told %v, the provider serves %v", binding["name"], served["name"])
+	}
+	if binding["internal-name"] != served["internal-name"] || binding["internal-name"] == nil {
+		t.Fatalf("internal name: module told %v, provider serves %v",
+			binding["internal-name"], served["internal-name"])
+	}
+
+	conf := fileAt(t, out, "/var/lib/board/app.conf")
+	want := "root = https://git.example.tld/\ninternal = " + served["internal-name"].(string) + "\n"
+	if conf != want {
+		t.Fatalf("the file was rendered as\n%s\nwant\n%s", conf, want)
+	}
+}
+
+func TestTheNameAModuleIsToldFollowsTheNodesDomain(t *testing.T) {
+	// The whole point: the same definition, two machines, two names — nothing edited.
+	for _, domain := range []string{"example.tld", "other.example"} {
+		got, err := Resolve(shelf(servingProxy(), selfAware("git")), []string{"traefik", "board"},
+			onBoth(domain), World{})
+		if err != nil {
+			t.Fatal(err)
+		}
+		conf := fileAt(t, mustDeclare(t, got), "/var/lib/board/app.conf")
+		if !strings.HasPrefix(conf, "root = https://git."+domain+"/") {
+			t.Fatalf("on %s the module wrote %q", domain, conf)
+		}
+	}
+}
+
+func TestAModuleWithNoPublicNameIsNotToldOne(t *testing.T) {
+	// No public domain on the node: nothing composed, so no `name` — and a file asking for one is
+	// refused rather than rendered with a placeholder or an empty host.
+	m := selfAware("git")
+	m.Resources[0]["content"] = "root = https://${bound:reverse-proxy:name}/\n"
+	got, err := Resolve(shelf(servingProxy(), m), []string{"traefik", "board"}, workstation(), World{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := got.Declaration(Rendering{}); err == nil ||
+		!strings.Contains(err.Error(), `"name"`) {
+		t.Fatalf("a file asking for a name that was never composed was not refused: %v", err)
+	}
+}
+
+func TestAModuleIsToldItsNameByANodeScopedProviderToo(t *testing.T) {
+	m := selfAware("git")
+	m.Resources[0]["content"] = "root = https://${bound:reverse-proxy:name}/\n"
+	got, err := Resolve(shelf(nodeProxy(), m), []string{"board"},
+		withDomain("example.tld"), World{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	conf := fileAt(t, mustDeclare(t, got), "/var/lib/board/app.conf")
+	if !strings.HasPrefix(conf, "root = https://git.example.tld/") {
+		t.Fatalf("a same-machine, node-scoped answer did not tell the module its name: %q", conf)
+	}
+}