Let a provider serve its consumers its own composed names (hq ADR 0346, issue 624)

The forge writes every package tarball at its public name, and its
consumers had no source for that name but a second copy kept by hand,
though the mesh composes it for the forge's route. A served value may now
name the provider's own names; a name its machine does not compose leaves
the key out, and the plan says so.

cmd/mesh-controller/plan.go

@@ -289,9 +289,15 @@ func theRestOfTheMesh(ctx context.Context, inv *inventory.Inventory,
 			continue
 		}
 		caps, _ := inv.ProfileOf(ctx, n.Name)
+		// Its public domain too (novox/hq ADR 0346): a provider elsewhere serves its own composed names,
+		// and composes them as its own plan does, under its own domain.
+		domain, err := inv.PublicDomainOf(ctx, n.Name)
+		if err != nil {
+			return catalogue.World{}, err
+		}
 		others = append(others, candidate{
 			catalogue.Node{Name: n.Name, Site: siteOf[n.Name], Capabilities: caps,
-				At: onNetwork[n.Name]}, theirs})
+				At: onNetwork[n.Name], PublicDomain: domain}, theirs})
 	}
 
 	offered := map[string][]catalogue.Provider{}
@@ -314,8 +320,18 @@ func theRestOfTheMesh(ctx context.Context, inv *inventory.Inventory,
 				if err != nil {
 					return catalogue.World{}, err
 				}
+				// And its own composed names, as that node composes them (novox/hq ADR 0346): a name it
+				// does not compose leaves the key out, said under each consumer's need.
+				layers, err := inv.SettingsFor(ctx, o.node.Name, m.Module)
+				if err != nil {
+					return catalogue.World{}, err
+				}
+				serves, leftOut, err := got.ServedOwnNames(m, name, serves, catalogue.WithDefaults(m, layers))
+				if err != nil {
+					return catalogue.World{}, err
+				}
 				offered[name] = append(offered[name], catalogue.Provider{
-					Node: o.node.Name, At: o.node.At, Serves: serves, Module: m.Module})
+					Node: o.node.Name, At: o.node.At, Serves: serves, Module: m.Module, LeftOut: leftOut})
 			}
 		}
 	}
@@ -1426,6 +1442,16 @@ func planCommand(ctx context.Context, args []string) error {
 	// in this output would have told anybody that.
 	for _, n := range plan.Needs {
 		fmt.Printf("  needs %s from %s, for %s\n", n.Name, n.From, n.For)
+		// And a served key the provider left out, because its machine composes no name it asks for
+		// (novox/hq ADR 0346 §3).
+		for _, line := range n.LeftOut {
+			fmt.Printf("    %s\n", line)
+		}
+	}
+	// What the providers on this machine leave out of what they serve, and why: said where the remedy
+	// is (novox/hq ADR 0346 §3).
+	for _, line := range plan.ServedLeftOut(settings) {
+		fmt.Printf("%s: %s\n", args[0], line)
 	}
 	for _, line := range unboundLines(plan) {
 		fmt.Println(line)

cmd/mesh-controller/served_own_names_test.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/novox/mesh-controller/internal/catalogue"
+)
+
+// novox/hq ADR 0346, issue 624: a provider on another machine serves its consumers its own composed
+// names, as that machine composes them; one it does not compose is left out, said under the need.
+func TestAProviderElsewhereServesItsOwnComposedName(t *testing.T) {
+	open := aMesh(t)
+	ctx := t.Context()
+	forge, err := catalogue.ParseManifest([]byte(`{"module":"forge","version":"1","requires":["route"],
+	  "provides":[{"name":"npm-package-registry","scope":"mesh"}],
+	  "contributes":{"route":{"web":{"label":"git","port":3000}}},
+	  "serves":{"npm-package-registry":{"scheme":"http","port":3000,"npm-path":"/api/packages/novox/npm/",
+	    "public-root":"https://${bound:route:name-web}/api/packages/novox/npm/"}}}`))
+	if err != nil {
+		t.Fatal(err)
+	}
+	register(t, open, catalogue.Manifest{Module: "proxy", Version: "1", Provides: catalogue.FromAnywhere("route"),
+		Receives: map[string]string{"route": "/var/lib/proxy/routes.json"}})
+	register(t, open, forge)
+	register(t, open, catalogue.Manifest{Module: "lab", Version: "1", Requires: []string{"npm-package-registry"},
+		Binds: map[string]string{"npm-package-registry": "/var/lib/lab/package-registry.json"}})
+	for _, a := range [][2]string{{"anchor", "proxy"}, {"anchor", "forge"}, {"laptop", "lab"}} {
+		if _, err := assign(ctx, open, a[0], a[1]); err != nil {
+			t.Fatalf("assign %s %s: %v", a[0], a[1], err)
+		}
+	}
+
+	if err := open.inventory.SetPublicDomain(ctx, "anchor", "example.test"); err != nil {
+		t.Fatal(err)
+	}
+	plan, _, err := planFor(ctx, open, "laptop")
+	if err != nil {
+		t.Fatal(err)
+	}
+	n := need(t, plan, "lab", "npm-package-registry")
+	if n.Serves["public-root"] != "https://git.example.test/api/packages/novox/npm/" || len(n.LeftOut) != 0 {
+		t.Fatalf("the consumer elsewhere is served the forge's public root: %v, left out %v", n.Serves, n.LeftOut)
+	}
+
+	if err := open.inventory.SetPublicDomain(ctx, "anchor", ""); err != nil {
+		t.Fatal(err)
+	}
+	plan, _, err = planFor(ctx, open, "laptop")
+	if err != nil {
+		t.Fatal(err)
+	}
+	n = need(t, plan, "lab", "npm-package-registry")
+	if _, there := n.Serves["public-root"]; there {
+		t.Fatalf("anchor composes no public name, so the key is left out: %v", n.Serves)
+	}
+	if len(n.LeftOut) != 1 || !strings.Contains(n.LeftOut[0], `without "public-root"`) {
+		t.Fatalf("and the need says so: %v", n.LeftOut)
+	}
+}

internal/catalogue/bound.go

@@ -127,6 +127,7 @@ func boundNeed(n Needed, bound Chosen, catalogue map[string]Manifest, node Node,
 		identity = pm.IdentityBoundOf(n.Name)
 	}
 	held.From, held.At, held.Module, held.Serves, held.Identity = p.Node, p.At, p.Module, p.Serves, identity
+	held.LeftOut = p.LeftOut
 	return held, true, ""
 }
 

internal/catalogue/consumer_into_serves.go

@@ -143,6 +143,8 @@ func CheckServes(m Manifest) []string {
 				problems = append(problems, fmt.Sprintf(
 					"%s serves %s, and the value it serves as %q %s", m.Module, provision, key, err))
 			}
+			// And the provider's own names it may serve (novox/hq ADR 0346).
+			problems = append(problems, checkServedOwnNames(m, provision, key, text)...)
 			// A label longer than DNS keeps is not truncated here (asDNSLabel), so the offer's own
 			// bound has to keep the identity inside one (ADR 0225).
 			if strings.Contains(text, "${consumer:as:dns}") {

internal/catalogue/declaration.go

@@ -2039,7 +2039,13 @@ func (r Resolution) servedOnThisMachine(provision string, with Rendering) (map[s
 		if err != nil {
 			return nil, false, fmt.Errorf("%s serving %s: %w", m.Module, provision, err)
 		}
-		return settled, true, nil
+		// And the provider's own names, as this machine composes them (novox/hq ADR 0346); one it does
+		// not compose leaves its key out, said by the plan on this machine (ServedLeftOut).
+		named, _, err := r.ServedOwnNames(m, provision, settled, WithDefaults(m, with.Settings[m.Module]))
+		if err != nil {
+			return nil, false, fmt.Errorf("%s serving %s: %w", m.Module, provision, err)
+		}
+		return named, true, nil
 	}
 	return nil, false, nil
 }

internal/catalogue/resolve.go

@@ -111,6 +111,9 @@ type Provider struct {
 	// (novox/hq to-be 23), and the pair is what tells the holder of a seat apart from another module
 	// providing the same thing (ADR 0110).
 	Module string
+	// LeftOut says each served key left out of Serves because that node composes no name it asks
+	// for (novox/hq ADR 0346 §3): said under each consumer's need.
+	LeftOut []string
 }
 
 // Held is a claim somebody already has, used for the scopes wider than one node.
@@ -230,6 +233,9 @@ type Needed struct {
 	// state, not a consumer missing its key. Set by the plan, which is the only layer that knows a
 	// licence's manager; empty for every consumer.
 	Manager bool
+	// LeftOut says each served key the provider left out, because its machine composes no name the
+	// value asks for (novox/hq ADR 0346 §3).
+	LeftOut []string
 	// Module is the providing module on From, empty for a need answered by a record or by nothing
 	// that serves it. A provider is a (node, module) pair (novox/hq to-be 23), and a binding to data
 	// is a binding to the pair (ADR 0232).
@@ -582,7 +588,7 @@ func Resolve(catalogue map[string]Manifest, assigned []string, node Node, world
 					bound = pm.IdentityBoundOf(want)
 				}
 				needs = append(needs, Needed{Name: want, From: p.Node, At: p.At, Module: p.Module,
-					Serves: p.Serves, For: because[want], SharedOwn: shared, Identity: bound})
+					Serves: p.Serves, For: because[want], SharedOwn: shared, Identity: bound, LeftOut: p.LeftOut})
 			}
 			switch {
 			case world.Unchecked:

internal/catalogue/served_own_names.go

@@ -0,0 +1,173 @@
+package catalogue
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+)
+
+// A provider may tell its consumers its own composed names (novox/hq ADR 0346, issue 624).
+//
+// **The name is already the mesh's.** A module contributes a label to a requirement — a route — and
+// the mesh joins it with the providing machine's domains; the module reads the result in its own files
+// as `${bound:<requirement>:name}` (novox/hq 04-ISSUES/122). Its consumers could not be told it: a
+// served value named only the consumer (ADR 0202) and settings. The forge's package registry writes
+// every tarball at its public name, and a consumer that must trust that name had no source for it but a
+// second copy kept by hand. So a served value may say `${bound:<requirement>:<name>}` for a requirement
+// the provider contributes to, and the mesh fills it from the same composition the provider's own files
+// and its proxy receive.
+//
+// **A name the providing machine does not compose leaves the key out** (ADR 0346 §3): a machine with
+// no public domain has no public name to give, and an empty value or a refusal would be worse than a
+// consumer told nothing — a refused provider machine takes every provision it offers down with it. The
+// plan says which key was left out, and why, on the provider's machine and under each consumer's need.
+
+// ownNameFacts are what a served value may name of the provider's own composition: the names, as its
+// own files read them (withOwnNames).
+var ownNameFacts = []string{"name", "internal-name"}
+
+// requirementsContributedTo is every requirement m contributes to, sorted.
+func requirementsContributedTo(m Manifest) []string {
+	seen := map[string]bool{}
+	for to := range m.Contributes {
+		seen[to] = true
+	}
+	for to := range m.ContributesMany {
+		seen[to] = true
+	}
+	out := make([]string, 0, len(seen))
+	for to := range seen {
+		out = append(out, to)
+	}
+	sort.Strings(out)
+	return out
+}
+
+// ownNameKeys is every name a served value of m may say for one requirement it contributes to:
+// `name` and `internal-name`, and `name-<local>` and `internal-name-<local>` for each local name it
+// contributes under.
+func ownNameKeys(m Manifest, to string) []string {
+	keys := append([]string{}, ownNameFacts...)
+	for _, local := range sortedKeys(m.ContributesMany[to]) {
+		for _, fact := range ownNameFacts {
+			keys = append(keys, fact+"-"+local)
+		}
+	}
+	return keys
+}
+
+// ServedOwnNames fills the provider's own composed names into what it serves one provision's
+// consumers, from this resolution's composition of the provider's machine (ADR 0346).
+//
+// A value naming a name this machine does not compose is left out, with its key, and said. The map is
+// copied only when something changes, as ServedTo does: the caller's may be the manifest's.
+func (r Resolution) ServedOwnNames(m Manifest, provision string, serves map[string]any, layers []Layer) (
+	map[string]any, []string, error) {
+	var asking []string
+	for _, key := range sortedAnyKeys(serves) {
+		if text, ok := serves[key].(string); ok && bound.MatchString(text) {
+			asking = append(asking, key)
+		}
+	}
+	if len(asking) == 0 {
+		return serves, nil, nil
+	}
+	own := map[string]map[string]string{}
+	for _, to := range requirementsContributedTo(m) {
+		names, err := r.ownNames(m, to, layers)
+		if err != nil {
+			return nil, nil, err
+		}
+		values := map[string]string{}
+		withOwnNames(values, names)
+		own[to] = values
+	}
+	out := make(map[string]any, len(serves))
+	for k, v := range serves {
+		out[k] = v
+	}
+	var said []string
+	for _, key := range asking {
+		text := serves[key].(string)
+		var missing string
+		filled := bound.ReplaceAllStringFunc(text, func(token string) string {
+			parts := bound.FindStringSubmatch(token)
+			if value := own[parts[1]][parts[2]]; value != "" && parts[3] == "" {
+				return value
+			}
+			if missing == "" {
+				missing = token
+			}
+			return token
+		})
+		if missing != "" {
+			delete(out, key)
+			said = append(said, fmt.Sprintf(
+				"%s serves %s without %q: it names %s, and %s composes no such name for %s (it has no "+
+					"public domain, or the endpoint is not reached publicly) (novox/hq ADR 0346)",
+				m.Module, provision, key, missing, orHere(r.Node), m.Module))
+			continue
+		}
+		out[key] = filled
+	}
+	return out, said, nil
+}
+
+func orHere(node string) string {
+	if node == "" {
+		return "this machine"
+	}
+	return node
+}
+
+// ServedLeftOut is what the providers in this node's own set leave out of what they serve, because
+// this machine composes no name a served value asks for (ADR 0346 §3): said on the provider's machine,
+// where the remedy is.
+func (r Resolution) ServedLeftOut(settings SettingsBy) []string {
+	var said []string
+	for _, m := range r.Modules {
+		for _, provision := range sortedServes(m.Serves) {
+			_, lines, err := r.ServedOwnNames(m, provision, m.Serves[provision], WithDefaults(m, settings[m.Module]))
+			if err != nil {
+				said = append(said, fmt.Sprintf("%s serves %s, and its own names could not be composed: %v",
+					m.Module, provision, err))
+				continue
+			}
+			said = append(said, lines...)
+		}
+	}
+	return said
+}
+
+// checkServedOwnNames refuses a served `${bound:…}` that names a requirement the module does not
+// contribute to, a fact other than its own names, or a local name it does not contribute under; and
+// one with a default, since a served value is left out rather than given one (ADR 0346 §3, §4).
+func checkServedOwnNames(m Manifest, provision, key, text string) []string {
+	var problems []string
+	contributes := requirementsContributedTo(m)
+	for _, parts := range bound.FindAllStringSubmatch(text, -1) {
+		to, fact, fallback := parts[1], parts[2], parts[3]
+		says := fmt.Sprintf("%s serves %s, and the value it serves as %q says %s", m.Module, provision, key, parts[0])
+		switch {
+		case fallback != "":
+			problems = append(problems, says+": a served name takes no default; one the machine does not "+
+				"compose leaves the key out (novox/hq ADR 0346)")
+		case !oneOf(contributes, to):
+			problems = append(problems, fmt.Sprintf(
+				"%s, and %s contributes to %s: a served value names only the provider's own names "+
+					"(novox/hq ADR 0346)", says, m.Module, orNothing(quoted(contributes))))
+		case !oneOf(ownNameKeys(m, to), fact):
+			problems = append(problems, fmt.Sprintf("%s, and what %s is called through %s is %s (novox/hq ADR 0346)",
+				says, m.Module, to, strings.Join(ownNameKeys(m, to), ", ")))
+		}
+	}
+	return problems
+}
+
+func quoted(values []string) []string {
+	out := make([]string, len(values))
+	for i, v := range values {
+		out[i] = fmt.Sprintf("%q", v)
+	}
+	return out
+}

internal/catalogue/served_own_names_test.go

@@ -0,0 +1,149 @@
+package catalogue
+
+import (
+	"strings"
+	"testing"
+)
+
+// novox/hq ADR 0346, issue 624: the forge's package registry writes every tarball at its public name,
+// and the lab, its consumer, must trust that name and no other. The name is the mesh's own composition
+// of the forge's route, which the forge's files read as ${bound:route:name-web}; a consumer can now be
+// served it.
+
+const aRegistryForge = `{"module":"forge","version":"1","requires":["route"],
+  "provides":[{"name":"npm-package-registry","scope":"mesh"}],
+  "contributes":{"route":{"web":{"label":"git","port":3000}}},
+  "serves":{"npm-package-registry":{"scheme":"http","port":3000,"npm-path":"/api/packages/novox/npm/",
+    "public-root":"https://${bound:route:name-web}/api/packages/novox/npm/"}}}`
+
+func aForgeManifest(t *testing.T) Manifest {
+	t.Helper()
+	m, err := ParseManifest([]byte(aRegistryForge))
+	if err != nil {
+		t.Fatal(err)
+	}
+	return m
+}
+
+func TestAProviderServesItsOwnComposedName(t *testing.T) {
+	m := aForgeManifest(t)
+	r := Resolution{Node: "home", PublicDomain: "example.org"}
+	got, said, err := r.ServedOwnNames(m, "npm-package-registry", m.Serves["npm-package-registry"], nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got["public-root"] != "https://git.example.org/api/packages/novox/npm/" || len(said) != 0 {
+		t.Fatalf("the public root is the route's composed name: %v, said %v", got, said)
+	}
+	if got["npm-path"] != "/api/packages/novox/npm/" || got["port"] != float64(3000) {
+		t.Fatalf("the rest is served as it was: %v", got)
+	}
+	if m.Serves["npm-package-registry"]["public-root"] != "https://${bound:route:name-web}/api/packages/novox/npm/" {
+		t.Fatal("the manifest's own map was rewritten")
+	}
+}
+
+func TestANameTheMachineDoesNotComposeLeavesTheKeyOutAndSaysSo(t *testing.T) {
+	m := aForgeManifest(t)
+	r := Resolution{Node: "home"} // no public domain
+	got, said, err := r.ServedOwnNames(m, "npm-package-registry", m.Serves["npm-package-registry"], nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, there := got["public-root"]; there {
+		t.Fatalf("a name not composed is left out, never written as the placeholder or empty: %v", got)
+	}
+	if got["npm-path"] == nil {
+		t.Fatalf("only the key that names it is left out: %v", got)
+	}
+	if len(said) != 1 || !strings.Contains(said[0], `forge serves npm-package-registry without "public-root"`) ||
+		!strings.Contains(said[0], "home composes no such name") {
+		t.Fatalf("said: %v", said)
+	}
+	if lines := (Resolution{Node: "home", Modules: []Manifest{m}}).ServedLeftOut(nil); len(lines) != 1 {
+		t.Fatalf("the plan on the provider's machine says it: %v", lines)
+	}
+	if lines := (Resolution{Node: "home", PublicDomain: "example.org", Modules: []Manifest{m}}).ServedLeftOut(nil); len(lines) != 0 {
+		t.Fatalf("nothing to say when the name is composed: %v", lines)
+	}
+}
+
+// On the provider's own machine the consumer is served the same name (ADR 0346 §2).
+func TestAConsumerBesideTheProviderIsServedItsName(t *testing.T) {
+	m := aForgeManifest(t)
+	consumer := Manifest{Module: "lab", Version: "1", Requires: []string{"npm-package-registry"},
+		Binds: map[string]string{"npm-package-registry": "/var/lib/lab/package-registry.json"}}
+	node := workstation()
+	node.PublicDomain = "example.org"
+	got, err := Resolve(shelf(minimalRouteProxy(), m, consumer), []string{"route-proxy", "forge", "lab"}, node, World{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	served, answered, err := got.servedOnThisMachine("npm-package-registry", Rendering{})
+	if err != nil || !answered {
+		t.Fatalf("answered %v: %v", answered, err)
+	}
+	if served["public-root"] != "https://git.example.org/api/packages/novox/npm/" {
+		t.Fatalf("served beside the provider: %v", served)
+	}
+	out, err := got.Declaration(Rendering{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	var binding string
+	for _, r := range out {
+		if r["path"] == "/var/lib/lab/package-registry.json" {
+			binding, _ = r["content"].(string)
+		}
+	}
+	if !strings.Contains(binding, `"public-root": "https://git.example.org/api/packages/novox/npm/"`) &&
+		!strings.Contains(binding, `"public-root":"https://git.example.org/api/packages/novox/npm/"`) {
+		t.Fatalf("the consumer's binding carries the name:\n%s", binding)
+	}
+	if strings.Contains(binding, "${bound:") {
+		t.Fatalf("a placeholder reached the consumer:\n%s", binding)
+	}
+}
+
+// From another machine, the provider's served values carry what that machine composed, and a key it
+// left out is said on the consumer's need (ADR 0346 §2, §3).
+func TestAConsumerElsewhereIsToldWhatTheProviderLeftOut(t *testing.T) {
+	consumer := Manifest{Module: "lab", Version: "1", Requires: []string{"npm-package-registry"},
+		Binds: map[string]string{"npm-package-registry": "/var/lib/lab/package-registry.json"}}
+	node := workstation()
+	node.At = "workstation.internal"
+	world := World{Offered: map[string][]Provider{"npm-package-registry": {{Node: "home", At: "home.internal",
+		Module: "forge", Serves: map[string]any{"port": 3000},
+		LeftOut: []string{`forge serves npm-package-registry without "public-root"`}}}}}
+	got, err := Resolve(shelf(aForgeManifest(t), consumer), []string{"lab"}, node, world)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, n := range got.Needs {
+		if n.Name == "npm-package-registry" {
+			if len(n.LeftOut) != 1 {
+				t.Fatalf("the need carries what was left out: %+v", n)
+			}
+			return
+		}
+	}
+	t.Fatalf("no need: %+v", got.Needs)
+}
+
+func TestAServedNameIsCheckedWhenTheDefinitionIsRead(t *testing.T) {
+	for bad, want := range map[string]string{
+		`"public-root":"https://${bound:route:name-api}/x"`:           "what forge is called through route is name, internal-name, name-web, internal-name-web",
+		`"public-root":"https://${bound:postgres-database:name}/x"`:   `forge contributes to "route"`,
+		`"public-root":"https://${bound:route:name-web|default:x}/x"`: "takes no default",
+		`"public-root":"https://${bound:route:at}/x"`:                 "what forge is called through route",
+	} {
+		raw := strings.Replace(aRegistryForge, `"public-root":"https://${bound:route:name-web}/api/packages/novox/npm/"`, bad, 1)
+		_, err := ParseManifest([]byte(raw))
+		if err == nil || !strings.Contains(err.Error(), want) {
+			t.Errorf("%s: want a refusal saying %q, got %v", bad, want, err)
+		}
+	}
+	if _, err := ParseManifest([]byte(aRegistryForge)); err != nil {
+		t.Fatalf("its own name is accepted: %v", err)
+	}
+}