node-tools/internal/announce/announce.go

@@ -0,0 +1,209 @@
+// Package announce answers the NATS services protocol's discovery for what a runtime serves, and
+// gathers the answers (novox/hq ADR 0197).
+//
+// A runtime does not re-serve its tools through a services library: serving is unchanged. It answers
+// `$SRV.PING`, `$SRV.INFO` and `$SRV.STATS` — and the same followed by its service name, and by its
+// name and id — in the format NATS's own tools read, with what it is serving at the moment it is
+// asked. One service per runtime process: the bus admits one reply per request from each responder,
+// so a runtime serving many modules and seats answers once, one endpoint per tool per subject, and
+// says in each endpoint's metadata which module, seat, scope and machine it is.
+package announce
+
+import (
+	"encoding/json"
+	"strings"
+	"time"
+
+	"github.com/nats-io/nats.go/micro"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+)
+
+// Version is the announced service version (semver, as the protocol requires).
+const Version = "0.1.0"
+
+// Window is how long the console gathers discovery answers: every instance answers one request, and
+// how many will is what is being found out.
+var Window = 750 * time.Millisecond
+
+// Kinds of endpoint.
+const (
+	KindTool = "tool" // a module's own tool
+	KindSeat = "seat" // a seat's verb, served by the module holding it
+)
+
+// Endpoint is one tool served on one subject, as it is announced.
+type Endpoint struct {
+	Kind            string
+	Module          string // the module whose code answers
+	Tool            string // the tool's or the verb's name
+	Seat            string // for a seat's verb
+	Scope           string // "mesh" or "node", for a seat's verb
+	Node            string
+	Description     string
+	Schema          json.RawMessage
+	Interchangeable bool
+	Subject         string
+	Queue           string
+}
+
+// Name is the endpoint's name as the protocol allows it — letters, digits, `-` and `_` — the
+// prefix and the tool joined by `__`; the metadata, not the name, is what identifies it.
+func (e Endpoint) Name() string {
+	prefix := e.Module
+	if e.Kind == KindSeat {
+		prefix = e.Seat
+	}
+	return clean(prefix) + "__" + clean(e.Tool)
+}
+
+func clean(s string) string {
+	var b strings.Builder
+	for _, r := range s {
+		if r == '-' || r == '_' || (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || (r >= '0' && r <= '9') {
+			b.WriteRune(r)
+		} else {
+			b.WriteRune('_')
+		}
+	}
+	return b.String()
+}
+
+func (e Endpoint) info() micro.EndpointInfo {
+	md := map[string]string{
+		"kind": e.Kind, "module": e.Module, "tool": e.Tool, "node": e.Node,
+		"description": e.Description, "interchangeable": boolWord(e.Interchangeable),
+	}
+	schema := strings.TrimSpace(string(e.Schema))
+	if schema == "" || schema == "null" {
+		schema = "{}"
+	}
+	md["schema"] = schema
+	if e.Kind == KindSeat {
+		md["seat"] = e.Seat
+		md["scope"] = e.Scope
+	}
+	return micro.EndpointInfo{Name: e.Name(), Subject: e.Subject, QueueGroup: e.Queue, Metadata: md}
+}
+
+func boolWord(b bool) string {
+	if b {
+		return "true"
+	}
+	return "false"
+}
+
+// Service is who answers: the runtime's name, its instance, and a word about it.
+type Service struct {
+	Name        string
+	ID          string
+	Description string
+	Metadata    map[string]string
+}
+
+func (s Service) identity() micro.ServiceIdentity {
+	md := s.Metadata
+	if md == nil {
+		md = map[string]string{}
+	}
+	return micro.ServiceIdentity{Name: s.Name, ID: s.ID, Version: Version, Metadata: md}
+}
+
+// Info is the info_response for these endpoints.
+func Info(s Service, endpoints []Endpoint) micro.Info {
+	out := micro.Info{ServiceIdentity: s.identity(), Type: micro.InfoResponseType,
+		Description: s.Description, Endpoints: []micro.EndpointInfo{}}
+	for _, e := range endpoints {
+		out.Endpoints = append(out.Endpoints, e.info())
+	}
+	return out
+}
+
+// Serve answers discovery for one service until stopped, asking `current` for its endpoints each
+// time — so what is announced is what is served now, re-served memberships included.
+func Serve(conn *bus.Conn, s Service, current func() []Endpoint) (func(), error) {
+	started := time.Now().UTC()
+	answer := func(subject string, _ []byte) []byte {
+		parts := strings.Split(subject, ".")
+		if len(parts) < 2 || parts[0] != "$SRV" {
+			return nil
+		}
+		if len(parts) >= 3 && parts[2] != s.Name {
+			return nil // another service's
+		}
+		if len(parts) >= 4 && parts[3] != s.ID {
+			return nil // another instance's
+		}
+		var v any
+		switch parts[1] {
+		case "PING":
+			v = micro.Ping{ServiceIdentity: s.identity(), Type: micro.PingResponseType}
+		case "INFO":
+			v = Info(s, current())
+		case "STATS":
+			st := micro.Stats{ServiceIdentity: s.identity(), Type: micro.StatsResponseType, Started: started,
+				Endpoints: []*micro.EndpointStats{}}
+			for _, e := range current() {
+				st.Endpoints = append(st.Endpoints, &micro.EndpointStats{Name: e.Name(), Subject: e.Subject, QueueGroup: e.Queue})
+			}
+			v = st
+		default:
+			return nil
+		}
+		body, err := json.Marshal(v)
+		if err != nil {
+			return nil
+		}
+		return body
+	}
+	var stops []func()
+	for _, verb := range []string{"PING", "INFO", "STATS"} {
+		for _, subject := range []string{"$SRV." + verb, "$SRV." + verb + ".>"} {
+			stop, err := conn.Raw(subject, answer)
+			if err != nil {
+				for _, st := range stops {
+					st()
+				}
+				return func() {}, err
+			}
+			stops = append(stops, stop)
+		}
+	}
+	return func() {
+		for _, st := range stops {
+			st()
+		}
+	}, nil
+}
+
+// Gather asks every service on the bus what it serves and answers what came back within the window.
+// An answer that is not an info_response is skipped.
+func Gather(conn *bus.Conn) ([]micro.Info, error) {
+	raw, err := conn.Gather("$SRV.INFO", nil, Window)
+	if err != nil {
+		return nil, err
+	}
+	var out []micro.Info
+	for _, b := range raw {
+		var i micro.Info
+		if json.Unmarshal(b, &i) != nil || i.Type != micro.InfoResponseType {
+			continue
+		}
+		out = append(out, i)
+	}
+	return out, nil
+}
+
+// Endpoints reads an info_response's endpoints back into what they announce.
+func Endpoints(i micro.Info) []Endpoint {
+	var out []Endpoint
+	for _, e := range i.Endpoints {
+		md := e.Metadata
+		out = append(out, Endpoint{
+			Kind: md["kind"], Module: md["module"], Tool: md["tool"], Seat: md["seat"], Scope: md["scope"],
+			Node: md["node"], Description: md["description"], Schema: json.RawMessage(md["schema"]),
+			Interchangeable: md["interchangeable"] == "true", Subject: e.Subject, Queue: e.QueueGroup,
+		})
+	}
+	return out
+}

node-tools/internal/bus/bus.go

@@ -512,6 +512,59 @@ func (c *Conn) PublishAs(module string, env Envelope) error {
 	return err
 }
 
+// ServedOn is where a served module's tool is answered right now: the membership's subjects when
+// issued, the derived shape otherwise — what Handle subscribes, for what announces it (ADR 0197).
+func (c *Conn) ServedOn(module, tool string) []Served { return c.servedOn(module, tool) }
+
+// Raw answers one subject with a function of the request, not a tool's reply envelope: the NATS
+// services protocol's discovery subjects answer in their own format (novox/hq ADR 0197). A nil
+// answer is no reply — the request was for another service.
+func (c *Conn) Raw(subject string, answer func(subject string, data []byte) []byte) (func(), error) {
+	sub, err := c.nc.Subscribe(subject, func(msg *nats.Msg) {
+		if body := answer(msg.Subject, msg.Data); body != nil {
+			_ = msg.Respond(body)
+		}
+	})
+	if err != nil {
+		return func() {}, err
+	}
+	c.track(sub)
+	return func() { _ = sub.Unsubscribe() }, nil
+}
+
+// Gather publishes one request and collects every answer that arrives within the window: a
+// discovery request every service instance answers (ADR 0197). It never stops early — how many will
+// answer is what it is finding out.
+func (c *Conn) Gather(subject string, body []byte, window time.Duration) ([][]byte, error) {
+	inbox := c.nc.NewRespInbox()
+	sub, err := c.nc.SubscribeSync(inbox)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = sub.Unsubscribe() }()
+	if err := c.nc.PublishRequest(subject, inbox, body); err != nil {
+		return nil, err
+	}
+	var out [][]byte
+	deadline := time.Now().Add(window)
+	for {
+		left := time.Until(deadline)
+		if left <= 0 {
+			return out, nil
+		}
+		msg, err := sub.NextMsg(left)
+		if err != nil {
+			if errors.Is(err, nats.ErrTimeout) {
+				return out, nil
+			}
+			return out, err
+		}
+		if len(msg.Data) > 0 {
+			out = append(out, msg.Data)
+		}
+	}
+}
+
 // Flush waits until the bus has every subscription made so far, so what is served is answerable
 // when this returns.
 func (c *Conn) Flush() { _ = c.nc.Flush() }

node-tools/internal/console/address.go

@@ -19,12 +19,12 @@ package console
 import (
 	"encoding/json"
 	"fmt"
-	"regexp"
 	"sort"
 	"strings"
 	"sync"
 	"time"
 
+	"github.com/novox/mesh-tools/node-tools/internal/announce"
 	"github.com/novox/mesh-tools/node-tools/internal/bus"
 )
 
@@ -159,188 +159,181 @@ func controllerOutput(conn *bus.Conn, verb string) (string, error) {
 // jsonIn is the JSON document a command printed, after any lines it said first: a seat verb runs
 // the controller's command, and a command may warn before it answers.
 func jsonIn(output string) string {
-	if strings.HasPrefix(strings.TrimSpace(output), "{") {
-		return strings.TrimSpace(output)
+	t := strings.TrimSpace(output)
+	if strings.HasPrefix(t, "{") || strings.HasPrefix(t, "[") {
+		return t
 	}
-	if i := strings.Index(output, "\n{"); i >= 0 {
-		return strings.TrimSpace(output[i+1:])
+	for _, open := range []string{"\n{", "\n["} {
+		if i := strings.Index(output, open); i >= 0 {
+			return strings.TrimSpace(output[i+1:])
+		}
 	}
 	return ""
 }
 
-// A machine as `node list` prints it: its name, when it was last heard from, its mode — converged
-// or adopted, the only two the command prints — and its id. Lines the command says around them
-// (a warning about the bus's users, "no node records yet") are not machines and are skipped.
-var nodeLine = regexp.MustCompile(`^([a-z0-9][a-z0-9-]*)\s+.*\s(converged|adopted)\s+\S+\s*$`)
-
-// machinesIn reads the machines from `node list`'s output.
-func machinesIn(output string) []string {
-	var out []string
-	for _, line := range strings.Split(output, "\n") {
-		if m := nodeLine.FindStringSubmatch(line); m != nil {
-			out = append(out, m[1])
-		}
-	}
-	sort.Strings(out)
-	return out
+// recordedModule is a module as the controller's records hold it (`module list --json`): where the
+// mesh assigned it, and whether it declares tools — what should announce itself, and where.
+type recordedModule struct {
+	Module string   `json:"module"`
+	On     []string `json:"on"`
+	Tools  bool     `json:"tools"`
 }
 
-// A module as `module list` prints it: name, version, how it was built, and where it runs.
-var moduleLine = regexp.MustCompile(`^([a-z0-9][a-z0-9-]*)\s+\S+\s+.*?\s+on (.+)$`)
-
-// assignmentsIn reads, from `module list`'s output, the machines each module runs on.
-func assignmentsIn(output string) map[string][]string {
-	out := map[string][]string{}
-	for _, line := range strings.Split(output, "\n") {
-		if line == "" || line[0] == ' ' || line[0] == '\t' {
-			continue
-		}
-		m := moduleLine.FindStringSubmatch(strings.TrimRight(line, " "))
-		if m == nil {
-			continue
-		}
-		on := strings.TrimSpace(m[2])
-		if on == "nothing" {
-			out[m[1]] = []string{}
-			continue
-		}
-		var nodes []string
-		for _, n := range strings.Split(on, ",") {
-			if n = strings.TrimSpace(n); n != "" {
-				nodes = append(nodes, n)
-			}
-		}
-		sort.Strings(nodes)
-		out[m[1]] = nodes
-	}
-	return out
+// recordedMachine is a machine as the controller's records hold it (`node list --json`).
+type recordedMachine struct {
+	Name string `json:"name"`
 }
 
-// interchangeable is whether the mesh issued the module a plain subject for this tool — one any of
-// its instances answers (ADR 0160): the module's own subject with no machine after it.
-func interchangeable(module string, t Tool) bool {
-	plain := "mesh.mod." + module + ".tool." + t.Name
-	for _, s := range t.Subjects {
-		if s == plain {
-			return true
-		}
-	}
-	return false
-}
-
-// indexOn asks the mesh what it holds: the flat listing (catalogue, modules, the seats' tools),
-// and from the controller the seats' holders, the machines and the assignments — at once.
+// indexOn asks the mesh what it holds (novox/hq ADR 0197): what answers, from every runtime's own
+// announcement on the bus — one `$SRV.INFO` request — and what should, from the controller's records
+// read as JSON. Nothing is inferred from a roster and nothing is parsed from print.
 func indexOn(conn *bus.Conn) (*index, error) {
 	var wg sync.WaitGroup
-	var seatsOut, nodesOut, modulesOut string
-	wg.Add(3)
-	go func() { defer wg.Done(); seatsOut, _ = controllerOutput(conn, "seats") }()
+	var nodesOut, modulesOut string
+	wg.Add(2)
 	go func() { defer wg.Done(); nodesOut, _ = controllerOutput(conn, "nodes") }()
 	go func() { defer wg.Done(); modulesOut, _ = controllerOutput(conn, "modules") }()
-	l, err := toolsOn(conn)
+	infos, err := announce.Gather(conn)
 	wg.Wait()
 	if err != nil {
 		return nil, err
 	}
 
-	x := &index{Modules: map[string]*moduleInfo{}, NotAnswering: l.NotAnswering, Listing: l}
-
-	// The seats: their verbs from the mesh's records, their holders from the controller.
-	var held struct {
-		Seats []struct {
-			Seat    string   `json:"seat"`
-			Scope   string   `json:"scope"`
-			Holders []holder `json:"holders"`
-		} `json:"seats"`
-	}
-	_ = json.Unmarshal([]byte(jsonIn(seatsOut)), &held)
-	holders := map[string][]holder{}
-	scopes := map[string]string{}
-	for _, s := range held.Seats {
-		holders[s.Seat] = s.Holders
-		scopes[s.Seat] = s.Scope
-	}
-	bySeat := map[string]*seatInfo{}
-	for _, t := range l.Tools {
-		if !t.Seat {
-			continue
-		}
-		s := bySeat[t.Module]
-		if s == nil {
-			scope := t.Scope
-			if scope == "" {
-				scope = scopes[t.Module]
+	l := &Listing{Tools: []Tool{}, NotAnswering: []string{}}
+	x := &index{Modules: map[string]*moduleInfo{}, Listing: l}
+	announced := map[string]map[string]bool{} // module → node → announced something
+	seats := map[string]*seatInfo{}
+	toolAt := map[string]int{} // <module>.<tool> or <seat>.<verb> → index in l.Tools
+	machines := map[string]bool{}
+	for _, info := range infos {
+		for _, e := range announce.Endpoints(info) {
+			if e.Node != "" {
+				machines[e.Node] = true
 			}
-			if scope != "node" {
-				scope = "mesh"
+			if announced[e.Module] == nil {
+				announced[e.Module] = map[string]bool{}
 			}
-			s = &seatInfo{Seat: t.Module, Scope: scope, Holders: holders[t.Module]}
-			bySeat[t.Module] = s
-		}
-		s.Verbs = append(s.Verbs, t)
-	}
-	for _, s := range bySeat {
-		x.Seats = append(x.Seats, *s)
-	}
-	sort.Slice(x.Seats, func(i, j int) bool { return x.Seats[i].Seat < x.Seats[j].Seat })
-
-	// The machines: what the controller knows, and any that hold a seat.
-	seen := map[string]bool{}
-	for _, n := range machinesIn(nodesOut) {
-		seen[n] = true
-	}
-	for _, s := range x.Seats {
-		for _, h := range s.Holders {
-			if h.Node != "" {
-				seen[h.Node] = true
+			announced[e.Module][e.Node] = true
+			switch e.Kind {
+			case announce.KindSeat:
+				st := seats[e.Seat]
+				if st == nil {
+					st = &seatInfo{Seat: e.Seat, Scope: e.Scope}
+					seats[e.Seat] = st
+				}
+				if st.Scope != "node" && e.Scope == "node" {
+					st.Scope = "node"
+				}
+				h := holder{Module: e.Module, Node: e.Node}
+				if !containsHolder(st.Holders, h) {
+					st.Holders = append(st.Holders, h)
+				}
+				key := e.Seat + "." + e.Tool
+				if _, have := toolAt[key]; !have {
+					toolAt[key] = len(l.Tools)
+					t := Tool{Module: e.Seat, Name: e.Tool, Description: e.Description, Input: e.Schema, Seat: true, Scope: st.Scope}
+					l.Tools = append(l.Tools, t)
+					st.Verbs = append(st.Verbs, t)
+				}
+			case announce.KindTool:
+				m := x.Modules[e.Module]
+				if m == nil {
+					m = &moduleInfo{Module: e.Module}
+					x.Modules[e.Module] = m
+				}
+				if e.Node != "" && !contains(m.On, e.Node) {
+					m.On = append(m.On, e.Node)
+				}
+				m.Interchangeable = m.Interchangeable || e.Interchangeable
+				key := e.Module + "." + e.Tool
+				i, have := toolAt[key]
+				if !have {
+					i = len(l.Tools)
+					toolAt[key] = i
+					l.Tools = append(l.Tools, Tool{Module: e.Module, Name: e.Tool, Description: e.Description, Input: e.Schema})
+				}
+				if !contains(l.Tools[i].Subjects, e.Subject) {
+					l.Tools[i].Subjects = append(l.Tools[i].Subjects, e.Subject)
+				}
 			}
 		}
 	}
-
-	// The modules that answer tools, where they run, and whether any instance will do.
-	on := assignmentsIn(modulesOut)
-	for _, t := range l.Tools {
+	// A tool's subjects as a call looks them up: the plain one any instance answers first, then each
+	// machine's.
+	for i := range l.Tools {
+		t := &l.Tools[i]
 		if t.Seat {
 			continue
 		}
-		m := x.Modules[t.Module]
-		if m == nil {
-			m = &moduleInfo{Module: t.Module, On: on[t.Module]}
-			x.Modules[t.Module] = m
-		}
-		m.Tools = append(m.Tools, t)
-		if interchangeable(t.Module, t) {
-			m.Interchangeable = true
+		plain := "mesh.mod." + t.Module + ".tool." + t.Name
+		sort.SliceStable(t.Subjects, func(a, b int) bool {
+			if (t.Subjects[a] == plain) != (t.Subjects[b] == plain) {
+				return t.Subjects[a] == plain
+			}
+			return t.Subjects[a] < t.Subjects[b]
+		})
+	}
+	for _, t := range l.Tools {
+		if !t.Seat {
+			x.Modules[t.Module].Tools = append(x.Modules[t.Module].Tools, t)
 		}
 	}
 	for _, m := range x.Modules {
-		// A module the controller could not place is placed where its own answer says it runs.
-		if len(m.On) == 0 {
-			nodes := map[string]bool{}
-			for _, t := range m.Tools {
-				for _, s := range t.Subjects {
-					base := "mesh.mod." + m.Module + ".tool." + t.Name + "."
-					if strings.HasPrefix(s, base) {
-						nodes[strings.TrimPrefix(s, base)] = true
-					}
+		sort.Strings(m.On)
+	}
+	for _, st := range seats {
+		sort.Slice(st.Holders, func(a, b int) bool { return st.Holders[a].Node < st.Holders[b].Node })
+		x.Seats = append(x.Seats, *st)
+	}
+	sort.Slice(x.Seats, func(i, j int) bool { return x.Seats[i].Seat < x.Seats[j].Seat })
+	sort.SliceStable(l.Tools, func(i, j int) bool {
+		return l.Tools[i].Module+"."+l.Tools[i].Name < l.Tools[j].Module+"."+l.Tools[j].Name
+	})
+
+	// What should have answered: every assignment of a module that declares tools. Silence is named;
+	// a module with no tools is never a name here.
+	var recorded []recordedModule
+	if json.Unmarshal([]byte(jsonIn(modulesOut)), &recorded) == nil {
+		for _, m := range recorded {
+			if !m.Tools {
+				continue
+			}
+			for _, n := range m.On {
+				if !announced[m.Module][n] {
+					l.NotAnswering = append(l.NotAnswering, m.Module+" on "+n)
 				}
 			}
-			for n := range nodes {
-				m.On = append(m.On, n)
-			}
-			sort.Strings(m.On)
 		}
-		for _, n := range m.On {
-			seen[n] = true
+	} else {
+		l.NotAnswering = append(l.NotAnswering, "mesh-controller (its records of the modules did not answer, so what is missing cannot be said)")
+	}
+	sort.Strings(l.NotAnswering)
+	x.NotAnswering = l.NotAnswering
+
+	var known []recordedMachine
+	if json.Unmarshal([]byte(jsonIn(nodesOut)), &known) == nil {
+		for _, n := range known {
+			if n.Name != "" {
+				machines[n.Name] = true
+			}
 		}
 	}
-	for n := range seen {
+	for n := range machines {
 		x.Machines = append(x.Machines, n)
 	}
 	sort.Strings(x.Machines)
 	return x, nil
 }
 
+func containsHolder(hs []holder, h holder) bool {
+	for _, x := range hs {
+		if x == h {
+			return true
+		}
+	}
+	return false
+}
+
 func (s *Surface) index() (*index, error) {
 	s.mu.Lock()
 	if s.idx != nil && time.Since(s.idxAt) <= IndexKept {
@@ -520,7 +513,7 @@ func failure(text string) map[string]any {
 func (s *Surface) discover(name string, args map[string]any) map[string]any {
 	x, err := s.index()
 	if err != nil {
-		return failure(whyItFailed(catalogueModules, err))
+		return failure("the mesh's discovery failed: " + err.Error())
 	}
 	str := func(k string) string { v, _ := args[k].(string); return strings.TrimSpace(v) }
 

node-tools/internal/console/address_test.go

@@ -4,9 +4,11 @@ import (
 	"encoding/json"
 	"fmt"
 	"strings"
+	"sync/atomic"
 	"testing"
 	"time"
 
+	"github.com/novox/mesh-tools/node-tools/internal/announce"
 	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
 	"github.com/novox/mesh-tools/node-tools/internal/runtime"
 )
@@ -56,14 +58,20 @@ func TestTheMeshsToolsAreFoundByAddress(t *testing.T) {
 	}
 	defer stop()
 
-	catalogue := connect(t, "mesh-catalog", "")
-	stopCat, _ := catalogue.Handle("catalog_modules", func(json.RawMessage) (any, error) {
-		return map[string]any{"modules": []map[string]string{{"module": "alpha"}, {"module": "beta"}, {"module": "gamma"}}}, nil
-	})
-	defer stopCat()
+	// Nothing may be asked for a roster or a module's `tools` any more (ADR 0197): counted.
+	var asked atomic.Int32
+	watcher := connect(t, "watcher", "")
+	for _, subject := range []string{"mesh.mod.*.tool.tools", "mesh.mod.*.tool.tools.*", "mesh.mod.mesh-catalog.>"} {
+		stop, err := watcher.Raw(subject, func(string, []byte) []byte { asked.Add(1); return nil })
+		if err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(stop)
+	}
 
-	// The controller, answering as its seat verbs do: the command's printed output.
-	controller := connect(t, "mesh-controller", "")
+	// The controller: its records as JSON, as its seat verbs answer them, and its own seat's verbs
+	// announced on the bus like every runtime's.
+	controller := connect(t, "mesh-controller", "bench")
 	out := func(s string) map[string]any { return map[string]any{"output": s, "ok": true} }
 	serve := func(verb string, answer func() any) {
 		stop, err := controller.HandleSubject("mesh.seat.mesh-controller.tool."+verb, func(json.RawMessage) (any, error) {
@@ -74,34 +82,28 @@ func TestTheMeshsToolsAreFoundByAddress(t *testing.T) {
 		}
 		t.Cleanup(stop)
 	}
-	serve("tools", func() any {
-		return map[string]any{"seats": []map[string]any{
-			{"seat": "mesh-controller", "scope": "mesh", "tools": []map[string]any{
-				{"name": "nodes", "description": "Every machine the mesh knows.", "input": map[string]any{}}}},
-			{"seat": "node-shelf", "scope": "node", "tools": []map[string]any{
-				{"name": "list", "description": "what is on the shelf", "input": map[string]any{}},
-				{"name": "clear", "description": "take it all off", "input": map[string]any{}}}},
-		}}
-	})
 	serve("nodes", func() any {
-		return out("bench                3m ago         converged 1f2e\ndesk                 here           converged 9a8b\n")
+		return out("the bus's user list leaves out 2 user(s)\n" +
+			`[{"name":"bench","heard":"3m ago","mode":"converged","id":"1f2e"},{"name":"desk","heard":"here","mode":"converged","id":"9a8b"}]`)
 	})
-	serve("seats", func() any {
-		return out("a warning the command printed first\n" + `{
-  "seats": [
-    {"seat": "mesh-controller", "scope": "mesh", "decision": "x", "holders": [{"module": "mesh-controller", "node": "bench"}]},
-    {"seat": "node-shelf", "scope": "node", "decision": "y", "holders": [{"module": "beta", "node": "desk"}]}
-  ]
-}`)
-	})
-	gammaOn := "nothing"
+	var gammaOn atomic.Value
+	gammaOn.Store("[]")
 	serve("modules", func() any {
-		return out(fmt.Sprintf("alpha              1        built 1a2b3c4d          on desk\n    needs container-runtime\n"+
-			"beta               1        built 1a2b3c4d          on desk\n"+
-			"gamma              1        built 1a2b3c4d          on %s\n", gammaOn))
+		return out(fmt.Sprintf(`[{"module":"alpha","on":["desk"],"tools":true},{"module":"beta","on":["desk"],"tools":true},`+
+			`{"module":"gamma","on":%s,"tools":true},{"module":"delta","on":["desk"],"tools":false},`+
+			`{"module":"epsilon","on":["bench"],"tools":true}]`, gammaOn.Load().(string)))
 	})
-	catalogue.Flush()
+	stopAnn, err := announce.Serve(controller, announce.Service{Name: "mesh-controller", ID: "bench"}, func() []announce.Endpoint {
+		return []announce.Endpoint{{Kind: announce.KindSeat, Module: "mesh-controller", Seat: "mesh-controller", Scope: "mesh",
+			Tool: "nodes", Node: "bench", Description: "Every machine the mesh knows.", Schema: json.RawMessage(`{}`),
+			Subject: "mesh.seat.mesh-controller.tool.nodes"}}
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stopAnn)
 	controller.Flush()
+	watcher.Flush()
 
 	up, err := Serve(NewSurface(nodeTools, "desk.node-tools"), "127.0.0.1:0")
 	if err != nil {
@@ -132,6 +134,11 @@ func TestTheMeshsToolsAreFoundByAddress(t *testing.T) {
 		!strings.Contains(overview, `"bench"`) || !strings.Contains(overview, `"desk"`) {
 		t.Errorf("overview: %s", overview)
 	}
+	// Silence is named only where tools should have answered: epsilon declares tools on bench and
+	// nothing there announced it; delta declares none and is never a name.
+	if !strings.Contains(overview, "epsilon on bench") || strings.Contains(overview, "delta") {
+		t.Errorf("not answering: %s", overview)
+	}
 	machine, isErr := call(t, endpoint, "mesh_machine", map[string]any{"node": "desk"})
 	if isErr || !strings.Contains(machine, "desk/node-shelf.list") || !strings.Contains(machine, "desk/beta.three") ||
 		!strings.Contains(machine, "desk/alpha.one") {
@@ -181,7 +188,7 @@ func TestTheMeshsToolsAreFoundByAddress(t *testing.T) {
 		t.Fatalf("gamma was found before it served: %s", got)
 	}
 	mesh.Issue(t, mt.MembershipOf("gamma", "desk", false, nil))
-	gammaOn = "desk"
+	gammaOn.Store(`["desk"]`)
 	late := connect(t, "node-tools", "desk")
 	stopLate, err := runtime.Run(late, []runtime.Served{{Module: "gamma", Entrypoints: []string{mt.Fixture("env-gamma.serve.mjs")}}},
 		nil, (&mt.Logs{}).Logf)
@@ -201,22 +208,21 @@ func TestTheMeshsToolsAreFoundByAddress(t *testing.T) {
 		t.Errorf("a module that arrived later was not found: %s", found)
 	}
 
+	if n := asked.Load(); n != 0 {
+		t.Errorf("discovery asked a roster or a module's tools %d time(s); it asks the bus", n)
+	}
+
 	// The old names still answer, unannounced.
 	if got, isErr := call(t, endpoint, "alpha.one", nil); isErr || !strings.Contains(got, `"alpha": 1`) {
 		t.Errorf("an old name: %s", got)
 	}
 }
 
-func TestTheControllersPrintedListsAreRead(t *testing.T) {
-	machines := machinesIn("the bus's user list leaves out 2 user(s)\nace                  2m ago         converged 0c1d\n" +
-		"g14                  here           converged 77aa\nnovox                5s ago         adopted   3e4f\n")
-	if got := strings.Join(machines, ","); got != "ace,g14,novox" {
-		t.Errorf("machines: %s", got)
+func TestTheControllersRecordsAreReadAsJSON(t *testing.T) {
+	if got := jsonIn("a warning printed first\n[{\"name\":\"ace\"}]"); got != `[{"name":"ace"}]` {
+		t.Errorf("an array after a warning: %q", got)
 	}
-	on := assignmentsIn("baserow            1        built 7c800705          on ace\n    requires postgres-database\n" +
-		"confluence         1        built 7c800705          on nothing\n" +
-		"mesh-wireguard     1        with the control plane  on ace, g14, novox, shanks\n")
-	if strings.Join(on["baserow"], ",") != "ace" || len(on["confluence"]) != 0 || strings.Join(on["mesh-wireguard"], ",") != "ace,g14,novox,shanks" {
-		t.Errorf("assignments: %v", on)
+	if got := jsonIn(`{"seats":[]}`); got != `{"seats":[]}` {
+		t.Errorf("an object: %q", got)
 	}
 }

node-tools/internal/console/client.go

@@ -5,19 +5,11 @@ import (
 	"errors"
 	"fmt"
 	"regexp"
-	"sort"
 	"strings"
-	"sync"
 
 	"github.com/novox/mesh-tools/node-tools/internal/bus"
 )
 
-const (
-	catalogueModules = "mesh-catalog.catalog_modules"
-	seatTools        = "seat:mesh-controller.tools"
-	toolsVerb        = "tools"
-)
-
 // Tool is a tool as its module — or, for a role's tool, the mesh's records — describes it.
 type Tool struct {
 	Module      string
@@ -67,107 +59,14 @@ func toolKey(name string, seats Seats) string {
 	return name
 }
 
-// toolsOn asks the mesh what tools it has: the catalogue which modules it holds, each module what it
-// serves, the controller's seat every role's tools — at once, so a restarting control plane hides
-// nothing else.
+// toolsOn is the flat catalogue (MESH_CONSOLE_FLAT=1): what announced itself on the bus, every
+// tool and seat verb, and the assignments with tools that did not (novox/hq ADR 0197).
 func toolsOn(conn *bus.Conn) (*Listing, error) {
-	type rolesAnswer struct {
-		Seats []struct {
-			Seat  string `json:"seat"`
-			Scope string `json:"scope"`
-			Tools []struct {
-				Name        string          `json:"name"`
-				Description string          `json:"description"`
-				Input       json.RawMessage `json:"input"`
-			} `json:"tools"`
-		} `json:"seats"`
-	}
-	var wg sync.WaitGroup
-	var roles *rolesAnswer
-	wg.Add(1)
-	go func() {
-		defer wg.Done()
-		if got, err := conn.Ask(seatTools, map[string]any{}, ""); err == nil {
-			var r rolesAnswer
-			if json.Unmarshal(got.Result, &r) == nil {
-				roles = &r
-			}
-		}
-	}()
-	answered, err := conn.Ask(catalogueModules, map[string]any{}, "")
+	x, err := indexOn(conn)
 	if err != nil {
-		wg.Wait()
 		return nil, err
 	}
-	var held struct {
-		Modules []struct {
-			Module string `json:"module"`
-		} `json:"modules"`
-	}
-	_ = json.Unmarshal(answered.Result, &held)
-	names := make([]string, 0, len(held.Modules))
-	for _, m := range held.Modules {
-		if m.Module != "" {
-			names = append(names, m.Module)
-		}
-	}
-	type outcome struct {
-		ok     bool
-		answer struct {
-			Tools *[]struct {
-				Name        string          `json:"name"`
-				Description string          `json:"description"`
-				Input       json.RawMessage `json:"input"`
-				Subjects    []string        `json:"subjects"`
-			} `json:"tools"`
-			Failed *string `json:"failed"`
-		}
-	}
-	outcomes := make([]outcome, len(names))
-	for i, module := range names {
-		wg.Add(1)
-		go func(i int, module string) {
-			defer wg.Done()
-			got, err := conn.Ask(module+"."+toolsVerb, map[string]any{}, "")
-			if err != nil {
-				return
-			}
-			if json.Unmarshal(got.Result, &outcomes[i].answer) == nil {
-				outcomes[i].ok = true
-			}
-		}(i, module)
-	}
-	wg.Wait()
-	l := &Listing{Tools: []Tool{}, NotAnswering: []string{}}
-	if roles != nil {
-		for _, s := range roles.Seats {
-			for _, t := range s.Tools {
-				l.Tools = append(l.Tools, Tool{Module: s.Seat, Name: t.Name, Description: t.Description,
-					Input: t.Input, Seat: true, Scope: s.Scope})
-			}
-		}
-	} else {
-		l.NotAnswering = append(l.NotAnswering, "mesh-controller (seat)")
-	}
-	for i, module := range names {
-		o := outcomes[i]
-		switch {
-		case o.ok && o.answer.Failed != nil:
-			l.NotAnswering = append(l.NotAnswering, fmt.Sprintf("%s (its tools bundle failed to load: %s)", module, *o.answer.Failed))
-		case o.ok && o.answer.Tools != nil:
-			for _, t := range *o.answer.Tools {
-				l.Tools = append(l.Tools, Tool{Module: module, Name: t.Name, Description: t.Description,
-					Input: t.Input, Subjects: t.Subjects})
-			}
-		default:
-			l.NotAnswering = append(l.NotAnswering, module)
-		}
-	}
-	sort.SliceStable(l.Tools, func(i, j int) bool {
-		return l.Tools[i].Module+"."+l.Tools[i].Name < l.Tools[j].Module+"."+l.Tools[j].Name
-	})
-	sort.Strings(l.NotAnswering)
-	return l, nil
+	return x.Listing, nil
 }
 
 // callTool calls `<module>.<tool>[@<node>]`, on the subject the listing names for it when it names one.

node-tools/internal/console/console_test.go

@@ -55,20 +55,13 @@ func TestTheConsoleListsAndCallsOverHTTP(t *testing.T) {
 	}
 	defer stop()
 
-	catalogue := connect(t, "mesh-catalog", "")
-	stopCat, _ := catalogue.Handle("catalog_modules", func(json.RawMessage) (any, error) {
-		return map[string]any{"modules": []map[string]string{{"module": "alpha"}, {"module": "beta"}, {"module": "ghost"}}}, nil
-	})
-	defer stopCat()
+	// The controller's records (ADR 0197): ghost declares tools on desk and nothing announces it.
 	controller := connect(t, "mesh-controller", "")
-	stopSeat, _ := controller.HandleSubject("mesh.seat.mesh-controller.tool.tools", func(json.RawMessage) (any, error) {
-		return map[string]any{"seats": []map[string]any{{"seat": "node-shelf", "scope": "node", "tools": []map[string]any{
-			{"name": "list", "description": "what is on the shelf", "input": map[string]any{}},
-			{"name": "clear", "description": "take it all off", "input": map[string]any{}},
-		}}}}, nil
+	stopSeat, _ := controller.HandleSubject("mesh.seat.mesh-controller.tool.modules", func(json.RawMessage) (any, error) {
+		return map[string]any{"ok": true, "output": `[{"module":"alpha","on":["desk"],"tools":true},` +
+			`{"module":"beta","on":["desk"],"tools":true},{"module":"ghost","on":["desk"],"tools":true}]`}, nil
 	})
 	defer stopSeat()
-	catalogue.Flush()
 	controller.Flush()
 
 	flat := NewSurface(nodeTools, "desk.node-tools")
@@ -92,7 +85,7 @@ func TestTheConsoleListsAndCallsOverHTTP(t *testing.T) {
 	if got := strings.Join(names, ","); got != "alpha.one,alpha.two,beta.five,beta.four,beta.three,node-shelf.clear,node-shelf.list" {
 		t.Errorf("listed %s", got)
 	}
-	if got := listed["_meta"].(map[string]any)["notAnswering"]; len(got.([]any)) != 1 || got.([]any)[0] != "ghost" {
+	if got := listed["_meta"].(map[string]any)["notAnswering"]; len(got.([]any)) != 1 || got.([]any)[0] != "ghost on desk" {
 		t.Errorf("not answering: %v", got)
 	}
 	for _, x := range listed["tools"].([]any) {

node-tools/internal/console/mcp.go

@@ -122,7 +122,7 @@ func (s *Surface) Handle(r Request) *Reply {
 		}
 		l, err := s.listing()
 		if err != nil {
-			return refuse(r.ID, -32603, whyItFailed(catalogueModules, err))
+			return refuse(r.ID, -32603, "the mesh's discovery failed: "+err.Error())
 		}
 		tools := make([]map[string]any, 0, len(l.Tools))
 		for _, t := range l.Tools {

node-tools/internal/meshtest/meshtest.go

@@ -1,5 +1,9 @@
 // Package meshtest raises what the controller would, for tests against a real bus: the ASSIGNMENTS
 // and EVENTS streams, memberships issued by hand, and a fixture's path.
+//
+// **The packages share one bus, so run them one at a time: `go test -p 1 ./...`.** Each test raises
+// the streams afresh, and the console discovers every runtime that announces itself on the bus
+// (novox/hq ADR 0197) — a runtime from another package's test is, correctly, found.
 package meshtest
 
 import (

node-tools/internal/runtime/announce_test.go

@@ -0,0 +1,113 @@
+package runtime
+
+import (
+	"encoding/json"
+	"sort"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go"
+	"github.com/nats-io/nats.go/micro"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
+)
+
+// novox/hq ADR 0197: what a runtime serves, it announces — the NATS services protocol's discovery,
+// read here with NATS's own types, each endpoint a subject actually served — and the announcement
+// follows a re-issued membership.
+func TestTheRuntimeAnnouncesWhatItServesInTheServicesProtocol(t *testing.T) {
+	mesh := mt.New(t)
+	mesh.Issue(t, mt.MembershipOf("alpha", "anchor", false, nil))
+	mesh.Issue(t, mt.MembershipOf("beta", "anchor", false, map[string][]string{"node-shelf": {"list", "clear"}}))
+	nodeTools := connect(t, "node-tools", "anchor")
+	stop, err := Run(nodeTools, []Served{
+		{"alpha", []string{mt.Fixture("many-alpha.serve.mjs")}},
+		{"beta", []string{mt.Fixture("many-beta.serve.mjs")}},
+	}, nil, (&mt.Logs{}).Logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stop()
+
+	nc, err := nats.Connect(mt.URL(t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer nc.Close()
+	info := func() micro.Info {
+		t.Helper()
+		msg, err := nc.Request("$SRV.INFO.node-tools.anchor", nil, 2*time.Second)
+		if err != nil {
+			t.Fatal(err)
+		}
+		var i micro.Info
+		if err := json.Unmarshal(msg.Data, &i); err != nil {
+			t.Fatal(err)
+		}
+		return i
+	}
+	subjects := func(i micro.Info) string {
+		var out []string
+		for _, e := range i.Endpoints {
+			out = append(out, e.Subject+"|"+e.QueueGroup+"|"+e.Metadata["kind"]+"|"+e.Metadata["module"]+"|"+e.Metadata["seat"]+"|"+e.Metadata["scope"]+"|"+e.Metadata["interchangeable"])
+		}
+		sort.Strings(out)
+		return strings.Join(out, "\n")
+	}
+
+	got := info()
+	if got.Type != micro.InfoResponseType || got.Name != "node-tools" || got.ID != "anchor" || got.Version == "" {
+		t.Errorf("identity: %+v", got.ServiceIdentity)
+	}
+	want := strings.Join([]string{
+		"mesh.mod.alpha.tool.one.anchor||tool|alpha|||false",
+		"mesh.mod.alpha.tool.two.anchor||tool|alpha|||false",
+		"mesh.mod.beta.tool.five.anchor||tool|beta|||false",
+		"mesh.mod.beta.tool.four.anchor||tool|beta|||false",
+		"mesh.mod.beta.tool.three.anchor||tool|beta|||false",
+		"mesh.seat.node-shelf.tool.clear.anchor||seat|beta|node-shelf|node|false",
+		"mesh.seat.node-shelf.tool.list.anchor||seat|beta|node-shelf|node|false",
+	}, "\n")
+	if s := subjects(got); s != want {
+		t.Errorf("announced:\n%s\nwant:\n%s", s, want)
+	}
+	for _, e := range got.Endpoints {
+		if e.Metadata["node"] != "anchor" || e.Metadata["description"] == "" || !json.Valid([]byte(e.Metadata["schema"])) {
+			t.Errorf("endpoint metadata: %+v", e)
+		}
+	}
+
+	// Every subject announced is answered.
+	asker := connect(t, "console", "workstation")
+	for _, e := range got.Endpoints {
+		if _, err := asker.Ask("", map[string]any{}, e.Subject); err != nil {
+			t.Errorf("announced %s and does not answer it: %v", e.Subject, err)
+		}
+	}
+
+	// PING answers with the same identity, and a request for another service is not answered.
+	if msg, err := nc.Request("$SRV.PING", nil, 2*time.Second); err != nil || !strings.Contains(string(msg.Data), micro.PingResponseType) {
+		t.Errorf("ping: %v %v", msg, err)
+	}
+	if _, err := nc.Request("$SRV.INFO.somebody-else", nil, 300*time.Millisecond); err == nil {
+		t.Error("answered a request for another service")
+	}
+
+	// alpha is re-issued a plain subject: the announcement says so, and says it is interchangeable.
+	mesh.Issue(t, mt.MembershipOf("alpha", "anchor", true, nil))
+	var after string
+	for i := 0; i < 40; i++ {
+		after = subjects(info())
+		if strings.Contains(after, "mesh.mod.alpha.tool.one|serve.alpha|tool|alpha|||true") {
+			break
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+	if !strings.Contains(after, "mesh.mod.alpha.tool.one|serve.alpha|tool|alpha|||true") ||
+		!strings.Contains(after, "mesh.mod.alpha.tool.one.anchor||tool|alpha|||true") {
+		t.Errorf("after a re-issued membership:\n%s", after)
+	}
+	_ = bus.Served{}
+}

node-tools/internal/runtime/runtime.go

@@ -14,6 +14,7 @@ import (
 	"strings"
 	"sync"
 
+	"github.com/novox/mesh-tools/node-tools/internal/announce"
 	"github.com/novox/mesh-tools/node-tools/internal/bus"
 	"github.com/novox/mesh-tools/node-tools/internal/launch"
 )
@@ -276,10 +277,83 @@ func Run(conn *bus.Conn, served []Served, envs map[string]map[string]string, log
 	}
 	logf("%s", line)
 	stops = append(stops, serveSeats(conn, modules, registrations, logf))
+
+	// **What it serves, it announces** (novox/hq ADR 0197): the NATS services protocol's discovery,
+	// answered with what is served at the moment it is asked — re-served memberships included.
+	announced, err := announce.Serve(conn, announce.Service{
+		Name: conn.Module(), ID: instanceOf(conn),
+		Description: "the mesh's tool runtime on " + node + ": every assigned module's tools and the seats they hold",
+		Metadata:    map[string]string{"node": node},
+	}, func() []announce.Endpoint { return endpointsOf(conn, own, registrations, modules) })
+	if err != nil {
+		logf("[mesh-tools] cannot announce what it serves: %v", err)
+	} else {
+		stops = append(stops, announced)
+	}
 	conn.Flush()
 	return stopAll, nil
 }
 
+// instanceOf is this runtime's instance on the bus: its machine, which is what tells two instances of
+// one service apart; the connection's module where it has no machine.
+func instanceOf(conn *bus.Conn) string {
+	if n := conn.Node(); n != "" {
+		return n
+	}
+	return conn.Module()
+}
+
+// endpointsOf is everything this runtime serves now: each served module's tools on every subject the
+// mesh issued for them, and each held seat's verbs on the seat's subject (ADR 0197).
+func endpointsOf(conn *bus.Conn, own []registration, registrations []registration, modules []string) []announce.Endpoint {
+	node := conn.Node()
+	var out []announce.Endpoint
+	for _, r := range own {
+		for _, t := range r.tools {
+			served := conn.ServedOn(r.module, t.Name)
+			interchangeable := false
+			for _, s := range served {
+				interchangeable = interchangeable || s.Subject == "mesh.mod."+r.module+".tool."+t.Name
+			}
+			for _, s := range served {
+				out = append(out, announce.Endpoint{Kind: announce.KindTool, Module: r.module, Tool: t.Name,
+					Node: node, Description: t.Description, Schema: t.Input, Interchangeable: interchangeable,
+					Subject: s.Subject, Queue: s.Queue})
+			}
+		}
+	}
+	impl := map[string]map[string]launch.Tool{}
+	for _, r := range registrations {
+		if impl[r.module] == nil {
+			impl[r.module] = map[string]launch.Tool{}
+		}
+		for _, t := range r.tools {
+			impl[r.module][t.Name] = t
+		}
+	}
+	have := map[string]bool{}
+	for _, module := range modules {
+		m := conn.Membership(module)
+		if m == nil {
+			continue
+		}
+		for _, v := range m.Seats {
+			t, ok := impl[v.Seat][v.Verb]
+			if !ok || have[v.Subject] {
+				continue
+			}
+			have[v.Subject] = true
+			scope := "mesh"
+			if node != "" && strings.HasSuffix(v.Subject, "."+node) {
+				scope = "node"
+			}
+			out = append(out, announce.Endpoint{Kind: announce.KindSeat, Module: module, Tool: v.Verb, Seat: v.Seat,
+				Scope: scope, Node: node, Description: t.Description, Schema: t.Input, Subject: v.Subject})
+		}
+	}
+	return out
+}
+
 func orNone(names []string) string {
 	if len(names) == 0 {
 		return "(none)"