Ask at most three at a time, wait out a refusal, need a router, and act only on a claimed open ask, as the review asked (hq ADR 0259)

cmd/mesh-controller/asker_wire.go

@@ -9,6 +9,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"sort"
 	"strings"
 	"time"
 
@@ -93,6 +94,41 @@ func (b busAsked) All(ctx context.Context) ([]asked, error) {
 	return out, nil
 }
 
+// Claim marks an open ask acting, by compare-and-set on its key's revision: only the write that stands acts.
+func (b busAsked) Claim(ctx context.Context, id string, w asks.Warrant) (bool, error) {
+	kv, err := b.kv(ctx)
+	if err != nil {
+		return false, err
+	}
+	e, err := kv.Get(ctx, id)
+	if errors.Is(err, jetstream.ErrKeyNotFound) {
+		return false, nil
+	}
+	if err != nil {
+		return false, err
+	}
+	var r asked
+	if err := json.Unmarshal(e.Value(), &r); err != nil {
+		return false, err
+	}
+	if r.State != askOpen || r.Acted != "" {
+		return false, nil
+	}
+	r.State, r.Warrant, r.Acted = string(asks.OutcomeChosen), &w, "acting"
+	body, err := json.Marshal(r)
+	if err != nil {
+		return false, err
+	}
+	if _, err := kv.Update(ctx, id, body, e.Revision()); err != nil {
+		var api *jetstream.APIError
+		if errors.Is(err, jetstream.ErrKeyExists) || (errors.As(err, &api) && api.ErrorCode == jetstream.JSErrCodeStreamWrongLastSequence) {
+			return false, nil
+		}
+		return false, err
+	}
+	return true, nil
+}
+
 // callAction performs an action's verb as the controller, through the grant that names it.
 func callAction(conn *nats.Conn) func(ctx context.Context, a conditions.Action, args map[string]string) error {
 	return func(ctx context.Context, a conditions.Action, args map[string]string) error {
@@ -174,6 +210,53 @@ func asksRecords(ctx context.Context, inv *inventory.Inventory) (string, error)
 	return "", nil
 }
 
+// routerHereIn says whether a module declaring the asks seat, with its ask named by its caller, is assigned:
+// without it nothing takes an ask, and asking would only fill a queue nobody reads.
+func routerHereIn(inv *inventory.Inventory) func(ctx context.Context) (bool, error) {
+	return func(ctx context.Context) (bool, error) {
+		entries, err := inv.Catalogued(ctx)
+		if err != nil {
+			return false, err
+		}
+		for _, e := range entries {
+			for _, s := range e.Manifest.DefinesSeats {
+				if s.Name == broker.AsksSeat && s.NamedByCaller("ask") && len(e.On) > 0 {
+					return true, nil
+				}
+			}
+		}
+		return false, nil
+	}
+}
+
+// channelsIn is what the channels are now, as a fingerprint: each module claiming a kind of the channel
+// bench, where, promising what, and whether of its own account. An ask the router refused is asked again
+// once this changes.
+func channelsIn(inv *inventory.Inventory) func(ctx context.Context) string {
+	return func(ctx context.Context) string {
+		entries, err := inv.Catalogued(ctx)
+		if err != nil {
+			return ""
+		}
+		var parts []string
+		for _, e := range entries {
+			for _, c := range e.Manifest.Claims {
+				if c.Kind == "" || !catalogue.KindedBenches[c.Name] {
+					continue
+				}
+				on := append([]string(nil), e.On...)
+				sort.Strings(on)
+				caps := append([]string(nil), c.Capabilities...)
+				sort.Strings(caps)
+				parts = append(parts, fmt.Sprintf("%s/%s=%s@%s[%s]own:%t", c.Name, c.Kind, e.Manifest.Module,
+					strings.Join(on, ","), strings.Join(caps, ","), e.Manifest.RunsAs != ""))
+			}
+		}
+		sort.Strings(parts)
+		return strings.Join(parts, ";")
+	}
+}
+
 // startAsking makes the serving controller's asker and hands it the router's words.
 func startAsking(ctx context.Context, open *stores, server *link.Server, conn *nats.Conn, keeper *conditions.Keeper) {
 	js, err := jetstream.New(conn)
@@ -198,6 +281,8 @@ func startAsking(ctx context.Context, open *stores, server *link.Server, conn *n
 			return err
 		},
 		routerRecord: routerRecordOf(conn, open.inventory),
+		routerHere:   routerHereIn(open.inventory),
+		channels:     channelsIn(open.inventory),
 		now:          time.Now,
 		logf:         func(format string, args ...any) { fmt.Printf(format+"\n", args...) },
 	}