mesh-watcher: read who holds the controller and the bus from the placement seat's state, not the controller's seats (issue 1955, ADR 0571 clause 4)

modules/mesh-watcher/cmd/mesh-watcher/main.go

@@ -15,6 +15,7 @@ import (
 	"time"
 
 	stdio "git.novox.be/novox/mesh-sdk/go"
+	"git.novox.be/novox/mesh-sdk/go/delivery"
 	"git.novox.be/novox/mesh-sdk/go/health"
 )
 
@@ -150,60 +151,46 @@ func roundTrip(node string) error {
 	}
 }
 
-// controlNodes reads which machines hold the controller and the bus.
+// controlNodes reads which machines hold the controller and the bus, from the placement seat's state of who holds
+// which seat (novox/hq ADR 0571 clause 4).
 func controlNodes() ([]string, error) {
-	raw, err := stdio.Ask("seat:mesh-controller.seats", map[string]any{})
+	st := stdio.State(delivery.SeatHoldersRead)
+	names, err := st.Keys()
 	if err != nil {
 		return nil, err
 	}
-	return holdersOf(raw, "mesh-controller", "mesh-broker")
+	keys := map[string][]byte{}
+	for _, k := range names {
+		e, err := st.Get(k)
+		if err != nil {
+			return nil, err
+		}
+		if e != nil {
+			keys[k] = e.Value
+		}
+	}
+	return holderNodes(keys, "mesh-controller", "mesh-broker")
 }
 
-// holdersOf reads the seats verb's answer, bare or inside a tool reply, for the named seats' machines.
-func holdersOf(raw json.RawMessage, seats ...string) ([]string, error) {
-	var answer struct {
-		Seats []struct {
-			Seat    string `json:"seat"`
-			Holders []struct {
-				Node string `json:"node"`
-			} `json:"holders"`
-		} `json:"seats"`
-		Output  string `json:"output"`
-		Content []struct {
-			Text string `json:"text"`
-		} `json:"content"`
-	}
-	if err := json.Unmarshal(raw, &answer); err != nil {
-		var s string
-		if json.Unmarshal(raw, &s) == nil {
-			return holdersOf(json.RawMessage(s), seats...)
-		}
-		return nil, fmt.Errorf("the seats answer is not JSON")
-	}
-	if len(answer.Seats) == 0 {
-		switch {
-		case answer.Output != "":
-			return holdersOf(json.RawMessage(answer.Output), seats...)
-		case len(answer.Content) > 0:
-			return holdersOf(json.RawMessage(answer.Content[0].Text), seats...)
-		}
-		return nil, fmt.Errorf("the seats answer lists no seat")
-	}
+// holderNodes is the machines holding any of the seats, in the order the seats are named, each once.
+func holderNodes(keys map[string][]byte, seats ...string) ([]string, error) {
 	var out []string
 	seen := map[string]bool{}
-	for _, s := range answer.Seats {
-		for _, want := range seats {
-			if s.Seat != want {
-				continue
-			}
-			for _, h := range s.Holders {
-				if !seen[h.Node] {
-					seen[h.Node] = true
-					out = append(out, h.Node)
-				}
+	for _, seat := range seats {
+		holders, err := delivery.HoldersOf(keys, seat, "")
+		if err != nil {
+			return nil, err
+		}
+		for _, h := range holders {
+			if !seen[h.Node] {
+				seen[h.Node] = true
+				out = append(out, h.Node)
 			}
 		}
 	}
+	if len(out) == 0 {
+		return nil, fmt.Errorf("the placement seat's state names no holder of %s", strings.Join(seats, " or "))
+	}
 	return out, nil
 }
 

modules/mesh-watcher/cmd/mesh-watcher/manifest_test.go

@@ -37,7 +37,7 @@ func TestTheManifestSaysWhatTheCodeDoes(t *testing.T) {
 	if !reflect.DeepEqual(m.Consumes, []string{ControllerSeat + "." + HeartbeatEvent, "mesh-self-check.checked"}) {
 		t.Fatalf("consumes %v", m.Consumes)
 	}
-	if !reflect.DeepEqual(m.Invokes, []string{m.Module + ".watcher_ping", "seat:mesh-controller.seats"}) {
+	if !reflect.DeepEqual(m.Invokes, []string{m.Module + ".watcher_ping"}) {
 		t.Fatalf("invokes %v", m.Invokes)
 	}
 	if len(m.Claims) != 0 {

modules/mesh-watcher/cmd/mesh-watcher/watcher_test.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"encoding/json"
 	"errors"
 	"strings"
 	"testing"
@@ -214,16 +213,18 @@ func TestOnTheControlNodeItSaysItIsMisplaced(t *testing.T) {
 	}
 }
 
-func TestTheSeatsAnswerIsReadInEitherShape(t *testing.T) {
-	bare := `{"seats":[{"seat":"mesh-controller","holders":[{"node":"n1","module":"mesh-controller"}]},
-		{"seat":"mesh-broker","holders":[{"node":"n1"},{"node":"n2"}]},{"seat":"git","holders":[{"node":"n3"}]}]}`
-	wrapped, _ := json.Marshal(map[string]any{"content": []map[string]string{{"type": "text", "text": bare}}})
-	output, _ := json.Marshal(map[string]any{"ok": true, "output": bare})
-	for _, raw := range []string{bare, string(wrapped), string(output)} {
-		got, err := holdersOf(json.RawMessage(raw), "mesh-controller", "mesh-broker")
-		if err != nil || strings.Join(got, ",") != "n1,n2" {
-			t.Errorf("%s: %v %v", raw, got, err)
-		}
+func TestTheHoldersAreReadFromThePlacementSeatsState(t *testing.T) {
+	keys := map[string][]byte{
+		"mesh-controller": []byte(`{"v":1,"seat":"mesh-controller","scope":"mesh","holders":[{"module":"mesh-controller","node":"n1"}]}`),
+		"mesh-broker":     []byte(`{"v":1,"seat":"mesh-broker","scope":"mesh","holders":[{"module":"nats","node":"n1"},{"module":"nats","node":"n2"}]}`),
+		"git":             []byte(`{"v":1,"seat":"git","scope":"mesh","holders":[{"module":"gitea","node":"n3"}]}`),
+	}
+	got, err := holderNodes(keys, "mesh-controller", "mesh-broker")
+	if err != nil || strings.Join(got, ",") != "n1,n2" {
+		t.Errorf("%v %v", got, err)
+	}
+	if _, err := holderNodes(map[string][]byte{}, "mesh-controller", "mesh-broker"); err == nil {
+		t.Error("no holder named, and no error")
 	}
 }
 

modules/mesh-watcher/go.mod

@@ -2,4 +2,4 @@ module mesh-watcher
 
 go 1.26.0
 
-require git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261029214732-6b8c6943811a
+require git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261029220947-f9a496d3e121

modules/mesh-watcher/go.sum

@@ -1,2 +1,2 @@
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261029214732-6b8c6943811a h1:elC2IjB+qbeXG+pWItLz71DenegbrdsqbcH5kyGo56Q=
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261029214732-6b8c6943811a/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261029220947-f9a496d3e121 h1:OsA1v6n736a7RqEV8Nkip8pf5ILMbzj0PWuKqcBOhK0=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261029220947-f9a496d3e121/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=

modules/mesh-watcher/module.json

@@ -7,11 +7,11 @@
     "mesh-self-check.checked"
   ],
   "reads": [
-    "mesh-conditions.takeover"
+    "mesh-conditions.takeover",
+    "mesh-delivery-assigner.seat-holders"
   ],
   "invokes": [
-    "mesh-watcher.watcher_ping",
-    "seat:mesh-controller.seats"
+    "mesh-watcher.watcher_ping"
   ],
   "own-secrets": {
     "telegram-token": "${dir:state}/telegram-token"
@@ -43,7 +43,9 @@
       "type": "file",
       "path": "${dir:state}/settings.json",
       "mode": "0600",
-      "takes-config": ["telegram-chat-id"],
+      "takes-config": [
+        "telegram-chat-id"
+      ],
       "merge": "json",
       "template": "files/settings.json"
     }