Merge pull request 'catalogue-mqtt: mosquitto seeded by a run-once step (ADR 0052 proof, green)' (#7) from feat/catalogue-mqtt into main

2026-09-06 01:06:10 +02:00
parent 8558ffdc8e 62e479b9fe
commit 132b9e3a7b
3 changed files with 420 additions and 1 deletions
@@ -0,0 +1,46 @@
+# One machine that becomes a mesh and then assigns itself mosquitto — the bed that proves the
+# run-once primitive (novox/hq ADR 0052) end to end.
+#
+# mosquitto is the sharp case ADR 0052 was written for: its Dynamic Security plugin loads at broker
+# start and refuses to come up unless `dynamic-security.json` already holds an admin client. That
+# file is not state a reconcile loop can carry — it is a step that must run once, after the data
+# directory exists and BEFORE the broker container starts. mosquitto's manifest declares that step
+# as a `run-once: true` init container, placed before the `server` (broker) container: the same
+# runtime image, carrying mosquitto's own `bootstrap/` entrypoint and `mosquitto_ctrl`, run to
+# completion under the module's own account. The host runs it, requires exit 0, and only then reaches
+# the broker — so "the broker came up" is itself the proof the seed ran, because an unseeded store
+# crash-loops the broker.
+#
+#   MESH_LAB_HOST_BINARY=.../mesh-host   MESH_LAB_BUNDLE=.../examples/substrate-first-node.lock
+#   scripts/build-module-runtime.sh mosquitto builds mesh-runtime-mosquitto:development (carrying
+#   mosquitto_ctrl and the compiled bootstrap entrypoint) into the local daemon, which this scenario
+#   stocks and serves by digest from its own registry. eclipse-mosquitto:2 must be in the local
+#   daemon to be stocked.
+scenario: catalogue-mqtt
+
+segments:
+  hosting:
+    kind: public
+    cidr: [192.0.2.0/24]
+
+machines:
+  anchor:
+    at: { segment: hosting, address: [192.0.2.10] }
+    inbound: allow
+    memory: 3GiB
+    cpus: 2
+
+images:
+  # The first-node substrate: store, broker, control.
+  - postgres:17-alpine
+  - cloudamqp/lavinmq:latest
+  - mesh-control:development
+  # mosquitto's broker (the service image) and its runtime, the latter built by
+  # scripts/build-module-runtime.sh mosquitto into the local daemon and stocked into the scenario's
+  # own registry, which is where the host pulls it from. The runtime image is reused for the
+  # run-once bootstrap step and for the serve container.
+  - eclipse-mosquitto:2
+  - mesh-runtime-mosquitto:development
+
+place:
+  all: [host, runtime]
@@ -21,7 +21,7 @@ BASE="${RUNTIME_BASE:-node:22-bookworm-slim}"
 ( cd "$MESH_SDK" && npm run build >/dev/null )
 ( cd "$MESH_TOOLS" && npm run build >/dev/null )
 # Compile whichever of the module's entrypoints exist.
-SRCS=(); for f in client.ts index.ts tools/index.ts provisioner/index.ts; do [ -f "$MOD/$f" ] && SRCS+=("$f"); done
+SRCS=(); for f in client.ts index.ts tools/index.ts provisioner/index.ts bootstrap/index.ts; do [ -f "$MOD/$f" ] && SRCS+=("$f"); done
 TSC="$MESH_SDK/node_modules/.bin/tsc"; ( cd "$MOD" && "$TSC" "${SRCS[@]}" --module NodeNext --moduleResolution NodeNext --target ES2022 --outDir dist >/dev/null )

 STAGE="$(mktemp -d)"; trap 'rm -rf "$STAGE"' EXIT
@@ -41,6 +41,11 @@ EXTRA=""
 case "$MODULE" in
  postgres) EXTRA='RUN apt-get update && apt-get install -y --no-install-recommends postgresql-client && rm -rf /var/lib/apt/lists/*' ;;
  minio)    EXTRA='COPY --from=minio/mc:latest /usr/bin/mc /usr/bin/mc' ;;
+  # mosquitto drives its dynsec admin — and its run-once bootstrap seeds the store — through
+  # `mosquitto_ctrl`. It is not in `mosquitto-clients` on bookworm; the `mosquitto` package carries
+  # it (with its shared libraries), and installing from apt keeps them together — copying the binary
+  # out of the (musl) eclipse-mosquitto image into this (glibc) base would not load.
+  mosquitto) EXTRA='RUN apt-get update && apt-get install -y --no-install-recommends mosquitto && rm -rf /var/lib/apt/lists/*' ;;
  # mongodb's client shells out to `mongosh`. Install it from MongoDB's own apt repo so its shared
  # libraries come with it — copying just the binary out of the mongo image leaves it unable to load.
  mongodb)  EXTRA='RUN apt-get update && apt-get install -y --no-install-recommends gnupg curl ca-certificates && curl -fsSL https://pgp.mongodb.com/server-7.0.asc | gpg --dearmor -o /usr/share/keyrings/mongodb.gpg && echo "deb [signed-by=/usr/share/keyrings/mongodb.gpg] https://repo.mongodb.org/apt/debian bookworm/mongodb-org/7.0 main" > /etc/apt/sources.list.d/mongodb.list && apt-get update && apt-get install -y --no-install-recommends mongodb-mongosh && rm -rf /var/lib/apt/lists/*' ;;
@@ -0,0 +1,368 @@
+/**
+ * The mesh assigns mosquitto, and a run-once step seeds the Dynamic Security store BEFORE the broker
+ * starts — the end-to-end proof of the run-once primitive (novox/hq ADR 0052).
+ *
+ * mosquitto is the case ADR 0052 was written for. Its dynsec plugin loads at broker start and refuses
+ * to bring the broker up unless `dynamic-security.json` already holds an admin client — a file that is
+ * not state a reconcile loop can carry, but a step that must run once, after the data directory
+ * exists and before the broker container starts. The manifest declares that step as a `run-once: true`
+ * init container placed before the `server` (broker) container: the module's own runtime image,
+ * carrying mosquitto's `bootstrap/` entrypoint and `mosquitto_ctrl`, run to completion under the
+ * module's own account (ADR 0047). The host runs it, requires exit 0, and — because a failed step
+ * gates the apply — only then reaches the broker.
+ *
+ * So the proof is layered, and the centre of it is that the broker came up at all:
+ *   - the run-once step ran to completion and was not left running (a step, not a service);
+ *   - the seed file is on disk, owned by the broker's uid so the broker can read it AND persist to it
+ *     (the ownership question ADR 0052 left for the lab to settle — fixed in mosquitto's bootstrap);
+ *   - the broker is up and STABLE — which it cannot be against an unseeded store, so a broker that
+ *     stays up is itself the proof the seed ran at the right phase;
+ *   - the node reached `current`, which the apply reaches only past a completed run-once step.
+ * And, as a consumer-facing proof on top: the seeded admin authenticates over MQTT (the plugin loaded
+ * the seed), and mosquitto's provisioner — running in the assigned runtime — creates a scoped client
+ * for a contribution the mesh delivered, which then authenticates with the password the mesh minted.
+ *
+ *   MESH_LAB_HOST_BINARY=.../mesh-host   MESH_LAB_BUNDLE=.../examples/substrate-first-node.lock
+ *   scripts/build-module-runtime.sh mosquitto builds mesh-runtime-mosquitto:development (carrying
+ *   mosquitto_ctrl and the compiled bootstrap entrypoint) into the local daemon, which
+ *   scenarios/catalogue-mqtt.yml stocks. eclipse-mosquitto:2 must be in the local daemon to be
+ *   stocked; the host pulls both from the scenario's own registry by digest.
+ */
+
+import { test, before, after } from "node:test";
+import assert from "node:assert/strict";
+import { existsSync, readFileSync } from "node:fs";
+import { loadScenario } from "../../src/declaration/parse.ts";
+import { raise } from "../../src/lifecycle/raise.ts";
+import { destroy, exec } from "../../src/lifecycle/operate.ts";
+import { hostBinaryPath, HOST_PATH } from "../../src/lifecycle/place.ts";
+import { labIsUsable, destroyAll } from "./harness.ts";
+
+const capability = await labIsUsable();
+const binary = hostBinaryPath();
+const bundle = process.env["MESH_LAB_BUNDLE"] ?? "";
+
+const skip = !capability.usable
+  ? `lab not usable: ${capability.why}`
+  : !binary || !existsSync(binary)
+    ? "MESH_LAB_HOST_BINARY is not set to a built mesh-host"
+    : !bundle || !existsSync(bundle)
+      ? "MESH_LAB_BUNDLE is not set to a substrate bundle (mesh-host examples/)"
+      : false;
+
+const SCENARIO = "catalogue-mqtt";
+const MACHINE = "anchor";
+
+let instanceId = "";
+let stocked: string[] = [];
+
+function quote(s: string): string {
+  return `'${s.replaceAll("'", `'\\''`)}'`;
+}
+
+async function on(command: string, timeoutMs?: number): Promise<{ out: string; ok: boolean }> {
+  const { stdout } = await exec(instanceId, MACHINE, [
+    "sh", "-c", `exec 2>&1\n${command}\necho "__exit=$?"`,
+  ], timeoutMs);
+  const marker = stdout.lastIndexOf("__exit=");
+  if (marker < 0) return { out: stdout, ok: false };
+  return { out: stdout.slice(0, marker), ok: stdout.slice(marker + 7).trim() === "0" };
+}
+
+async function must(command: string, timeoutMs?: number): Promise<string> {
+  const { out, ok } = await on(command, timeoutMs);
+  if (!ok) throw new Error(`${MACHINE}: ${command}\n${out}`);
+  return out;
+}
+
+/** The control plane, a container on the node. */
+async function mesh(command: string, timeoutMs?: number): Promise<string> {
+  return must(`docker exec mesh-control /mesh-control ${command}`, timeoutMs);
+}
+
+/** The pinned reference for one of the scenario's images, by repository. */
+function pinned(repository: string): string {
+  const found = stocked.find((r) => r.slice(r.indexOf("/") + 1, r.indexOf("@")) === repository);
+  assert.ok(found, `the scenario stocks no ${repository}; it serves ${stocked.join(", ")}`);
+  return found;
+}
+
+/** The substrate bundle, its image references pointed at this scenario's own registry. */
+function bundleFor(images: string[]): string {
+  let text = readFileSync(bundle, "utf8");
+  for (const ref of images) {
+    const repository = ref.slice(ref.indexOf("/") + 1, ref.indexOf("@"));
+    const escaped = repository.replaceAll("/", "\\/").replaceAll(".", "\\.");
+    text = text.replaceAll(new RegExp(`[A-Za-z0-9_.:-]+\\/${escaped}@sha256:[0-9a-f]+`, "g"), ref);
+  }
+  return text;
+}
+
+function tokenFrom(said: string): string {
+  const found = said.split("\n").map((l) => l.trim()).find((l) => l.length > 100 && !l.includes(" "));
+  assert.ok(found, `no token in:\n${said}`);
+  return found;
+}
+
+async function settled(withinMs = 600_000): Promise<void> {
+  const until = Date.now() + withinMs;
+  let last = "";
+  while (Date.now() < until) {
+    const asked = await on(`docker exec mesh-control /mesh-control status --json`);
+    if (asked.ok) {
+      try {
+        const state = JSON.parse(asked.out) as {
+          wrong: { node: string; outcome: string }[];
+          waiting: { node: string }[];
+          reported: { node: string; outcome: string; current: boolean }[];
+        };
+        const bad = state.wrong.find((w) => w.node === MACHINE);
+        if (bad) throw new Error(`${MACHINE} did not apply what it was sent: ${bad.outcome}\n${asked.out}`);
+        const word = state.reported.find((r) => r.node === MACHINE);
+        if (!state.waiting.some((w) => w.node === MACHINE) && word?.outcome === "applied" && word.current) return;
+        last = asked.out;
+      } catch (err) {
+        if (err instanceof Error && err.message.includes("did not apply")) throw err;
+        last = asked.out;
+      }
+    }
+    await new Promise((r) => setTimeout(r, 5000));
+  }
+  throw new Error(`${MACHINE} never caught up within ${Math.round(withinMs / 1000)}s. Last:\n${last}`);
+}
+
+before(async () => {
+  if (skip) return;
+
+  const raised = await raise(loadScenario(`scenarios/${SCENARIO}.yml`), {
+    onProgress: (m) => console.log(`raise: ${m}`),
+  });
+  instanceId = raised.instanceId;
+  stocked = raised.images;
+
+  // Raise the substrate — store, broker, control — from the bundle.
+  await must(`cat > /tmp/substrate.lock <<'MESHBUNDLE'\n${bundleFor(raised.images)}\nMESHBUNDLE`);
+  await must(`${HOST_PATH} apply /tmp/substrate.lock`, 600_000);
+  const up = await must(`docker ps --format '{{.Names}}'`);
+  for (const c of ["mesh-store", "mesh-broker", "mesh-control"]) {
+    assert.match(up, new RegExp(c), `the substrate did not raise ${c}:\n${up}`);
+  }
+
+  // The node joins its own mesh and starts the host so it applies what it is pushed.
+  await mesh(`node add ${MACHINE}`);
+  const token = tokenFrom(await mesh(`token issue --node ${MACHINE}`));
+  await must(`${HOST_PATH} enrol --token ${quote(token)}`);
+  await must(`nohup ${HOST_PATH} run > /var/log/mesh-host.log 2>&1 & sleep 3`);
+}, { timeout: 1_800_000 });
+
+after(async () => {
+  if (instanceId) await destroy(instanceId);
+  await destroyAll(`${SCENARIO}-`);
+}, { timeout: 600_000 });
+
+test("the mesh assigns mosquitto: a run-once step seeds dynsec before the broker, and the broker comes up", {
+  skip, timeout: 1_500_000,
+}, async () => {
+  // mosquitto's dynsec config: the plugin refuses to start unless dynamic-security.json holds an
+  // admin client, so the store MUST be seeded first. The `run-once` bootstrap container is declared
+  // BEFORE `server` (the broker) and reuses the module's runtime image; the host runs it to
+  // completion, then starts the broker. The runtime `server`/`runtime` shape mirrors the committed
+  // manifest, with images pinned to what this scenario serves by digest.
+  const mosquittoConf =
+    "persistence true\n" +
+    "persistence_location /mosquitto/data\n\n" +
+    "log_dest stdout\n" +
+    "log_type warning\n" +
+    "log_type error\n" +
+    "log_type notice\n\n" +
+    "# Every client authenticates; identities and their per-topic ACLs are managed\n" +
+    "# at runtime by the dynamic security plugin, whose store the plugin itself owns.\n" +
+    "allow_anonymous false\n" +
+    "plugin /usr/lib/mosquitto_dynamic_security.so\n" +
+    "plugin_opt_config_file /mosquitto/data/dynamic-security.json\n\n" +
+    "# MQTT listener\n" +
+    "listener 1883\n\n" +
+    "# MQTT-over-WebSockets listener\n" +
+    "listener 8081\n" +
+    "protocol websockets\n";
+
+  const manifest = JSON.stringify({
+    module: "mosquitto",
+    version: "1",
+    provides: [{ name: "mqtt-topic", scope: "mesh" }],
+    serves: { "mqtt-topic": {} },
+    emits: ["module.mosquitto.topic.provisioned", "module.mosquitto.topic.deprovisioned"],
+    // The events entrypoint subscribes to its own lifecycle events (an audit log), so it consumes
+    // them too — declared, or the substrate never makes the queue the runtime binds (ADR 0046).
+    consumes: ["module.mosquitto.topic.provisioned", "module.mosquitto.topic.deprovisioned"],
+    receives: { "mqtt-topic": "/var/lib/mosquitto-module/grants/mesh.json" },
+    grants: { "mqtt-topic": "/var/lib/mosquitto-module/grants" },
+    "own-secrets": {
+      admin: "/var/lib/mosquitto-module/admin.secret",
+      broker: "/var/lib/mesh/mosquitto/broker",
+    },
+    resources: [
+      { id: "mesh-state", type: "directory", path: "/var/lib/mesh/mosquitto", mode: "0700" },
+      { id: "state", type: "directory", path: "/var/lib/mosquitto-module", mode: "0700" },
+      { id: "grants-dir", type: "directory", path: "/var/lib/mosquitto-module/grants", mode: "0700" },
+      // The broker runs as uid 1883, so the shared data directory it seeds into and persists to is
+      // its own.
+      { id: "data", type: "directory", path: "/services/mosquitto/data", mode: "0700", owner: "1883:1883" },
+      {
+        id: "server-conf", type: "file", path: "/var/lib/mosquitto-module/mosquitto.conf",
+        mode: "0600", owner: "1883:1883", content: mosquittoConf,
+      },
+      { id: "net", type: "network", name: "mosquitto" },
+      // THE run-once step: seed dynsec offline, once, before the broker. It reuses the runtime image
+      // (`mesh-tools run <bootstrap>` imports mosquitto's bootstrap entrypoint, which writes the
+      // admin client into dynamic-security.json and chowns it to the broker's uid, then exits). It is
+      // declared BEFORE `server`; the host runs it to completion and requires exit 0 before starting
+      // the broker.
+      {
+        id: "bootstrap", type: "container", name: "mosquitto-bootstrap",
+        image: pinned("mesh-runtime-mosquitto"), "run-once": true,
+        volumes: [
+          "/services/mosquitto/data:/mosquitto/data",
+          "/var/lib/mosquitto-module/admin.secret:/run/secrets/admin:ro",
+        ],
+        env: {
+          MESH_PROVISION_MQTT: "mosquitto:1883",
+          MESH_PROVISION_ADMIN_USER: "mesh-admin",
+          MESH_PROVISION_PASSWORD_FILE: "/run/secrets/admin",
+          MESH_DYNSEC_FILE: "/mosquitto/data/dynamic-security.json",
+        },
+        args: ["run", "/app/modules/mosquitto/dist/bootstrap/index.js"],
+      },
+      {
+        id: "server", type: "container", name: "mosquitto", image: pinned("eclipse-mosquitto"),
+        network: "mosquitto", ports: ["1883", "8081"],
+        volumes: [
+          "/services/mosquitto/data:/mosquitto/data",
+          "/var/lib/mosquitto-module/mosquitto.conf:/mosquitto/config/mosquitto.conf:ro",
+        ],
+      },
+      {
+        id: "runtime", type: "container", name: "mesh-mosquitto",
+        image: pinned("mesh-runtime-mosquitto"), network: "mosquitto",
+        volumes: [
+          "/var/lib/mesh/mosquitto/broker:/run/secrets/broker:ro",
+          "/var/lib/mosquitto-module/grants:/var/lib/mosquitto-module/grants:ro",
+          "/var/lib/mosquitto-module/admin.secret:/run/secrets/admin:ro",
+        ],
+        env: {
+          MESH_BROKER_FILE: "/run/secrets/broker",
+          MESH_RECEIVES: "/var/lib/mosquitto-module/grants/mesh.json",
+          MESH_PROVISION_MQTT: "mosquitto:1883",
+          MESH_PROVISION_ADMIN_USER: "mesh-admin",
+          MESH_PROVISION_PASSWORD_FILE: "/run/secrets/admin",
+        },
+      },
+    ],
+  });
+
+  await must(`printf %s ${quote(manifest)} > /tmp/mosquitto.json && docker cp /tmp/mosquitto.json mesh-control:/mosquitto.json`);
+  await mesh("module add /mosquitto.json");
+  const issued = await mesh(`module issue mosquitto --node ${MACHINE}`);
+  assert.match(issued, /scoped to what it emits and consumes/, issued);
+  await mesh(`assign ${MACHINE} mosquitto`);
+
+  // ONE push, ONE convergence — and reaching `current` requires the run-once step to have completed,
+  // because the apply is gated on it and stops if it fails.
+  await mesh(`push ${MACHINE}`);
+  await settled();
+
+  // --- the run-once step ran to completion, and is NOT left running -------------------------------
+  // A step is run in the foreground and removed once it exits 0; a service is left running. So the
+  // bootstrap container must be gone from `docker ps -a`, not lingering.
+  const allContainers = await must(`docker ps -a --format '{{.Names}}'`);
+  assert.doesNotMatch(allContainers, /(^|\n)mosquitto-bootstrap(\n|$)/,
+    `the run-once bootstrap was left as a container instead of run to completion:\n${allContainers}`);
+
+  // --- the seed is on disk, owned by the broker's uid so the broker can read AND persist it --------
+  const seedPath = "/services/mosquitto/data/dynamic-security.json";
+  const seedExists = await on(`test -f ${seedPath}`);
+  assert.ok(seedExists.ok,
+    `the run-once step did not seed ${seedPath}:\n${(await on(`tail -40 /var/log/mesh-host.log`)).out}`);
+  const owner = (await must(`stat -c '%u:%g' ${seedPath}`)).trim();
+  assert.equal(owner, "1883:1883",
+    `the seeded store is not owned by the broker's uid, so the broker cannot read/persist it: ${owner}`);
+  const seed = await must(`cat ${seedPath}`);
+  assert.match(seed, /mesh-admin/, `the seed does not hold the dynsec admin client:\n${seed}`);
+
+  // --- the broker is up and STABLE — the proof the seed was loaded --------------------------------
+  // An unseeded store crash-loops the broker: dynsec aborts start. So a broker that is up now, and
+  // still up after a moment with no restart, is the end-to-end proof the store was seeded before it
+  // started.
+  const running = await must(`docker ps --format '{{.Names}}'`);
+  for (const name of ["mosquitto", "mesh-mosquitto"]) {
+    assert.match(running, new RegExp(`(^|\\n)${name}(\\n|$)`),
+      `${name} is not running after the push:\n${running}\n---host log---\n${(await on(`tail -40 /var/log/mesh-host.log`)).out}`);
+  }
+  await new Promise((r) => setTimeout(r, 8000));
+  const brokerState = (await must(`docker inspect -f '{{.State.Running}} {{.RestartCount}}' mosquitto`)).trim();
+  assert.equal(brokerState, "true 0",
+    `the broker is not up and stable — it crash-loops against an unseeded store:\n${brokerState}\n` +
+      `${(await on(`docker logs mosquitto 2>&1 | tail -30`)).out}`);
+  const brokerLog = (await on(`docker logs mosquitto 2>&1`)).out;
+  assert.doesNotMatch(brokerLog, /Error found at|Unable to load|unable to load Dynamic security/i,
+    `the broker reported a dynsec load error against the seeded store:\n${brokerLog}`);
+
+  // --- the scoped broker account exists ------------------------------------------------------------
+  const users = await must(`docker exec mesh-broker lavinmqctl list_users 2>&1`);
+  assert.match(users, /anchor-mosquitto/, `the scoped account is not on the broker:\n${users}`);
+
+  // --- the seeded admin authenticates over MQTT: the plugin loaded the seed ------------------------
+  const adminPw = (await must(`cat /var/lib/mosquitto-module/admin.secret`)).trim();
+  let adminClients = { out: "", ok: false };
+  const untilAdmin = Date.now() + 60_000;
+  while (Date.now() < untilAdmin) {
+    adminClients = await on(
+      `docker exec mosquitto mosquitto_ctrl -h 127.0.0.1 -p 1883 -u mesh-admin -P ${quote(adminPw)} dynsec listClients 2>&1`,
+    );
+    if (adminClients.ok && /mesh-admin/.test(adminClients.out)) break;
+    await new Promise((r) => setTimeout(r, 3000));
+  }
+  assert.match(adminClients.out, /mesh-admin/,
+    `the seeded admin could not authenticate / dynsec did not load the seed:\n${adminClients.out}`);
+
+  // --- the provider path: a consumer the mesh delivered gets a scoped client that authenticates ----
+  // mosquitto's provisioner reconciles the contributions file the mesh writes at MESH_RECEIVES: for
+  // each consumer it reads the login the mesh derived and the mesh-minted password the host unsealed,
+  // and creates exactly that dynsec client, scoped to its own topic subtree (ADR 0048). A
+  // hand-written contributions file + secret stand in for the control plane's write; their SHAPE is
+  // what mesh-control produces. The proof is authentication as the consumer with the mesh's password
+  // — a provisioner that invented its own would refuse the connection.
+  const consumerPw = "mesh-minted-mqtt-7b2e1a";
+  await must(`printf %s ${quote(consumerPw)} > /var/lib/mosquitto-module/grants/app.secret`);
+  const contributions = JSON.stringify({
+    contributions: 1,
+    requirement: "mqtt-topic",
+    generated: "by the mesh — do not edit",
+    given: [
+      { as: "app-one", node: "app-node", at: "192.0.2.20:1883", secret: "/var/lib/mosquitto-module/grants/app.secret", values: {} },
+    ],
+  });
+  await must(`printf %s ${quote(contributions)} > /var/lib/mosquitto-module/grants/mesh.json`);
+
+  let created = { out: "", ok: false };
+  const untilCreated = Date.now() + 90_000;
+  while (Date.now() < untilCreated) {
+    created = await on(
+      `docker exec mosquitto mosquitto_ctrl -h 127.0.0.1 -p 1883 -u mesh-admin -P ${quote(adminPw)} dynsec listClients 2>&1`,
+    );
+    if (created.ok && /app-one/.test(created.out)) break;
+    await new Promise((r) => setTimeout(r, 3000));
+  }
+  assert.match(created.out, /app-one/,
+    `mosquitto's provisioner never created the consumer's scoped client from the delivered contribution:\n` +
+      `${(await on(`docker logs mesh-mosquitto 2>&1 | tail -30`)).out}\n---\n${created.out}`);
+
+  // Authenticate as that consumer with the password the MESH minted, and publish to its own subtree.
+  // A successful connect+publish (exit 0) means the provisioner created the client with exactly that
+  // password; a wrong password would refuse the connection.
+  const published = await on(
+    `docker exec mosquitto mosquitto_pub -h 127.0.0.1 -p 1883 -u app-one -P ${quote(consumerPw)} -q 1 -t app-one/hello -m hi 2>&1`,
+  );
+  assert.ok(published.ok,
+    `the consumer could not authenticate as app-one with the mesh-minted password and publish to its subtree:\n${published.out}`);
+});