Billing: request telemetry in its own table, 30-day retention (#63)

ddiff --git a/migrations/0007_telemetry.sql b/migrations/0007_telemetry.sql
nnew file mode 100644
iindex 0000000..14260fa
---- /dev/null
++++ b/migrations/0007_telemetry.sql
@@@ -0,0 +1,28 @@
++-- phase: expand
++-- Request telemetry (openvibe-sdk/telemetry telemetrySchema()): one row per aggregated sample, pruned after 30 days (server/index.js).
++CREATE TABLE IF NOT EXISTS telemetry_samples (
++    id                    bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
++    at                    timestamptz NOT NULL,
++    service               text NOT NULL,
++    project               text,
++    subject               text,
++    resource              text,
++    provider              text,
++    node                  text,
++    cell                  text,
++    region                text,
++    operation             text NOT NULL,
++    latency_ms            double precision,
++    queue_delay_ms        double precision,
++    ttfb_ms               double precision,
++    throughput_per_second double precision,
++    bytes                 bigint,
++    status                text,
++    cache_status          text,
++    cost_estimate         double precision,
++    route_epoch           bigint,
++    trace_id              text,
++    extra                 jsonb NOT NULL DEFAULT '{}'::jsonb
++);
++CREATE INDEX IF NOT EXISTS telemetry_samples_at_idx ON telemetry_samples (at);
++CREATE INDEX IF NOT EXISTS telemetry_samples_service_idx ON telemetry_samples (service, operation, at);
ddiff --git a/server/app.js b/server/app.js
iindex 7c28acc..afbff69 100644
---- a/server/app.js
++++ b/server/app.js
@@@ -66,6 +66,7 @@ async function createApp(opts = {}) {
      const metrics = createMetrics({ db, config, now: ctx.now, outbox });
      const release = createRelease({ service: 'billing', root: path.join(__dirname, '..') });
      instrument(app, { service: 'billing', release: release.release, registry: metrics.registry });
++    app.use(require('openvibe-sdk/service').telemetryMiddleware);   // request telemetry: a no-op until server/index.js calls telemetry.init()
      // GET /release.json (ADR-016, D43) and POST /release-metrics: what this deployment is, for tabs and deploy checks.
      release.mount(app, { registry: metrics.registry });
      app.use(http.middleware());
ddiff --git a/server/index.js b/server/index.js
iindex 7861341..a5cd829 100644
---- a/server/index.js
++++ b/server/index.js
@@@ -19,7 +19,8 @@ const subscriptions = require('./ops/subscriptions');
  const rating = require('./ops/rating');
  const { isFrozen } = require('./ops/common');
  const { runScheduled } = require('./reconcile');
--const { gracefulStop } = require('openvibe-sdk/service');
++const { gracefulStop, telemetry } = require('openvibe-sdk/service');
++const { createPgTelemetrySink, startTelemetryRetention } = require('openvibe-sdk/telemetry');
  
  (async () => {
      const config = loadConfig();
@@@ -61,6 +62,10 @@ const { gracefulStop } = require('openvibe-sdk/service');
          console.log(`[Billing] money authority: ${config.authority}${config.authority === 'live' ? ' (shadow: EXTERNAL tips are recorded, not announced)' : ' (EXTERNAL tips are announced as billing.receipt.external)'}`);
      });
      server.keepAliveTimeout = 65_000;
++    // Request telemetry (openvibe-sdk/service, plan T1): one aggregated sample per route template, method and status
++    // class each 15 s, stored in this service's telemetry_samples table; rows older than 30 days go daily.
++    telemetry.init({ service: 'billing', sink: createPgTelemetrySink({ db: ctx.db, log: console }), skipPrefixes: ['/shared'] });
++    const telemetryRetention = startTelemetryRetention({ db: ctx.db, log: console });
  
      // SIGTERM/SIGINT (openvibe-sdk/service): the kit installs the handlers, stops the job timers, the outbox
      // relay and the Network key refresh, drains the HTTP server (requests in flight get Connection: close),
@@@ -78,6 +83,7 @@ const { gracefulStop } = require('openvibe-sdk/service');
          ],
          close: [
              () => app.locals.valkey && app.locals.valkey.close().catch(() => {}),
++            async () => { if (telemetryRetention) await telemetryRetention.stop(); await telemetry.stop(); },
              () => ctx.db.close(),
          ],
      });
ddiff --git a/test/service-kit.test.js b/test/service-kit.test.js
iindex 1f146d6..217d9bd 100644
---- a/test/service-kit.test.js
++++ b/test/service-kit.test.js
@@@ -45,7 +45,7 @@ async function waitFor(fn, ms = 2000) {
      console.log('service-kit');
  
      await check('server/index.js imports gracefulStop from openvibe-sdk/service and owns no signal handler', () => {
--        assert.match(source, /const \{ gracefulStop \} = require\('openvibe-sdk\/service'\)/);
++        assert.match(source, /const \{ gracefulStop(, [A-Za-z]+)* \} = require\('openvibe-sdk\/service'\)/);
          assert.doesNotMatch(source, /process\.on\('SIGTERM'/, 'server/index.js still installs its own SIGTERM handler');
          assert.doesNotMatch(source, /process\.on\('SIGINT'/, 'server/index.js still installs its own SIGINT handler');
          assert.doesNotMatch(source, /process\.exit\(0\), 5000\)/, 'the old 5 s exit-0 timer is gone');
ddiff --git a/test/telemetry.test.js b/test/telemetry.test.js
nnew file mode 100644
iindex 0000000..9aadda2
---- /dev/null
++++ b/test/telemetry.test.js
@@@ -0,0 +1,50 @@
++'use strict';
++/**
++ * Request telemetry (openvibe-sdk/service, plan T1 step 10): app.js mounts the process-wide telemetryMiddleware (a no-op
++ * until init), server/index.js calls telemetry.init() for service 'billing' with a PostgreSQL sink, starts the 30-day
++ * retention and flushes on stop. Five hits on one route flush as ONE aggregated http.request sample; /metrics and
++ * /shared make none; the retention deletes only rows older than 30 days.
++ */
++const assert = require('assert');
++const fs = require('fs');
++const path = require('path');
++const { telemetry } = require('openvibe-sdk/service');
++const { pruneTelemetry } = require('openvibe-sdk/telemetry');
++const { boot } = require('./helpers/app');
++(async () => {
++    const read = (p) => fs.readFileSync(path.join(__dirname, '..', p), 'utf8');
++    assert.match(read('server/index.js'), /telemetry\.init\(\{ service: 'billing', sink: createPgTelemetrySink\(/, 'index.js starts the collector');
++    assert.match(read('server/index.js'), /startTelemetryRetention\(/, 'index.js starts the retention');
++    assert.match(read('server/index.js'), /[Rr]etention\.stop\(\); await telemetry\.stop\(\);/, 'the stop flushes');
++
++    const t = await boot();
++    const samples = [];
++    telemetry.init({ service: 'billing', sink: async (batch) => { samples.push(...batch); }, intervalMs: 3600e3 });
++    const requests = () => samples.filter((s) => s.operation === 'http.request');
++    try {
++        for (let i = 0; i < 5; i++) assert.strictEqual((await t.call('GET', '/policy', { token: null })).status, 200);
++        await telemetry.flush();
++        const hit = requests().filter((s) => s.resource === '/policy' && s.status === '2xx');
++        assert.strictEqual(hit.length, 1, JSON.stringify(requests()));
++        assert.strictEqual(hit[0].service, 'billing');
++        assert.strictEqual(hit[0].extra.count, 5);
++
++        samples.length = 0;
++        await await t.call('GET', '/metrics', { token: null });
++        await await t.call('GET', '/shared/navbar.js', { token: null });
++        await telemetry.flush();
++        assert.deepStrictEqual(requests(), [], '/metrics and /shared make no sample');
++
++        const db = t.db;
++        await db.query('DELETE FROM telemetry_samples');
++        const insert = (days) => db.query("INSERT INTO telemetry_samples (at, service, operation) VALUES (now() - make_interval(days => $1), 'billing', 'http.request')", [days]);
++        await insert(45);
++        await insert(1);
++        assert.strictEqual(await pruneTelemetry({ db }), 1);
++        assert.strictEqual((await db.query('SELECT count(*)::int AS n FROM telemetry_samples')).rows[0].n, 1);
++        console.log('telemetry ok');
++    } finally {
++        await telemetry.stop();
++        await t.close();
++    }
++})().catch((err) => { console.error(err); process.exit(1); });