test(chaos): fault-proxy campaign — byte-identical backfill under injected Portal faults

.gitignore

@@ -1,6 +1,7 @@
 node_modules/
 harness/results.*.json
 harness/bench/results.md
+harness/chaos/.faultproxy/
 harness/euler/vaults.*.json
 *.log
 .DS_Store

harness/chaos/chaos-aimd-trace.cjs

@@ -0,0 +1,134 @@
+const fs = require('node:fs');
+
+const traceFile =
+  process.env.CHAOS_AIMD_TRACE_FILE || process.env.AIMD_TRACE_FILE || '';
+let seq = 0;
+let inFlight = 0;
+let maxInFlight = 0;
+
+function append(event) {
+  if (!traceFile) return;
+  const record = {
+    ts: new Date().toISOString(),
+    pid: process.pid,
+    run: Number(process.env.CHAOS_RUN || 0),
+    attempt: Number(process.env.CHAOS_ATTEMPT || 0),
+    seq: ++seq,
+    ...event,
+  };
+  try {
+    fs.appendFileSync(traceFile, `${JSON.stringify(record)}\n`);
+  } catch {
+    // Evidence-only hook. Never perturb the app under test.
+  }
+}
+
+function parseGateLine(args) {
+  const line = args.map((a) => (typeof a === 'string' ? a : '')).join(' ');
+  const m = line.match(
+    /\[portalGate\]\s+concurrency_limit=(\d+)\s+active=(\d+)\s+buffered_rows=(\d+)/,
+  );
+  if (!m) return;
+  append({
+    event: 'aimd-gate-log',
+    source: 'portalGate-log',
+    concurrency: Number(m[1]),
+    limit: Number(m[1]),
+    active: Number(m[2]),
+    rows: Number(m[3]),
+  });
+}
+
+const originalLog = console.log;
+console.log = function aimdConsoleLog(...args) {
+  try {
+    parseGateLine(args);
+  } catch {
+    // Ignore trace parse errors.
+  }
+  return originalLog.apply(this, args);
+};
+
+function isFinalizedStream(input) {
+  const url =
+    typeof input === 'string'
+      ? input
+      : input instanceof URL
+        ? input.href
+        : input?.url;
+  return typeof url === 'string' && url.includes('/finalized-stream');
+}
+
+const originalFetch = globalThis.fetch;
+if (typeof originalFetch !== 'function') {
+  append({ event: 'aimd-env', error: 'global fetch is unavailable' });
+} else {
+  globalThis.fetch = async function aimdFetch(input, _init) {
+    const traced = isFinalizedStream(input);
+    if (!traced) {
+      return originalFetch.apply(this, arguments);
+    }
+
+    inFlight += 1;
+    maxInFlight = Math.max(maxInFlight, inFlight);
+    append({
+      event: 'aimd-fetch-start',
+      source: 'fetch-derived',
+      inFlight,
+      concurrency: inFlight,
+      maxInFlight,
+    });
+
+    try {
+      const response = await originalFetch.apply(this, arguments);
+      append({
+        event: 'aimd-fetch-end',
+        source: 'fetch-derived',
+        status: response?.status ?? null,
+        ok: response?.ok ?? null,
+        inFlight,
+        concurrency: inFlight,
+        maxInFlight,
+      });
+      return response;
+    } catch (error) {
+      append({
+        event: 'aimd-fetch-error',
+        source: 'fetch-derived',
+        error: error instanceof Error ? error.name : 'Error',
+        message: error instanceof Error ? error.message : String(error),
+        inFlight,
+        concurrency: inFlight,
+        maxInFlight,
+      });
+      throw error;
+    } finally {
+      inFlight = Math.max(0, inFlight - 1);
+      append({
+        event: 'aimd-fetch-release',
+        source: 'fetch-derived',
+        inFlight,
+        concurrency: inFlight,
+        maxInFlight,
+      });
+    }
+  };
+
+  append({
+    event: 'aimd-env',
+    source: 'hook',
+    min: Number(process.env.PORTAL_MIN_CONCURRENCY || 1),
+    max: Number(process.env.PORTAL_MAX_CONCURRENCY || 32),
+    start: Number(process.env.PORTAL_START_CONCURRENCY || 4),
+  });
+}
+
+process.on('exit', () => {
+  append({
+    event: 'aimd-exit',
+    source: 'hook',
+    inFlight,
+    concurrency: inFlight,
+    maxInFlight,
+  });
+});

harness/chaos/chaos-pg-driver.sh

@@ -1813,9 +1813,11 @@ backend_label_cmd () {
   echo "$label"
 }
 
-case "${1:-campaign}" in
-  selftest) selftest ;;
-  campaign) campaign ;;
-  backend-label) backend_label_cmd ;;
-  *) echo "usage: chaos-pg-driver.sh [campaign|selftest|backend-label]"; exit 2 ;;
-esac
+if [ -z "${CHAOS_LIB_ONLY:-}" ]; then
+  case "${1:-campaign}" in
+    selftest) selftest ;;
+    campaign) campaign ;;
+    backend-label) backend_label_cmd ;;
+    *) echo "usage: chaos-pg-driver.sh [campaign|selftest|backend-label]"; exit 2 ;;
+  esac
+fi