Sessions 5-7a: 955 tests, deployment ready

src/services/training/jsonlLogger.js

@@ -0,0 +1,49 @@
+/**
+ * Append-only JSONL logger for Engine 2 training.
+ *
+ * Each resolved prop becomes one line. Files rotate monthly:
+ *   data/training/resolutions-2026-06.jsonl
+ *
+ * Fire-and-forget: logResolution() returns void and swallows errors so a
+ * disk-full or permission issue can never break the resolution endpoint.
+ * Operationally, monitor disk usage and surface alerts separately.
+ *
+ * IMPORTANT: `data/` MUST be a persistent Docker volume in Coolify.
+ * Otherwise every redeploy nukes the training corpus.
+ */
+
+const fs = require('fs');
+const path = require('path');
+
+const ROOT = path.join(process.cwd(), 'data', 'training');
+let initialized = false;
+
+function ensureDir() {
+  if (initialized) return;
+  try {
+    fs.mkdirSync(ROOT, { recursive: true });
+    initialized = true;
+  } catch (err) {
+    console.warn('[jsonlLogger] mkdir failed:', err.message);
+  }
+}
+
+function monthKey(date = new Date()) {
+  const y = date.getUTCFullYear();
+  const m = String(date.getUTCMonth() + 1).padStart(2, '0');
+  return `${y}-${m}`;
+}
+
+function logResolution(data) {
+  // Never throw. Resolution must not fail because of a logging issue.
+  try {
+    ensureDir();
+    const file = path.join(ROOT, `resolutions-${monthKey()}.jsonl`);
+    const line = JSON.stringify({ ts: new Date().toISOString(), ...data }) + '\n';
+    fs.appendFileSync(file, line);
+  } catch (err) {
+    console.warn('[jsonlLogger] append failed:', err.message);
+  }
+}
+
+module.exports = { logResolution, monthKey };