slop

server/src/services/commandService/recording.js

@@ -0,0 +1,55 @@
+// Optional detailed command observation, separate from payload-free analytics.
+// Subscribers must only enqueue work; recorder failures cannot fail a command.
+const { AsyncLocalStorage } = require('node:async_hooks');
+const { randomUUID } = require('node:crypto');
+
+const observers = new Set();
+const requests = new AsyncLocalStorage();
+
+function subscribeCommandRecording(observer) {
+  observers.add(observer);
+  return () => observers.delete(observer);
+}
+
+function observeCommand(event) {
+  if (!observers.size) return;
+  const scope = requests.getStore();
+  const context = scope?.active ? scope.context : null;
+  for (const observer of observers) {
+    try {
+      // Snapshot before safety code or a caller mutates a nested payload. Each
+      // subscriber receives its own copy and cannot change command delivery.
+      observer(structuredClone({
+        ts: Date.now(),
+        monotonicNs: process.hrtime.bigint().toString(),
+        source: context ? 'client' : 'server',
+        ...context,
+        ...event,
+      }));
+    } catch {
+      // Recording is deliberately best-effort at this boundary. The owning
+      // recorder reports its storage health independently of driver replies.
+    }
+  }
+}
+
+function recordCommandRequest(socket, request, reply, execute) {
+  if (!observers.size) return execute(request, reply);
+  const context = { requestId: randomUUID(), socketId: socket.id, userId: socket.data?.userId || null };
+  const scope = { active: true, context };
+  return requests.run(scope, () => {
+    try {
+      observeCommand({ phase: 'requested', roverId: request?.roverId, command: request });
+      return execute(request, (result) => {
+        observeCommand({ phase: 'result', roverId: request?.roverId, result });
+        if (typeof reply === 'function') reply(result);
+      });
+    } finally {
+      // The command handler is synchronous. A safety timer created inside it
+      // inherits async context but its later commands are server actions.
+      scope.active = false;
+    }
+  });
+}
+
+module.exports = { subscribeCommandRecording, observeCommand, recordCommandRequest };