slop

2026-11-14 18:58:49 -05:00 · 2026-09-27 18:41:24 -04:00
parent dbcb7f6a7a
commit 73a78eef20
11 changed files with 1024 additions and 2 deletions
@@ -0,0 +1,119 @@
+// One bounded recording session. Video packets retain receiver wall-clock PTS;
+// telemetry uses the same server clock, not an assumed browser playback clock.
+const fs = require('node:fs');
+const fsp = require('node:fs/promises');
+const path = require('node:path');
+const { randomUUID } = require('node:crypto');
+const { spawn } = require('node:child_process');
+
+const MAX_BUFFER_BYTES = 2 * 1024 * 1024;
+
+async function saveMetadata(directory, metadata) {
+  const filename = path.join(directory, 'session.json');
+  await fsp.writeFile(`${filename}.tmp`, JSON.stringify(metadata, null, 2));
+  await fsp.rename(`${filename}.tmp`, filename);
+}
+
+async function createRecording({ root, roverId, snapshot, logger }) {
+  const id = `${Date.now()}-${randomUUID()}`;
+  const directory = path.join(root, id);
+  await fsp.mkdir(directory);
+  const metadata = {
+    version: 1, id, roverId, startedAt: Date.now(), endedAt: null,
+    timing: 'Video PTS uses server receiver Unix seconds. Events use Unix milliseconds and process monotonic nanoseconds. Browser display delay is not measured.',
+    video: { file: 'video.mkv', codec: 'source-copy', timestampUnit: 'seconds', origin: 'unix' },
+    events: 'events.ndjson', droppedEvents: 0,
+  };
+  await saveMetadata(directory, metadata);
+  const output = fs.createWriteStream(path.join(directory, 'events.ndjson'), { flags: 'wx' });
+  let failure = null;
+  let stopping = false;
+  let stopPromise;
+  let child;
+  let childClosed = false;
+  let stderr = '';
+  let videoResult = null;
+  let resolveVideo;
+  const videoClosed = new Promise((resolve) => { resolveVideo = resolve; });
+  output.on('error', (error) => {
+    failure = error.message;
+    // Stop file growth immediately when telemetry is no longer writable.
+    child?.kill('SIGTERM');
+  });
+
+  function append(kind, data, timestamp = {}) {
+    if (stopping || failure) return false;
+    try {
+      const line = JSON.stringify({
+        ts: Date.now(), monotonicNs: process.hrtime.bigint().toString(), ...timestamp, kind, data,
+      }) + '\n';
+      // Never wait for disk from a control/sensor callback. Explicit loss counts
+      // prevent an overloaded recorder from pretending its history is complete.
+      if (output.writableLength + Buffer.byteLength(line) > MAX_BUFFER_BYTES) {
+        metadata.droppedEvents += 1;
+        return true;
+      }
+      output.write(line);
+    } catch (error) {
+      metadata.droppedEvents += 1;
+      failure = error.message;
+      child?.kill('SIGTERM');
+    }
+    return true;
+  }
+
+  append('snapshot', snapshot);
+  // Read the local published stream, as replay does, without depending on the
+  // replay service or re-encoding camera video. No audio/chat is captured.
+  child = spawn(process.env.FFMPEG_BIN || 'ffmpeg', [
+    '-hide_banner', '-loglevel', 'warning', '-nostdin', '-n',
+    '-rtsp_transport', 'tcp', '-timeout', '10000000',
+    '-use_wallclock_as_timestamps', '1', '-copyts',
+    '-i', `rtsp://127.0.0.1:8554/${encodeURIComponent(roverId)}`,
+    '-map', '0:v:0', '-an', '-c:v', 'copy', '-avoid_negative_ts', 'disabled',
+    '-f', 'matroska', path.join(directory, 'video.mkv'),
+  ], { stdio: ['ignore', 'ignore', 'pipe'] });
+  child.stderr.on('data', (chunk) => { stderr = (stderr + chunk.toString()).slice(-4096); });
+  child.on('error', (error) => { failure = error.message; });
+  child.once('close', (code, signal) => {
+    childClosed = true;
+    videoResult = { code, signal, stderr };
+    if (!stopping) failure ||= `Video recorder exited (${code ?? signal})`;
+    resolveVideo();
+  });
+
+  async function stop(reason) {
+    if (stopPromise) return stopPromise;
+    stopPromise = (async () => {
+      append('sessionEnd', { reason, droppedEvents: metadata.droppedEvents });
+      stopping = true;
+      if (!childClosed) child.kill('SIGTERM');
+      // A stuck RTSP read must not leave a recorder behind after disable.
+      const killTimer = setTimeout(() => { if (!childClosed) child.kill('SIGKILL'); }, 2000);
+      await videoClosed;
+      clearTimeout(killTimer);
+      await new Promise((resolve) => {
+        if (output.closed) return resolve();
+        output.once('close', resolve);
+        output.end();
+      });
+      metadata.endedAt = Date.now();
+      metadata.reason = reason;
+      metadata.error = failure;
+      metadata.video.result = videoResult;
+      await saveMetadata(directory, metadata);
+      if (failure) logger.warn('Recording session incomplete', { roverId, id, error: failure, stderr });
+    })();
+    return stopPromise;
+  }
+
+  return {
+    id, directory, startedAt: metadata.startedAt, append, stop,
+    get failed() { return Boolean(failure); },
+    get stopping() { return stopping; },
+    // Process exit is synchronous; normal disable uses stop() and awaits close.
+    kill: () => { if (!childClosed) child.kill('SIGKILL'); },
+  };
+}
+
+module.exports = { createRecording, saveMetadata };