Memory Monitoring

Remix Studio exposes a lightweight memory snapshot endpoint and emits a periodic memory log line, so you can tell whether high container RSS is a real JavaScript leak or just native (Sharp / ffmpeg / Buffer) growth.

What You Get

1. HTTP Endpoint

GET /api/internal/memory

Returns the current process.memoryUsage() snapshot in MB:

{
  "rss": 420.3,
  "heapUsed": 180.1,
  "heapTotal": 210.5,
  "external": 85.2,
  "arrayBuffers": 12.4,
  "uptimeSec": 3724,
  "unit": "MB"
}

The endpoint is unauthenticated (same posture as /healthz and /readyz). It exposes only memory counters — no secrets, no user data.

WARNING

If your server is reachable from the public internet, restrict /api/internal/* at your reverse proxy.

2. Periodic Log Line

Every 30 seconds the server prints:

[mem] rss=420.3MB heap=180.1/210.5MB ext=85.2MB

• rss — what the OS / container metrics see (the number on your dashboards).
• heap — V8 used / total.
• ext — native memory tied to V8 objects (Buffers, Sharp pipelines, etc.).

Common Usage

One-off check:

curl -s localhost:3000/api/internal/memory | jq

Live trend in a terminal:

watch -n 2 'curl -s localhost:3000/api/internal/memory | jq'

Historical view from container logs:

docker logs -f <container> | grep '\[mem\]'

How to Interpret

Pattern	Likely cause
rss rises, heap flat, ext rises with rss	Native growth — Sharp / ffmpeg / large Buffers. Not a JS leak; V8 also doesn't return RSS to the OS quickly.
heap rises monotonically and never drops after GC	Real JS leak. Take a heap snapshot.
Both spike during media jobs, then settle	Normal concurrent media processing peak.
rss stuck high long after activity ended	Expected V8 behaviour — pages are reused on the next spike.

When to Take a Heap Snapshot

If heap keeps growing across hours with no plateau:

# Start the server with the inspector enabled
node --inspect dist-server/server.js
# Then open chrome://inspect in Chrome -> Memory -> Heap snapshot

Or dump programmatically from inside the process:

import v8 from 'v8';
v8.writeHeapSnapshot('/tmp/heap.heapsnapshot');

Copy the file out of the container and load it in Chrome DevTools' Memory tab.