Video uploads on production fail with "missing ffmpeg" because the
backend container ships nothing usable for the video pipeline.
Two compounding causes:
1. **Alpine + glibc mismatch.** The npm `@ffmpeg-installer/ffmpeg`
dependency added with the video-support PR (commit 68a9dc5)
ships per-platform binaries via optionalDependencies. The Linux
binaries are built against glibc, but the backend image runs on
`node:22-alpine` (musl libc) — known to either fail to execute
or fail on shared-library lookups on Alpine.
2. **`ffprobe` missing entirely.** `@ffmpeg-installer/ffmpeg`
bundles only the `ffmpeg` binary. There's a separate
`@ffprobe-installer/ffprobe` package that the codebase never
depended on. But `videoProcessor.js:21` calls
`ffmpeg.ffprobe(videoPath, …)` — the very first step of the
video pipeline shells out to a `ffprobe` binary that doesn't
exist in the image. Even if (1) worked, every video upload
would 500 here.
The fix is to install Alpine's `ffmpeg` package via apk. It ships
both `ffmpeg` and `ffprobe` built natively against musl, ~70MB
extra image size, single line in the Dockerfile, no per-arch
handling needed (apk pulls the right binary for both linux/amd64
and linux/arm64 — works with the multi-arch infra from #349).
- `backend/Dockerfile`: add `ffmpeg` to the apk install line.
- `backend/Dockerfile.dev`: same for dev parity.
- `backend/src/services/videoProcessor.js`: remove the
`setFfmpegPath(require('@ffmpeg-installer/ffmpeg').path)` line
— without removing it, fluent-ffmpeg would prefer the broken
bundled binary over the working apk one. Letting fluent-ffmpeg
fall back to PATH lookup picks up the apk binary in the
container and the developer's locally-installed binary on dev
hosts (Homebrew on macOS, apt on Debian).
- `backend/package.json`: drop the now-unused
`@ffmpeg-installer/ffmpeg` dependency. `npm install` removes
2 packages from the lockfile.
Verified: `videoProcessor.js` still loads cleanly (`node -e
"require('./src/services/videoProcessor')"`); lint clean.
Paul Nothaft
96818c7ae8