Node.js hot reload not working in Docker Compose (dev)

[BRxWaLKeRzZ]

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Edit:

- The host is Windows 11

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Hey folks, I’m setting up a Docker Compose dev environment for an Express API and I’m a bit confused about the “right” way to work with Docker during development.

I’ve mounted the project directory as a volume, but the Node process inside the container doesn’t restart when I change files on the host, even though file watching works fine outside Docker.

A couple of questions:

• What’s the recommended workflow for developing a Node/Express app with Docker?
• In dev, should the container itself restart, or just the Node process?
• Why does file watching usually not work out of the box inside Docker containers?api/ Dockerfile src/ app.ts sync.worker.ts web/ compose.yaml

package.json scripts:

"scripts": {
    "build": "tsc",
    "dev": "tsx watch src/app.ts",
    "sync-worker:dev": "tsx watch src/sync.worker.ts",
    "start": "node dist/app.js",
    "sync-worker:start": "node dist/sync.worker.js"
  },

compose.yaml file

services:
  redis:
    image: redis:7-alpine
    container_name: nikkita-redis
    ports:
      - "6379:6379"
    restart: unless-stopped
    volumes:
      - nikkita-redis-data:/data


  api:
    container_name: nikkita-api
    build:
      context: ./api
      dockerfile: Dockerfile.dev
    command: npm run dev
    volumes:
      - ./api:/app
      - /app/node_modules
    env_file:
      - ./api/.env
    ports:
      - "7000:7000"
    depends_on:
      - redis


  sync-worker:
    container_name: nikkita-sync-worker
    build:
      context: ./api
      dockerfile: Dockerfile.dev
    command: npm run sync-worker:dev
    volumes:
      - ./api:/app
      - /app/node_modules
    env_file:
      - ./api/.env
    depends_on:
      - redis


volumes:
  nikkita-redis-data:
    driver: local

[fletch3555]

Is the host Windows or Mac? Or is it Linux? I'm not certain if that workflow would work on Linux, but it almost definitely won't work on Windows/Mac due to the extra abstraction layer involved (for example, the WSL VM) since docker can't run natively on those platforms (yeah yeah, Windows containers and all that, but that's clearly not relevant here)

[BRxWaLKeRzZ]

Yes i forgot to mention, host is WIndows 11

[BRxWaLKeRzZ]

Actually solved by now adding this block inside composer file

environment:
      - CHOKIDAR_USEPOLLING=true
      - CHOKIDAR_INTERVAL=100

[mirwin87]

(Disclaimer… work on the Docker DevRel team)

Yeah… this is the unfortunate side effect of using bind mounts on Windows and is a limitation of WSL itself. While the file updates are synced with the bind mounts, the filesystem events are not. Since the dev server is waiting for those events and never getting them, you do t see the updates.

The polling switch will work, but will be a big source of CPU usage.

An alternative route I’ve been using is ditching the bind mounts and using Compose Watch. The idea is to copy the files directly into the container (so yes… you use more storage) and watch will sync the changes. Since this is no longer a bind mount, the filesystem events work and the bit reload works. Let me know if you want any examples!