Docker Compose Watch

docker compose watch is a feature that enables automatic rebuilds and restarts of services when files change. This is useful in development environments, where frequent code modifications require a quick feedback loop.

🚀 Why Use It?

• Automatically detects changes in your source files.
• Rebuilds and restarts services when necessary.
• Reduces manual effort in development workflows.

🔧 Basic Usage

To enable file watching, define a watch section in docker-compose.yml:

services:
  app:
    build: .
    volumes:
      - .:/app
    develop:
      watch:
        - path: ./src
          action: sync
        - path: ./Dockerfile
          action: rebuild

Explanation:

• sync: Synchronizes changes without restarting the container.
• rebuild: Triggers a full image rebuild and restart.

Starting the Watch Mode

Run the following command to enable live watching:

docker compose watch

This starts the services (if they are not already running) and monitors file changes.

⚙️ Watch Actions

Action	Description
sync	Syncs file changes into the running container without restarting.
rebuild	Triggers a full rebuild when files change.
restart	Restarts the container without rebuilding.

🎯 Use Cases

1️⃣ Live Code Sync Without Restart

For interpreted languages (e.g., Python, JavaScript), use sync to reflect changes without downtime.

2️⃣ Automatic Rebuilds for Configuration Changes

Use rebuild to trigger updates when modifying Dockerfiles or dependency files (e.g., requirements.txt, package.json).

3️⃣ Auto-Restart for Configuration Updates

If config files change (e.g., .env, .yaml), restart ensures the container reloads them.

🔄 Comparison: docker compose watch vs. Bind Mounts

Feature	docker compose watch	Bind Mounts (volumes)
Updates files in container	✅	✅
Triggers rebuild on changes	✅	❌
Works across OS platforms	✅	Some issues on Windows/macOS
Auto-restarts services	✅	❌

🏗️ When Should You Use It?

✅ Development workflows that require live updates. ✅ Containerized applications where code needs frequent rebuilding. ✅ Projects with dependency management, such as Python (requirements.txt) or Node.js (package.json).

📌 Conclusion

docker compose watch simplifies containerized development by eliminating the need for manual rebuilds and restarts. It’s especially useful when working on IoT edge devices, microservices, or cloud applications.

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💡 Need More Help?

Check out the official Docker documentation: Docker Compose Watch.