How to debug Nest JS Application
Debugging a NestJS application running inside a Docker container involves a few steps, but it's quite manageable. Here's a general guide along with an example:
Enable Debugging in Your NestJS Application:
- Ensure your NestJS application is configured to support debugging. You typically do this by setting up a debugging configuration in your
package.json
ortsconfig.json
.
- Ensure your NestJS application is configured to support debugging. You typically do this by setting up a debugging configuration in your
Expose Debugging Ports:
- When running your NestJS application inside a Docker container, you need to expose the debugging port to your host machine. This allows you to attach a debugger from your development environment.
Update Dockerfile:
- Modify your Dockerfile to include the necessary debugging configurations and expose the debugging port.
Build Docker Image:
- Build your Docker image with the updated Dockerfile.
Run Docker Container:
- Start your Docker container, ensuring that you map the exposed debugging port to a port on your host machine.
Attach Debugger:
- Finally, attach your debugger from your development environment to the debugging port on your host machine.
Here's an example of how you might update your NestJS application and Docker configuration:
1. Enable Debugging in Your NestJS Application
Add a debugging configuration in your package.json
:
"scripts": {
"start:debug": "nest start --debug --watch"
}
2. Update Dockerfile
# Use node:latest as base image
FROM node:latest
# Set working directory
WORKDIR /app
# Copy package.json and package-lock.json
COPY package*.json ./
# Install dependencies
RUN npm install
# Copy the rest of the application code
COPY . .
# Expose debugging port
EXPOSE 9229
# Command to run the application
CMD ["npm", "run", "start:debug"]
3. Build Docker Image
Build your Docker image:
docker build -t my-nest-app .
4. Run Docker Container
Run your Docker container, mapping the debugging port to a port on your host machine:
docker run -p 3000:3000 -p 9229:9229 my-nest-app
5. Attach Debugger
In your development environment (e.g., Visual Studio Code), attach your debugger to localhost:9229
.
With these steps and configurations, you should be able to debug your NestJS application running inside a Docker container effectively.