Unlocking Seamless Communication: How to Grant Communication Between NG App and NESTJS API in Docker Env Using Remote IP of Docker Host

Are you struggling to connect your Angular (NG) application with your NestJS API in a Docker environment? Do you find yourself lost in a maze of containerization and networking? Fear not, dear developer! In this comprehensive guide, we’ll take you by the hand and walk you through the process of granting communication between your NG app and NestJS API in a Docker environment, using the remote IP of the Docker host.

Prerequisites

Before we dive into the juicy stuff, make sure you have the following setup:

• A Docker environment with a running container for your NestJS API
• An Angular application created using the Angular CLI
• A basic understanding of Docker networking and containerization

Understanding the Problem

When you run your NestJS API in a Docker container, it’s isolated from the outside world, including your Angular application. By default, Docker containers cannot communicate with each other or the host machine. This is a security feature, but it can be a major hurdle when you need to connect your frontend and backend.

One solution is to use the `–network` flag when running your Docker container, but this can lead to complexity and difficulties in managing your application’s network topology. Instead, we’ll focus on using the remote IP of the Docker host to establish communication between your NG app and NestJS API.

Step 1: Get the Docker Host IP

To communicate with your NestJS API from your Angular application, you’ll need to get the IP address of the Docker host. You can do this using the following command:

docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' <container_name>

Replace `` with the name of your NestJS API container. This command will output the IP address of the Docker host.

Step 2: Update Your NestJS API

In your NestJS API, you need to configure the server to listen on the IP address and port you want to use for communication. In this example, we’ll use port 3000:

import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  app.listen(3000, '0.0.0.0');
}

In the code above, we’re telling NestJS to listen on all available network interfaces (`0.0.0.0`) and on port 3000.

Step 3: Update Your Angular Application

In your Angular application, you need to update your API calls to use the remote IP of the Docker host and the port you specified in your NestJS API. You can do this by creating a proxy configuration file (`proxy.conf.json`) with the following content:

{
  "/api": {
    "target": "http://<docker_host_ip>:3000",
    "changeOrigin": true,
    "pathRewrite": { "^/api": "" }
  }
}

Replace `` with the IP address you obtained in Step 1. This configuration tells Angular to proxy requests to your NestJS API using the remote IP and port.

Step 4: Run Your Angular Application with the Proxy

To run your Angular application with the proxy configuration, use the following command:

ng serve --proxy-config proxy.conf.json

This will start your Angular application and configure it to use the proxy settings.

Step 5: Test Your Application

Finally, open your Angular application in a web browser and test the API calls. You should see the data fetched from your NestJS API.

Troubleshooting Tips

If you encounter issues, check the following:

• Verify that your NestJS API is running and listening on the correct port
• Check that your Angular application is configured to use the correct proxy settings
• Ensure that the Docker host IP address is reachable from your Angular application

Conclusion

With these simple steps, you’ve successfully granted communication between your NG app and NestJS API in a Docker environment using the remote IP of the Docker host. This approach allows you to keep your application’s network topology simple while still enabling seamless communication between your frontend and backend.

Remember to update your `proxy.conf.json` file whenever you change the IP address or port of your NestJS API. Happy coding!

Bonus: Additional Docker Networking Concepts

If you’re interested in exploring more advanced Docker networking concepts, here are a few terms to get you started:

Concept	Description
Bridge Network	A default network created by Docker, which allows containers to communicate with each other.
Host Network	A network that allows containers to use the host machine’s network stack, providing direct access to the host’s IP address and ports.
Custom Network	A user-defined network that allows containers to communicate with each other in a isolated environment.
Service Discovery	A mechanism that allows containers to discover and communicate with each other using a service name, rather than IP addresses.

These concepts can help you design a more robust and scalable network architecture for your application. However, for the purposes of this guide, using the remote IP of the Docker host provides a simple and effective solution for granting communication between your NG app and NestJS API.

I hope you found this article helpful! If you have any questions or need further clarification, please don’t hesitate to ask.

Frequently Asked Question

Are you struggling to establish communication between your NG App and NESTJS Api in a Docker environment, using the remote IP of the Docker host? Worry not, friend! We’ve got you covered!