Microservices with NodeJS

A simple example of a Node App using Microservices, Docker and Nginx.

Containers

• Installation for Windows:

  • https://hub.docker.com/editions/community/docker-ce-desktop-windows/
  • You may need the Linux Kernel update package: https://docs.microsoft.com/en-us/windows/wsl/wsl2-kernel
  • $ docker version
  • You can also run $ docker run hello-world to verify that Docker can pull and run images.

• Configuration:

  • Dockerfile is an environment file to specify how Docker should package your application, so it can be reproduced anywhere.
    • FROM base container;
    • COPY . /{sourceFolder} copy everything in the current directory to the source folder;
    • WORKDIR /{sourceFolder} all the commands will run inside this sourced folder;
    • RUN run the main commands/scripts, such as installing all the dependencies: npm install --production;
    • EXPOSE {port} expose the port of this container to be available for others containers;
    • CMD command that will run when the container starts running. e.g.: npm start.
  • docker-compose.yml is a YAML file to configure your application’s services. Then, with a single command, you create and start all the services from your configuration: $ docker-compose up

• Main Commands:

  • Run a new Container: $ docker run {IMAGE}

    • Flags:
      • --name {CONTAINER} assign a name
      • -p {HOSTPORT}:{CONTAINERPORT} map a port
      • -it interactive terminal (what's going on)
      • -d {IMAGE} start container in background
      • --hostname {HOSTNAME} assign a hostname
      • --add-host {HOSTNAME}:{IP} add a DNS entry
    • Example of running mongo in a Docker container: $ docker run -d -p 27017:27017 mongo

  • Manage Containers:

    • $ docker ps list of running containers
    • $ docker ps -a list of all containers
    • $ docker stop {CONTAINER} stop a running container. You can use just the first few characters of it: $ docker stop e8
    • $ docker stop $(docker ps -aq) stop all the containers.
    • $ docker start {CONTAINER} start a stopped container
    • $ docker rm {CONTAINER} delete a container
    • $ docker rm -f {CONTAINER} delete a running container
    • $ docker container prune delete stopped containers

  • Manage Images:

    • $ docker images show a list of all images
    • $ docker pull {IMAGE} download an image
    • $ docker rmi {IMAGE} delete an image
    • $ docker images prune delete dangling images
    • $ docker images prune -a delete all unused images

  • Info & Stats:

    • $ docker logs {CONTAINER} show the logs of a container
    • $ docker stats show stats of running containers

Nginx

NGINX is open source software for web serving, reverse proxying, caching, load balancing,...NGINX can also function as a proxy server for email (IMAP, POP3, and SMTP) and a reverse proxy and load balancer for HTTP, TCP, and UDP servers.

• default.conf set the basic configuration for web serving:

  • try_files will look for files in the root (srv/www/static), and if it's not found it will use the @web location/microservice.

      root /srv/www/static;
      location / {
        # Get static files from nginx first
        try_files $uri $uri/ @web;
      }
      location @web {
        proxy_pass http://web:3000;
      }
    

    localhost:3000 < --- > localhost:8080