Docker-Compose Lab

In this lab we will create and deploy our container with docker compose
We will build and deploy 2 separate apps (nodejs servers) using a single compose file

Table Of Context:

Preparations

First review the server code located at the folders named server
Both of the servers should be the same code with a single difference -
- The port which the server listen on.

// The server code - same beside port and output string
const
    // Set the server port which wiill be listenig to
    // Those 2 values are passed from the compose file
    SERVER_PORT = process.env.port,
    SERVER_NAME = process.env.name,

    // Other required libraries
    os = require('os'),
    fs = require('fs-extra'),
    FILE_NAME = `/shared_volume/shared.log`;

// Create the basic http server
require('http')
    .createServer((request, response) => {

        // Write to the shared folder
        fs.ensureFile(FILE_NAME);
        fs.appendFile(FILE_NAME, `Hello from ${SERVER_NAME}. ${request.url}${os.EOL}`);

        // Send reply to user
        response.end(`<h1>Hello from server1.</h1>`);

    }).listen(SERVER_PORT, () => {
        // Notify users that the server is up and running
        console.log(`Server is up. 
            Please click or point your browser to:
            http://localhost:${SERVER_PORT}`);
    });

Next to the server there is the package.json file which is required for building the app

Creating Dockerfile

The next step is pack the app as Docker container.
To do so we need a Dockerfile.
Here is the Dockerfile for server1 (same)

# Our server is based upon nodejs
FROM node

# Copy the local server code to our container
# Important !!! dont forget the [.] which means the local folder
COPY server.js .
COPY package.json .

# Install the npms
RUN npm i 

# Start the server once the ocntainer is running
CMD node ./server1.js

Creating the compose file

# We are using version 2
version: "2"

# Define the deployed services
services:

    # Server1
    server1:
        build: server

        # Server 1 will listen on port 3000
        ports:
        - "3000:3000"
    
    # The shared volume for both servers
    volumes:
    - "./shared_volume:/shared_volume"
    restart: always
    
    ###
    ### Here we pass the environment (runtime) values
    ###  
    environment:
      port: 3000
      name: 'Server1'
  
  # Same comments as for server1 but with port 5000
  server2:
    build: server
    ports:
    - "5000:5000"
    volumes:
    - "./shared_volume:/shared_volume"
    environment:
      port: 5000
      name: 'Server2'

Build and run the compose

Build the composed servers

$ docker-compose build
Building server1
Step 1/5 : FROM node
---> 760e12e87878
Step 2/5 : COPY server.js .
---> Using cache
---> d39e9dd85c99
Step 3/5 : COPY package.json .
---> Using cache
---> 68f538521089
Step 4/5 : RUN npm i
---> Using cache
---> 2b8f7da6a48b
Step 5/5 : CMD node ./server.js
---> Using cache
---> c145d38b5c17
Successfully built c145d38b5c17
Successfully tagged docker-compose_server1:latest
Building server2
Step 1/5 : FROM node
---> 760e12e87878
Step 2/5 : COPY server.js .
---> Using cache
---> d39e9dd85c99
Step 3/5 : COPY package.json .
---> Using cache
---> 68f538521089
Step 4/5 : RUN npm i
---> Using cache
---> 2b8f7da6a48b
Step 5/5 : CMD node ./server.js
---> Using cache
---> c145d38b5c17
Successfully built c145d38b5c17
Successfully tagged docker-compose_server2:latest

Run the compose and open your browser to see the messages

$ docker-compose up
Starting docker-compose_server2_1 ... done
Starting docker-compose_server1_1 ... done
Attaching to docker-compose_server2_1, docker-compose_server1_1
server2_1  | Server2 is up.
server2_1  |             Please click or point your browser to:
server2_1  |             http://localhost:5000
server1_1  | Server1 is up.
server1_1  |             Please click or point your browser to:
server1_1  |             http://localhost:3000

nirgeier/DockerComposeLabs

Docker-Compose Lab

Table Of Context:

Preparations

Creating Dockerfile

Creating the compose file

Build and run the compose