This tutorial is out of date and no longer maintained.
Note: Update: 30/03/2019
This article has been updated based on the updates to both docker
and angular
since this article was written. The current version of angular
is 7, the updates also adds an attached docker volume to the angular
client so that you don’t need to run docker-compose
build every time.
Docker allows us to run applications inside containers. These containers in most cases communicate with each other.
Docker containers wrap a piece of software in a complete filesystem that contains everything needed to run: code, runtime, system tools, system libraries – anything that can be installed on a server. This guarantees that the software will always run the same, regardless of its environment.
We’ll build an angular app in one container, point it to an Express API in another container, which connects to MongoDB in another container.
If you haven’t worked with Docker before, this would be a good starting point as we will explain every step covered, in some detail.
You need to have docker and docker-compose installed in your setup. Instructions for installing docker in your given platform can be found here.
Instructions for installing docker-compose can be found here.
Verify your installation by running:
- docker -v
OutputDocker version 18.09.2, build 6247962
- docker-compose -v
Outputdocker-compose version 1.23.2, build 1110ad01
- node -v
Outputv11.12.0
Next, you need to know how to build a simple Angular app and an Express App. We’ll be using the Angular CLI to build a simple app.
We’ll now separately build out these three parts of our app. The approach we are going to take is building the app in our local environment, then dockerizing the app.
Once these are running, we’ll connect the three docker containers. Note that we are only building two containers, Angular and the Express/Node API. The third container will be from a MongoDB image that we’ll just pull from the Docker Hub.
Docker Hub is a repository for docker images. It’s where we pull down official docker images such as MongoDB, NodeJs, Ubuntu, and we can also create custom images and push them to Docker Hub for other people to pull and use.
Let’s create a directory for our whole setup, we’ll call it mean-docker
.
- mkdir mean-docker
Next, we’ll create an Angular app and make sure it runs in a docker
container.
Create a directory called angular-client
inside the mean-docker
directory we created above, and initialize an Angular App with the Angular CLI.
We’ll use npx
, a tool that allows us to run CLI apps without installing them into our system. It comes preinstalled when you install Node.js since version 5.2.0
- npx @angular/cli new angular-client
? Would you like to add Angular routing? No
? Which stylesheet format would you like to use? CSS
This scaffolds an Angular app, and npm installs the app’s dependencies. Our directory structure should be like this
└── mean-docker
└── angular-client
├── README.md
├── angular.json
├── e2e
├── node_modules
├── package.json
├── package-lock.json
├── src
├── tsconfig.json
└── tslint.json
Running npm start, inside the angular-client
directory should start the angular app at http://localhost:4200
.
To dockerize any app, we usually need to write a Dockerfile
A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image.
To quickly brainstorm on what our angular app needs in order to run,
package.json
file has it as a dependency, so it’s not a requirement.localhost:4200
.npm start
in the container, which in turn runs ng serve
since it’s a script in the package.json
file, created from the image and our app should run.Those are the exact instructions we are going to write in our Dockerfile.
# Create image based on the official Node 10 image from dockerhub
FROM node:10
# Create a directory where our app will be placed
RUN mkdir -p /app
# Change directory so that our commands run inside this new directory
WORKDIR /app
# Copy dependency definitions
COPY package*.json /app/
# Install dependencies
RUN npm install
# Get all the code needed to run the app
COPY . /app/
# Expose the port the app runs in
EXPOSE 4200
# Serve the app
CMD ["npm", "start"]
I’ve commented on the file to show what each instruction clearly does.
Note: Before we build the image, if you are keen, you may have noticed that the line COPY . /app/
copies our whole directory into the container, including node_modules
. To ignore this, and other files that are irrelevant to our container, we can add a .dockerignore
file and list what is to be ignored. This file is usually sometimes identical to the .gitignore
file.
Create a .dockerignore
file.
node_modules/
One last thing we have to do before building the image is to ensure that the app is served from the host created by the docker
image. To ensure this, go into your package.json
and change the start
script to:
{
...
"scripts": {
"start": "ng serve --host 0.0.0.0",
...
},
...
}
To build the image we will use docker build
command. The syntax is
- docker build -t <image_tag>:<tag> <directory_with_Dockerfile>
Make sure you are in the mean_docker/angular-client
directory, then build your image.
- cd angular-client
- docker build -t angular-client:dev .
-t
is a shortform of --tag
, and refers to the name or tag given to the image to be built. In this case the tag will be angular-client:dev
.
The .
(dot) at the end refers to the current directory. Docker will look for the Dockerfile in our current directory and use it to build an image.
This could take a while depending on your internet connection.
Now that the image is built, we can run a container based on that image, using this syntax
- docker run -d --name <container_name> -p <host-port:exposed-port> <image-name>
The -d
flag tells docker
to run the container in detached
mode. Meaning, it will run and get you back to your host, without going into the container.
- docker run -d --name angular-client -p 4200:4200 angular-client:dev 8310253fe80373627b2c274c5a9de930dc7559b3dc8eef4abe4cb09aa1828a22
--name
refers to the name that will be assigned to the container.
-p
or --port
refers to which port our host machine should point to in the docker
container. In this case, localhost:4200
should point to dockerhost:4200
, and thus the syntax 4200:4200
.
Visit localhost:4200
in your host browser should be serving the angular
app from the container.
You can stop the container running with:
- docker stop angular-client
We’ve containerized the angular
app, we are now two steps away from our complete setup.
Containerizing an express app should now be straightforward. Create a directory in the mean-docker
directory called express-server
.
- mkdir express-server
Add the following package.json
file inside the app.
{
"name": "express-server",
"version": "0.0.0",
"private": true,
"scripts": {
"start": "node server.js"
},
"dependencies": {
"body-parser": "~1.15.2",
"express": "~4.14.0"
}
}
Then, we’ll create a simple express app inside it. Create a file server.js
- cd express-serve
- touch server.js
- mkdir routes && cd routes
- touch api.js
// Get dependencies
const express = require('express');
const path = require('path');
const http = require('http');
const bodyParser = require('body-parser');
// Get our API routes
const api = require('./routes/api');
const app = express();
// Parsers for POST data
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
// Set our api routes
app.use('/', api);
// Get port from environment and store in Express.
const port = process.env.PORT || '3000';
app.set('port', port);
// Create HTTP server.
const server = http.createServer(app);
// Listen on provided port, on all network interfaces.
server.listen(port, () => console.log(`API running on localhost:${port}`));
[labe mean-docker/express-server/routes/api.js]
const express = require('express');
const router = express.Router();
// GET api listing.
router.get('/', (req, res) => {
res.send('api works');
});
module.exports = router;
This is a simple express
app, install the dependencies and start the app.
- npm install
- npm start
Going to localhost:3000
in your browser should serve the app.
To run this app inside a Docker container, we’ll also create a Dockerfile for it. It should be pretty similar to what we already have for the angular-client
.
# Create image based on the official Node 6 image from the dockerhub
FROM node:6
# Create a directory where our app will be placed
RUN mkdir -p /usr/src/app
# Change directory so that our commands run inside this new directory
WORKDIR /usr/src/app
# Copy dependency definitions
COPY package.json /usr/src/app
# Install dependencies
RUN npm install
# Get all the code needed to run the app
COPY . /usr/src/app
# Expose the port the app runs in
EXPOSE 3000
# Serve the app
CMD ["npm", "start"]
You can see the file is pretty much the same as the angular-client
Dockerfile, except for the exposed port.
You could also add a .dockerignore
file to ignore files we do not need.
node_modules/
We can then build the image and run a container based on the image with:
- docker build -t express-server:dev .
- docker run -d --name express-server -p 3000:3000 express-server:dev
Going to localhost:3000
in your browser should serve the API.
Once you are done, you can stop the container with
- docker stop express-server
The last part of our MEAN setup, before we connect them all together is the MongoDB. Now, we can’t have a Dockerfile to build a MongoDB image, because one already exists from the Docker Hub. We only need to know how to run it.
Assuming we had a MongoDB image already, we’d run a container based on the image with
- docker run -d --name mongodb -p 27017:27017 mongo
The image name in this instance is mongo
, the last parameter, and the container name will be mongodb
.
Docker will check to see if you have a mongo image already downloaded, or built. If not, it will look for the image in the Dockerhub. If you run the above command, you should have a mongodb
instance running inside a container.
To check if MongoDB is running, simply go to http://localhost:27017
in your browser, and you should see this message. It looks like you are trying to access MongoDB over HTTP on the native driver port.
Alternatively, if you have mongo installed in your host machine, simply run mongo
in the terminal. And it should run and give you the mongo shell, without any errors.
To connect and run multiple containers with docker, we use Docker Compose.
Compose is a tool for defining and running multi-container Docker applications. With Compose, you use a Compose file to configure your application’s services. Then, using a single command, you create and start all the services from your configuration.
docker-compose
is usually installed when you install docker
. So to simply check if you have it installed, run:
- docker-compose
You should see a list of commands from docker-compose. If not, you can go through the installation here
Note: Ensure that you have docker-compose version 1.6 and above by running docker-compose -v
Create a docker-compose.yml
file at the root of our setup.
- touch docker-compose.yml
Our directory tree should now look like this.
.
├── angular-client
├── docker-compose.yml
└── express-server
Then edit the docker-compose.yml
file
version: '2' # specify docker-compose version
# Define the services/containers to be run
services:
angular: # name of the first service
build: angular-client # specify the directory of the Dockerfile
ports:
- "4200:4200" # specify port forewarding
express: #name of the second service
build: express-server # specify the directory of the Dockerfile
ports:
- "3000:3000" #specify ports forwarding
database: # name of the third service
image: mongo # specify image to build container from
ports:
- "27017:27017" # specify port forwarding
The docker-compose.yml
file is a simple configuration file telling docker-compose
which containers to build. That’s pretty much it.
Now, to run containers based on the three images, simply run
- docker-compose up
This will build the images if not already built, and run them. Once it’s running, and your terminal looks something like this.
You can visit all three apps: http://localhost:4200
, http://localhost:3000
, or mongodb://localhost:27017
. And you’ll see that all three containers are running.
Finally, the fun part.
We now finally need to connect the three containers. We’ll first create a simple CRUD feature in our API using mongoose. You can go through Easily Develop Node.js and MongoDB Apps with Mongoose to get a more detailed explanation of mongoose.
First of all, add mongoose
to your express
server package.json
{
"name": "express-server",
"version": "0.0.0",
"private": true,
"scripts": {
"start": "node server.js"
},
"dependencies": {
"body-parser": "~1.15.2",
"express": "~4.14.0",
"mongoose": "^4.7.0"
}
}
We need to update our API to use MongoDB:
// Import dependencies
const mongoose = require('mongoose');
const express = require('express');
const router = express.Router();
// MongoDB URL from the docker-compose file
const dbHost = 'mongodb://database/mean-docker';
// Connect to mongodb
mongoose.connect(dbHost);
// create mongoose schema
const userSchema = new mongoose.Schema({
name: String,
age: Number
});
// create mongoose model
const User = mongoose.model('User', userSchema);
// GET api listing.
router.get('/', (req, res) => {
res.send('api works');
});
// GET all users.
router.get('/users', (req, res) => {
User.find({}, (err, users) => {
if (err) res.status(500).send(error)
res.status(200).json(users);
});
});
// GET one users.
router.get('/users/:id', (req, res) => {
User.findById(req.param.id, (err, users) => {
if (err) res.status(500).send(error)
res.status(200).json(users);
});
});
// Create a user.
router.post('/users', (req, res) => {
let user = new User({
name: req.body.name,
age: req.body.age
});
user.save(error => {
if (error) res.status(500).send(error);
res.status(201).json({
message: 'User created successfully'
});
});
});
module.exports = router;
Two main differences, first of all, our connection to MongoDB is in the line const dbHost = 'mongodb://database/mean-docker';
. This database
is the same as the database service we created in the docker-compose
file.
We’ve also added rest routes GET /users
, GET /users/:id
and POST /user
.
Update the docker-compose
file, telling the express service to link to the database service.
version: '2' # specify docker-compose version
# Define the services/containers to be run
services:
angular: # name of the first service
build: angular-client # specify the directory of the Dockerfile
ports:
- "4200:4200" # specify port forewarding
volumes:
- ./angular-client:/app # this will enable changes made to the angular app reflect in the container
express: #name of the second service
build: express-server # specify the directory of the Dockerfile
ports:
- "3000:3000" #specify ports forewarding
links:
- database
database: # name of the third service
image: mongo # specify image to build container from
ports:
- "27017:27017" # specify port forwarding
The links
property of the docker-compose file creates a connection to the other service with the name of the service as the hostname. In this case database
will be the hostname. Meaning, to connect to it from the express
service, we should use database:27017
. That’s why we made the dbHost
equal to mongodb://database/mean-docker
.
Also, I’ve added a volume to the angular
service. This will enable changes we make to the Angular App to automatically trigger recompilation in the container
The last part is to connect the Angular app to the express server. To do this, we’ll need to make some modifications to our angular
app to consume the express
API.
Add the Angular HTTP Client.
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { HttpClientModule } from '@angular/common/http'; // add http client module
import { AppComponent } from './app.component';
@NgModule({
declarations: [
AppComponent
],
imports: [
BrowserModule,
HttpClientModule // import http client module
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
import { Component, OnInit } from '@angular/core';
import { HttpClient } from '@angular/common/http';
@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit {
title = 'app works!';
// Link to our api, pointing to localhost
API = 'http://localhost:3000';
// Declare empty list of people
people: any[] = [];
constructor(private http: HttpClient) {}
// Angular 2 Life Cycle event when component has been initialized
ngOnInit() {
this.getAllPeople();
}
// Add one person to the API
addPerson(name, age) {
this.http.post(`${this.API}/users`, {name, age})
.subscribe(() => {
this.getAllPeople();
})
}
// Get all users from the API
getAllPeople() {
this.http.get(`${this.API}/users`)
.subscribe((people: any) => {
console.log(people)
this.people = people
})
}
}
Angular best practices guides usually recommend separating most logic into a service/provider. We’ve placed all the code in the component here for brevity.
We’ve imported the OnInit
interface, to call events when the component is initialized, then added two methods AddPerson
and getAllPeople
, that call the API.
Notice that this time around, our API
is pointing to localhost
. This is because while the Angular 2 app will be running inside the container, it’s served to the browser. And the browser is the one that makes requests. It will thus make a request to the exposed Express API. As a result, we don’t need to link Angular and Express in the docker-compose.yml
file.
Next, we need to make some changes to the template. I first added bootstrap via CDN to the index.html
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Angular Client</title>
<base href="/">
<meta name="viewport" content="width=device-width, initial-scale=1">
<!-- Bootstrap CDN -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.2/css/bootstrap.min.css">
<link rel="icon" type="image/x-icon" href="favicon.ico">
</head>
<body>
<app-root>Loading...</app-root>
</body>
</html>
Then update the app.component.html
template
<!-- Bootstrap Navbar -->
<nav class="navbar navbar-light bg-faded">
<div class="container">
<a class="navbar-brand" href="#">Mean Docker</a>
</div>
</nav>
<div class="container">
<h3>Add new person</h3>
<form>
<div class="form-group">
<label for="name">Name</label>
<input type="text" class="form-control" id="name" #name>
</div>
<div class="form-group">
<label for="age">Age</label>
<input type="number" class="form-control" id="age" #age>
</div>
<button type="button" (click)="addPerson(name.value, age.value)" class="btn btn-primary">Add person</button>
</form>
<h3>People</h3>
<!-- Bootstrap Card -->
<div class="card card-block col-md-3" *ngFor="let person of people">
<h4 class="card-title">{{person.name}} {{person.age}}</h4>
</div>
</div>
The above template shows the components’ properties and bindings. We are almost done.
Since we’ve made changes to our code, we need to do a build for our Docker Compose
- docker-compose up --build
The --build
flag tells docker compose
that we’ve made changes and it needs to do a clean build of our images.
Once this is done, go to localhost:4200
in your browser,
We are getting a No 'Access-Control-Allow-Origin'
error. To quickly fix this, we need to enable Cross-Origin
in our express
app. We’ll do this with a simple middleware.
// Code commented out for brevity
// Parsers for POST data
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
// Cross Origin middleware
app.use(function(req, res, next) {
res.header("Access-Control-Allow-Origin", "*")
res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept")
next()
})
// Set our api routes
app.use('/', api);
// Code commented out for brevity
We can now run docker-compose
again with the build
flag. You should be in the mean-docker
directory.
- docker-compose up --build
Going to localhost:4200
on the browser.
Note: I added an attached volume to the docker-compose
file, and we now no longer need to rebuild the service every time we make a change.
I bet you’ve learned a thing or two about MEAN or docker
and docker-compose
.
The problem with our set up however is that any time we make changes to either the angular
app or the express
API, we need to run docker-compose up --build
.
This can get tedious or even boring over time. We’ll look at this in another article.
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