├── LICENSE
├── README.md
└── solutions
├── 1-express-web-server
├── app.js
└── package.json
├── 2-dockerized-web-server
├── Dockerfile
├── Dockerfile.ubuntu
├── app.js
└── package.json
└── 3-chat-app
├── chat
├── Dockerfile
├── app.js
└── package.json
├── diceroll
├── Dockerfile
├── app.js
└── package.json
└── docker-compose.yml
/LICENSE:
--------------------------------------------------------------------------------
1 | GNU AFFERO GENERAL PUBLIC LICENSE
2 | Version 3, 19 November 2007
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4 | Copyright (C) 2007 Free Software Foundation, Inc.
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575 | by the Free Software Foundation.
576 |
577 | If the Program specifies that a proxy can decide which future
578 | versions of the GNU Affero General Public License can be used, that proxy's
579 | public statement of acceptance of a version permanently authorizes you
580 | to choose that version for the Program.
581 |
582 | Later license versions may give you additional or different
583 | permissions. However, no additional obligations are imposed on any
584 | author or copyright holder as a result of your choosing to follow a
585 | later version.
586 |
587 | 15. Disclaimer of Warranty.
588 |
589 | THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
590 | APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
591 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
592 | OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
593 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
594 | PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
595 | IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
596 | ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
597 |
598 | 16. Limitation of Liability.
599 |
600 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
601 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
602 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
603 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
604 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
605 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
606 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
607 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
608 | SUCH DAMAGES.
609 |
610 | 17. Interpretation of Sections 15 and 16.
611 |
612 | If the disclaimer of warranty and limitation of liability provided
613 | above cannot be given local legal effect according to their terms,
614 | reviewing courts shall apply local law that most closely approximates
615 | an absolute waiver of all civil liability in connection with the
616 | Program, unless a warranty or assumption of liability accompanies a
617 | copy of the Program in return for a fee.
618 |
619 | END OF TERMS AND CONDITIONS
620 |
621 | How to Apply These Terms to Your New Programs
622 |
623 | If you develop a new program, and you want it to be of the greatest
624 | possible use to the public, the best way to achieve this is to make it
625 | free software which everyone can redistribute and change under these terms.
626 |
627 | To do so, attach the following notices to the program. It is safest
628 | to attach them to the start of each source file to most effectively
629 | state the exclusion of warranty; and each file should have at least
630 | the "copyright" line and a pointer to where the full notice is found.
631 |
632 |
633 | Copyright (C)
634 |
635 | This program is free software: you can redistribute it and/or modify
636 | it under the terms of the GNU Affero General Public License as published
637 | by the Free Software Foundation, either version 3 of the License, or
638 | (at your option) any later version.
639 |
640 | This program is distributed in the hope that it will be useful,
641 | but WITHOUT ANY WARRANTY; without even the implied warranty of
642 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
643 | GNU Affero General Public License for more details.
644 |
645 | You should have received a copy of the GNU Affero General Public License
646 | along with this program. If not, see .
647 |
648 | Also add information on how to contact you by electronic and paper mail.
649 |
650 | If your software can interact with users remotely through a computer
651 | network, you should also make sure that it provides a way for users to
652 | get its source. For example, if your program is a web application, its
653 | interface could display a "Source" link that leads users to an archive
654 | of the code. There are many ways you could offer source, and different
655 | solutions will be better for different programs; see section 13 for the
656 | specific requirements.
657 |
658 | You should also get your employer (if you work as a programmer) or school,
659 | if any, to sign a "copyright disclaimer" for the program, if necessary.
660 | For more information on this, and how to apply and follow the GNU AGPL, see
661 | .
662 |
--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
1 | # lauzhack-docker-workshop
2 |
3 | Materials for the LauzHack Days workshop on "Intro to Docker" (April 11, 2022)
4 |
5 | Inspired by https://github.com/ageapps/lauzhack-docker-workshop
6 |
7 | ## Setup
8 |
9 | - Install a code editor (example: [Visual Studio Code](https://code.visualstudio.com/))
10 |
11 | - Install [NodeJS](https://nodejs.org/en/) ([Linux](https://nodejs.org/en/download/package-manager/), [MacOS](https://nodejs.org/dist/v16.14.2/node-v16.14.2.pkg), [Windows](https://nodejs.org/dist/v16.14.2/node-v16.14.2-x86.msi)) a JavaScript runtime execution environment for back-end and desktop systems to write and run general-purpose JavaScript code
12 |
13 | - Install [Docker Engine](https://docs.docker.com/engine/install/)
14 |
15 | - Install [Docker Compose](https://docs.docker.com/compose/install/) (depending on your system, this step is not required if you installed Docker through Docker Desktop)
16 |
17 | - Create a new directory for the project (for instance in your `Documents` folder) and move inside:
18 | ```bash
19 | cd ~/Documents
20 | mkdir lauzhack-docker-workshop
21 | cd lauzhack-docker-workshop
22 | ```
23 |
24 | ## Task 1
25 |
26 | In this task, we will write a simple web server using [ExpressJS](https://expressjs.com/), a popular web framework library. We will simply display a Hello World message to visitors.
27 |
28 | ```bash
29 | mkdir express-web-server
30 | cd express-web-server
31 | ```
32 |
33 | Initialize a new project (press Enter until `npm` stops asking for input):
34 |
35 | ```bash
36 | npm init
37 | ```
38 |
39 | Install the Express dependency:
40 |
41 | ```bash
42 | npm install express
43 | ```
44 |
45 | You should now see a "node_modules" folder, a "package.json" file and a "package-lock.json" file in your folder. These files contain all the dependencies of your software.
46 |
47 | Create a new file named `app.js` copy the following web server code:
48 |
49 | ```js
50 | // import and initialize dependencies
51 | const express = require('express')
52 | const app = express()
53 |
54 | const port = 3000
55 |
56 | // define a text "Hello World!" response on the root GET route
57 | // i.e. when a client performs a request to http://:3000
58 | app.get('/', (req, res) => {
59 | res.send('Hello World!')
60 | })
61 |
62 | // wait for requests indefinitely
63 | app.listen(port, () => {
64 | console.log(`Example app listening on port ${port}`)
65 | })
66 | ```
67 |
68 | That's it! You now have a working web server.
69 |
70 | Once this is complete, you should be able to run and access your web server with:
71 |
72 | ```bash
73 | node app.js
74 | ```
75 |
76 | And then by typing http://localhost:3000 in your web browser. You should see a "Hello World!" message.
77 |
78 | ## Task 2
79 |
80 | We will now dockerize this web application by writing a Dockerfile. Create a new file named `Dockerfile` (no extension) in the project directory and write the instructions to build an image which will contain the application.
81 |
82 | Hints: find each [Dockerfile instruction in the reference](https://docs.docker.com/engine/reference/builder/) which does the following:
83 |
84 | - Start with the [`node` base image](https://hub.docker.com/_/node?tab=description), specifically the `lts-alpine` tag, which is the latest long-term support NodeJS distribution based on Alpine Linux (a very slim image) and which will contain the NodeJS runtime.
85 | - Set the working directory inside your container to the `/app` folder for instance
86 | - Copy `package.json` and `app.js` into the container to this same folder
87 | - Install the dependencies inside the container using `npm install`
88 | - As a good practice, document the port to expose (3000)
89 | - Change the user to an unprivileged user (the `node` image already includes an unprivileged user named `node`). In general, the default user is root by default, it is hence a good practice to use a least privileged user (in case an attacker is able to escape the process sandbox).
90 | - Instruct Docker to run the application with the same command as before
91 |
92 | You can now build your application into an immutable image with name `express-web-server` and a tag `v1`:
93 |
94 | ```bash
95 | docker build -t express-web-server:v1 .
96 | ```
97 |
98 | Once successfully built, run the container using
99 |
100 | ```bash
101 | docker run -d -p 3000:3000 express-web-server:v1
102 | ```
103 |
104 | The `-p` (publish) option binds the internal port 3000 inside the container to the local host port 3000 of the machine.
105 |
106 | You should be able to access the web server again using your web browser at http://localhost:3000.
107 |
108 | You can also list running containers using:
109 |
110 | ```
111 | docker ps
112 | ```
113 |
114 | To stop the container (since we did not implement graceful handling of `SIGTERM` in our application), find the container id using `docker ps` and then:
115 |
116 | ```
117 | docker kill
118 | ```
119 |
120 | ### Level up
121 |
122 | - Now run the the container using the following command: `docker run -d -p 8000:3000 express-web-server:v1`. On what virtual and local ports does the app run, and what is the URL that you should now type in your web browser to see your app?
123 |
124 | - Create a new `Dockerfile` using the newest `current-alpine` NodeJS image version, and give it a new tag `v2`.
125 |
126 | - Run locally 2 versions of the app with both versions of Node.js (use different host ports)
127 |
128 | - In `app.js`, replace
129 | ```diff
130 | - const port = 3000
131 | + const port = process.env.PORT || 3000
132 | ```
133 | Use the `-e` option to change the virtual port of the container
134 |
135 | - Create a new `Dockerfile` and instead of using the `node` base image, start with the [`ubuntu:latest`](https://hub.docker.com/_/ubuntu) base image.
136 | - You will need to automate the installation of NodeJS inside the container, as well as create an unprivileged `node` user
137 |
138 | ## Task 3
139 |
140 | In this task, we will create a more complex application composed of multiple services. We will build a real-time chat application, which is able to persist messages into a [MongoDB](https://www.mongodb.com/) database instance, which can send real-time updates to clients, and which can query a dice roll service to get random numbers through the virtual network.
141 |
142 | ### Dice roll microservice
143 |
144 | Go back to the folder you first created, e.g. `~/Documents/lauzhack-docker-workshop` and create a new directory named `diceroll` and access inside of it:
145 |
146 | ```bash
147 | cd ~/Documents/lauzhack-docker-workshop
148 | mkdir diceroll
149 | cd diceroll
150 | ```
151 |
152 | We will create a microservice which will generate a dice roll on each request:
153 |
154 | ```
155 | npm init
156 | npm install express
157 | ```
158 |
159 | Create a new file `app.js` and copy the following content:
160 |
161 | ```js
162 | const express = require('express')
163 | const app = express()
164 | const port = 3001
165 |
166 | function rollDice() {
167 | // random integer between 1 and 6
168 | return Math.floor(Math.random() * 6) + 1;
169 | }
170 |
171 | app.get('/', (req, res) => {
172 | // return the value as structured JSON
173 | res.json({ value: rollDice() })
174 | })
175 |
176 | app.listen(port, () => {
177 | console.log(`Example app listening on port ${port}`)
178 | })
179 | ```
180 |
181 | You can now roll random numbers by running:
182 |
183 | ```bash
184 | node app.js
185 | ```
186 |
187 | in the `diceroll` folder and accessing http://localhost:3001/ (notice the 300**1**). Refresh the page for new random numbers.
188 |
189 | Create a new `Dockerfile` and copy the following contents:
190 |
191 | ```Dockerfile
192 | FROM node:lts-alpine
193 |
194 | WORKDIR /app
195 |
196 | COPY . /app
197 |
198 | RUN npm install
199 |
200 | EXPOSE 3001
201 |
202 | USER node
203 |
204 | CMD ["node", "app.js"]
205 | ```
206 |
207 | ### Chat application
208 |
209 | Go back to the folder you first created, e.g. `~/Documents/lauzhack-docker-workshop` and create a new directory named `chat` and access inside of it:
210 |
211 | ```bash
212 | cd ~/Documents/lauzhack-docker-workshop
213 | mkdir chat
214 | cd chat
215 | ```
216 |
217 | We will create yet another microservice for the main chat application:
218 |
219 | ```
220 | npm init
221 | npm install express bulma socket.io mongodb cross-fetch
222 | ```
223 |
224 | We use `bulma` as CSS library to style our front-end, `socket.io` to provide real-time communication (using websockets or polling), `mongodb` as our database driver and `cross-fetch` to perform HTTP requests from the NodeJS process directly.
225 |
226 | Create a new file `app.js` and copy the following content:
227 |
228 | ```js
229 | // import and initialize dependencies
230 | const express = require('express')
231 | const http = require('http')
232 | const Socket = require('socket.io').Server
233 | const { MongoClient } = require('mongodb')
234 | const fetch = require('cross-fetch')
235 |
236 | const app = express()
237 | const server = http.createServer(app)
238 | const socket = new Socket(server)
239 |
240 | // URI of other services (database, dice roll)
241 | const MONGO_URI = "mongodb://root:example@mongodb:27017?maxPoolSize=20&w=majority"
242 | const DICEROLL_URI = "http://diceroll:3001/"
243 |
244 | // initialize database client
245 | const db = new MongoClient(MONGO_URI)
246 |
247 | const port = 3002
248 |
249 | // expose client front-end libraries for browsers
250 | app.use('/static', express.static('node_modules/bulma/css'))
251 | app.use('/static', express.static('node_modules/socket.io/client-dist'))
252 |
253 | // main route will send the pretty HTML + front-end JS app
254 | app.get('/', (req, res) => {
255 | res.send(`
256 |
257 |
258 |
259 | Chat app
260 |
261 |
297 |
298 |
299 |
300 |
317 |
318 |
319 |
320 |
321 | `)
322 | })
323 |
324 | // hook triggered when socket.io sees a new client
325 | socket.on('connection', (client) => {
326 | console.log('New user connected')
327 |
328 | // hook triggered when client disconnects
329 | client.on('disconnect', () => {
330 | console.log('User disconnected')
331 | })
332 |
333 | // on first connection, send all past messages
334 | db.db("chat").collection("messages").find({}).forEach(doc => {
335 | client.emit('chat', doc)
336 | })
337 |
338 | // hook triggered when a client sends something through socket.io
339 | client.on('message', (data) => {
340 | console.log(JSON.stringify(data))
341 |
342 | const { user, msg } = data
343 | const time = Date.now()
344 | const out = { user, msg, time }
345 |
346 | // if the message is "/diceroll", make a request to the service
347 | if (msg === "/diceroll") {
348 | fetch(DICEROLL_URI)
349 | .then(res => {
350 | if (res.status >= 400) throw new Error("Bad response from diceroll server")
351 | return res.json()
352 | })
353 | .then(data => {
354 | const number = data.value
355 | // send the dice roll value as system message
356 | socket.emit('chat', { user: "System", msg: `${user} requested a dice roll: ${number}`, time })
357 | })
358 | .catch(console.err)
359 | } else {
360 | // otherwise just broadcast the message to everyone
361 | socket.emit('chat', out)
362 | // and store it in database
363 | db.db("chat").collection("messages").insertOne(out).catch(console.err)
364 | }
365 | })
366 | })
367 |
368 | // try to connect to DB first
369 | db.connect()
370 | .then(() => db.db("admin").command({ ping: 1 }))
371 | .then(() => {
372 | console.log("Database connected")
373 | // if DB is up, then listen for requests indefinitely
374 | server.listen(port, () => {
375 | console.log(`Chat server listening on port ${port}`)
376 | })
377 | })
378 | // otherwise just die
379 | .catch(console.error)
380 | ```
381 |
382 | You will however not be able to run it directly, as this code will attempt to connect to a MongoDB server instance and fail.
383 |
384 | Add a `Dockerfile` and copy the following contents:
385 |
386 | ```Dockerfile
387 | FROM node:lts-alpine
388 |
389 | WORKDIR /app
390 |
391 | COPY . /app
392 |
393 | RUN npm install
394 |
395 | EXPOSE 3002
396 |
397 | USER node
398 |
399 | CMD ["node", "app.js"]
400 | ```
401 |
402 | ### Compose everything together
403 |
404 | In the parent directory of the chat and diceroll services, create a new file named `docker-compose.yml`. Have a look at the [Compose specification reference](https://docs.docker.com/compose/compose-file/) for examples and syntax.
405 |
406 | It should define a services section with 3 containers:
407 |
408 | - the chat application, which should be built from its Dockerfile and which needs to export a public port (e.g. 3002)
409 | - the dice roll microservice, which should be built from its Dockerfile. The chat application expects the service to be named `diceroll`, and will connect to its default port 3001.
410 | - a MongoDB instance, which should be pulled from the `mongo` image. The chat application expects the service to be named `mongodb`, with root username `root` and password `example`.
411 | - optionally, you can add a `mongo-express` instance, which will help you debug the contents of the database
412 |
413 | It should define a volumes section with a volume dedicated to the persistent data of the Mongo database, such that data is not lost across application restarts. The volume should be bound to the MongoDB container.
414 |
415 | ### Level up
416 |
417 | - Connect all the computers from a small group of people to the same local area network (e.g. by using the "4G modem" functionality of a smartphone for instance). Boot up the server stack from one computer, find out its local IP address: all computers should be able to access the web interface through the local IP - chat port pair, and you should be able to chat together.
418 |
419 | - Modify the code and the docker-compose file such that all environment configuration (such as host names, ports, passwords, ...) are passed as environment variables (for instance, directly through the docker-compose file).
--------------------------------------------------------------------------------
/solutions/1-express-web-server/app.js:
--------------------------------------------------------------------------------
1 | const express = require('express')
2 | const app = express()
3 | const port = 3000
4 |
5 | app.get('/', (req, res) => {
6 | res.send('Hello World!')
7 | })
8 |
9 | app.listen(port, () => {
10 | console.log(`Example app listening on port ${port}`)
11 | })
--------------------------------------------------------------------------------
/solutions/1-express-web-server/package.json:
--------------------------------------------------------------------------------
1 | {
2 | "name": "express-web-server",
3 | "version": "1.0.0",
4 | "description": "",
5 | "main": "index.js",
6 | "scripts": {
7 | "test": "echo \"Error: no test specified\" && exit 1"
8 | },
9 | "author": "",
10 | "license": "ISC",
11 | "dependencies": {
12 | "express": "^4.17.3"
13 | }
14 | }
15 |
--------------------------------------------------------------------------------
/solutions/2-dockerized-web-server/Dockerfile:
--------------------------------------------------------------------------------
1 | FROM node:lts-alpine
2 |
3 | WORKDIR /app
4 |
5 | COPY . /app
6 |
7 | RUN npm install
8 |
9 | EXPOSE 3000
10 |
11 | USER node
12 |
13 | CMD ["node", "app.js"]
--------------------------------------------------------------------------------
/solutions/2-dockerized-web-server/Dockerfile.ubuntu:
--------------------------------------------------------------------------------
1 | FROM ubuntu:latest
2 |
3 | RUN apt-get update && apt-get install -y \
4 | curl \
5 | && rm -rf /var/lib/apt/lists/*
6 |
7 | RUN curl -fsSL https://deb.nodesource.com/setup_20.x | bash
8 |
9 | RUN apt-get update && apt-get install -y nodejs \
10 | && rm -rf /var/lib/apt/lists/*
11 |
12 | RUN groupadd --gid 1000 node \
13 | && useradd --uid 1000 --gid node --shell /bin/bash --create-home node
14 |
15 | WORKDIR /app
16 |
17 | COPY . /app
18 |
19 | RUN npm install
20 |
21 | EXPOSE 3000
22 |
23 | USER node
24 |
25 | CMD ["node", "app.js"]
26 |
--------------------------------------------------------------------------------
/solutions/2-dockerized-web-server/app.js:
--------------------------------------------------------------------------------
1 | const express = require('express')
2 | const app = express()
3 | const port = 3000
4 |
5 | app.get('/', (req, res) => {
6 | res.send('Hello World!')
7 | })
8 |
9 | app.listen(port, () => {
10 | console.log(`Example app listening on port ${port}`)
11 | })
--------------------------------------------------------------------------------
/solutions/2-dockerized-web-server/package.json:
--------------------------------------------------------------------------------
1 | {
2 | "name": "express-web-server",
3 | "version": "1.0.0",
4 | "description": "",
5 | "main": "index.js",
6 | "scripts": {
7 | "test": "echo \"Error: no test specified\" && exit 1"
8 | },
9 | "author": "",
10 | "license": "ISC",
11 | "dependencies": {
12 | "express": "^4.17.3"
13 | }
14 | }
15 |
--------------------------------------------------------------------------------
/solutions/3-chat-app/chat/Dockerfile:
--------------------------------------------------------------------------------
1 | FROM node:lts-alpine
2 |
3 | WORKDIR /app
4 |
5 | COPY . /app
6 |
7 | RUN npm install
8 |
9 | EXPOSE 3002
10 |
11 | USER node
12 |
13 | CMD ["node", "app.js"]
--------------------------------------------------------------------------------
/solutions/3-chat-app/chat/app.js:
--------------------------------------------------------------------------------
1 | const express = require('express')
2 | const http = require('http')
3 | const Socket = require('socket.io').Server
4 | const { MongoClient } = require('mongodb')
5 | const fetch = require('cross-fetch')
6 |
7 | const app = express()
8 | const server = http.createServer(app)
9 | const socket = new Socket(server)
10 |
11 | const MONGO_URI = "mongodb://root:example@mongodb:27017?maxPoolSize=20&w=majority"
12 | const db = new MongoClient(MONGO_URI)
13 |
14 | const DICEROLL_URI = "http://diceroll:3001/"
15 |
16 | const port = 3002
17 |
18 | app.use('/static', express.static('node_modules/bulma/css'))
19 | app.use('/static', express.static('node_modules/socket.io/client-dist'))
20 |
21 | app.get('/', (req, res) => {
22 | res.send(`
23 |
24 |
25 |
26 | Chat app
27 |
28 |
64 |
65 |
66 |