In this tutorial, we’ll create an Ethereum Dapp and will run its different components in a separate docker container.
You can clone the project using this GitHub link.
Thanks to the people who’s article and courses helped a lot:
Before beginning lets understand what we’re going to build and how the structure of our Dapp will look like.
In the Dapp there will be three modules:
1. ganache-cli 2. Ethereum-Dapp and Server 3. Client (React App)
The above 3 modules will run in individual docker containers.
Why we’re building individual container for each service when they all can be build in one container?
Yeah, all can be build in one container and everything will be straight forward. Just for some fun, we’re using different containers.
Create a project folder and give it the name docker-ethereum.
docker-ethereum - client - ethereum - server - .dockerignore - docker-compose.yml - Dockerfile - Dockerfile.ganache - package.json
package.json and paste the below code:
We have finished installing the dependencies for the project.
To build any application our network should be ready. So, let’s first start with our ganache-cli as the network.
It is a test network which comes with 10 accounts with 100 ethers each. It is best for development where you don’t have to wait for the transactions to mine.
Ganache is a personal blockchain for Ethereum development you can use to deploy contracts, develop your applications, and run tests.
In our application ganache-cli will run in a docker container.
Inside the project directory, create a
In this Dockerfile, we’ll write all the instructions to set up and run the ganache-cli inside the container.
Line 2: to build this ganache-cli image, we’re taking node:alpine as a base image.
Line 5: we’re setting /app folder as the working directory of the image where all our instructions will run.
Line 8: we’re installing ganache-cli globally.
Line 12: we’re setting
ganache-cli -h 0.0.0.0 as the default command of the image.
Ganache-cli’s default host is 127.0.0.1 but for docker instance it is 0.0.0.0
I have explained all the above instructions in detail in my last post. Please check it, if you find any difficulty here.
Our network is configured.
2. Ethereum Dapp and Server
Ethereumfolder in the project directory.
Ethereum - build - contracts - Message.sol - compile.js - deploy.js - logic.js - receipt-ganache.json - web3.js
Inside the Ethereum directory:
Create a new folder
contractsand a new file
Message.sol in the contracts folder and paste the below code.
We’re creating a simple message contract. There will be 3 functions in this smart contract
In the Message smart contract when it will run for the first time, that time the
constructorwill set the message as the initial message.
setMessage function will set a new message.
getMessage is a view function and it’ll return the value of the message variable which was set either by
Create a new file
compile.js and paste the below code in it. This will compile the
Message.solsmart contract and save the compiled contract in the
build folder as
web3.js file which will work as a bridge between the application and the ethereum network.
web3.js is a collection of libraries which allow you to interact with a local or remote Ethereum node, using an HTTP, WebSocket or IPC connection.
web3.js can be used in 2 ways,
- server-side web3js: transaction signed on the server side
- client-side web3js: transaction signed on the browser side. In this web3js invoked by third-party like Mist or Metamask. In the client-side web3js invoked in the html pages.
For this project, we’re using server-side web3js.
Copy and paste the below code to the
Take note of web3 provider
http://ganache:8545. Here, ganache is the name of the container in which ganache-cli is running.
deploy.js file and paste the below code in it. It will take the compiled contract
Message.json and deploy the contract to the network.
deploy.js import the
web3 instance of
Create a new file
logic.js and paste the below code in it. It consists of all the logic to interact with the deployed
Message contract on the network.
There are 3 functions inside the
- getContractObject it will return the contract object/instance which was deployed on the network using
deploy.js. This object will then call the smart contract.
- setMessage it requires 1 string argument and set this as a message to the
messagevariable in the smart contract.
- getMessage will return the message set either by
ethereum module is complete.
server needs to be set up which will call the
server folder in the project directory.
server - routes - contract-API.js - smart-contract-API.js - index.js
routes folder inside the
contract-API.js file and paste the below the code.
To compile and deploy the contract we have created APIs instead of manually compiling and deploying it on the network.
If you remember, our
Message smart contract’s constructor requires an initial message. To keep it simple, by default we’re setting initial message as
Hello World! . You can change it in the deploy router.
smart-contract-API.js and paste the below code.
smart-contract-API.js routers will call
index.js file in the
server folder and paste the below code.
This is the server for ethereum dapp.
At the top, we’re importing routes
smart-contract-API.js . The server is listening at the port
The server module is complete here.
Let’s dockerize it.
Dockerfile in the root project directory and paste the below code.
The docker image will create according to Dockerfile.
node:alpineTo create an image we require a base image which comes with some pre-requisite software. Our server and ethereum are dependent on
nodethat’s why we are using
node:alpineas a base image.
alpinein short, is the minimum required libraries to run a node application.
/appdirectory of base image as the working directory.
- Line 8 & 9 Installing the pre-requisite software for the ethereum dapp like
pythonis required to install the
COPY ./package.json .Copy
RUN npm installInstall the dependencies mentioned in
COPY . .Copy the complete root directory and paste in the
CMD ["npm","start"]set the default command
If you noticed we are copying the complete root directory which includes
node_modules . This will make the image large and it makes no sense as we’re installing it from the copied
package.json inside the image.
To ignore the files or folders while building the docker image just like the
.gitignore in docker there is
.dockerignore file and paste the below code.
It will ignore the
client directory which we’ll create in the next section. If we don’t ignore the
client directory then it will copy the client application too.
Now, we can move to our last module React application the
3. Client (React Application)
For the react application, we’re using
create-react-app tool for the Dapp.
Create React App is a tool (built by developers at Facebook) that gives you a massive head start when building React apps. It saves you from time-consuming setup and configuration. — treehouse
Installing Create React App
We need to install the
create-react-appglobally. Open your Terminal or console and run:
npm install -g create-react-app
From the project directory, open the terminal or console to create the react app by name
client and run the below command.
client - public - favicon.ico - index.html - manifest.json - src - App.css - App.js - App.test.js - index.css - index.js - logo.svg - message.js - serviceWorker.js - .dockerignore - Dockerfile - package-lock.json - package.json - README.md
client is created you will see a folder structure like above except
message.js inside the
For more information on react please follow the below links:
index.html from the
public folder and change the title to
Message App . Add the below link in the
<head> tag. This is the fonts which are used in the application.
<link href='https://fonts.googleapis.com/css?family=Open+Sans:300' rel='stylesheet' type='text/css'>
App.css from the
src folder and paste the
css from this link.
message.js in the
src folder and paste the below code. This is the file which will work as the front-end of the application.
Note: I am not good at React so I can just give details of methods which are used in it.
A component is the building block of any react app. To create a component it requires
Component module from
reactthe library. The endpoint is set to
http://localhost:4000 as the server is running at
To make any request to the server
axios library is used. To learn more about it follow this link.
Open the terminal from the
client directory and run the below command:
npm install axios --save
We have created a
Message component by extending the
Component and at the bottom exported the
There are 2 states in the
States are the data which defines and control the behaviour of the component. Learn more about states in this link.
messagestate will store the message entered in the form and this state will use as an argument to send the POST request to
output state will store the response from the server and display it.
Following methods are used in
messagestate according to the entered input
onsubmitcompilesend the request to
localhost:4000/compileto compile the smart contract
onsubmitdeploysend the request to
localhost:4000/deployto deploy the smart contract
onsubmitsetmsgsend the request to
messagestate as an argument to set the message to the smart contract
onsubmitgetmsgsend the request to
localhost:4000/to get the message from the smart contract
src folder and paste the below code. The application’s
Route set at
/ . On this route, it will serve the
To create the route
react-router-dom library is used.
Open the terminal from
client directory and run the below command:
npm install react-router-dom --save
With this Dockerfile our client module will complete.
In this Dockerfile we will write the instruction to create the image of the react application.
Dockerfile in the
client directory and paste the below code.
All the commands are self-explanatory. According to this Dockerfile, a docker image will build. The client (react-app) will run inside the container using this image.
COPY command is copying the
node_modules too. Create a
.dockerignore file in the client directory and paste the below code.
Our client module is also finished.
Everything is set. Now, the last thing we have to do, build these docker images and run them as individual containers.
docker-compose.yml in the root project directory and paste the below code.
You might be thinking about why we even need
It just makes the application bit smooth. How?
Compose is a tool for defining and running multi-container Docker applications.
We have created 3 Dockerfile for the 3 modules of the application. If we don’t use the
docker-compose.yml then we have to separately build the 3 images and then run them separately in 3 different terminals. So, that’s a drag.
docker-compose.yml we can define all the containers’ configuration and all can be run with a single command.
versionthe version of a docker-compose file
servicesall the containers’ definition.
There are 3 services/containers:
ganacheis the name of the container
buildwhere to find the Dockerfile to build. If we don’t give the name of Dockerfile then by default it builds the
ganachewe have created
Dockerfile.ganache. Its syntax will be a little different. Under the
contextit is a path of
dockerfilename of the
portsA container is isolated from outside which means whatever request we will try to make from the outside of the container it will not respond. That’s why we set the
portswhich maps the outside’s port to container’s port. Here we mapped port
8545if we make any request from outside to
8545it will send the request to the container at
dappis the name of the container.
Dockerfilein current directory
portsmap the ports at
depends_onstart after the
reactis the name of the container
portsmap the ports at
depends_onstart after the
To learn more about
docker-compose.yml follow this link.
So, the hard part is over. Now, the fun part let’s run the application.
Open the terminal from the root project directory and run the below command:
docker-compose up --build
It will check for
docker-compose.yml file in the current directory and will run it. For the first time, it will take some time so have patience.
Once everything is running, open the browser and go to
localhost:3000 you’ll see the react application running.
- Compile Contract: You’ll see the message as compiled successfully.
- Deploy contract: It will send back the address of the contract at which it is deployed.
Note: After compile or deploy command wait for a couple of seconds before running any other commands as both commands restart the server. Why?
On compile, it saves the compiled contract in build, if the server doesn’t restart then it will use the last compiled contract to deploy the contract.
On deploy, it saves the receipt in which deployed contract address is saved, if the server doesn’t restart, it will interact with the last deployed contract as the server is still using the last deployed contract’s address.
- Get Message: If you remember we set the initial message as
- Set Message: Set the message and it’ll return the transaction hash of the transaction. I set the message as “Docker Ethereum Dapp” and “ 0x464385a1914b0d8ffb48d660aa55d419f0afe040e0def20ff581338bbce545e2” is the transaction hash.
Check the message using “Get Message”
We successfully created the Ethereum Dapp with React and Docker.
You don’t have to build the
docker-compose.yml every time. Next time you just have to run the below command to run the application.
You can clone the complete project from the GitHub link.