Using brownie for Solidity Smart Contracts

This project is an appendix to a blogpost I wrote. It can be used as a starting point to learn brownie and its functionalities.

It may help you:

• get your development environemnt configured,
• get an overview of a simple brownie project and its files,
• get started with testing and deployments.

Note: the setup was tested with Python v3.9 on Debian 11. For Windows users external docs will be linked.

Clone the project

To clone this project you will need git.

Use https:

git clone https://codeberg.org/tardigrde/mndwrk-brownie-blogpost.git

or ssh:

git clone git@codeberg.org:tardigrde/mndwrk-brownie-blogpost.git

Developer environment

VSCode

Solidity Plugin

Python env

pipx

Brownie recommends that you install it via pipx. Consult the docs on how to install brownie.

Fow Windows users, probably this is the easier way.

pip in a virtualenv

With Python v3.9 we can just use pip. To create a new Python virtualenv, use the following commands (tested on Debian 11, should be applicable for most Linux distros):

python3 -m pip install virtualenv
virtualenv venv --python=python3.9

Then activate it, and install requirements:

source venv/bin/activate
pip install -r requirements.txt 

Windows users, please consult the virtualenv installation docs, and user guide.

At this point you have to make sure that brownie is now on your path, and you execute brownie --help from the terminal.

Since this is a ready-made brownie project, you are now all set up.

Project setup

.
├── build               # contains generated build artifacts after you compiled the contract
├── contracts           # all the contracts relevant to this project
│   └── Lottery.sol
├── scripts             # contains utility and deployment scripts
│   ├── lottery.py
│   └── utils.py
└── tests               # pytests home directory
    ├── conftest.py
    └── test_lottery.py

Contracts

The only contract in this project is Lottery.sol. It's a dead-simple Lottery application, where users can enter with some money and have a chance to win the game when it concludes.

It is inspired by jspruance's' block-explorer-tutorials/Lottery.sol with some extra features and comments.

Run the tests

Brownie uses pytest for testing. The tests can be found in the tests subdirectory.

Navigate to the project root in the terminal. If you use the virtualenv, activate the virtual environment, and run the tests:

brownie test

Simulate lottery

The lottery.py script simulates a lottery game. To run it, use:

brownie run scripts/lottery.py

Create a new brownie project

In order to create a new brownie project, the following command was used in an empty directory:

brownie init <path>

You could also use a ready-made template, also known as a brownie mix. Use the following command to learn more:

brownie bake --help