Web3.py

A Python implementation of web3.js

• Python 3.6+ support

Read more in the documentation on ReadTheDocs. View the change log on Github.

Developer Setup

git clone git@github.com:ethereum/web3.py.git
cd web3.py

Please see OS-specific instructions for:

• Linux
• Mac
• Windows
• FreeBSD

Then run these install commands:

virtualenv venv
. venv/bin/activate
pip install -e .[dev]

For different environments, you can set up multiple virtualenv. For example, if you want to create a venvdocs, then you do the following:

virtualenv venvdocs
. venvdocs/bin/activate
pip install -e .[docs]
pip install -e .

Using Docker

If you would like to develop and test inside a Docker environment, use the sandbox container provided in the docker-compose.yml file.

To start up the test environment, run:

docker-compose up -d

This will build a Docker container set up with an environment to run the Python test code.

Note: This container does not have go-ethereum installed, so you cannot run the go-ethereum test suite.

To run the Python tests from your local machine:

docker-compose exec sandbox bash -c 'pytest -n 4 -f -k "not goethereum"'

You can run arbitrary commands inside the Docker container by using the bash -c prefix.

docker-compose exec sandbox bash -c ''

Or, if you would like to just open a session to the container, run:

docker-compose exec sandbox bash

Testing Setup

During development, you might like to have tests run on every file save.

Show flake8 errors on file change:

# Test flake8
when-changed -v -s -r -1 web3/ tests/ ens/ -c "clear; flake8 web3 tests ens && echo 'flake8 success' || echo 'error'"

You can use pytest-watch, running one for every Python environment:

pip install pytest-watch

cd venv
ptw --onfail "notify-send -t 5000 'Test failure ⚠⚠⚠⚠⚠' 'python 3 test on web3.py failed'" ../tests ../web3

Or, you can run multi-process tests in one command, but without color:

# in the project root:
pytest --numprocesses=4 --looponfail --maxfail=1
# the same thing, succinctly:
pytest -n 4 -f --maxfail=1

How to Execute the Tests?

1. Setup your development environment.

2. Execute tox for the tests

There are multiple components of the tests. You can run test to against specific component. For example:

# Run Tests for the Core component (for Python 3.6):
tox -e py36-core

# Run Tests for the Core component (for Python 3.7):
tox -e py37-core

If for some reason it is not working, add --recreate params.

tox is good for testing against the full set of build targets. But if you want to run the tests individually, pytest is better for development workflow. For example, to run only the tests in one file:

pytest tests/core/gas-strategies/test_time_based_gas_price_strategy.py

Release setup

For Debian-like systems:

apt install pandoc

The final step before releasing is to build and test the code that will be released. There is a test script that will build and install the wheel locally, then generate a temporary virtualenv where you can do some smoke testing:

# Branch name could be either master or a version branch - ex. v5

$ git checkout <branch name> && git pull

$ make package

# in another shell, navigate to the virtualenv mentioned in output of ^

# load the virtualenv with the packaged trinity release
$ source package-smoke-test/bin/activate

# smoke test the release
$ pip install ipython
$ ipython
>>> from web3.auto import w3
>>> w3.isConnected()
>>> ...

# Preview the upcoming release notes
$ towncrier --draft

To release a new version:

make release bump=$$VERSION_PART_TO_BUMP$$

To preview the upcoming release notes:

towncrier --draft

How to bumpversion

The version format for this repo is {major}.{minor}.{patch} for stable, and {major}.{minor}.{patch}-{stage}.{devnum} for unstable (stage can be alpha or beta).

To issue the next version in line, specify which part to bump, like make release bump=minor or make release bump=devnum.

If you are in a beta version, make release bump=stage will switch to a stable.

To issue an unstable version when the current version is stable, specify the new version explicitly, like make release bump="--new-version 4.0.0-alpha.1 devnum"