We welcome contributions to the
How to Contribute
esptool.py - fixing bugs, adding features, adding documentation - are welcome. We accept contributions via Github Pull Requests.
Development mode allows you to run the latest development version from the esptool.py repository on GitHub.
$ git clone https://github.com/espressif/esptool.git $ cd esptool $ pip install --user -e .
This will install
esptool.py’s dependencies and create some executable script wrappers in the user’s
bin directory. The wrappers will run the scripts found in the git working directory directly, so any time the working directory contents change it will pick up the new versions.
It’s also possible to run the scripts directly from the working directory with this Development Mode installation.
To also install additional tools needed for actually developing and testing
esptool.py, run this command to install a development copy of
esptool.py plus packages useful for development:
$ pip install --user -e ".[dev]"
(This command uses the “extras” feature of setuptools.)
Please report bugs in
esptool.py if you find them. However, before reporting a bug please check through the following:
Troubleshooting Guide - common problems and known issues.
Existing Open Issues - someone might have already encountered this.
If you don’t find anything, please open a new issue.
Sending Feature Requests
Feel free to post feature requests. It’s helpful if you can explain exactly why the feature would be useful.
There are usually some outstanding feature requests in the existing issues list, feel free to add comments to them.
Before sending us a Pull Request, please consider this list of points:
Have you tried running
esptool.pytest suite locally?
Is the code adequately commented for people to understand how it is structured?
Is there documentation or examples that go with code contributions?
Are comments and documentation written in clear English, with no spelling or grammar errors?
If the contribution contains multiple commits, are they grouped together into logical changes (one major change per pull request)? Are any commits with names like “fixed typo” squashed into previous commits?
If you’re unsure about any of these points, please open the Pull Request anyhow and then ask us for feedback.
Code Style & Static Analysis
Please follow these coding standards when writing code for
pre-commit is a framework for managing pre-commit hooks. These hooks help to identify simple issues before committing code for review.
To use the tool, first install
pre-commit. Then enable the
commit-msg git hooks:
$ python -m pip install pre-commit $ pre-commit install -t pre-commit -t commit-msg
On the first commit
pre-commit will install the hooks, subsequent checks will be significantly faster. If an error is found an appropriate error message will be displayed. If the error was with
black then the tool will fix them for you automatically. Review the changes and re-stage for commit if you are happy with them.
esptool.py complies with flake8 style guide enforcement.
All files should be formatted using the Black auto-formatter.
Conventional Precommit Linter tools will be automatically run by
pre-commit if that is configured. To check your code manually before submitting, run
python -m flake8 and
black . (the tools are installed as part of the development requirements shown at the beginning of this document).
When you submit a Pull Request, the GitHub Actions automated build system will run automated checks using these tools.
Automated Integration Tests
The test directory contains a pytest integration suite with some integration tests for
It is necessary to have
esptool.py installed (see Development Setup) in your environment in order to run these tests.
The following tests run automatically by GitHub Actions for each Pull Request. You can run them locally to check for regressions in the respective functionality:
test_modules.pytests the modules used by
test_espsecure_hsm.pytests support of extarnal HSM signing in
espsecure.py. These tests require additional prerequisites, see
SoftHSM2 setupin the tests workflow definition for more information.
The following tests are not run automatically by GitHub Actions, because they need real connected hardware. Therefore, they need to be run locally in a command line:
test_esptool.pycontains integration tests for
esptool.pyand needs to be run against real Espressif hardware with the following format:
pytest test_esptool.py --port <serial port> --chip <name of chip> --baud <baud rate>
For example, to run all tests on an ESP32 board connected to /dev/ttyUSB0, at 230400bps:
pytest test_esptool.py --port /dev/ttyUSB0 --chip esp32 --baud 230400
Or to run the TestFlashing suite only (using the pytest
-koption to select tests based on their name) on an ESP8266 board connected to /dev/ttyUSB2, at 460800bps:
pytest test_esptool.py --port /dev/ttyUSB2 --chip esp8266 --baud 460800 -k TestFlashing
Some tests might fail at higher baud rates on some hardware.
The following tests are not run automatically by GitHub Actions, but can be run locally in a command line:
espefuse.pyfunctionality. To run it:
pytest test_espefuse.py --chip <name of chip>
These test use the
--virtvirtual mode of
espefuse.pyto safely test the functionality without a connection to a chip and without the possibility of affecting the actual eFuses in a real hardware.
Do not attempt to run these tests on real hardware! You risk damaging or destroying the ESP chip!
The whole test suite (without the tests needing an actual hardware or installation of additional prerequisites) can be easily run with the following command in the esptool root folder:
pytest -m host_test
Pull Request Process
If you are developing the stub flasher and plan to send a pull request, please use the latest toolchains available.
After you open the Pull Request, there will probably be some discussion in the comments field of the request itself.
Once the Pull Request is ready to merge, it will first be merged into our internal git system for in-house automated testing.
If this process passes, it will be merged onto the public github repository, hooray!