Instructions for contributors¶
In order to make a clone of the GitHub repo: open the link and press the “Fork” button on the upper-right menu of the web page.
I hope everybody knows how to work with git and github nowadays :)
Workflow is pretty straightforward:
Make sure you are reading the latest version of this document. It can be found in the GitHub repo in the
Clone the GitHub repo using the
Setup your machine with the required development environment
Make a change
Make sure all tests passed
Add a file into the
CHANGESfolder (see Making a pull request for how).
Commit changes to your own aiohttp clone
Make a pull request from the github page of your clone against the master branch
Optionally make backport Pull Request(s) for landing a bug fix into released aiohttp versions.
The project uses Squash-and-Merge strategy for GitHub Merge button.
Basically it means that there is no need to rebase a Pull Request against
master branch. Just
git merge master into your working copy (a fork) if
needed. The Pull Request is automatically squashed into the single commit
once the PR is accepted.
GitHub issue and pull request threads are automatically locked when there has not been any recent activity for one year. Please open a new issue for related bugs.
If you feel like there are important points in the locked discussions, please include those excerpts into that new issue.
Preconditions for running aiohttp test suite¶
We expect you to use a python virtual environment to run our tests.
There are several ways to make a virtual environment.
If you like to use virtualenv please run:
$ cd aiohttp
$ virtualenv --python=`which python3` venv
$ . venv/bin/activate
For standard python venv:
$ cd aiohttp
$ python3 -m venv venv
$ . venv/bin/activate
$ cd aiohttp
$ mkvirtualenv --python=`which python3` aiohttp
There are other tools like pyvenv but you know the rule of thumb now: create a python3 virtual environment and activate it.
After that please install libraries required for development:
$ pip install -r requirements/dev.txt
For now, the development tooling depends on
make and assumes an Unix OS If you wish to contribute to aiohttp from a Windows machine, the easiest way is probably to configure the WSL so you can use the same instructions. If it’s not possible for you or if it doesn’t work, please contact us so we can find a solution together.
Install pre-commit hooks:
$ pre-commit install
If you plan to use temporary
ipdb within the test suite, execute it with
$ pytest tests -s
in order to run the tests without output capturing.
Congratulations, you are ready to run the test suite!
When building aiohttp from source, there is a pure Python parser used by default. For better performance, you may want to build the higher performance C parser.
To build this
llhttp parser, first get/update the submodules (to update to a
newer release, add
git submodule update --init --recursive
Then build our parser:
Then you can build or install it with
python -m build or
pip install -e .
$ make fmt
Run aiohttp test suite¶
After all the preconditions are met you can run tests typing the next command:
$ make test
The command at first will run the linters (sorry, we don’t accept pull requests with pyflakes, black, isort, or mypy errors).
On lint success the tests will be run.
Please take a look on the produced output.
Any extra texts (print statements and so on) should be removed.
If you see that CI build is failing on a specific Python version and you don’t have this version on your computer, you can use the helper to run it (only if you have docker):
For example, if you want to run tests for python3.10 without extensions, you can run this command:
We use codecov.io as an indispensable tool for analyzing our coverage results. Visit https://codecov.io/gh/aio-libs/aiohttp to see coverage reports for the master branch, history, pull requests etc.
We’ll use an example from a real PR to demonstrate how we use this. Once the tests run in a PR, you’ll see a comment posted by codecov. The most important thing to check here is whether there are any new missed or partial lines in the report:
Here, the PR has introduced 1 miss and 2 partials. Now we click the link in the comment header to open the full report:
Now, if we look through the diff under ‘Files changed’ we find one of our partials:
In this case, the while loop is never skipped in our tests. This is probably not worth writing a test for (and may be a situation that is impossible to trigger anyway), so we leave this alone.
We’re still missing a partial and a miss, so we switch to the ‘Indirect changes’ tab and take a look through the diff there. This time we find the remaining 2 lines:
After reviewing the PR, we find that this code is no longer needed as the changes mean that this method will never be called under those conditions. Thanks to this report, we were able to remove some redundant code from a performance-critical part of our codebase (this check would have been run, probably multiple times, for every single incoming request).
Sometimes the diff on codecov.io doesn’t make sense. This is usually caused by the branch being out of sync with master. Try merging master into the branch and it will likely fix the issue. Failing that, try checking coverage locally as described in the next section.
The browser extension https://docs.codecov.io/docs/browser-extension is also a useful tool for analyzing the coverage directly from Files Changed tab on the GitHub Pull Request review page.
You can also produce coverage reports locally with
or just adding
This will run the test suite and collect coverage information. Once
finished, coverage results can be view by opening:
$ python -m webbrowser -n file://"$(pwd)"/htmlcov/index.html
We encourage documentation improvements.
Please before making a Pull Request about documentation changes run:
$ make doc
Once it finishes it will output the index html page
Go to the link and make sure your doc changes looks good.
sphinxcontrib-spelling for running spell
checker for documentation:
$ make doc-spelling
Unfortunately there are problems with running spell checker on MacOS X.
To run spell checker on Linux box you should install it first:
$ sudo apt-get install enchant
$ pip install sphinxcontrib-spelling
Making a pull request¶
When making a pull request, please include a short summary of the changes and a reference to any issue tickets that the PR is intended to solve. All PRs with code changes should include tests. All changes should include a changelog entry.
Adding change notes with your PRs¶
It is very important to maintain a log for news of how updating to the new version of the software will affect end-users. This is why we enforce collection of the change fragment files in pull requests as per Towncrier philosophy.
The idea is that when somebody makes a change, they must record the bits that would affect end-users, only including information that would be useful to them. Then, when the maintainers publish a new release, they’ll automatically use these records to compose a change log for the respective version. It is important to understand that including unnecessary low-level implementation related details generates noise that is not particularly useful to the end-users most of the time. And so such details should be recorded in the Git history rather than a changelog.
Alright! So how to add a news fragment?¶
aiohttp uses towncrier
for changelog management.
To submit a change note about your PR, add a text file into the
CHANGES/ folder. It should contain an
explanation of what applying this PR will change in the way
end-users interact with the project. One sentence is usually
enough but feel free to add as many details as you feel necessary
for the users to understand what it means.
Use the past tense for the text in your fragment because,
combined with others, it will be a part of the “news digest”
telling the readers what changed in a specific version of
the library since the previous version. You should also use
reStructuredText syntax for highlighting code (inline or block),
linking parts of the docs or external sites.
However, you do not need to reference the issue or PR numbers here
as towncrier will automatically add a reference to all of the
affected issues when rendering the news file.
If you wish to sign your change, feel free to add
-- by :user:`github-username` at the end (replace
github-username with your own!).
Finally, name your file following the convention that Towncrier
understands: it should start with the number of an issue or a
PR followed by a dot, then add a patch type, like
contrib etc., and add
.rst as a suffix. If you
need to add more than one fragment, you may add an optional
sequence number (delimited with another period) between the type
and the suffix.
In general the name will follow
where the categories are:
bugfix: A bug fix for something we deemed an improper undesired behavior that got corrected in the release to match pre-agreed expectations.
feature: A new behavior, public APIs. That sort of stuff.
deprecation: A declaration of future API removals and breaking changes in behavior.
breaking: When something public gets removed in a breaking way. Could be deprecated in an earlier release.
doc: Notable updates to the documentation structure or build process.
packaging: Notes for downstreams about unobvious side effects and tooling. Changes in the test invocation considerations and runtime assumptions.
contrib: Stuff that affects the contributor experience. e.g. Running tests, building the docs, setting up the development environment.
misc: Changes that are hard to assign to any of the above categories.
A pull request may have more than one of these components, for example a code change may introduce a new feature that deprecates an old feature, in which case two fragments should be added. It is not necessary to make a separate documentation fragment for documentation changes accompanying the relevant code changes.
Examples for adding changelog entries to your Pull Requests¶
Added a ``:user:`` role to Sphinx config -- by :user:`webknjaz`
Fixed HTTP client requests to honor ``no_proxy`` environment
variables -- by :user:`scirelli`
Added support for ``ETag`` to :py:class:`~aiohttp.web.FileResponse`
-- by :user:`greshilov`, :user:`serhiy-storchaka` and :user:`asvetlov`
pyproject.toml for all available categories
Making a Pull Request¶
After finishing all steps make a GitHub Pull Request with master base branch.
All Pull Requests are created against master git branch.
If the Pull Request is not a new functionality but bug fixing backport to maintenance branch would be desirable.
aiohttp project committer may ask for making a backport of the PR into maintained branch(es), in this case he or she adds a github label like needs backport to 3.1.
- Backporting is performed after main PR merging into master.
Please do the following steps:
Find Pull Request’s commit for cherry-picking.
aiohttp does squashing PRs on merging, so open your PR page on github and scroll down to message like
asvetlov merged commit f7b8921 into master 9 days ago.
f7b8921is the required commit number.
Run cherry_picker tool for making backport PR (the tool is already pre-installed from
cherry_picker f7b8921 3.1.
In case of conflicts fix them and continue cherry-picking by
cherry_picker --abortstops the process.
cherry_picker --statusshows current cherry-picking status (like
After all conflicts are done the tool opens a New Pull Request page in a browser with pre-filed information. Create a backport Pull Request and wait for review/merging.
aiohttp committer should remove backport Git label after merging the backport.
How to become an aiohttp committer¶
The easiest way is providing Pull Requests for issues in our bug tracker. But if you have a great idea for the library improvement – please make an issue and Pull Request.
The rules for committers are simple:
No wild commits! Everything should go through PRs.
Take a part in reviews. It’s very important part of maintainer’s activity.
Pickup issues created by others, especially if they are simple.
Keep test suite comprehensive. In practice it means leveling up coverage. 97% is not bad but we wish to have 100% someday. Well, 99% is good target too.
Don’t hesitate to improve our docs. Documentation is a very important thing, it’s the key for project success. The documentation should not only cover our public API but help newbies to start using the project and shed a light on non-obvious gotchas.
After positive answer aiohttp committer creates an issue on github with the proposal for nomination. If the proposal will collect only positive votes and no strong objection – you’ll be a new member in our team.