# Contributing and feedback guidelines

There are many ways to contribute to Pelican. You can improve the documentation, add missing features, and fix bugs (or just report them). You can also help out by reviewing and commenting on existing issues.

Don’t hesitate to fork Pelican and submit an issue or pull request on GitHub. When doing so, please consider the following guidelines.

## Filing issues

- Before you file an issue, try asking for help first.

- If determined to file an issue, first check for existing issues, including closed issues.

## How to get help

Before you ask for help, please make sure you do the following:

1. Read the documentation thoroughly. If in a hurry, at least use the search field that is provided at top-left on the documentation pages. Make sure you read the docs for the Pelican version you are using.

2. Use a search engine (e.g., DuckDuckGo, Google) to search for a solution to your problem. Someone may have already found a solution, perhaps in the form of a plugin or a specific combination of settings.

3. Try reproducing the issue in a clean environment, ensuring you are using:

- latest Pelican release (or an up-to-date Git clone of Pelican master)

- latest releases of libraries used by Pelican

- no plugins or only those related to the issue

NOTE: The most common sources of problems are anomalies in (1) themes, (2) settings files, and (3) `make`/`invoke` automation wrappers. If you can’t reproduce your problem when using the following steps to generate your site, then the problem is almost certainly with your chosen theme and/or settings file (and not Pelican itself):

    cd ~/projects/your-site
    git clone https://github.com/getpelican/pelican ~/projects/pelican
    pelican content -s ~/projects/pelican/samples/pelican.conf.py -t ~/projects/pelican/pelican/themes/notmyidea

If despite the above efforts you still cannot resolve your problem, be sure to include in your inquiry the following information, preferably in the form of links to content uploaded to a paste service, GitHub repository, or other publicly-accessible location:

- Describe what version of Pelican you are running (output of `pelican --version` or the HEAD commit hash if you cloned the repo) and how exactly you installed it (the full command you used, e.g. `python -m pip install pelican`).

- If you are looking for a way to get some end result, prepare a detailed description of what the end result should look like (preferably in the form of an image or a mock-up page) and explain in detail what you have done so far to achieve it.

- If you are trying to solve some issue, prepare a detailed description of how to reproduce the problem. If the issue cannot be easily reproduced, it cannot be debugged by developers or volunteers. Describe only the minimum steps necessary to reproduce it (no extra plugins, etc.).

- Upload your settings file or any other custom code that would enable people to reproduce the problem or to see what you have already tried to achieve the desired end result.

- Upload detailed and complete output logs and backtraces (remember to add the `--debug` flag: `pelican --debug content [...]`)

Once the above preparation is ready, you can contact people willing to help via (preferably) the `#pelican` IRC channel or send a message to `authors at getpelican dot com`. Remember to include all the information you prepared.

### The #pelican IRC channel

- Because of differing time zones, you may not get an immediate response to your question, but please be patient and stay logged into IRC — someone will almost always respond if you wait long enough (it may take a few hours).

- If you don’t have an IRC client handy, use the webchat.

- You can direct your IRC client to the channel using this IRC link or you can manually join the `#pelican` IRC channel on the freenode IRC network.

## Contributing code

Before you submit a contribution, please ask whether it is desired so that you don’t spend a lot of time working on something that would be rejected for a known reason. Consider also whether your new feature might be better suited as a plugin — you can ask for help to make that determination.

### Using Git and GitHub

- Create a new git branch specific to your change (as opposed to making your commits in the master branch).

- Don’t put multiple unrelated fixes/features in the same branch / pull request. For example, if you’re working on a new feature and find a bugfix that doesn’t require your new feature, make a new distinct branch and pull request for the bugfix.

- Add a `RELEASE.md` file in the root of the project that contains the release type (major, minor, patch) and a summary of the changes that will be used as the release changelog entry. For example:

      Release type: minor

      Reload browser window upon changes to content, settings, or theme

- Check for unnecessary whitespace via `git diff --check` before committing.

- First line of your commit message should start with present-tense verb, be 50 characters or less, and include the relevant issue number(s) if applicable. Example: `Ensure proper PLUGIN_PATH behavior. Refs #428.` If the commit completely fixes an existing bug report, please use `Fixes #585` or `Fix #585` syntax (so the relevant issue is automatically closed upon PR merge).

- After the first line of the commit message, add a blank line and then a more detailed explanation (when relevant).

- Squash your commits to eliminate merge commits and ensure a clean and readable commit history.

- If you have previously filed a GitHub issue and want to contribute code that addresses that issue, please use `hub pull-request` instead of using GitHub’s web UI to submit the pull request. This isn’t an absolute requirement, but makes the maintainers’ lives much easier! Specifically: install hub and then run hub pull-request -i [ISSUE] to turn your GitHub issue into a pull request containing your code.

- After you have issued a pull request, the continuous integration (CI) system will run the test suite for all supported Python versions and check for PEP8 compliance. If any of these checks fail, you should fix them. (If tests fail on the CI system but seem to pass locally, ensure that local test runs aren’t skipping any tests.)

### Contribution quality standards

- Adhere to PEP8 coding standards. This can be eased via the pycodestyle or flake8 tools, the latter of which in particular will give you some useful hints about ways in which the code/formatting can be improved. We try to keep line length within the 79-character maximum specified by PEP8. Because that can sometimes compromise readability, the hard/enforced maximum is 88 characters.

- Ensure your code is compatible with the officially-supported Python releases.

- Add docs and tests for your changes. Undocumented and untested features will not be accepted.

- Run all the tests on all versions of Python supported by Pelican to ensure nothing was accidentally broken.

Check out our Git Tips page or ask for help if you need assistance or have any questions about these guidelines.

## Setting up the development environment

While there are many ways to set up one’s development environment, the following instructions will utilize Pip and Poetry. These tools facilitate managing virtual environments for separate Python projects that are isolated from one another, so you can use different packages (and package versions) for each.

Please note that Python 3.6+ is required for Pelican development.

(Optional) If you prefer to install Poetry once for use with multiple projects, you can install it via:

    curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python -

Point your web browser to the Pelican repository and tap the Fork button at top-right. Then clone the source for your fork and add the upstream project as a Git remote:

    mkdir ~/projects
    git clone https://github.com/YOUR_USERNAME/pelican.git ~/projects/pelican
    cd ~/projects/pelican
    git remote add upstream https://github.com/getpelican/pelican.git

While Poetry can dynamically create and manage virtual environments, we’re going to manually create and activate a virtual environment:

    mkdir ~/virtualenvs && cd ~/virtualenvs
    python3 -m venv pelican
    source ~/virtualenvs/pelican/*/activate

Install the needed dependencies and set up the project:

    python -m pip install invoke
    invoke setup
    python -m pip install -e ~/projects/pelican

Your local environment should now be ready to go!

## Development

Once Pelican has been set up for local development, create a topic branch for your bug fix or feature:

    git checkout -b name-of-your-bugfix-or-feature

Now you can make changes to Pelican, its documentation, and/or other aspects of the project.

### Running the test suite

Each time you make changes to Pelican, there are two things to do regarding tests: check that the existing tests pass, and add tests for any new features or bug fixes. The tests are located in `pelican/tests`, and you can run them via:

    invoke tests

In addition to running the test suite, it is important to also ensure that any lines you changed conform to code style guidelines. You can check that via:

    invoke lint

If code style violations are found in lines you changed, correct those lines and re-run the above lint command until they have all been fixed. You do not need to address style violations, if any, for code lines you did not touch.

After making your changes and running the tests, you may see a test failure mentioning that “some generated files differ from the expected functional tests output.” If you have made changes that affect the HTML output generated by Pelican, and the changes to that output are expected and deemed correct given the nature of your changes, then you should update the output used by the functional tests. To do so, make sure you have both `en_EN.utf8` and `fr_FR.utf8` locales installed, and then run the following command:

    invoke update-functional-tests

You may also find that some tests are skipped because some dependency (e.g., Pandoc) is not installed. This does not automatically mean that these tests have passed; you should at least verify that any skipped tests are not affected by your changes.

You should run the test suite under each of the supported versions of Python. This is best done by creating a separate Python environment for each version. Tox is a useful tool to automate running tests inside `virtualenv` environments.

### Building the docs

If you make changes to the documentation, you should build and inspect your changes before committing them:

    invoke docserve

Open http://localhost:8000 in your browser to review the documentation. While the above task is running, any changes you make and save to the documentation should automatically appear in the browser, as it live-reloads when it detects changes to the documentation source files.

### Plugin development

To create a new Pelican plugin, please refer to the plugin template repository for detailed instructions.

If you want to contribute to an existing Pelican plugin, follow the steps above to set up Pelican for local development, and then create a directory to store cloned plugin repositories:

    mkdir -p ~/projects/pelican-plugins

Assuming you wanted to contribute to the Simple Footnotes plugin, you would first browse to the Simple Footnotes repository on GitHub and tap the Fork button at top-right. Then clone the source for your fork and add the upstream project as a Git remote:

    git clone https://github.com/YOUR_USERNAME/simple-footnotes.git ~/projects/pelican-plugins/simple-footnotes
    cd ~/projects/pelican-plugins/simple-footnotes
    git remote add upstream https://github.com/pelican-plugins/simple-footnotes.git

Install the needed dependencies and set up the project:

    invoke setup

Create a topic branch for your plugin bug fix or feature:

    git checkout -b name-of-your-bugfix-or-feature

After writing new tests for your plugin changes, run the plugin test suite and check for code style compliance via:

    invoke tests
    invoke lint

If style violations are found, many of them can be addressed automatically via:

    invoke black
    invoke isort

If style violations are found even after running the above auto-formatters, you will need to make additional manual changes until `invoke lint` no longer reports any code style violations.

### Submitting your changes

Assuming linting validation and tests pass, add a `RELEASE.md` file in the root of the project that contains the release type (major, minor, patch) and a summary of the changes that will be used as the release changelog entry. For example:

    Release type: patch

    Fix browser reloading upon changes to content, settings, or theme

Commit your changes and push your topic branch:

    git add .
    git commit -m "Your detailed description of your changes"
    git push origin name-of-your-bugfix-or-feature

Finally, browse to your repository fork on GitHub and submit a pull request.

## Logging tips

Try to use logging with appropriate levels.

For logging messages that are not repeated, use the usual Python way:

    # at top of file
    import logging
    logger = logging.getLogger(__name__)

    # when needed
    logger.warning("A warning with %s formatting", arg_to_be_formatted)

Do not format log messages yourself. Use `%s` formatting in messages and pass arguments to logger. This is important, because the Pelican logger will preprocess some arguments, such as exceptions.

### Limiting extraneous log messages

If the log message can occur several times, you may want to limit the log to prevent flooding. In order to do that, use the `extra` keyword argument for the logging message in the following format:

    logger.warning("A warning with %s formatting", arg_to_be_formatted,
        extra={'limit_msg': 'A generic message for too many warnings'})

Optionally, you can also set `'limit_args'` as a tuple of arguments in `extra` dict if your generic message needs formatting.

Limit is set to `5`, i.e, first four logs with the same `'limit_msg'` are outputted normally but the fifth one will be logged using `'limit_msg'` (and `'limit_args'` if present). After the fifth, corresponding log messages will be ignored.

For example, if you want to log missing resources, use the following code:

    for resource in resources:
        if resource.is_missing:
            logger.warning(
                'The resource %s is missing', resource.name,
                extra={'limit_msg': 'Other resources were missing'})

The log messages will be displayed as follows:

    WARNING: The resource prettiest_cat.jpg is missing
    WARNING: The resource best_cat_ever.jpg is missing
    WARNING: The resource cutest_cat.jpg is missing
    WARNING: The resource lolcat.jpg is missing
    WARNING: Other resources were missing

### Outputting traceback in the logs

If you’re logging inside an `except` block, you may want to provide the traceback information as well. You can do that by setting `exc_info` keyword argument to `True` during logging. However, doing so by default can be undesired because tracebacks are long and can be confusing to regular users. Try to limit them to `--debug` mode like the following:

    try:
        some_action()
    except Exception as e:
        logger.error('Exception occurred: %s', e,
            exc_info=settings.get('DEBUG', False))