Description: The LXD team appreciates contributions to the project, through pull requests, issues on the GitHub repository, or discussions or questions on the forum. Check the following guidelines before contri...

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# How to contribute to LXD

The LXD team appreciates contributions to the project, through pull requests, issues on the GitHub repository, or discussions or questions on the forum.

Check the following guidelines before contributing to the project.

## Code of Conduct

When contributing, you must adhere to the Code of Conduct, which is available at: `https://github.com/canonical/lxd/blob/main/CODE_OF_CONDUCT.md`

## License and copyright

All contributors must sign the Canonical contributor license agreement, which gives Canonical permission to use the contributions. The author of a change remains the copyright holder of their code (no copyright assignment).

By default, any contribution to this project is licensed out under the project license: AGPL-3.0-only.

By exception, Canonical may import code under licenses compatible with AGPL-3.0-only, such as Apache-2.0. Such code will remain under its original license and will be identified as such in the commit message or its file header.

Some files and commits are licensed out under Apache-2.0 rather than AGPL-3.0-only. These are marked as Apache-2.0 in their package-level COPYING file, file header or commit message.

## Pull requests

Changes to this project should be proposed as pull requests on GitHub at: `https://github.com/canonical/lxd`

Proposed changes will then go through review there and once approved, be merged in the main branch.

### Commit structure

Separate commits should be used for:

- API extension (`api: Add XYZ extension`, contains `doc/api-extensions.md` and `shared/version/api.go`)

- Documentation (`doc: Update XYZ` for files in `doc/`)

- API structure (`shared/api: Add XYZ` for changes to `shared/api/`)

- Go client package (`client: Add XYZ` for changes to `client/`)

- CLI (`lxc/<command>: Change XYZ` for changes to `lxc/`)

- Scripts (`scripts: Update bash completion for XYZ` for changes to `scripts/`)

- LXD daemon (`lxd/<package>: Add support for XYZ` for changes to `lxd/`)

- Tests (`tests: Add test for XYZ` for changes to `tests/`)

The same kind of pattern extends to the other tools in the LXD code tree and depending on complexity, things may be split into even smaller chunks.

When updating strings in the CLI tool (`lxc/`), you may need a commit to update the templates:

    make i18n
    git commit -a -s -m "i18n: Update translation templates" po/

When updating API (`shared/api`), you may need a commit to update the swagger YAML:

    make update-api
    git commit -s -m "doc/rest-api: Refresh swagger YAML" doc/rest-api.yaml

This structure makes it easier for contributions to be reviewed and also greatly simplifies the process of back-porting fixes to stable branches.

### Developer Certificate of Origin

To improve tracking of contributions to this project we use the DCO 1.1 and use a “sign-off” procedure for all changes going into the branch.

The sign-off is a simple line at the end of the explanation for the commit which certifies that you wrote it or otherwise have the right to pass it on as an open-source contribution.

    Developer Certificate of Origin
    Version 1.1

    Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
    660 York Street, Suite 102,
    San Francisco, CA 94110 USA

    Everyone is permitted to copy and distribute verbatim copies of this
    license document, but changing it is not allowed.

    Developer's Certificate of Origin 1.1

    By making a contribution to this project, I certify that:

    (a) The contribution was created in whole or in part by me and I
        have the right to submit it under the open source license
        indicated in the file; or

    (b) The contribution is based upon previous work that, to the best
        of my knowledge, is covered under an appropriate open source
        license and I have the right under that license to submit that
        work with modifications, whether created in whole or in part
        by me, under the same open source license (unless I am
        permitted to submit under a different license), as indicated
        in the file; or

    (c) The contribution was provided directly to me by some other
        person who certified (a), (b) or (c) and I have not modified
        it.

    (d) I understand and agree that this project and the contribution
        are public and that a record of the contribution (including all
        personal information I submit with it, including my sign-off) is
        maintained indefinitely and may be redistributed consistent with
        this project or the open source license(s) involved.

An example of a valid sign-off line is:

    Signed-off-by: Random J Developer <random@developer.org>

Use a known identity and a valid e-mail address. Sorry, no anonymous contributions are allowed.

We also require each commit be individually signed-off by their author, even when part of a larger set. You may find `git commit -s` useful.

## Contribute to the code

Follow the steps below to set up your development environment to get started working on new features for LXD.

### Install LXD from source

To build the dependencies, follow the instructions in Install LXD from source.

### Add your fork as a remote

After setting up your build environment, add your GitHub fork as a remote:

    git remote add myfork git@github.com:<your_username>/lxd.git
    git remote update

Then switch to it:

    git checkout myfork/main

### Build LXD

Finally, you should be able to run `make` inside the repository and build your fork of the project.

At this point, you most likely want to create a new branch for your changes on your fork:

    git checkout -b [name_of_your_new_branch]
    git push myfork [name_of_your_new_branch]

### Important notes for new LXD contributors

- Persistent data is stored in the `LXD_DIR` directory, which is generated by `lxd init`. The `LXD_DIR` defaults to `/var/lib/lxd`, or `/var/snap/lxd/common/lxd` for snap users.

- As you develop, you may want to change the `LXD_DIR` for your fork of LXD so as to avoid version conflicts.

- Binaries compiled from your source will be generated in the `$(go env GOPATH)/bin` directory by default.

  - You will need to explicitly invoke these binaries (not the global `lxd` you may have installed) when testing your changes.

  - You may choose to create an alias in your `~/.bashrc` to call these binaries with the appropriate flags more conveniently.

- If you have a `systemd` service configured to run the LXD daemon from a previous installation of LXD, you may want to disable it to avoid version conflicts.

## Contribute to the documentation

We want LXD to be as easy and straight-forward to use as possible. Therefore, we aim to provide documentation that contains the information that users need to work with LXD, that covers all common use cases, and that answers typical questions.

You can contribute to the documentation in various different ways. We appreciate your contributions!

Typical ways to contribute are:

- Add or update documentation for new features or feature improvements that you contribute to the code. We’ll review the documentation update and merge it together with your code.

- Add or update documentation that clarifies any doubts you had when working with the product. Such contributions can be done through a pull request or through a post in the Tutorials section on the forum. New tutorials will be considered for inclusion in the docs (through a link or by including the actual content).

- To request a fix to the documentation, open a documentation issue on GitHub. We’ll evaluate the issue and update the documentation accordingly.

- Post a question or a suggestion on the forum. We’ll monitor the posts and, if needed, update the documentation accordingly.

- Ask questions or provide suggestions in the `#lxd` channel on IRC. Given the dynamic nature of IRC, we cannot guarantee answers or reactions to IRC posts, but we monitor the channel and try to improve our documentation based on the received feedback.

If images are added (`doc/images`), prioritize either SVG or PNG format and make sure to optimize PNG images for smaller size using a service like TinyPNG or similar.

### Documentation framework

LXD’s documentation is built with Sphinx and hosted on Read the Docs.

It is written in Markdown with MyST extensions. For syntax help and guidelines, see the MyST style guide and the documentation cheat sheet (source).

For structuring, the documentation uses the Diátaxis approach.

### Build the documentation

To build the documentation, run `make doc` from the root directory of the repository. This command installs the required tools and renders the output to the `doc/_build/` directory. To update the documentation for changed files only (without re-installing the tools), run `make doc-incremental`.

Before opening a pull request, make sure that the documentation builds without any warnings (warnings are treated as errors). To preview the documentation locally, run `make doc-serve` and go to `http://localhost:8000` to view the rendered documentation.

When you open a pull request, a preview of the documentation output is built automatically. To see the output, view the details for the `docs/readthedocs.com:canonical-lxd` check on the pull request.

### Automatic documentation checks

GitHub runs automatic checks on the documentation to verify the spelling, the validity of links, correct formatting of the Markdown files, and the use of inclusive language.

You can (and should!) run these tests locally as well with the following commands:

- Check the spelling: `make doc-spellcheck` (or `make doc-spelling` to first build the documentation and then check it)

- Check the validity of links: `make doc-linkcheck`

- Check the Markdown formatting: `make doc-lint`

- Check for inclusive language: `make doc-woke`

### Document configuration options

The documentation of configuration options is extracted from comments in the Go code. Look for comments that start with `lxdmeta:generate` in the code.

When you add or change a configuration option, make sure to include the required documentation comment for it. See the `lxd-metadata` README file for information about the format.

Then run `make generate-config` to re-generate the `doc/config_options.txt` file. The updated file should be checked in.

The documentation includes sections from the `doc/config_options.txt` to display a group of configuration options. For example, to include the core server options:

    % Include content from [config_options.txt](config_options.txt)
    ```{include} config_options.txt
        :start-after: <!-- config group server-core start -->
        :end-before: <!-- config group server-core end -->
    ```

If you add a configuration option to an existing group, you don’t need to do any updates to the documentation files. The new option will automatically be picked up. You only need to add an include to a documentation file if you are defining a new group.