Cement is an open-source project, and is open to any and all contributions that other developers would like to provide. This document provides some guidelines that all contributors should be aware of, and abide by to have their submissions included in the source.


The Cement source code is licensed under the BSD three-clause license and is approved by the Open Source Initiative. All contributed source code must be either the original work of the contributing author, which will be contributed under the BSD license, or work taken from another project that is released under a BSD-compatible license.

Submitting Bug Reports and Feature Requests

If you've found a bug, or would like to request a feature please create a detailed issue for it at

The ideal bug report would include:

  • Bug description

  • The version of Python, Cement, and any dependencies in use

  • Steps to reproduce the bug

  • Code samples that show the bug in action

  • A pull request including code that:

    a. Fixes the bug

    b. Atleast one test case that tests for the bug specifically

The ideal feature request would include:

  • Feature description

  • Example code, or pseudo code of how you might use the feature

  • Example command line session showing how the feature would be used by the end-user

  • A pull request including:

    a. The feature you would like added

    b. At least one test case that tests the feature and maintains 100% code coverage when tests are run (meaning that your tests should cover 100% of your contributed code)

    c. Documentation that outlines how to use the feature

Guidelines for Code Contributions

If you are new to Cement, looking for something quick to fix, or just want an opportunity to contribute to the project, the best place to start is to review the issues labeled as low-hanging-fruit on Github.

All contributors should attempt to abide by the following:

  • Contributors fork the project on GitHub onto their own account

  • All changes should be commited, and pushed to their repository

  • All pull requests are from a topic branch, not an existing Cement branch

  • Contributors make every effort to comply with PEP8

  • Before starting on a new feature, or bug fix, always do the following:

    • git pull --rebase to get latest changes from upstream

    • Checkout a new branch. For example:

      • git checkout -b feature/<feature_name>

      • git checkout -b bug/<bug_number>

  • Code must include the following:

    • All tests pass successfully

    • Coverage reports 100% code coverage when running tests

    • New features are documented in the appropriate section of the doc

    • Significant changes are mentioned in the ChangeLog

  • All contributions must be associated with at least one issue in GitHub. If the issue does not exist, create one (per the guidelines above).

  • Commit comments must include something like the following:

    • Resolves Issue #1127

    • Partially Resolves Issue #9873

  • A single commit per issue.

  • Contributors should add their full name or handle to the CONTRIBUTORS file.

Regarding git commit messages, please read the following:

Source Code and Versioning

One of the primary goals of Cement is stability in the source code. For this reason we maintain a number of different git branches for focused development.

Development Branches

Active 'forward' development happens out of two branches:

  • master - Development for the next minor stable release.

  • portland - Development for the next major release.

Additionally, specific development branches might exist in the future for larger releases that may require iterative 'release candidate' handling before an official stable release. These branches will have the format of:

  • dev/3.1.x

  • dev/3.3.x

  • dev/4.1.x

  • dev/4.3.x

  • etc

Stable Branches

  • stable/0.8.x

  • stable/1.0.x

  • stable/1.2.x

  • stable/2.0.x

  • stable/2.2.x

  • stable/3.0.x

  • stable/3.2.x

  • etc

There is a system for versioning that may seem complex, and needs some explanation. Version numbers are broken up into three parts:

  • <Major>.<Minor>.<Bugfix>

This means:

  • Major - The major version of the source code generally relates to extensive incompatible changes, or entire code base rewrites. Applications built on the 1.x.x version of Cement will need to be completely rewritten for the 2.x.x versions of Cement.

  • Minor - The minor version signifies the addition of new features. It may also indicate minor incompatibilities with the previous stable version, but should be easily resolvable with minimal coding effort.

  • Bugfix - During the lifecycle of a stable release such as 2.2.x, the only updates should be bug and/or security related. At times, minor features may be introduced during a 'bugfix' release but that should not happen often.

It should be noted that both the Minor, and Bugfix versions follow a even == stable, and odd == development scheme. Therefore, the current version in git will always end in an 'odd number'. For example, if the current stable version is 2.0.18, then the version in stable/2.0.x would be 2.0.19. That said, the master branch might then be 2.1.1 which is the first version of the next minor release. Bugfixes would get applied to both branches, however feature updates would only be applied to master. The next stable release would then be 2.2.0 and a new git branch of stable/2.2.x will be created.

The portland branch is always very forward looking, and will contain significant (and likely broken) code changes. It should never be used for anything other than development and testing.

New Release Checklist

For maintainers before finalizing a release, create a Github issue called Cement X.YY.Z Release Tracker with the following:

- [ ] 100% Test Passing on Travis CI
    - [ ] Python 3.7
    - [ ] Python 3.8
    - [ ] Python 3.9
    - [ ] Python 3.10
    - [ ] Python 3.11
- [ ] 100% Test Coverage
- [ ] Core Tests on Windows
- [ ] Cement CLI Smoke Tests
    - [ ] Linux
    - [ ] macOS
    - [ ] Windows
- [ ] Git Builds 
    - Archs:
        - linux/amd64
        - linux/arm64
    - Tags:
        - [ ] X
        - [ ] X.Y
        - [ ] X.Y.Z
- [ ] Git Merge to Version Branch
    - stable/X.Y
- [ ] API Documentation Builds (Read The Docs)
    - [ ] X.Y
- [ ] Developer Documentation (Gitbook)
    - [ ] stable/X.Y
    - [ ] Update Change Log
    - [ ] Update Release Notes
    - [ ] Update Deprecations
- [ ] Docker Image Builds (Docker Hub)
    - [ ] datafolklabs/cement:X
    - [ ] datafolklabs/cement:X.Y
    - [ ] datafolklabs/cement:X.Y.Z
- [ ] PyPi Distribution
- [ ] Notify mailing list
- [ ] Notify Slack channel

Replace X.Y.Z with the release versions.


Multi-arch Docker Images

docker buildx build \
    --platform linux/amd64,linux/arm64 \
    --push \
    -t datafolklabs/cement:latest \

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