Package: cruft
Trending ContributorsRead Latest Documentation-Browse GitHub Code Repositorycruftallows you to maintain all the necessary boilerplate for packaging and building projects separate from the code you intentionally write.
Fully compatible with existingCookiecuttertemplates.Creating new projects from templates using cruft is easy:And, so is updating them as the template changes overtime:Many project template utilities exist that automate the copying and pasting of code to create new projects. Thisseemsgreat! However, once created, most leave you with that copy-and-pasted code to manage through the life of your project.cruft is different. It automates the creation of new projects like the others, but then it also helps you to manage the boilerplate through the life of the project. cruft makes sure your code stays in-sync with the template it came from for you.Key FeaturesCookiecutter Compatible: cruft utilizesCookiecutteras its template expansion engine. Meaning it retains full compatibility with all existingCookiecuttertemplates.Template Validation: cruft can quickly validate whether or not a project is using the latest version of a template usingcruft check. This check can easily be added to CI pipelines to ensure your projects stay in-sync.Automatic Template Updates: cruft automates the process of updating code to match the latest version of a template, making it easy to utilize template improvements across many projects.InstallationTo get started - installcruftusing a Python package manager:pip3 install cruftORpoetry add cruftORpipenv install cruftCreating a New ProjectTo create a new project using cruft runcruft create PROJECT_URLfrom the command line.For example:cruft create https://github.com/timothycrosley/cookiecutter-python/cruft will then ask you any necessary questions to create your new project. It will use your answers to expand the provided template, and then return the directory it placed the expanded project.
Behind the scenes, cruft usesCookiecutterto do the project expansion. The only difference in the resulting output is a.cruft.jsonfile that
contains the git hash of the template used as well as the template variables specified.Updating a ProjectTo update an existing project, that was created using cruft, runcruft updatein the root of the project.
If there are any updates, cruft will have you review them before applying. If you accept the changes cruft will apply them to your project
and update the.cruft.jsonfile for you.!!! tip
Sometimes certain files just aren't good fits for updating. Such as test cases or__init__files. You can tell cruft to always skip updating these files on a project by generating project with--skip cruft/__init__.py --skip testsarguments or manually adding them to a skip section within your.cruft.jsonfile:{
        "template": "https://github.com/timothycrosley/cookiecutter-python",
        "commit": "8a65a360d51250221193ed0ec5ed292e72b32b0b",
        "skip": [
            "cruft/__init__.py",
            "tests"
        ],
        ...
    }

Or, if you have toml installed, you can add skip files directly to a `tool.cruft` section of your `pyproject.toml` file:

    [tool.cruft]
    skip = ["cruft/__init__.py", "tests"]

Note that it is possible to use glob patterns for selecting the files to skip:
    {
        "skip": [
            "**/__init__.py",
            "tests/*"
        ],
        ...
    }Updating Values of Template Variablescruftcan also be used to update a project to use new values of template variables; avoiding the need to regenerate
the project from sratch usingcookiecutter.For example, imagine a project that was initially generated some while ago, and then later on, you want to change the
values of some of the template variables, e.g. to changeuse_some_featureto"yes"or to changeproject_nameto"new-project-name".There are 2 ways this can be done, as described below.Update Variables via the Command LineYou can perform the update directly via the command line if you have only a handful of simple variables.This will changeuse_some_featureto"yes"while leaving all other variables unchanged:cruftupdate--variables-to-update'{ "use_some_feature" : "yes" }'This will change bothuse_some_featureto"yes"andproject_nameto"new-project-name"(and still leaving all
other variables unchanged):cruftupdate--variables-to-update'{ "use_some_feature" : "yes", "project_name" : "new-project-name" }'The provided argument must be a valid JSON string (i.e. using double quotes, no trailing comma etc.).Update Variables via a Cruft FileIf you prefer to use and editor or you have many or complex variables, you can also perform the changes via providing an
updated .cruft.json.# copy the existing cruft file to a temporary location (outside of your repo)cp.cruft.json~/tmp/new-cruft.json# edit the file using your faviourite editoredit~/tmp/new-cruft.json# perform the update# (this will also update your original .cruft.json automatically)cruftupdate--variables-to-update-file~/tmp/new-cruft.jsonChecking a ProjectChecking to see if a project is missing a template update is as easy as runningcruft check. If the project is out-of-date an error and exit code 1 will be returned.cruft checkcan be added to CI pipelines to ensure projects don't unintentionally drift.Linking an Existing ProjectHave an existing project that you created from a template in the past using Cookiecutter directly? You can link it to the template that was used to create it using:cruft link TEMPLATE_REPOSITORY.For example:cruft link https://github.com/timothycrosley/cookiecutter-python/You can then specify the last commit of the template the project has been updated to be consistent with, or accept the default of using the latest commit from the template.Compute the diffWith time, your boilerplate may end up being very different from the actual cookiecutter template. Cruft allows you to quickly see what changed in your local project compared to the template. It is as easy as runningcruft diff. If any local file differs from the template, the diff will appear in your terminal in a similar fashion togit diff.Thecruft diffcommand optionally accepts an--exit-codeflag that will make cruft exit with a non-0 code should any diff is found. You can combine this flag with theskipsection of your.cruft.jsonto make stricter CI checks that ensures any improvement to the template is always submitted upstream.Automating updates with GitHub ActionsIf you have many repositories to manage, you can automate the change detection process with GitHub Actions. This example runs every Monday at 2am UTC and creates a new pull request if there are changes detected which a maintainer can accept or reject. It creates two PRs - one to pull in the new files to the repository and one to update the.cruft.jsonfile only, which has the effect of rejecting the change from the upstream repository.Since Jan 2022, registries/organisations must explicitly grant the authority to create a pull request. This can be enabled on a per-organisation level, or a per-registry level for personal projects. SeeGitHubfor more details.# /.github/workflows/cruft-update.ymlname:Update repository with Cruftpermissions:contents:writepull-requests:writeon:schedule:-cron:"02**1"# Every Monday at 2amjobs:update:runs-on:ubuntu-lateststrategy:fail-fast:truematrix:include:-add-paths:.body:Use this to merge the changes to this repository.branch:cruft/updatecommit-message:"chore:acceptnewCruftupdate"title:New updates detected with Cruft-add-paths:.cruft.jsonbody:Use this to reject the changes in this repository.branch:cruft/rejectcommit-message:"chore:rejectnewCruftupdate"title:Reject new updates detected with Cruftsteps:-uses:actions/checkout@v3-uses:actions/setup-python@v4with:python-version:"3.10"-name:Install Cruftrun:pip3 install cruft-name:Check if update is availablecontinue-on-error:falseid:checkrun:|CHANGES=0if [ -f .cruft.json ]; thenif ! cruft check; thenCHANGES=1fielseecho "No .cruft.json file"fiecho "has_changes=$CHANGES" >> "$GITHUB_OUTPUT"-name:Run update if availableif:steps.check.outputs.has_changes == '1'run:|git config --global user.email "you@example.com"git config --global user.name "GitHub"cruft update --skip-apply-ask --refresh-private-variablesgit restore --staged .-name:Create pull requestif:steps.check.outputs.has_changes == '1'uses:peter-evans/create-pull-request@v4with:token:${{ secrets.GITHUB_TOKEN }}add-paths:${{ matrix.add-paths }}commit-message:${{ matrix.commit-message }}branch:${{ matrix.branch }}delete-branch:truebranch-suffix:timestamptitle:${{ matrix.title }}body:|This is an autogenerated PR. ${{ matrix.body }}[Cruft](https://cruft.github.io/cruft/) has detected updates from the Cookiecutter repository.Why Create cruft?Since I first saw videos ofquicklybeing used to automate Ubuntu application creation, I've had a love/hate relationship with these kinds of tools.
I've used them for many projects and certainly seen them lead to productivity improvements. However, I've always felt like they were a double-edged sword. Sure, they would automate away the copying and pasting many would do to create projects. However, by doing so,
they encouraged more code to be copied and pasted! Then, over time, you could easily be left with hundreds of projects that contained copy-and-pasted code with no way to easy way to update them. I created cruft to be a tool that recognized that balance between project creation and maintenance and provided mechanisms to keep built projects up-to-date.I hope you too findcruftuseful!~Timothy Crosley