Dependabot Core is the heart of Dependabot. It handles the logic for updating dependencies on GitHub (including GitHub Enterprise) and GitLab.
If you want to host your own automated dependency update bot then this repo should give you the tools you need. A reference implementation is available here.
What's in this repo?
- Logic to check for the latest version of a dependency that's resolvable given a project's other dependencies
- Logic to generate updated manifest and lockfiles for a new dependency version
- Logic to find changelogs, release notes, and commits for a dependency update
Other Dependabot resources
In addition to this library, you may be interested in:
- The dependabot-script repo, which provides a collection of scripts that use this library to update dependencies on GitHub Enterprise or GitLab
- The API docs for Dependabot's hosted instance (dependabot.com)
To run all of Dependabot Core, you'll need Ruby, Python, PHP, Elixir, Node, Go, Elm and Rust installed. However, if you just wish to run it for a single language you can get away with just having that language and Ruby.
To install the helpers for each language:
cd npm_and_yarn/helpers && yarn install --production && cd -
cd composer/helpers && composer install --no-dev && cd -
cd python/helpers && pyenv exec pip install -r requirements.txt && cd -
cd elixir/helpers && mix deps.get && cd -
cd terraform && helpers/build helpers/install-dir/terraform && cd -
Run the tests by running
rspec spec inside each of the packages. Style is
enforced by RuboCop. To check for style violations, simply run
each of the packages.
Running with Docker
While you can run Dependabot Core without Docker, we also provide a development Dockerfile. In most cases, you'll be better off running Dependabot in the development Docker container as it bakes in all required dependencies.
Start by building the initial Dependabot Core image, or pull it from the Docker registry.
$ docker pull dependabot/dependabot-core # OR $ docker build -t dependabot/dependabot-core . # this may take a while
Once you have the base Docker image, you can build and run the development
container using the
docker-dev-shell script. The script will automatically
build the container if it's not present, and can be forced to rebuild with the
--rebuild flag. The image includes all dependencies, and the script runs the
image, mounting the local copy of Dependabot Core so changes made locally will
be reflected inside the container. This means you can continue to use your
editor of choice, while running the tests inside the container.
$ bin/docker-dev-shell => building image from Dockerfile.development => running docker development shell [dependabot-core-dev] ~/dependabot-core $
Dry run script
Note: you must have run
bundle install in the
omnibus directory before
running this script.
You can use the "dry-run" script to simulate a dependency update job, printing the diff that would be generated to the terminal. It takes two positional arguments: the package manager and the GitHub repo name (including the account):
$ cd omnibus && bundle install && cd - $ bin/dry-run.rb go_modules rsc/quote => fetching dependency files => parsing dependency files => updating 2 dependencies ...
Dependabot Core is a collection of Ruby packages (gems), which contain the logic for updating dependencies in a number of languages.
common package contains all general-purpose / shared functionality. For
instance the code for creating pull requests via GitHub's API lives here, as
does most of the logic for handling Git dependencies (as most languages support
Git dependencies in one way or another). There are also base classes defined for
each of the major concerns required to implement support for a language or
There is a gem for each package manager or language that Dependabot supports. At a minimum, each of these gems will implement the following classes:
||Fetches the relevant dependency files for a project (e.g., the
||Parses a dependency file and extracts a list of dependencies for a project. See the README for more details.|
||Checks whether a given dependency is up-to-date. See the README for more details.|
||Updates a dependency file to use the latest version of a given dependency. See the README for more details.|
||Looks up metadata about a dependency, such as its GitHub URL. See the README for more details.|
||Describes the logic for comparing dependency versions. See the hex Version class for an example.|
||Describes the format of a dependency requirement (e.g.
The high level flow looks like this:
This is a "meta" gem, that simply depends on all the others. If you want to automatically include support for all languages, you can just include this gem and you'll get all you need.
Why is this public?
As the name suggests, Dependabot Core is the core of Dependabot (the rest of the app is pretty much just a UI and database). If we were paranoid about someone stealing our business then we'd be keeping it under lock and key.
Dependabot Core is public because we're more interested in it having an impact than we are in making a buck from it. We'd love you to use Dependabot, so that we can continue to develop it, but if you want to build and host your own version then this library should make doing so a lot easier.
If you use Dependabot Core then we'd love to hear what you build!
We use the License Zero Prosperity Public License, which essentially enshrines the following:
- If you would like to use Dependabot Core in a non-commercial capacity, such as to host a bot at your workplace, then we give you full permission to do so. In fact, we'd love you to, and will help and support you however we can.
- If you would like to add Dependabot's functionality to your for-profit company's offering then we DO NOT give you permission to use Dependabot Core to do so. Please contact us directly to discuss a partnership or licensing arrangement.
If you make a significant contribution to Dependabot Core then you will be asked to transfer the IP of that contribution to Dependabot Ltd so that it can be licensed in the same way as the above.
Dependabot and Dependabot Core started life as Bump and Bump Core, back when Harry and Grey were working at GoCardless. We remain grateful for the help and support of GoCardless in helping make Dependabot possible - if you need to collect recurring payments from Europe, check them out.