renovate/docs/local-development.md

Local Development

This document serves to give tips and tricks on how to run Renovate locally to add features or fix bugs. Please submit PRs to improve it if you think anything is unclear or you can think of something that should be added.

Install

Fork and Clone

If you will contribute to the project, you should first "fork" it using the GitHub Website and then clone your fork.

Node version

Renovate supports node.js versions 8 and above. Use a version manager like nvm or n if you'll need to switch between versions easily.

Install dependencies

We use yarn so run yarn install to install dependencies instead of npm install.

Verify installation

Run yarn start. You should see this error:

FATAL: Renovate fatal error: You need to supply a GitHub token.

Platform Account Setup

Although it's possible to make small source code improvements without testing against a real repository, in most cases it's important that you run a "real" test on a repository before you submit a feature or fix. It's possible to do this against GitHub or GitLab public hosts, and you can also use both.

Register new account (optional)

It's recommended that you set up a dedicated test account on GitHub or GitLab, so that you minimise the risk that you accidentally cause problems when testing out Renovate.

e.g. if your GitHub username is "alex88" then maybe you register "alex88-testing" for use with Renovate.

Generate platform token

Once you have decided on your platform and account, log in and generate a "Personal Access Token" that can be used to authenticate Renovate.

Export platform token

Although you can specify a token to Renovate using --token=, it is annoying if you need to include this every time. You are better off to instead export an Environment Variable for this.

If your platform of choice is GitHub, then export GITHUB_TOKEN, and if it's GitLab then export GITLAB_TOKEN. It's also find to export both so that you can switch between platforms.

Tests

You can run yarn test locally to test your code. We test all PRs using the same tests, run on TravisCI. yarn test runs an eslint check, a prettier check, and then all the unit tests using jest.

Jest

You can run just the Jest unit tests by running yarn jest. You can also run just a subset of the Jest tests using file matching, e.g. yarn jest lock-files or yarn jest workers/branch. If you get a test failure due to a "snapshot" mismatch, and you are sure that you need to update the snapshot, then you can append -u to the end. e.g. yarn jest lock-files -u would update the saved Snapshots for all tests in test/workers/branch/lock-files.spec.js.

Coverage

The Renovate project maintains 100% test coverage, so any Pull Request will fail if it does not contain full coverage for code. Using // istanbul ignore is not ideal but sometimes is a pragmatic solution if an additional test wouldn't really prove anything.

To view the current test coverage locally, open up coverage/lcov-report/index.html in your browser.

Do not let coverage put you off submitting a PR! Maybe we can help, or at least guide. Also, it can be good to submit your PR as a work in progress (WIP) without tests first so that you can get a thumbs up from others about the changes, and write tests after.

Linting and formatting

We use Prettier for code formatting. If your code fails yarn test due to a prettier rule then you should find that the offending file will be updated automatically and pass the second time you run yarn test because each time you run it, it includes the --fix command automatically. You usually shouldn't need to fix any prettier errors manually.

Tips and tricks

Forked repositories

Quite often, the quickest way for you to test or fix something is to fork an existing repository. However, by default Renovate skips over repositories that are forked. To override this default, you need to specify the setting renovateFork as true.

Option 1: Add "renovateFork": true to the renovate.json of the repository Option 2: Run Renovate with the CLI flag --renovate-fork=true

Log files

Usually, debug is good enough to troubleshoot most problems or verify functionality.

When logging at debug, it's usually easiest to view the logs in a text editor, so in that case you can run like this:

$ rm -f debug.log && yarn start myaccount/therepo --log-level=debug > debug.log

The above will delete any existing debug.log and then save Renovate's output to that file.

Adding configuration options

We wish to keep backwards-compatibility as often as possible, as well as make the code configurable, so most new functionality should be controllable via configuration options.

If you wish to add one, add it to lib/config/definitions.js and then add documentation to website/docs/_posts/2017-10-05-configuration-options.md.

Debugging

It's really easy to debug Renovate using Chrome's inspect tool. Try like this:

1. Open chrome://inspect in Chrome, then click on "Open dedicated DevTools for Node"
2. Run yarn debug ... instead of yarn start ...
3. Add a debugger; statement somewhere in the source code where you want to start debugging
4. Click "Resume script execution" in Chrome DevTools and wait for your break point to be triggered