superlint/docs/add-new-linter.md

How to add support for a new tool to super-linter

If you want to propose a Pull Request to add new language support or a new tool, it should include:

• Update documentation:

  • README.md

• Provide test cases:

  1. Create the .automation/test/<LANGUGAGE> directory.
  2. Provide at least one test case with a file that is supposed to pass validation: .automation/test/<LANGUAGE>/<name-of-tool>-good.ext
  3. Provide at least one test case with a file that is supposed to fail validation: .automation/test/<LANGUAGE>/<name-of-tool>-bad.ext

• Update the test suite to check for installed packages, the commands that your new tool needs in the PATH, and the expected version command:

  • test/inspec/super-linter/controls/super_linter.rb

• Install the tool by pointing to specific package or container image versions:

  • If there are PyPi packages, create a text file named dependencies/python/<name-of-tool>.txt and list the packages there.

  • If there are npm packages, update dependencies/package.json and dependencies/package-lock.json. by adding the new packages.

  • If there are Ruby Gems, update dependencies/Gemfile and dependencies/Gemfile.lock

  • If there are Maven or Java packages:

    1. Create a directory named dependencies/<name-of-tool>.

    2. Create a dependencies/<name-of-tool>/build.gradle file with the following contents:

       repositories {
         mavenLocal()
         mavenCentral()
       }
       
       // Hold this dependency here so we can get automated updates using DependaBot
       dependencies {
         implementation 'your:dependency-here:version'
       }
       
       group 'com.github.super-linter'
       version '1.0.0-SNAPSHOT'
       

    3. Update the dependencies section in dependencies/<name-of-tool>/build.gradle to install your dependencies.

    4. Add the following content to the Dockerfile:

       COPY scripts/install-<name-of-tool>.sh /
       RUN --mount=type=secret,id=GITHUB_TOKEN /<name-of-tool>.sh && rm -rf /<name-of-tool>.sh
       

    5. Create scripts/install-<name-of-tool>.sh, and implement the logic to install your tool. You get the version of a dependency from build.gradle. Example:

       GOOGLE_JAVA_FORMAT_VERSION="$(grep <"google-java-format/build.gradle" "google-java-format" | awk -F ':' '{print $3}' | tr -d "'")"
       

    6. Add the new to DependaBot configuration:

         - package-ecosystem: "gradle"
           directory: "/dependencies/<name-of-tool>"
           schedule:
             interval: "weekly"
           open-pull-requests-limit: 10
       

  • If there is a container (Docker) image:

    1. Add a new build stage to get the image:

       FROM your/image:version as <name-of-tool>
       

    2. Copy the necessary binaries and libraries to the relevant locations. Example:

       COPY --from=<name-of-tool> /usr/local/bin/<name-of-command> /usr/bin/
       

• Configure the new tool:

  • Provide a default configuration file only if the tool cannot function without one: TEMPLATES/<template file for language>
  • Provide a configuration file for the new linter only if the default configuration is unsuitable for the super-linter repository: .github/linters/.<lintrc>

• Update the orchestration scripts to run the new tool:

  • lib/linter.sh

  • Provide the logic to populate the list of files or directories to examine: lib/buildFileList.sh

  • If necessary, provide elaborate logic to detect if the tool should examine a file or a directory: lib/detectFiles.sh

  • If the tool needs to take into account special cases:

    • Provide new runtime validation checks in lib/validation.sh.
    • Customize the logic to get the installed version of the tool: lib/linterVersions.sh
    • Provide custom logic to load configuration files: lib/linterRules.sh
    • Provide custom logic for test cases and to run the tool: lib/worker.sh