MegaLinter, by

MegaLinter is an Open-Source tool for CI/CD workflows that analyzes the consistency of your code, IAC, configuration, and scripts in your repository sources, to ensure all your projects sources are clean and formatted whatever IDE/toolbox is used by their developers, powered by OX Security.

Supporting 61 languages, 24 formats, 21 tooling formats and ready to use out of the box, as a GitHub action or any CI system highly configurable and free for all uses.

Switch to MegaLinter v7 !

See Online Documentation Web Site which has a much easier user navigation than this README

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Process

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Console reporter

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Github PR reporter

Table of Contents

• MegaLinter, by
  • Table of Contents
  • Why MegaLinter
  • Quick Start
  • Supported Linters
  • Languages
  • Formats
  • Tooling formats
  • Other
  • Installation
  • Assisted installation
  • Which version to use ?
  • GitHub Action
  • GitLab CI
    • Manual Setup
    • Using R2Devops
  • Azure Pipelines
  • Bitbucket Pipelines
  • Jenkins
  • Concourse
    • Pipeline step
    • Use it as reusable task
  • Drone CI
    • (Optional) Adjusting trigger rules
  • Docker container
  • Run MegaLinter locally
  • Configuration
  • .mega-linter.yml file
  • Common variables
  • Activation and deactivation
  • Filter linted files
  • Apply fixes
    • Apply fixes issues
    • Notes
  • Linter specific variables
  • Pre-commands
  • Post-commands
  • Environment variables security
    • Secured env variables
    • Secured configuration examples
    • Default secured variables
    • Unhide variables for linters
  • CLI lint mode
  • Reporters
  • Flavors
  • Badge
  • Markdown
  • reStructuredText
  • Plugins
  • External Plugins Catalog
  • Use external plugins
    • Example
  • Create your own plugin
    • Limitations
  • They talk about MegaLinter
  • English articles
  • French articles
  • Videos
  • Web Sites
  • Linters
  • Frequently Asked Questions
  • How to contribute
  • Special thanks
  • Maintainers
  • Contributors
  • Open-source teams
  • Super-Linter team
  • License
  • MegaLinter vs Super-Linter
  • Security
  • Performances
  • More languages and formats linted
  • Automatically apply formatting and fixes
  • Run locally
  • Reports
    • Capabilities
    • Additional Reporters
  • Enhanced Configuration
  • Enhanced Documentation
  • Plugins management
  • Simplify architecture and evolutive maintenance
  • Improve robustness \& stability

Why MegaLinter

Projects need to contain clean code, in order to avoid technical debt, that makes evolutive maintenance harder and time consuming.

By using code formatters and code linters, you ensure that your code base is easier to read and respects best practices, from the kick-off to each step of the project lifecycle

Not all developers have the good habit to use linters in their IDEs, making code reviews harder and longer to process

By using MegaLinter, you'll enjoy the following benefits for you and your team:

• At each pull request it will automatically analyze all updated code in all languages
• Reading error logs, developers learn best practices of the language they're using
• MegaLinter documentation provides the list of IDE plugins integrating each linter, so developers know which linter and plugins to install
• MegaLinter is ready out of the box after a quick setup
• Formatting and fixes can be automatically applied on the git branch or provided in reports
• This tool is 100% open-source and free for all uses (personal, professional, public and private repositories)
• MegaLinter can run on any CI tool and be run locally: no need to authorize an external application, and your code base never leaves your tooling ecosystem

Quick Start

• Run npx mega-linter-runner --install to generate configuration files (you need node.js to be installed)
• Commit, push, and create a pull request
• Watch !

Notes:

• This repo is a hard-fork of GitHub Super-Linter, rewritten in python to add lots of additional features
• If you are a Super-Linter user, you can transparently switch to MegaLinter and keep the same configuration (just replace super-linter/super-linter@v3 by oxsecurity/megalinter@v7 in your GitHub Action YML file, like on this PR)
• If you want to use MegaLinter extra features (recommended), please take 5 minutes to use MegaLinter assisted installation
• For a hand-holdy example of getting started with mega-linter check out this blog post by Alec Johnson

Supported Linters

All linters are integrated in the MegaLinter docker image, which is frequently upgraded with their latest versions

Languages

	Language	Linter	Additional
	BASH	bash-exec _BASHEXEC
	BASH	shellcheck _BASHSHELLCHECK
	BASH	shfmt _BASHSHFMT
	C	cpplint _CCPPLINT
	C	clang-format _C_CLANGFORMAT
	CLOJURE	clj-kondo _CLOJURE_CLJKONDO
	CLOJURE	cljstyle _CLOJURECLJSTYLE
	COFFEE	coffeelint _COFFEECOFFEELINT
	C++ (CPP)	cpplint _CPPCPPLINT
	C++ (CPP)	clang-format _CPP_CLANGFORMAT
	C# (CSHARP)	dotnet-format _CSHARP_DOTNETFORMAT
	C# (CSHARP)	csharpier _CSHARPCSHARPIER
	C# (CSHARP)	roslynator _CSHARPROSLYNATOR
	DART	dartanalyzer _DARTDARTANALYZER
	GO	golangci-lint _GO_GOLANGCILINT
	GO	revive _GOREVIVE
	GROOVY	npm-groovy-lint _GROOVY_NPM_GROOVYLINT
	JAVA	checkstyle _JAVACHECKSTYLE
	JAVA	pmd _JAVAPMD
	JAVASCRIPT	eslint _JAVASCRIPTES
	JAVASCRIPT	standard _JAVASCRIPTSTANDARD
	JAVASCRIPT	prettier _JAVASCRIPTPRETTIER
	JSX	eslint _JSXESLINT
	KOTLIN	ktlint _KOTLINKTLINT
	KOTLIN	detekt _KOTLINDETEKT
	LUA	luacheck _LUALUACHECK
	MAKEFILE	checkmake _MAKEFILECHECKMAKE
	PERL	perlcritic _PERLPERLCRITIC
	PHP	phpcs _PHPPHPCS
	PHP	phpstan _PHPPHPSTAN
	PHP	psalm _PHPPSALM
	PHP	phplint _PHPPHPLINT
	PHP	php-cs-fixer _PHPPHPCSFIXER
	POWERSHELL	powershell _POWERSHELLPOWERSHELL
	POWERSHELL	powershell_formatter _POWERSHELL_POWERSHELLFORMATTER
	PYTHON	pylint _PYTHONPYLINT
	PYTHON	black _PYTHONBLACK
	PYTHON	flake8 _PYTHONFLAKE8
	PYTHON	isort _PYTHONISORT
	PYTHON	bandit _PYTHONBANDIT
	PYTHON	mypy _PYTHONMYPY
	PYTHON	pyright _PYTHONPYRIGHT
	PYTHON	ruff _PYTHONRUFF
	R	lintr _RLINTR
	RAKU	raku _RAKURAKU
	RUBY	rubocop _RUBYRUBOCOP
	RUST	clippy _RUSTCLIPPY
	SALESFORCE	sfdx-scanner-apex _SALESFORCE_SFDX_SCANNERAPEX
	SALESFORCE	sfdx-scanner-aura _SALESFORCE_SFDX_SCANNERAURA
	SALESFORCE	sfdx-scanner-lwc _SALESFORCE_SFDX_SCANNERLWC
	SALESFORCE	lightning-flow-scanner _SALESFORCE_LIGHTNING_FLOWSCANNER
	SCALA	scalafix _SCALASCALAFIX
	SQL	sql-lint _SQL_SQLLINT
	SQL	sqlfluff _SQLSQLFLUFF
	SQL	tsqllint _SQLTSQLLINT
	SWIFT	swiftlint _SWIFTSWIFTLINT
	TSX	eslint _TSXESLINT
	TYPESCRIPT	eslint _TYPESCRIPTES
	TYPESCRIPT	ts-standard _TYPESCRIPTSTANDARD
	TYPESCRIPT	prettier _TYPESCRIPTPRETTIER
	Visual Basic .NET (VBDOTNET)	dotnet-format _VBDOTNET_DOTNETFORMAT

Formats

	Format	Linter	Additional
	CSS	stylelint _CSSSTYLELINT
	CSS	scss-lint _CSS_SCSSLINT
	ENV	dotenv-linter _ENV_DOTENVLINTER
	GRAPHQL	graphql-schema-linter _GRAPHQL_GRAPHQL_SCHEMALINTER
	HTML	djlint _HTMLDJLINT
	HTML	htmlhint _HTMLHTMLHINT
	JSON	jsonlint _JSONJSONLINT
	JSON	eslint-plugin-jsonc _JSON_ESLINT_PLUGINJSONC
	JSON	v8r _JSONV8R
	JSON	prettier _JSONPRETTIER
	JSON	npm-package-json-lint _JSON_NPM_PACKAGE_JSONLINT
	LATEX	chktex _LATEXCHKTEX
	MARKDOWN	markdownlint _MARKDOWNMARKDOWNLINT
	MARKDOWN	remark-lint _MARKDOWN_REMARKLINT
	MARKDOWN	markdown-link-check _MARKDOWN_MARKDOWN_LINKCHECK
	MARKDOWN	markdown-table-formatter _MARKDOWN_MARKDOWN_TABLEFORMATTER
	PROTOBUF	protolint _PROTOBUFPROTOLINT
	RST	rst-lint _RST_RSTLINT
	RST	rstcheck _RSTRSTCHECK
	RST	rstfmt _RSTRSTFMT
	XML	xmllint _XMLXMLLINT
	YAML	prettier _YAMLPRETTIER
	YAML	yamllint _YAMLYAMLLINT
	YAML	v8r _YAMLV8R

Tooling formats

	Tooling format	Linter	Additional
	ACTION	actionlint _ACTIONACTIONLINT
	ANSIBLE	ansible-lint _ANSIBLE_ANSIBLELINT
	API	spectral _APISPECTRAL
	ARM	arm-ttk _ARM_ARMTTK
	BICEP	bicep_linter _BICEP_BICEPLINTER
	CLOUDFORMATION	cfn-lint _CLOUDFORMATION_CFNLINT
	DOCKERFILE	hadolint _DOCKERFILEHADOLINT
	EDITORCONFIG	editorconfig-checker _EDITORCONFIG_EDITORCONFIGCHECKER
	GHERKIN	gherkin-lint _GHERKIN_GHERKINLINT
	KUBERNETES	kubeconform _KUBERNETESKUBECONFORM
	KUBERNETES	helm _KUBERNETESHELM
	KUBERNETES	kubescape _KUBERNETESKUBESCAPE
	OPENAPI	spectral _OPENAPISPECTRAL
	PUPPET	puppet-lint _PUPPET_PUPPETLINT
	SNAKEMAKE	snakemake _SNAKEMAKELINT
	SNAKEMAKE	snakefmt _SNAKEMAKESNAKEFMT
	TEKTON	tekton-lint _TEKTON_TEKTONLINT
	TERRAFORM	tflint _TERRAFORMTFLINT
	TERRAFORM	terrascan _TERRAFORMTERRASCAN
	TERRAFORM	terragrunt _TERRAFORMTERRAGRUNT
	TERRAFORM	terraform-fmt _TERRAFORM_TERRAFORMFMT

Other

	Code quality checker	Linter	Additional
	COPYPASTE	jscpd _COPYPASTEJSCPD
	REPOSITORY	checkov _REPOSITORYCHECKOV
	REPOSITORY	devskim _REPOSITORYDEVSKIM
	REPOSITORY	dustilock _REPOSITORYDUSTILOCK
	REPOSITORY	git_diff _REPOSITORY_GITDIFF
	REPOSITORY	gitleaks _REPOSITORYGITLEAKS
	REPOSITORY	grype _REPOSITORYGRYPE
	REPOSITORY	kics _REPOSITORYKICS
	REPOSITORY	ls-lint _REPOSITORY_LSLINT
	REPOSITORY	secretlint _REPOSITORYSECRETLINT
	REPOSITORY	semgrep _REPOSITORYSEMGREP
	REPOSITORY	syft _REPOSITORYSYFT
	REPOSITORY	trivy _REPOSITORYTRIVY
	REPOSITORY	trivy-sbom _REPOSITORY_TRIVYSBOM
	REPOSITORY	trufflehog _REPOSITORYTRUFFLEHOG
	SPELL	cspell _SPELLCSPELL
	SPELL	proselint _SPELLPROSELINT
	SPELL	vale _SPELLVALE
	SPELL	lychee _SPELLLYCHEE

Installation

Assisted installation

Just run npx mega-linter-runner --install at the root of your repository and answer questions, it will generate ready to use configuration files for MegaLinter :)

Which version to use ?

The following instructions examples are using latest MegaLinter stable version (v7 , always corresponding to the latest release)

• Docker image: oxsecurity/megalinter:v7
• GitHub Action: oxsecurity/megalinter@v7

You can also use beta version (corresponding to the content of main branch)

• Docker image: oxsecurity/megalinter:beta
• GitHub Action: oxsecurity/megalinter@beta

GitHub Action

1. Create a new file in your repository called .github/workflows/mega-linter.yml
2. Copy the example workflow from below into that new file, no extra configuration required
3. Commit that file to a new branch
4. Open up a pull request and observe the action working
5. Enjoy your more stable, and cleaner code base

NOTES:

• If you pass the Environment variable GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} in your workflow, then the MegaLinter will mark the status of each individual linter run in the Checks section of a pull request. Without this you will only see the overall status of the full run. There is no need to set the GitHub Secret as it's automatically set by GitHub, it only needs to be passed to the action.
• You can also use it outside of GitHub Actions (CircleCI, Azure Pipelines, Jenkins, GitLab, or even locally with a docker run) , and have status on Github Pull Request if GITHUB_TARGET_URL environment variable exists.

In your repository you should have a .github/workflows folder with GitHub Action similar to below:

• .github/workflows/mega-linter.yml

This file should have this code

```yml --- # MegaLinter GitHub Action configuration file # More info at https://megalinter.io name: MegaLinter on: # Trigger mega-linter at every push. Action will also be visible from Pull Requests to main push: # Comment this line to trigger action only on pull-requests (not recommended if you don't pay for GH Actions) pull_request: branches: [master, main] env: # Comment env block if you don't want to apply fixes # Apply linter fixes configuration APPLY_FIXES: all # When active, APPLY_FIXES must also be defined as environment variable (in github/workflows/mega-linter.yml or other CI tool) APPLY_FIXES_EVENT: pull_request # Decide which event triggers application of fixes in a commit or a PR (pull_request, push, all) APPLY_FIXES_MODE: commit # If APPLY_FIXES is used, defines if the fixes are directly committed (commit) or posted in a PR (pull_request) concurrency: group: ${{ github.ref }}-${{ github.workflow }} cancel-in-progress: true jobs: megalinter: name: MegaLinter runs-on: ubuntu-latest permissions: # Give the default GITHUB_TOKEN write permission to commit and push, comment issues & post new PR # Remove the ones you do not need contents: write issues: write pull-requests: write steps: # Git Checkout - name: Checkout Code uses: actions/checkout@v4 with: token: ${{ secrets.PAT || secrets.GITHUB_TOKEN }} fetch-depth: 0 # If you use VALIDATE_ALL_CODEBASE = true, you can remove this line to improve performances # MegaLinter - name: MegaLinter id: ml # You can override MegaLinter flavor used to have faster performances # More info at https://megalinter.io/flavors/ uses: oxsecurity/megalinter@v7 env: # All available variables are described in documentation # https://megalinter.io/configuration/ VALIDATE_ALL_CODEBASE: ${{ github.event_name == 'push' && github.ref == 'refs/heads/main' }} # Validates all source when push on main, else just the git diff with main. Override with true if you always want to lint all sources GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # ADD YOUR CUSTOM ENV VARIABLES HERE OR DEFINE THEM IN A FILE .mega-linter.yml AT THE ROOT OF YOUR REPOSITORY # DISABLE: COPYPASTE,SPELL # Uncomment to disable copy-paste and spell checks # Upload MegaLinter artifacts - name: Archive production artifacts if: success() || failure() uses: actions/upload-artifact@v4 with: name: MegaLinter reports path: | megalinter-reports mega-linter.log # Create pull request if applicable (for now works only on PR from same repository, not from forks) - name: Create Pull Request with applied fixes id: cpr if: steps.ml.outputs.has_updated_sources == 1 && (env.APPLY_FIXES_EVENT == 'all' || env.APPLY_FIXES_EVENT == github.event_name) && env.APPLY_FIXES_MODE == 'pull_request' && (github.event_name == 'push' || github.event.pull_request.head.repo.full_name == github.repository) && !contains(github.event.head_commit.message, 'skip fix') uses: peter-evans/create-pull-request@v6 with: token: ${{ secrets.PAT || secrets.GITHUB_TOKEN }} commit-message: "[MegaLinter] Apply linters automatic fixes" title: "[MegaLinter] Apply linters automatic fixes" labels: bot - name: Create PR output if: steps.ml.outputs.has_updated_sources == 1 && (env.APPLY_FIXES_EVENT == 'all' || env.APPLY_FIXES_EVENT == github.event_name) && env.APPLY_FIXES_MODE == 'pull_request' && (github.event_name == 'push' || github.event.pull_request.head.repo.full_name == github.repository) && !contains(github.event.head_commit.message, 'skip fix') run: | echo "Pull Request Number - ${{ steps.cpr.outputs.pull-request-number }}" echo "Pull Request URL - ${{ steps.cpr.outputs.pull-request-url }}" # Push new commit if applicable (for now works only on PR from same repository, not from forks) - name: Prepare commit if: steps.ml.outputs.has_updated_sources == 1 && (env.APPLY_FIXES_EVENT == 'all' || env.APPLY_FIXES_EVENT == github.event_name) && env.APPLY_FIXES_MODE == 'commit' && github.ref != 'refs/heads/main' && (github.event_name == 'push' || github.event.pull_request.head.repo.full_name == github.repository) && !contains(github.event.head_commit.message, 'skip fix') run: sudo chown -Rc $UID .git/ - name: Commit and push applied linter fixes if: steps.ml.outputs.has_updated_sources == 1 && (env.APPLY_FIXES_EVENT == 'all' || env.APPLY_FIXES_EVENT == github.event_name) && env.APPLY_FIXES_MODE == 'commit' && github.ref != 'refs/heads/main' && (github.event_name == 'push' || github.event.pull_request.head.repo.full_name == github.repository) && !contains(github.event.head_commit.message, 'skip fix') uses: stefanzweifel/git-auto-commit-action@v4 with: branch: ${{ github.event.pull_request.head.ref || github.head_ref || github.ref }} commit_message: "[MegaLinter] Apply linters fixes" commit_user_name: megalinter-bot commit_user_email: nicolas.vuillamy@ox.security ```

GitLab CI

Manual setup

Create or update .gitlab-ci.yml file at the root of your repository

# MegaLinter GitLab CI job configuration file
# More info at https://megalinter.io/

mega-linter:
  stage: test
  # You can override MegaLinter flavor used to have faster performances
  # More info at https://megalinter.io/flavors/
  image: oxsecurity/megalinter:v7
  script: [ "true" ] # if script: ["true"] doesn't work, you may try ->  script: [ "/bin/bash /entrypoint.sh" ]
  variables:
    # All available variables are described in documentation
    # https://megalinter.io/configuration/
    DEFAULT_WORKSPACE: $CI_PROJECT_DIR
    # ADD YOUR CUSTOM ENV VARIABLES HERE TO OVERRIDE VALUES OF .mega-linter.yml AT THE ROOT OF YOUR REPOSITORY
  artifacts:
    when: always
    paths:
      - megalinter-reports
    expire_in: 1 week

Create a Gitlab access token and define it in a variable GITLAB_ACCESS_TOKEN_MEGALINTER in the project CI/CD masked variables. Make sure your token (e.g. if a project token) as the appropriate role for commenting a merge request (at least developer).

Using R2Devops

Our friends at R2Devops have packaged a Gitlab-CI MegaLinter workflow on their open-source templates marketplace, and it can post MegaLinter results in Gitlab Code Quality Reports !

Azure Pipelines

Use the following Azure Pipelines YAML template

Add the following job in your azure-pipelines.yaml file

  # Run MegaLinter to detect linting and security issues
  - job: MegaLinter
    pool:
      vmImage: ubuntu-latest
    steps:
      # Checkout repo
      - checkout: self

      # Pull MegaLinter docker image
      - script: docker pull oxsecurity/megalinter:v7
        displayName: Pull MegaLinter

      # Run MegaLinter
      - script: |
          docker run -v $(System.DefaultWorkingDirectory):/tmp/lint \
            --env-file <(env | grep -e SYSTEM_ -e BUILD_ -e TF_ -e AGENT_) \
            -e SYSTEM_ACCESSTOKEN=$(System.AccessToken) \
            -e GIT_AUTHORIZATION_BEARER=$(System.AccessToken) \
            oxsecurity/megalinter:v7
        displayName: Run MegaLinter

      # Upload MegaLinter reports
      - task: PublishPipelineArtifact@1
        condition: succeededOrFailed()
        displayName: Upload MegaLinter reports
        inputs:
          targetPath: "$(System.DefaultWorkingDirectory)/megalinter-reports/"
          artifactName: MegaLinterReport

To benefit from Pull Request comments, please follow configuration instructions

You can also follow this detailed tutorial by DonKoning

Bitbucket Pipelines

1. Create a bitbucket-pipelines.yml file on the root directory of your repository

2. Copy and paste the following template or add the step to your existing pipeline.

image: atlassian/default-image:3
pipelines:
  default:
    - parallel:
      - step:
          name: Run MegaLinter
          image: oxsecurity/megalinter:v7
          script:
            - export DEFAULT_WORKSPACE=$BITBUCKET_CLONE_DIR && bash /entrypoint.sh
          artifacts:
            -  megalinter-reports/**

Jenkins

Add the following stage in your Jenkinsfile

You may activate File.io reporter or E-mail reporter to access detailed logs and fixed source

// Lint with MegaLinter: https://megalinter.io/
stage('MegaLinter') {
    agent {
        docker {
            image 'oxsecurity/megalinter:v7'
            args "-u root -e VALIDATE_ALL_CODEBASE=true -v ${WORKSPACE}:/tmp/lint --entrypoint=''"
            reuseNode true
        }
    }
    steps {
        sh '/entrypoint.sh'
    }
    post {
        always {
            archiveArtifacts allowEmptyArchive: true, artifacts: 'mega-linter.log,megalinter-reports/**/*', defaultExcludes: false, followSymlinks: false
        }
    }
}

CloudBees themselves made a nice tutorial about how to use MegaLinter with Jenkins !

Concourse

Pipeline step

Use the following job.step in your pipeline template

Note: make sure you have job.plan.get step which gets repo containing your repository as shown in example

---

  - name: linting
    plan:
      - get: repo
      - task: linting
        config:
          platform: linux
          image_resource:
            type: docker-image
            source:
              repository: oxsecurity/megalinter
              tag: v7
          inputs:
            - name: repo
          run:
            path: bash
            args:
            - -cxe
            - |
              cd repo
              export DEFAULT_WORKSPACE=$(pwd)
              bash -ex /entrypoint.sh
              ## doing this because concourse doesn't work as other CI systems
          # params:
            # PARALLEL: true
            # DISABLE: SPELL
            # APPLY_FIXES: all
            # DISABLE_ERRORS: true
            # VALIDATE_ALL_CODEBASE: true

OR

Use it as reusable task

Create reusable concourse task which can be used with multiple pipelines

1. Create task file task-linting.yaml

---
platform: linux
image_resource:
  type: docker-image
  source:
    repository: oxsecurity/megalinter
    tag: v7

inputs:
- name: repo

## uncomment this if you want reports as task output
# output:
# - name: reports
#   path: repo/megalinter-reports

run:
  path: bash
  args:
  - -cxe
  - |
    cd repo
    export DEFAULT_WORKSPACE=$(pwd)
    bash -ex /entrypoint.sh

2. Use that task-linting.yaml task in pipeline

Note:

1. make sure task-linting.yaml is available in that repo input at root

2. task output is not shown here

resources:

  - name: linting
    plan:
      - get: repo
      - task: linting
        file: repo/task-linting.yaml
        # params:
        #   PARALLEL: true
        #   DISABLE: SPELL
        #   APPLY_FIXES: all
        #   DISABLE_ERRORS: true
        #   VALIDATE_ALL_CODEBASE: true

Drone CI

Warning: Drone CI support is experimental and is undergoing heavy modifications (see issue #2047).

1. Create a .drone.yml file on the root directory of your repository

2. Copy and paste the following template:

kind: pipeline
type: docker
name: MegaLinter

workspace:
  path: /tmp/lint

steps:

- name: megalinter
  image: oxsecurity/megalinter:v7
  environment:
    DEFAULT_WORKSPACE: /tmp/lint

This uses the Drone CI docker runner, so it's needed to install and configure it beforehand on your Drone CI server.

(Optional) Adjusting trigger rules

The Drone CI workflow should trigger automatically for every scenario (push, pull request, sync…) however, you can optionally change this behavior by changing the trigger. For example:

kind: pipeline
type: docker
name: MegaLinter

workspace:
  path: /tmp/lint

steps:

- name: megalinter
  image: oxsecurity/megalinter:v7
  environment:
    DEFAULT_WORKSPACE: /tmp/lint

trigger:
  event:
  - push

The workflow above should only trigger on push, not on any other situation. For more information about how to configure Drone CI trigger rules, click here.

Docker container

You can also run megalinter with its Docker container, just execute this command:

docker run --rm -v /var/run/docker.sock:/var/run/docker.sock:rw -v $(pwd):/tmp/lint:rw oxsecurity/megalinter:v7

No extra arguments are needed, however, megalinter will lint all of the files inside the /tmp/lint folder, so it may be needed to configure your tool of choice to use the /tmp/lint folder as workspace. This can also be changed:

Example:

docker run --rm -v /var/run/docker.sock:/var/run/docker.sock:rw -v $(pwd):/example/folder:rw oxsecurity/megalinter:v7

Run MegaLinter locally

You can use mega-linter-runner to locally run MegaLinter with the same configuration defined in .mega-linter.yml file

See mega-linter-runner installation instructions

Example

npx mega-linter-runner --flavor salesforce -e "'ENABLE=DOCKERFILE,MARKDOWN,YAML'" -e 'SHOW_ELAPSED_TIME=true'

Note: You can also use such command line in your custom CI/CD pipelines

Configuration

.mega-linter.yml file

MegaLinter configuration variables are defined in a .mega-linter.yml file at the root of the repository or with environment variables. You can see an example config file in this repo: .mega-linter.yml

Configuration is assisted with autocompletion and validation in most commonly used IDEs, thanks to JSON schema stored on schemastore.org

• VSCode: You need a VSCode extension like Red Hat YAML
• IDEA family: Auto-completion natively supported

You can also define variables as environment variables.

• In case a variable exists in both ENV and .mega-linter.yml file, priority is given to ENV variable.

Common variables

ENV VAR	Default Value	Notes
ADDITIONAL_EXCLUDED_DIRECTORIES	[]	List of additional excluded directory basenames. they're excluded at any nested level.
APPLY_FIXES	none	Activates formatting and autofix (more info)
CLEAR_REPORT_FOLDER	false	Flag to clear files from report folder (usually megalinter-reports) before starting the linting process
CONFIG_PROPERTIES_TO_APPEND	[]	List of configuration properties to append their values (instead of replacing them) in case of using EXTENDS.
DEFAULT_BRANCH	HEAD	Deprecated: The name of the repository's default branch.
DEFAULT_WORKSPACE	/tmp/lint	The location containing files to lint if you are running locally.
DISABLE_ERRORS	false	Flag to have the linter complete with exit code 0 even if errors were detected.
DISABLE		List of disabled descriptors keys (more info)
DISABLE_LINTERS		List of disabled linters keys (more info)
DISABLE_ERRORS_LINTERS		List of enabled but not blocking linters keys (more info)
ENABLE		List of enabled descriptors keys (more info)
ENABLE_LINTERS		List of enabled linters keys (more info)
EXCLUDED_DIRECTORIES	[…many values…]	List of excluded directory basenames. they're excluded at any nested level.
EXTENDS		Base mega-linter.yml config file(s) to extend local configuration from. Can be a single URL or a list of .mega-linter.yml config files URLs. Later files take precedence.
FAIL_IF_MISSING_LINTER_IN_FLAVOR	false	If set to true, MegaLinter fails if a linter is missing in the selected flavor
FAIL_IF_UPDATED_SOURCES	false	If set to true, MegaLinter fails if a linter or formatter has autofixed sources, even if there are no errors
FILTER_REGEX_EXCLUDE	none	Regular expression defining which files will be excluded from linting (more info) .ex: .*src/test.*)
FILTER_REGEX_INCLUDE	all	Regular expression defining which files will be processed by linters (more info) .ex: .*src/.*)
FLAVOR_SUGGESTIONS	true	Provides suggestions about different MegaLinter flavors to use to improve runtime performances
FORMATTERS_DISABLE_ERRORS	true	Formatter errors will be reported as errors (and not warnings) if this variable is set to false
GIT_AUTHORIZATION_BEARER		If set, calls git with Authorization: Bearer+value
GITHUB_WORKSPACE		Base directory for REPORT_OUTPUT_FOLDER, for user-defined linter rules location, for location of linted files if DEFAULT_WORKSPACE isn't set
IGNORE_GENERATED_FILES	false	If set to true, MegaLinter will skip files containing @generated marker but without @not-generated marker (more info at https://generated.at)
IGNORE_GITIGNORED_FILES	true	If set to true, MegaLinter will skip files ignored by git using .gitignore file
JAVASCRIPT_DEFAULT_STYLE	standard	Javascript default style to check/apply. standard,prettier
LINTER_RULES_PATH	.github/linters	Directory for all linter configuration rules. Can be a local folder or a remote URL (ex: https://raw.githubusercontent.com/some_org/some_repo/mega-linter-rules )
LOG_FILE	mega-linter.log	The file name for outputting logs. All output is sent to the log file regardless of LOG_LEVEL. Use none to not generate this file.
LOG_LEVEL	INFO	How much output the script will generate to the console. One of INFO, DEBUG, WARNING or ERROR.
MARKDOWN_DEFAULT_STYLE	markdownlint	Markdown default style to check/apply. markdownlint,remark-lint
MEGALINTER_CONFIG	.mega-linter.yml	Name of MegaLinter configuration file. Can be defined remotely, in that case set this environment variable with the remote URL of .mega-linter.yml config file
MEGALINTER_FILES_TO_LINT	[]	Comma-separated list of files to analyze. Using this variable will bypass other file listing methods
PARALLEL	true	Process linters in parallel to improve overall MegaLinter performance. If true, linters of same language or formats are grouped in the same parallel process to avoid lock issues if fixing the same files
PARALLEL_PROCESS_NUMBER		All available cores are used by default. If there are too many, you need to decrease the number of used cores in order to enhance performances (example: 4)
PLUGINS	[]	List of plugin urls to install and run during MegaLinter run
POST_COMMANDS	[]	Custom bash commands to run after linters
PRE_COMMANDS	[]	Custom bash commands to run before linters
PRINT_ALPACA	true	Enable printing alpaca image to console
PRINT_ALL_FILES	false	Display all files analyzed by the linter instead of only the number
REPORT_OUTPUT_FOLDER	${GITHUB_WORKSPACE}/megalinter-reports	Directory for generating report files. Set to none to not generate reports
SECURED_ENV_VARIABLES	[]	Additional list of secured environment variables to hide when calling linters.
SECURED_ENV_VARIABLES_DEFAULT	MegaLinter & CI platforms sensitive variables	List of secured environment variables to hide when calling linters. Default list. This is not recommended to override this variable, use SECURED_ENV_VARIABLES
SHOW_ELAPSED_TIME	false	Displays elapsed time in reports
SHOW_SKIPPED_LINTERS	true	Displays all disabled linters mega-linter could have run
SKIP_CLI_LINT_MODES	[]	Comma-separated list of cli_lint_modes. To use if you want to skip linters with some CLI lint modes (ex: file,project). Available values: file,cli_lint_mode,project.
TYPESCRIPT_DEFAULT_STYLE	standard	Typescript default style to check/apply. standard,prettier
VALIDATE_ALL_CODEBASE	true	Will parse the entire repository and find all files to validate across all types. NOTE: When set to false, only new or edited files will be parsed for validation.

Activation and deactivation

MegaLinter have all linters enabled by default, but allows to enable only some, or disable only some

• If ENABLE isn't set, all descriptors are activated by default. If set, all linters of listed descriptors will be activated by default
• If ENABLE_LINTERS is set, only listed linters will be processed
• If DISABLE is set, the linters in the listed descriptors will be skipped
• If DISABLE_LINTERS is set, the listed linters will be skipped
• If DISABLE_ERRORS_LINTERS is set, the listed linters will be run, but if errors are found, they will be considered as non blocking

Examples:

• Run all javascript and groovy linters except STANDARD javascript linter. DevSkim errors will be non-blocking

ENABLE: JAVASCRIPT,GROOVY
DISABLE_LINTERS: JAVASCRIPT_STANDARD
DISABLE_ERRORS_LINTERS: REPOSITORY_DEVSKIM

• Run all linters except PHP linters (PHP_BUILTIN, PHP_PHPCS, PHP_PHPSTAN, PHP_PSALM)

DISABLE: PHP

• Run all linters except PHP_PHPSTAN and PHP_PSALM linters

DISABLE_LINTERS:
  - PHP_PHPSTAN
  - PHP_PSALM

Filter linted files

If you need to lint only a folder or exclude some files from linting, you can use optional environment parameters FILTER_REGEX_INCLUDE and FILTER_REGEX_EXCLUDE You can apply filters to a single linter by defining variable <LINTER_KEY>_FILTER_REGEX_INCLUDE and <LINTER_KEY>_FILTER_REGEX_EXCLUDE

Examples:

• Lint only src folder: FILTER_REGEX_INCLUDE: (src/)
• Don't lint files inside test and example folders: FILTER_REGEX_EXCLUDE: (test/|examples/)
• Don't lint javascript files inside test folder: FILTER_REGEX_EXCLUDE: (test/.*\.js)

Warning: not applicable with linters using CLI lint mode project (see details)

Apply fixes

Mega-linter is able to apply fixes provided by linters. To use this capability, you need 3 env variables defined at top level

• APPLY_FIXES: all to apply fixes of all linters, or a list of linter keys (ex: JAVASCRIPT_ES,MARKDOWN_MARKDOWNLINT)

Only for GitHub Action Workflow file if you use it:

• APPLY_FIXES_EVENT: all, push, pull_request, none (use none in case of use of Updated sources reporter)
• APPLY_FIXES_MODE: commit to create a new commit and push it on the same branch, or pull_request to create a new PR targeting the branch.

Apply fixes issues

You may see github permission errors, or workflows not run on the new commit.

To solve these issues, you can apply one of the following solutions.

• Method 1: The most secured

  • Create Fine Grained Personal Access Token, scoped only on your repository and then copy the PAT value
  • Define environment secret variable named PAT on your repository, and paste the PAT value
  • Update your Github Actions Workflow to add the environment name

• Method 2: Easier, but any contributor with write access can see your Personal Access Token

  • Create Classic Personal Access Token, then copy the PAT value
  • Define secret variable named PAT on your repository, and paste the PAT value

Notes

• You can use Updated sources reporter if you don't want fixes to be automatically applied on git branch, but download them in a zipped file and manually extract them in your project
• If used, APPLY_FIXES_EVENT and APPLY_FIXES_MODE can not be defined in .mega-linter.ymlconfig file, they must be set as environment variables
• If you use APPLY_FIXES, add the following line in your .gitignore file

megalinter-reports/

Linter specific variables

See variables related to a single linter behavior in linters documentations

Pre-commands

MegaLinter can run custom commands before running linters (for example, installing an plugin required by one of the linters you use)

Example in .mega-linter.yml config file

PRE_COMMANDS:
  - command: npm install eslint-plugin-whatever
    cwd: "root"        # Will be run at the root of MegaLinter docker image
    secured_env: true  # True by default, but if defined to false, no global variable will be hidden (for example if you need GITHUB_TOKEN)
  - command: echo "pre-test command has been called"
    cwd: "workspace"   # Will be run at the root of the workspace (usually your repository root)
    continue_if_failed: False  # Will stop the process if command is failed (return code > 0)
  - command: pip install flake8-cognitive-complexity
    venv: flake8 # Will be run within flake8 python virtualenv. There is one virtualenv per python-based linter, with the same name

Post-commands

MegaLinter can run custom commands after running linters (for example, running additional tests)

Example in .mega-linter.yml config file

POST_COMMANDS:
  - command: npm run test
    cwd: "workspace"   # Will be run at the root of the workspace (usually your repository root)
    continue_if_failed: False  # Will stop the process if command is failed (return code > 0)

Environment variables security

Secured env variables

MegaLinter runs on a docker image and calls the linters via command line to gather their results.

If you run it from your CI/CD pipelines, the docker image may have access to your environment variables, that can contain secrets defined in CI/CD variables.

As it can be complicated to trust the authors of all the open-source linters, MegaLinter removes variables from the environment used to call linters.

Thanks to this feature, you only need to trust MegaLinter and its internal python dependencies, but there is no need to trust all the linters that are used !

You can add secured variables to the default list using configuration property SECURED_ENV_VARIABLES in .mega-linter.yml or in an environment variable (priority is given to ENV variables above .mega-linter.yml property).

Values can be:

• String (ex: MY_SECRET_VAR)
• Regular Expression (ex: (MY.*VAR))

Environment variables are secured for each command line called (linters, plugins, sarif formatter...) except for PRE_COMMANDS , ONLY if you define secured_env: false in the command.

Secured configuration examples

• Example of adding extra secured variables .mega-linter.yml:

SECURED_ENV_VARIABLES:
  - MY_SECRET_TOKEN
  - ANOTHER_VAR_CONTAINING_SENSITIVE_DATA
  - OX_API_KEY
  - (MY.*VAR)  # Regex format

• Example of adding extra secured variables in CI variables, so they can not be overridden in .mega-linter.yml:

SECURED_ENV_VARIABLES=MY_SECRET_TOKEN,ANOTHER_VAR_CONTAINING_SENSITIVE_DATA,OX_API_KEY

Default secured variables

If you override SECURED_ENV_VARIABLES_DEFAULT, it replaces the default list, so it's better to only define SECURED_ENV_VARIABLES to add them to the default list !

SECURED_ENV_VARIABLES_DEFAULT contains:

• GITHUB_TOKEN
• PAT
• SYSTEM_ACCESSTOKEN
• GIT_AUTHORIZATION_BEARER
• CI_JOB_TOKEN
• GITLAB_ACCESS_TOKEN_MEGALINTER
• GITLAB_CUSTOM_CERTIFICATE
• WEBHOOK_REPORTER_BEARER_TOKEN
• NODE_TOKEN
• NPM_TOKEN
• DOCKER_USERNAME
• DOCKER_PASSWORD
• CODECOV_TOKEN
• GCR_USERNAME
• GCR_PASSWORD
• SMTP_PASSWORD
• CI_SFDX_HARDIS_GITLAB_TOKEN
• (SFDX_CLIENTID.*)
• (SFDX_CLIENTKEY.*)

Unhide variables for linters

You can configure exceptions for a specific linter by defining (linter-key)_UNSECURED_ENV_VARIABLES.

Variable names in this list won't be hidden to the linter commands.

TERRAFORM_TFLINT_UNSECURED_ENV_VARIABLES:
  - GITHUB_TOKEN # Can contain string only, not regex

CLI lint mode

Each linter is pre-configured to use a default lint mode, which are visible in the MegaLinter documentation (example). The possible values are:

• list_of_files: The linter is called only once, and passed a list of all the files to be processed
• project: The linter is called only once, from the root folder of the repository, and it scans for the files to process, as no file names are provided it
• file: The linter is called once per file, which hurts performance

You can override the CLI_LINT_MODE by using a configuration variable for each linter (see linters documentation).

• Linters that default to the file lint mode cannot be overridden to use the list_of_files lint mode
• Linters that default to the project lint mode cannot be overridden to use either the list_of_files or file lint modes.

Allowing file or list_of_files to be overridden to project is mostly for workarounds. For example, some linters have a problem finding their config file when the current folder isn't the repository's root folder.

Special considerations:

• Linters that are configured to use the project lint mode ignore variables like FILTER_REGEX_INCLUDE and FILTER_REGEX_EXCLUDE, as they are not passed a list of files to lint. For those linters, you must check their documentation to see if a linter can be configured to ignore specific files. For example, the Secretlint linter ignore files listed in ~/.secretlintignore by default, or it can be configured to instead ignore files listed in ~/.gitignore by setting REPOSITORY_SECRETLINT_ARGUMENTS to --secretlintignore .gitignore..

Reporters

MegaLinter can generate various reports that you can activate / deactivate and customize

Reporter	Description	Default
Text files	Generates One log file by linter + suggestions for fixes that can not be automated	Active
SARIF (beta)	Generates an aggregated SARIF output file	Inactive
GitHub Pull Request comments	MegaLinter posts a comment on the PR with a summary of lint results, and links to detailed logs	Active if GitHub Action
Gitlab Merge Request comments	Mega-Linter posts a comment on the MR with a summary of lint results, and links to detailed logs	Active if in Gitlab CI
Azure Pipelines Pull Request comments	Mega-Linter posts a comment on the PR with a summary of lint results, and links to detailed logs	Active if in Azure Pipelines
Bitbucket Pull Request comments	Mega-Linter posts a comment on the PR with a summary of lint results, and links to detailed logs	Active if in Bitbucket CI
Updated sources	Zip containing all formatted and autofixed sources so you can extract them in your repository	Active
IDE Configuration	Apply MegaLinter configuration in your local IDE with linter config files and IDE extensions	Active
GitHub Status	One GitHub status by linter on the PR, with links to detailed logs	Active if GitHub Action
File.io	Send reports on file.io so you can access them with a simple hyperlink provided at the end of console log	Inactive
JSON	Generates a JSON output report file	Inactive
Email	Receive all reports on your e-mail, if you can not use artifacts	Active
TAP files	One file by linter following Test Anything Protocol format	Active
Console	Execution logs visible in console with summary table and links to other reports at the end	Active
Markdown Summary	Generates a Markdown summary report file	Inactive

Flavors

To improve run performances, we generate Flavored MegaLinter images containing only the list of linters related to a project type

• When using default MegaLinter, if a MegaLinter Flavor would cover all your project requirements, a message is added in the logs
• If your project uses a MegaLinter Flavor not covering linter requirements, an error message will be thrown with instructions about how to solve the issue

The following table doesn't display docker pulls from MegaLinter v4 & v5 images.

	Flavor	Description	Embedded linters	Info
	all	Default MegaLinter Flavor	125
	c_cpp	Optimized for pure C/C++ projects	56
	ci_light	Optimized for CI items (Dockerfile, Jenkinsfile, JSON/YAML schemas,XML	21
	cupcake	MegaLinter for the most commonly used languages	84
	documentation	MegaLinter for documentation projects	51
	dotnet	Optimized for C, C++, C# or VB based projects	63
	dotnetweb	Optimized for C, C++, C# or VB based projects with JS/TS	72
	formatters	Contains only formatters	17
	go	Optimized for GO based projects	53
	java	Optimized for JAVA based projects	54
	javascript	Optimized for JAVASCRIPT or TYPESCRIPT based projects	61
	php	Optimized for PHP based projects	56
	python	Optimized for PYTHON based projects	64
	ruby	Optimized for RUBY based projects	52
	rust	Optimized for RUST based projects	52
	salesforce	Optimized for Salesforce based projects	56
	security	Optimized for security	24
	swift	Optimized for SWIFT based projects	52
	terraform	Optimized for TERRAFORM based projects	56

If you need a new flavor, post an issue :wink:

Badge

You can show MegaLinter status with a badge in your repository README

If your main branch is master , replace main by master in URLs

Markdown

• Format

[![MegaLinter](https://github.com/<OWNER>/<REPOSITORY>/workflows/MegaLinter/badge.svg?branch=main)](https://github.com/<OWNER>/<REPOSITORY>/actions?query=workflow%3AMegaLinter+branch%3Amain)

• Example

[![MegaLinter](https://github.com/nvuillam/npm-groovy-lint/workflows/MegaLinter/badge.svg?branch=main)](https://github.com/nvuillam/npm-groovy-lint/actions?query=workflow%3AMegaLinter+branch%3Amain)

reStructuredText

• Format

.. |MegaLinter yes| image:: https://github.com/<OWNER>/<REPOSITORY>/workflows/MegaLinter/badge.svg?branch=main
   :target: https://github.com/<OWNER>/<REPOSITORY>/actions?query=workflow%3AMegaLinter+branch%3Amain

• Example

.. |MegaLinter yes| image:: https://github.com/nvuillam/npm-groovy-lint/workflows/MegaLinter/badge.svg?branch=main
   :target: https://github.com/nvuillam/npm-groovy-lint/actions?query=workflow%3AMegaLinter+branch%3Amain

Note: IF you did not use MegaLinter as GitHub Action name, please read GitHub Actions Badges documentation{target=_blank}

Plugins

For performances and security reasons, we can not embed all linters of the world within MegaLinter.

But our core architecture allows to build and publish MegaLinter Plugins !

External Plugins Catalog

Name	Description	Author	Raw URL
jupyfmt	The uncompromising Jupyter notebook formatter	Kim Philipp Jablonski	Descriptor
linkcheck	Plugin to check and validate markdown links exist and working	Shiran Rubin	Descriptor
nitpick	Command-line tool and flake8 plugin to enforce the same settings across multiple language-independent projects	W. Augusto Andreoli	Descriptor
mustache	Plugin to validate Logstash pipeline definition files using mustache	Yann Jouanique	Descriptor
salt-lint	Checks Salt State files (SLS) for best practices and behavior that could potentially be improved.	Joachim Grimm	Descriptor

Note: Using an external plugin means you trust its author

Submit a Pull Request if you want your plugin to appear here :)

Use external plugins

Add plugin URLs in PLUGINS property of .mega-linter.yml. URLs must either begin with "https://" or take the form of "file://\<path>", where \<path> points to a valid plugin descriptor file.

Note: Both \<path> and the default mount directory (/tmp/lint/\<path>) will be checked for a valid descriptor.

Example

PLUGINS:
  - https://raw.githubusercontent.com/kpj/jupyfmt/master/mega-linter-plugin-jupyfmt/jupyfmt.megalinter-descriptor.yml
  - file://.automation/test/mega-linter-plugin-test/test.megalinter-descriptor.yml

Create your own plugin

You can implement your own descriptors and load them as plugins during MegaLinter runtime

• Descriptor format is exactly the same than MegaLinter embedded ones (see json schema documentation)
• Plugins descriptor files must be named **.megalinter-descriptor.yml and respect MegaLinter Json Schema
• Plugins must be hosted in a url containing **/mega-linter-plugin-**/
• File URLs must conform to the same directory and file naming criteria as defined above.

Limitations

• For now, the only install attributes managed are dockerfile instructions starting by RUN

They talk about MegaLinter

English articles

Article	Author
Introducing MegaLinter: Streamlining Code Quality Checks Across Multiple Languages{target=_blank}	Cloud Tuned{target=_blank}
Infrastructure as Code GitHub Codespace Template{target=_blank}	Luke Murray{target=_blank}
5 ways MegaLinter upped our DevSecOps game{target=_blank}	Wes Dean{target=_blank}
Achieve Code Consistency: MegaLinter Integration in Azure DevOps{target=_blank}	Don Koning{target=_blank} on Microsoft Tech Community{target=_blank}
MegaLinter in Azure DevOps{target=_blank}	James Cook{target=_blank}
Maximize your code consistency with Megalinter{target=_blank}	Tor Ivar Asbølmo{target=_blank} on codewithme.cloud{target=_blank}
8 Tools to Scan Node.js Applications for Security Vulnerability{target=_blank}	Chandan Kumar{target=_blank} on GeekFlare.com{target=_blank}
Use the Workflows JSON schema in your IDE{target=_blank}	Google Cloud{target=_blank}
Level up your Unity Packages with CI/CD{target=_blank}	RunningMattress{target=_blank}
Writing documentation as a champ in engineering teams{target=_blank}	Gijs Reijn{target=_blank}
GitHub Actions: sharing your secrets with third-party actions{target=_blank}	Constantin Bosse{target=_blank} and Stephen Hosom{target=_blank}
GitOps security topics you must address{target=_blank}	Wiebe de Roos{target=_blank}
Talk about the Kotlin plugins Kover, Ktlint and Detekt. Made for the AmsterdamJUG meetup.{target=_blank}	Simone de Gijt{target=_blank}
Linting - What is all the fluff about?{target=_blank}	Neil Shepard{target=_blank}, University Of Sheffield
How to apply security at the source using GitOps{target=_blank}	Edu Minguez{target=_blank}
How to linter basic things like trailing whitespaces and newlines{target=_blank}	Nicolai Antiferov{target=_blank}
Open-source linters landscape in 2021{target=_blank}	Cédric Teyton{target=_blank}
Node.js Coding Standard Tools with MegaLinter on Gitlab CI{target=_blank}	Albion Bame{target=_blank}
Linting a Jekyll blog with MegaLinter{target=_blank}	Alec Johnson{target=_blank}
MegaLinter sells his soul and joins OX Security{target=_blank}	Nicolas Vuillamy{target=_blank}
Limit your technical debt and secure your code base using MegaLinter{target=_blank}	Nicolas Vuillamy{target=_blank}

French articles

Article	Author
MegaLinter, votre meilleur ami pour un code de qualité{target=_blank}	Thomas Sanson{target=_blank}

Japanese articles

Article	Author
Try using MegaLinter{target=_blank}	Takashi Minayaga{target=_blank}

Videos

• How to: Secrets scanning, by Hackitect's playground

• How to use MegaLinter with Jenkins, by Darin Pope / Cloudbees

• (FR) MegaLinter presentation at DevCon 20 / Programmez Magazine, by Nicolas Vuillamy

• Code quality - Ep01 - MegaLinter, one linter to rule them all, by Bertrand Thomas

• DevSecOps Webinar using MegaLinter, by 5.15 Technologies{target=_blank}

• Ortelius Architecture Meeting, with a review of MegaLinter, by Steve Taylor{target=_blank} from Ortelius

• (FR) Coding Tech - L'importance de la CI/CD dans le développement de logiciels, by Arsene Fougerouse from R2DevOps

Web Sites

• analysis-tools.dev{target=_blank}
• awesome-linters{target=_blank}
• schemastore.org{target=_blank}
• r2devops.io{target=_blank}
• abhith.net{target=_blank}
• my-devops-lab.com{target=_blank}

Linters

• checkstyle{target=_blank}
• clj-kondo{target=_blank}
• cljstyle{target=_blank}
• cspell{target=_blank}
• detekt{target=_blank}
• djlint{target=_blank}
• dotenv-linter{target=_blank}
• editorconfig-checker{target=_blank}
• eslint{target=_blank}
• eslint-plugin-jsonc{target=_blank}
• hadolint{target=_blank}
• htmlhint{target=_blank}
• jscpd{target=_blank}
• kics{target=_blank}
• ktlint{target=_blank}
• lintr{target=_blank}
• markdown-link-check{target=_blank}
• npm-groovy-lint{target=_blank}
• npm-package-json-lint{target=_blank}
• pmd{target=_blank}
• rst-lint{target=_blank}
• rstcheck{target=_blank}
• rubocop{target=_blank}
• scalafix{target=_blank}
• secretlint{target=_blank}

Frequently Asked Questions

My repo CI already have linters and they're perfectly working, so why do I need MegaLinter ?

You can perfectly continue using your installed linters and deactivate them in .mega-linter.yml. For example, in a javascript project using eslint, you can configure MegaLinter with DISABLE: JAVASCRIPT. That way, you will benefit from both your installed linters but also from other MegaLinter linters checking JSON, YAML, Markdown, Dockerfile, Bash, spelling mistakes, dead URLs…

Ok but… how does it work ?

MegaLinter is based on Docker images containing either all linters, or just a selection of linters if you are using a MegaLinter flavor for a project using a specific language / format

The core architecture does the following:

• Initialization
  • List all project files:
  • except files in ignored folders (node_modules, etc…)
  • except files not matching FILTER_REGEX_INCLUDE (if defined by user)
  • except files matching FILTER_REGEX_EXCLUDE (if defined by user)
  • Collect files for each activated linter, matching their own filtering criteria:
  • file extensions
  • file names
  • file content
  • <descriptor_or_linter_key>_FILTER_REGEX_INCLUDE (if defined by user)
  • <descriptor_or_linter_key>_FILTER_REGEX_EXCLUDE (if defined by user)
• Linting
  • Parallelly, for each linter with matching files:
  • Call the linter on matching files (or the whole project for some linters like copy-paste detector)
  • Call activated linter-level reporters (GitHub Status Reporter…)
• Finalization
  • Call activated global level reporters (GitHub Pull Request Comment Reporter, File.io Reporter, Email Reporter…)
  • Manage return code:
  • 0 if no error (or only non blocking errors if user defined DISABLE_ERRORS or <descriptor_or_linter_key>_DISABLE_ERRORS)
  • 1 if errors

How to contribute

Contributions to MegaLinter are very welcome, the more we're, the stronger MegaLinter is ! Please follow Contributing Guide

To help, you can also:

• :star: star the repository
• :beer: offer a beer !
• report problems and request new features
• share on twitter{target=_blank}

Special thanks

Maintainers

MegaLinter wouldn't be what it is without its great team of maintainers !

• Kurt Von Laven
• Borja Dominguez
• Edouard Choiniere
• Nicolas Vuillamy (Creator)

Contributors

Open-source teams

MegaLinter obviously would not exist without its linters and libraries, so many thanks to all the dedicated Open-Source teams maintaining all these awesome linters !

Super-Linter team

MegaLinter has been built on the ashes of a rejected Pull Request{target=_blank} on GitHub Super-Linter{target=_blank}.

Even if I disagree with their decision to remain in bash, the core team has always been nice and supporting during the time I was a Super-Linter contributor{target=_blank} :)

License

• GNU Affero General Public License

MegaLinter vs Super-Linter

The hard-fork of Super-Linter to be rewritten in Python isn't just a language switch: use of python flexibility and libraries allowed to define lots of additional functions described below

Security

MegaLinter hides many environment variables when calling the linters.

That way you need to trust only MegaLinter core code with your secrets, not the 100+ embedded linters !

Performances

• MegaLinter Flavors allow to use smaller docker images, so the pull time is reduced
• Thanks to python multiprocessing capabilities, linters are run in parallel, which is way faster than Super-Linter bash script who runs all linters in sequence
• When the linter allows it, call it 1 time with N files, instead of calling N times with one file

More languages and formats linted

• C, C++, Copy-Paste detection, Credentials, GraphQL, JSON & YAML with JSON schemas, Markdown tables formatting, Puppet, reStructuredText, Rust, Scala, Spell checker, Swift, Visual Basic .NET …

Automatically apply formatting and fixes

MegaLinter can automatically apply fixes performed by linters, and push them to the same branch, or create a Pull Request that you can validate

This is pretty handy, especially for linter errors related to formatting (in that case, you don't have any manual update to perform)

Run locally

MegaLinter can be run locally thanks to mega-linter-runner

Reports

Capabilities

• Accuracy: Count the total number of errors and not only the number of files in error
• Show linter version and applied filters for each linter processed
• Reports stored as artefacts on GitHub Action run or other remote files
  • General log
  • One report file by linter

Additional Reporters

• Console

• Text files
• GitHub Pull Request comments

• Gitlab Merge Request comments

• Bitbucket Pull Request comments

• Azure Pull Request comments

• Markdown Summary

• Updated sources
• Email
• File.io

Enhanced Configuration

• Assisted installation and configuration using a yeoman generator and JSON schemas for configuration file

• Configure include and exclude regexes for a single language or linter: ex: JAVASCRIPT_FILTER_REGEX_INCLUDE (src)
• Configure additional CLI arguments for a linter: ex: JAVASCRIPT_ES_ARGUMENTS "--debug --env-info"
• Configure non blocking errors for a single language or linter: ex: JAVASCRIPT_DISABLE_ERRORS
• Simplify languages and linters variables
  • ENABLE = list of languages and formats to apply lint on codebase (default: all)
  • ENABLE_LINTERS = list of linters to apply lint on codebase (default: all)
  • DISABLE = list of languages and formats to skip (default: none)
  • DISABLE_LINTERS = list of linters to skip (default: none)
  • Variables VALIDATE_XXX are still taken in account (but should not be used in association with ENABLE and DISABLE variables)

Enhanced Documentation

• HTML documentation

• One page per linter documentation :
  • All variables that can be used with this linter
  • List of file extensions, names and filters applied by the linter
  • Link to MegaLinter default linter configuration
  • Link to linter Web-Site
  • Link to official page explaining how to customize the linter rules
  • Link to official page explaining how to disable rules from source comments
  • Examples of linter command line calls behind the hood
  • Help command text
  • Installation commands

• Installation links for related IDEs

• README
  • Separate languages, formats and tooling formats in the linters table
  • Add logos for each descriptor

Plugins management

For linters less commonly used, MegaLinters offers a plugins architecture so anyone can publish plugins

Simplify architecture and evolutive maintenance

• Refactoring runtime in Python, for easier handling than bash thanks to classes and python modules
• Everything related to each linter in a single descriptor YML file
  • easier evolutive maintenance
  • less conflicts to manage between PRs.
  • Few special cases require a python linter class)
• Default behaviours for all linters, with possibility to override part of them for special cases
• Hierarchical architecture: Apply fixes and new behaviours to all linters with a single code update
• Documentation as code
  • Generate linters tables (ordered by type: language, format & tooling format) and include it in README. (see result)
  • Generate one markdown file per Linter, containing all configuration variables, infos and examples (See examples)
• Automatic generation of Dockerfile using YML descriptors, always using the linter latest version
  • Dockerfile commands (FROM, ARG, ENV, COPY, RUN )
  • APK packages (linux)
  • NPM packages (node)
  • PIP packages (python)
  • GEM packages (ruby)
  • Phive packages (PHP)
• Have a centralized exclude list (node_modules,.rbenv, etc…)

Improve robustness & stability

• Test classes for each capability
• Test classes for each linter: Automatic generation of test classes using .automation/build.py
• Setup code coverage
• Development CD / CI
  • Validate multi-status on PR inside each PR (posted from step "Run against all code base")
  • Run test classes and code coverage with pytest during validation GitHub Action
  • Validate descriptor YML files with json schema during build
  • Automated job to upgrade linters to their latest stable version