yamllint

yamllint documentation

• Version in Mega-Linter: 1.26.3
• Visit Official Web Site
• See How to configure yamllint rules
  • If custom .yamllint.yml config file is not found, .yamllint.yml will be used
• See Index of problems detected by yamllint

Configuration in Mega-Linter

• Enable yamllint by adding YAML_YAMLLINT in ENABLE_LINTERS variable
• Disable yamllint by adding YAML_YAMLLINT in DISABLE_LINTERS variable

Variable	Description	Default value
YAML_YAMLLINT_ARGUMENTS	User custom arguments to add in linter CLI call Ex: -s --foo "bar"
YAML_YAMLLINT_FILTER_REGEX_INCLUDE	Custom regex including filter Ex: (src\|lib)	Include every file
YAML_YAMLLINT_FILTER_REGEX_EXCLUDE	Custom regex excluding filter Ex: (test\|examples)	Exclude no file
YAML_YAMLLINT_CLI_LINT_MODE	Override default CLI lint mode - file: Calls the linter for each file - list_of_files: Call the linter with the list of files as argument - project: Call the linter from the root of the project	{linter.cli_lint_mode}
YAML_YAMLLINT_FILE_EXTENSIONS	Allowed file extensions. "*" matches any extension, "" matches empty extension. Empty list excludes all files Ex: [".py", ""]	[".yml", ".yaml"]
YAML_YAMLLINT_FILE_NAMES_REGEX	File name regex filters. Regular expression list for filtering files by their base names using regex full match. Empty list includes all files Ex: ["Dockerfile(-.+)?", "Jenkinsfile"]	Include every file
YAML_YAMLLINT_PRE_COMMANDS	List of bash commands to run before the linter	None
YAML_YAMLLINT_POST_COMMANDS	List of bash commands to run after the linter	None
YAML_YAMLLINT_CONFIG_FILE	yamllint configuration file name Use LINTER_DEFAULT to let the linter find it	.yamllint.yml
YAML_YAMLLINT_RULES_PATH	Path where to find linter configuration file	Workspace folder, then Mega-Linter default rules
YAML_YAMLLINT_DISABLE_ERRORS	Run linter but consider errors as warnings	false
YAML_YAMLLINT_DISABLE_ERRORS_IF_LESS_THAN	Maximum number of errors allowed	0

IDE Integration

Use yamllint in your favorite IDE to catch errors before Mega-Linter !

	IDE	Extension Name	Install
	Emacs	flycheck	Visit Web Site
	vim	ale	Visit Web Site

Mega-Linter Flavours

This linter is available in the following flavours

	Flavor	Description	Embedded linters	Info
	all	Default Mega-Linter Flavor	94
	ci_light	Optimized for CI items (Dockerfile, Jenkinsfile, JSON/YAML schemas,XML	13
	dart	Optimized for DART based projects	41
	documentation	Mega-Linter for documentation projects	40
	dotnet	Optimized for C, C++, C# or VB based projects	47
	go	Optimized for GO based projects	42
	java	Optimized for JAVA based projects	42
	javascript	Optimized for JAVASCRIPT or TYPESCRIPT based projects	49
	php	Optimized for PHP based projects	44
	python	Optimized for PYTHON based projects	49
	ruby	Optimized for RUBY based projects	41
	rust	Optimized for RUST based projects	41
	salesforce	Optimized for Salesforce based projects	43
	scala	Optimized for SCALA based projects	41
	swift	Optimized for SWIFT based projects	41
	terraform	Optimized for TERRAFORM based projects	45

Behind the scenes

How are identified applicable files

• File extensions: .yml, .yaml

How the linting is performed

• yamllint is called once with the list of files as arguments

Example calls

yamllint myfile.yaml

yamllint -c .yamllint.yml myfile.yaml

Help content

usage: yamllint [-h] [-] [-c CONFIG_FILE | -d CONFIG_DATA]
                [-f {parsable,standard,colored,github,auto}] [-s]
                [--no-warnings] [-v]
                [FILE_OR_DIR ...]

A linter for YAML files. yamllint does not only check for syntax validity, but
for weirdnesses like key repetition and cosmetic problems such as lines
length, trailing spaces, indentation, etc.

positional arguments:
  FILE_OR_DIR           files to check

optional arguments:
  -h, --help            show this help message and exit
  -                     read from standard input
  -c CONFIG_FILE, --config-file CONFIG_FILE
                        path to a custom configuration
  -d CONFIG_DATA, --config-data CONFIG_DATA
                        custom configuration (as YAML source)
  -f {parsable,standard,colored,github,auto}, --format {parsable,standard,colored,github,auto}
                        format for parsing output
  -s, --strict          return non-zero exit code on warnings as well as
                        errors
  --no-warnings         output only error level problems
  -v, --version         show program's version number and exit

Installation on mega-linter Docker image

• PIP packages (Python):
  • yamllint

Example success log

Results of yamllint linter (version 1.25.0)
See documentation on https://megalinter.github.io/descriptors/yaml_yamllint/
-----------------------------------------------

[SUCCESS] .automation/test/yaml/yml_good_1.yml

Example error log

Results of yamllint linter (version 1.25.0)
See documentation on https://megalinter.github.io/descriptors/yaml_yamllint/
-----------------------------------------------

[ERROR] .automation/test/yaml/yml_bad_1.yml
    .automation/test/yaml/yml_bad_1.yml
      10:1      warning  missing document start "---"  (document-start)
      11:16     error    syntax error: mapping values are not allowed here (syntax)