yamllint's Introduction

yamllint

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.

Written in Python (compatible with Python 3 only).

Documentation

https://yamllint.readthedocs.io/

Overview

Screenshot

Installation

Using pip, the Python package manager:

pip install --user yamllint

yamllint is also packaged for all major operating systems, see installation examples (dnf, apt-get...) in the documentation.

Usage

# Lint one or more files
yamllint my_file.yml my_other_file.yaml ...

# Lint all YAML files in a directory
yamllint .

# Use a pre-defined lint configuration
yamllint -d relaxed file.yaml

# Use a custom lint configuration
yamllint -c /path/to/myconfig file-to-lint.yaml

# Output a parsable format (for syntax checking in editors like Vim, emacs...)
yamllint -f parsable file.yaml

Features

Here is a yamllint configuration file example:

extends: default

rules:
  # 80 chars should be enough, but don't fail if a line is longer
  line-length:
    max: 80
    level: warning

  # don't bother me with this rule
  indentation: disable

Within a YAML file, special comments can be used to disable checks for a single line:

This line is waaaaaaaaaay too long  # yamllint disable-line

or for a whole block:

# yamllint disable rule:colons
- Lorem       : ipsum
  dolor       : sit amet,
  consectetur : adipiscing elit
# yamllint enable

Specific files can be ignored (totally or for some rules only) using a .gitignore-style pattern:

# For all rules
ignore: |
  *.dont-lint-me.yaml
  /bin/
  !/bin/*.lint-me-anyway.yaml

rules:
  key-duplicates:
    ignore: |
      generated
      *.template.yaml
  trailing-spaces:
    ignore: |
      *.ignore-trailing-spaces.yaml
      /ascii-art/*