Yamllint

What is Yamllint?

Yamllint is a linter for YAML files. It checks your YAML files for syntax errors, style issues, and adherence to best practices. This tool is invaluable for developers and system administrators who work with configuration files, as it helps maintain consistency and prevent errors caused by malformed YAML. By using Yamllint, you can ensure your YAML documents are clean, readable, and syntactically correct, which is crucial for applications that rely on them.

How to Use Yamllint

Yamllint can be used directly from the command line to check individual files or entire directories. Here are some common usage examples:

Linting a Single YAML File

To lint a single YAML file, simply provide its path as an argument:

yamllint example.yaml

Linting Multiple YAML Files

You can lint all YAML files within a directory by specifying the directory path:

yamllint /path/to/directory

Using a Custom Configuration File

Yamllint supports custom configuration files to define specific linting rules. Use the -c flag to specify your configuration file:

yamllint -c .yamllint-config example.yaml

Ignoring Specific Files or Patterns

You can ignore certain files or patterns using the --ignore-globals option:

yamllint example.yaml --ignore-globals *.yaml

Controlling Verbosity and Output Format

Yamllint offers options to control the output. Use -v for increased verbosity or -f parsable for a format suitable for tooling integration:

yamllint -v example.yaml
yamllint -f parsable example.yaml

Customizing Rules

You can define specific rules or disable default ones directly in the command line using the -d flag:

yamllint -d "{extends: default, rules: {line-length: disable}}" example.yaml

Strict Mode and Linting Strings

For stricter checks, use the --strict flag. You can also lint YAML content directly from standard input:

yamllint --strict example.yaml
echo "key: value" | yamllint -

Benefits of Using Yamllint

Error Prevention: Catches syntax errors before they cause runtime issues.
Code Consistency: Enforces a uniform style across all YAML files.
Readability: Improves the clarity and maintainability of configuration files.
Automation: Integrates easily into CI/CD pipelines for automated checks.

Yamllint - Validate and Lint YAML Files Online