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Overview

A CLI tool to perform syntactic and semantic validation of YAML files.

$ iac-validate -h
Usage: iac-validate [OPTIONS] [PATHS]...

  A CLI tool to perform syntactic and semantic validation of YAML files.

Options:
  --version              Show the version and exit.
  -v, --verbosity LVL    Either CRITICAL, ERROR, WARNING, INFO or DEBUG
  -s, --schema FILE      Path to schema file. (optional, default:
                         '.schema.yaml', env: IAC_VALIDATE_SCHEMA)
  -r, --rules DIRECTORY  Path to semantic rules. (optional, default:
                         '.rules/', env: IAC_VALIDATE_RULES)
  -o, --output FILE      Write merged content from YAML files to a new YAML
                         file. (optional, env: IAC_VALIDATE_OUTPUT)
  --non-strict           Accept unexpected elements in YAML files.
  -h, --help             Show this message and exit.

Syntactic validation is done by basic YAML syntax validation (e.g., indentation) and by providing a Yamale schema and validating all YAML files against that schema. Semantic validation is done by providing a set of rules (implemented in Python) which are then validated against the YAML data. Every rule is implemented as a Python class and should be placed in a .py file located in the --rules path.

Each .py file must have a single class named Rule. This class must have the following attributes: id, description and severity. It must implement a classmethod() named match that has a single function argument data which is the data read from all YAML files. It should return a list of strings, one for each rule violation with a descriptive message. A sample rule can be found below.

class Rule:
    id = "101"
    description = "Verify child naming restrictions"
    severity = "HIGH"

    @classmethod
    def match(cls, data):
        results = []
        try:
            for child in data["root"]["children"]:
                if child["name"] == "FORBIDDEN":
                    results.append("root.children.name" + " - " + str(child["name"]))
        except KeyError:
            pass
        return results

Installation​

Python 3.7+ is required to install iac-validate. Don't have Python 3.7 or later? See Python 3 Installation & Setup Guide.

iac-validate can be installed in a virtual environment using pip:

pip install iac-validate

Pre-Commit Hook​

The tool can be integrated via a pre-commit hook with the following config (.pre-commit-config.yaml), assuming the default values (.schema.yaml, .rules/) are appropriate:

repos:
  - repo: https://github.com/netascode/iac-validate
    rev: v0.1.6
    hooks:
      - id: iac-validate

In case the schema or validation rules are located somewhere else the required CLI arguments can be added like this:

repos:
  - repo: https://github.com/netascode/iac-validate
    rev: v0.1.6
    hooks:
      - id: iac-validate
        args:
          - '-s'
          - 'my_schema.yaml'
          - '-r'
          - 'rules/'

Ansible Vault Support​

Values can be encrypted using Ansible Vault. This requires Ansible (ansible-vault command) to be installed and the following two environment variables to be defined:

export ANSIBLE_VAULT_ID=dev
export ANSIBLE_VAULT_PASSWORD=Password123

ANSIBLE_VAULT_ID is optional, and if not defined will be omitted.

Additional Tags​

Reading Environment Variables​

The !env YAML tag can be used to read values from environment variables.

root:
  name: !env VAR_NAME