Integrate YAMLlint rules

[roaldnefs]

Due to the usage of Jinja it's not always possible to validate the YAML syntax in state files. It would be nice if the YAMLlint rules could also be used to validate the state files.

SaltStack does include the option to lint the YAML output after detecting a successful render using salt.modules.yaml (new in version 3005).

Related issues:

• Feature Request: Implement yamllint rules #240
• Feature Request: Identify poorly indented states (e.g. only using one space instead of two) #246
• Add a check to defaults option in state if it exists #258

[roaldnefs]

It's possible to check the individual YAML tokens when the SLS file doesn't include any Jinja. The example below will find numbers starting with '0' that aren't enclosed in quotation marks. The would exclude the false positives discovered in #293 and #299 but requires filtering the Jinja statements first.

import re
import yaml

from saltlint.linter.rule import Rule
from saltlint.utils import LANGUAGE_SLS


class YamlImplicitOctalValueRule(Rule):
    id = '210'
    shortdesc = "Numbers that start with '0' should always be encapsulated in quotation marks"
    description = "Numbers that start with '0' should always be encapsulated in quotation marks"
    severity = 'HIGH'
    languages = [LANGUAGE_SLS]
    tags = ['formatting']
    version_added = 'develop'

    regex = re.compile(r"^0\d*$")

    def matchtext(self, file, text):
        results = []
        yaml_loader = yaml.BaseLoader(text)

        try:
            previous = None
            current = yaml_loader.get_token()
            while current is not None:
                next = yaml_loader.get_token()
                # Match YAML scalar (values) tokens and check the token style to verify
                # the value isn't enclosed in quotes.
                if isinstance(current, yaml.tokens.ScalarToken) and not current.style:
                    # Check if the whole value is a number starting with '0'.
                    if self.regex.match(current.value):
                        line_no = 0           # TODO: get line number, for now just return 0
                        line = current.value  # TODO: get line, for now just return the value
                        results.append((line_no, line, self.shortdesc))
                previous = current
                current = next
        except yaml.scanner.ScannerError:
            pass

        return results