yamllint version 1.17.0

Make sure values passed in allowed values are correct ones. This is
possible thanks to previous commit, and should prevent users from
writing incorrect configurations.

CHANGELOG.rst

@@ -1,6 +1,21 @@
 Changelog
 =========
 
+1.17.0 (2019-08-12)
+-------------------
+
+- Simplify installation instructions in the README
+- Add OpenBSD installation instructions
+- Make YAML file extensions configurable
+
+1.16.0 (2019-06-07)
+-------------------
+
+- Add FreeBSD installation instructions
+- Fix the ``line`` rule to correctly handle DOS new lines
+- Add the ``allowed-values`` option to the ``truthy`` rule
+- Allow configuration options to be a list of enums
+
 1.15.0 (2019-02-11)
 -------------------
 

README.rst

@@ -38,31 +38,16 @@ Screenshot
 Installation
 ^^^^^^^^^^^^
 
-On Fedora / CentOS (note: `EPEL <https://fedoraproject.org/wiki/EPEL>`_ is
+Using pip, the Python package manager:
-required on CentOS):
-
-.. code:: bash
-
- sudo dnf install yamllint
-
-On Debian 8+ / Ubuntu 16.04+:
-
-.. code:: bash
-
- sudo apt-get install yamllint
-
-On Mac OS 10.11+:
-
-.. code:: bash
-
- brew install yamllint
-
-Alternatively using pip, the Python package manager:
 
 .. code:: bash
 
  pip install --user yamllint
 
+yamllint is also packaged for all major operating systems, see installation
+examples (``dnf``, ``apt-get``...) `in the documentation
+<https://yamllint.readthedocs.io/en/stable/quickstart.html>`_.
+
 Usage
 ^^^^^
 

docs/configuration.rst

@@ -115,6 +115,21 @@ return code will be:
  * ``1`` if one or more errors occur
  * ``2`` if no errors occur, but one or more warnings occur
 
+YAML files extensions
+---------------------
+
+To configure what yamllint should consider as YAML files, set ``yaml-files``
+configuration option. The default is:
+
+.. code-block:: yaml
+
+ yaml-files:
+ - '*.yaml'
+ - '*.yml'
+
+The same rules as for ignoring paths apply (``.gitignore``-style path pattern,
+see below).
+
 Ignoring paths
 --------------
 

docs/quickstart.rst

@@ -4,7 +4,8 @@ Quickstart
 Installing yamllint
 -------------------
 
-On Fedora / CentOS:
+On Fedora / CentOS (note: `EPEL <https://fedoraproject.org/wiki/EPEL>`_ is
+required on CentOS):
 
 .. code:: bash
 
@@ -22,6 +23,18 @@ On Mac OS 10.11+:
 
  brew install yamllint
 
+On FreeBSD:
+
+.. code:: sh
+
+  pkg install py36-yamllint
+
+On OpenBSD:
+
+.. code:: sh
+
+  doas pkg_add py3-yamllint
+
 Alternatively using pip, the Python package manager:
 
 .. code:: bash

setup.py

@@ -14,7 +14,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from setuptools import setup, find_packages
+from setuptools import find_packages, setup
 
 from yamllint import (__author__, __license__,
                       APP_NAME, APP_VERSION, APP_DESCRIPTION)

tests/rules/test_empty_lines.py

@@ -78,3 +78,22 @@ class EmptyLinesTestCase(RuleTestCase):
                 'document-start: disable\n')
         self.check('non empty\n', conf)
         self.check('non empty\n\n', conf, problem=(2, 1))
+
+    def test_with_dos_newlines(self):
+        conf = ('empty-lines: {max: 2, max-start: 0, max-end: 0}\n'
+                'new-lines: {type: dos}\n'
+                'document-start: disable\n')
+        self.check('---\r\n', conf)
+        self.check('---\r\ntext\r\n\r\ntext\r\n', conf)
+        self.check('\r\n---\r\ntext\r\n\r\ntext\r\n', conf,
+                   problem=(1, 1))
+        self.check('\r\n\r\n\r\n---\r\ntext\r\n\r\ntext\r\n', conf,
+                   problem=(3, 1))
+        self.check('---\r\ntext\r\n\r\n\r\n\r\ntext\r\n', conf,
+                   problem=(5, 1))
+        self.check('---\r\ntext\r\n\r\n\r\n\r\n\r\n\r\n\r\ntext\r\n', conf,
+                   problem=(8, 1))
+        self.check('---\r\ntext\r\n\r\ntext\r\n\r\n', conf,
+                   problem=(5, 1))
+        self.check('---\r\ntext\r\n\r\ntext\r\n\r\n\r\n\r\n', conf,
+                   problem=(7, 1))

tests/rules/test_line_length.py

@@ -171,3 +171,12 @@ class LineLengthTestCase(RuleTestCase):
                    '# This is a test to check if “line-length” works nice\n'
                    'with: “unicode characters” that span accross bytes! ↺\n',
                    conf, problem1=(2, 53), problem2=(3, 53))
+
+    def test_with_dos_newlines(self):
+        conf = ('line-length: {max: 10}\n'
+                'new-lines: {type: dos}\n'
+                'new-line-at-end-of-file: disable\n')
+        self.check('---\r\nABCD EFGHI', conf)
+        self.check('---\r\nABCD EFGHI\r\n', conf)
+        self.check('---\r\nABCD EFGHIJ', conf, problem=(2, 11))
+        self.check('---\r\nABCD EFGHIJ\r\n', conf, problem=(2, 11))

tests/rules/test_new_lines.py

@@ -31,16 +31,20 @@ class NewLinesTestCase(RuleTestCase):
         self.check('---\r\ntext\r\n', conf)
 
     def test_unix_type(self):
-        conf = 'new-lines: {type: unix}'
+        conf = ('new-line-at-end-of-file: disable\n'
+                'new-lines: {type: unix}\n')
         self.check('', conf)
+        self.check('\r', conf)
         self.check('\n', conf)
         self.check('\r\n', conf, problem=(1, 1))
         self.check('---\ntext\n', conf)
         self.check('---\r\ntext\r\n', conf, problem=(1, 4))
 
     def test_dos_type(self):
-        conf = 'new-lines: {type: dos}\n'
+        conf = ('new-line-at-end-of-file: disable\n'
+                'new-lines: {type: dos}\n')
         self.check('', conf)
+        self.check('\r', conf)
         self.check('\n', conf, problem=(1, 1))
         self.check('\r\n', conf)
         self.check('---\ntext\n', conf, problem=(1, 4))

tests/rules/test_truthy.py

@@ -49,6 +49,54 @@ class TruthyTestCase(RuleTestCase):
                    problem3=(7, 3), problem4=(7, 7),
                    problem5=(8, 3), problem6=(8, 7))
 
+    def test_different_allowed_values(self):
+        conf = ('truthy:\n'
+                '  allowed-values: ["yes", "no"]\n')
+        self.check('---\n'
+                   'key1: foo\n'
+                   'key2: yes\n'
+                   'key3: bar\n'
+                   'key4: no\n', conf)
+        self.check('---\n'
+                   'key1: true\n'
+                   'key2: Yes\n'
+                   'key3: false\n'
+                   'key4: no\n'
+                   'key5: yes\n',
+                   conf,
+                   problem1=(2, 7), problem2=(3, 7),
+                   problem3=(4, 7))
+
+    def test_combined_allowed_values(self):
+        conf = ('truthy:\n'
+                '  allowed-values: ["yes", "no", "true", "false"]\n')
+        self.check('---\n'
+                   'key1: foo\n'
+                   'key2: yes\n'
+                   'key3: bar\n'
+                   'key4: no\n', conf)
+        self.check('---\n'
+                   'key1: true\n'
+                   'key2: Yes\n'
+                   'key3: false\n'
+                   'key4: no\n'
+                   'key5: yes\n',
+                   conf, problem1=(3, 7))
+
+    def test_no_allowed_values(self):
+        conf = ('truthy:\n'
+                '  allowed-values: []\n')
+        self.check('---\n'
+                   'key1: foo\n'
+                   'key2: bar\n', conf)
+        self.check('---\n'
+                   'key1: true\n'
+                   'key2: yes\n'
+                   'key3: false\n'
+                   'key4: no\n', conf,
+                   problem1=(2, 7), problem2=(3, 7),
+                   problem3=(4, 7), problem4=(5, 7))
+
     def test_explicit_types(self):
         conf = 'truthy: enable\n'
         self.check('---\n'

tests/test_cli.py

@@ -29,6 +29,7 @@ import unittest
 from tests.common import build_temp_workspace
 
 from yamllint import cli
+from yamllint import config
 
 
 class CommandLineTestCase(unittest.TestCase):
@@ -73,8 +74,9 @@ class CommandLineTestCase(unittest.TestCase):
         shutil.rmtree(cls.wd)
 
     def test_find_files_recursively(self):
+        conf = config.YamlLintConfig('extends: default')
         self.assertEqual(
-            sorted(cli.find_files_recursively([self.wd])),
+            sorted(cli.find_files_recursively([self.wd], conf)),
             [os.path.join(self.wd, 'a.yaml'),
              os.path.join(self.wd, 'empty.yml'),
              os.path.join(self.wd, 's/s/s/s/s/s/s/s/s/s/s/s/s/s/s/file.yaml'),
@@ -85,14 +87,14 @@ class CommandLineTestCase(unittest.TestCase):
         items = [os.path.join(self.wd, 'sub/ok.yaml'),
                  os.path.join(self.wd, 'empty-dir')]
         self.assertEqual(
-            sorted(cli.find_files_recursively(items)),
+            sorted(cli.find_files_recursively(items, conf)),
             [os.path.join(self.wd, 'sub/ok.yaml')],
         )
 
         items = [os.path.join(self.wd, 'empty.yml'),
                  os.path.join(self.wd, 's')]
         self.assertEqual(
-            sorted(cli.find_files_recursively(items)),
+            sorted(cli.find_files_recursively(items, conf)),
             [os.path.join(self.wd, 'empty.yml'),
              os.path.join(self.wd, 's/s/s/s/s/s/s/s/s/s/s/s/s/s/s/file.yaml')],
         )
@@ -100,11 +102,77 @@ class CommandLineTestCase(unittest.TestCase):
         items = [os.path.join(self.wd, 'sub'),
                  os.path.join(self.wd, '/etc/another/file')]
         self.assertEqual(
-            sorted(cli.find_files_recursively(items)),
+            sorted(cli.find_files_recursively(items, conf)),
             [os.path.join(self.wd, '/etc/another/file'),
              os.path.join(self.wd, 'sub/ok.yaml')],
         )
 
+        conf = config.YamlLintConfig('extends: default\n'
+                                     'yaml-files:\n'
+                                     '  - \'*.yaml\' \n')
+        self.assertEqual(
+            sorted(cli.find_files_recursively([self.wd], conf)),
+            [os.path.join(self.wd, 'a.yaml'),
+             os.path.join(self.wd, 's/s/s/s/s/s/s/s/s/s/s/s/s/s/s/file.yaml'),
+             os.path.join(self.wd, 'sub/ok.yaml'),
+             os.path.join(self.wd, 'warn.yaml')]
+        )
+
+        conf = config.YamlLintConfig('extends: default\n'
+                                     'yaml-files:\n'
+                                     '  - \'*.yml\'\n')
+        self.assertEqual(
+            sorted(cli.find_files_recursively([self.wd], conf)),
+            [os.path.join(self.wd, 'empty.yml')]
+        )
+
+        conf = config.YamlLintConfig('extends: default\n'
+                                     'yaml-files:\n'
+                                     '  - \'*.json\'\n')
+        self.assertEqual(
+            sorted(cli.find_files_recursively([self.wd], conf)),
+            [os.path.join(self.wd, 'no-yaml.json')]
+        )
+
+        conf = config.YamlLintConfig('extends: default\n'
+                                     'yaml-files:\n'
+                                     '  - \'*\'\n')
+        self.assertEqual(
+            sorted(cli.find_files_recursively([self.wd], conf)),
+            [os.path.join(self.wd, 'a.yaml'),
+             os.path.join(self.wd, 'empty.yml'),
+             os.path.join(self.wd, 'no-yaml.json'),
+             os.path.join(self.wd, 'non-ascii/utf-8'),
+             os.path.join(self.wd, 's/s/s/s/s/s/s/s/s/s/s/s/s/s/s/file.yaml'),
+             os.path.join(self.wd, 'sub/ok.yaml'),
+             os.path.join(self.wd, 'warn.yaml')]
+        )
+
+        conf = config.YamlLintConfig('extends: default\n'
+                                     'yaml-files:\n'
+                                     '  - \'*.yaml\'\n'
+                                     '  - \'*\'\n'
+                                     '  - \'**\'\n')
+        self.assertEqual(
+            sorted(cli.find_files_recursively([self.wd], conf)),
+            [os.path.join(self.wd, 'a.yaml'),
+             os.path.join(self.wd, 'empty.yml'),
+             os.path.join(self.wd, 'no-yaml.json'),
+             os.path.join(self.wd, 'non-ascii/utf-8'),
+             os.path.join(self.wd, 's/s/s/s/s/s/s/s/s/s/s/s/s/s/s/file.yaml'),
+             os.path.join(self.wd, 'sub/ok.yaml'),
+             os.path.join(self.wd, 'warn.yaml')]
+        )
+
+        conf = config.YamlLintConfig('extends: default\n'
+                                     'yaml-files:\n'
+                                     '  - \'s/**\'\n'
+                                     '  - \'**/utf-8\'\n')
+        self.assertEqual(
+            sorted(cli.find_files_recursively([self.wd], conf)),
+            [os.path.join(self.wd, 'non-ascii/utf-8')]
+        )
+
     def test_run_with_bad_arguments(self):
         sys.stdout, sys.stderr = StringIO(), StringIO()
         with self.assertRaises(SystemExit) as ctx:

tests/test_config.py

@@ -174,6 +174,25 @@ class SimpleConfigTestCase(unittest.TestCase):
         self.assertRaises(config.YamlLintConfigError,
                           config.validate_rule_conf, Rule, {'choice': 'abc'})
 
+        Rule.CONF = {'multiple': ['item1', 'item2', 'item3']}
+        Rule.DEFAULT = {'multiple': ['item1']}
+        config.validate_rule_conf(Rule, {'multiple': []})
+        config.validate_rule_conf(Rule, {'multiple': ['item2']})
+        config.validate_rule_conf(Rule, {'multiple': ['item2', 'item3']})
+        config.validate_rule_conf(Rule, {})
+        self.assertRaises(config.YamlLintConfigError,
+                          config.validate_rule_conf, Rule,
+                          {'multiple': 'item1'})
+        self.assertRaises(config.YamlLintConfigError,
+                          config.validate_rule_conf, Rule,
+                          {'multiple': ['']})
+        self.assertRaises(config.YamlLintConfigError,
+                          config.validate_rule_conf, Rule,
+                          {'multiple': ['item1', 4]})
+        self.assertRaises(config.YamlLintConfigError,
+                          config.validate_rule_conf, Rule,
+                          {'multiple': ['item4']})
+
 
 class ExtendedConfigTestCase(unittest.TestCase):
     def test_extend_on_object(self):

yamllint/__init__.py

@@ -22,7 +22,7 @@ indentation, etc."""
 
 
 APP_NAME = 'yamllint'
-APP_VERSION = '1.15.0'
+APP_VERSION = '1.17.0'
 APP_DESCRIPTION = __doc__
 
 __author__ = u'Adrien Vergé'

yamllint/cli.py

@@ -16,24 +16,25 @@
 
 from __future__ import print_function
 
-import os
-import sys
-import platform
 import argparse
+import os
+import platform
+import sys
 
 from yamllint import APP_DESCRIPTION, APP_NAME, APP_VERSION
+from yamllint import linter
 from yamllint.config import YamlLintConfig, YamlLintConfigError
 from yamllint.linter import PROBLEM_LEVELS
-from yamllint import linter
 
 
-def find_files_recursively(items):
+def find_files_recursively(items, conf):
     for item in items:
         if os.path.isdir(item):
             for root, dirnames, filenames in os.walk(item):
-                for filename in [f for f in filenames
+                for f in filenames:
-                                 if f.endswith(('.yml', '.yaml'))]:
+                    filepath = os.path.join(root, f)
-                    yield os.path.join(root, filename)
+                    if conf.is_yaml_file(filepath):
+                        yield filepath
         else:
             yield item
 
@@ -163,7 +164,7 @@ def run(argv=None):
 
     max_level = 0
 
-    for file in find_files_recursively(args.files):
+    for file in find_files_recursively(args.files, conf):
         filepath = file[2:] if file.startswith('./') else file
         try:
             with open(file) as f:

yamllint/conf/default.yaml

@@ -1,5 +1,9 @@
 ---
 
+yaml-files:
+  - '*.yaml'
+  - '*.yml'
+
 rules:
   braces: enable
   brackets: enable

yamllint/config.py

@@ -32,6 +32,9 @@ class YamlLintConfig(object):
 
         self.ignore = None
 
+        self.yaml_files = pathspec.PathSpec.from_lines(
+            'gitwildmatch', ['*.yaml', '*.yml'])
+
         if file is not None:
             with open(file) as f:
                 content = f.read()
@@ -42,6 +45,9 @@ class YamlLintConfig(object):
     def is_file_ignored(self, filepath):
         return self.ignore and self.ignore.match_file(filepath)
 
+    def is_yaml_file(self, filepath):
+        return self.yaml_files.match_file(filepath)
+
     def enabled_rules(self, filepath):
         return [yamllint.rules.get(id) for id, val in self.rules.items()
                 if val is not False and (
@@ -96,6 +102,15 @@ class YamlLintConfig(object):
             self.ignore = pathspec.PathSpec.from_lines(
                 'gitwildmatch', conf['ignore'].splitlines())
 
+        if 'yaml-files' in conf:
+            if not (isinstance(conf['yaml-files'], list)
+                    and all(isinstance(i, str) for i in conf['yaml-files'])):
+                raise YamlLintConfigError(
+                    'invalid config: yaml-files '
+                    'should be a list of file patterns')
+            self.yaml_files = pathspec.PathSpec.from_lines('gitwildmatch',
+                                                           conf['yaml-files'])
+
     def validate(self):
         for id in self.rules:
             try:
@@ -134,12 +149,26 @@ def validate_rule_conf(rule, conf):
                 raise YamlLintConfigError(
                     'invalid config: unknown option "%s" for rule "%s"' %
                     (optkey, rule.ID))
+            # Example: CONF = {option: (bool, 'mixed')}
+            #          → {option: true}         → {option: mixed}
             if isinstance(options[optkey], tuple):
                 if (conf[optkey] not in options[optkey] and
                         type(conf[optkey]) not in options[optkey]):
                     raise YamlLintConfigError(
                         'invalid config: option "%s" of "%s" should be in %s'
                         % (optkey, rule.ID, options[optkey]))
+            # Example: CONF = {option: ['flag1', 'flag2']}
+            #          → {option: [flag1]}      → {option: [flag1, flag2]}
+            elif isinstance(options[optkey], list):
+                if (type(conf[optkey]) is not list or
+                        any(flag not in options[optkey]
+                            for flag in conf[optkey])):
+                    raise YamlLintConfigError(
+                        ('invalid config: option "%s" of "%s" should only '
+                         'contain values in %s')
+                        % (optkey, rule.ID, str(options[optkey])))
+            # Example: CONF = {option: int}
+            #          → {option: 42}
             else:
                 if not isinstance(conf[optkey], options[optkey]):
                     raise YamlLintConfigError(

yamllint/parser.py

@@ -77,7 +77,10 @@ def line_generator(buffer):
     cur = 0
     next = buffer.find('\n')
     while next != -1:
-        yield Line(line_no, buffer, start=cur, end=next)
+        if next > 0 and buffer[next - 1] == '\r':
+            yield Line(line_no, buffer, start=cur, end=next - 1)
+        else:
+            yield Line(line_no, buffer, start=cur, end=next)
         cur = next + 1
         next = buffer.find('\n', cur)
         line_no += 1

yamllint/rules/colons.py

@@ -72,7 +72,7 @@ Use this rule to control the number of spaces before and after colons (``:``).
 
 import yaml
 
-from yamllint.rules.common import spaces_after, spaces_before, is_explicit_key
+from yamllint.rules.common import is_explicit_key, spaces_after, spaces_before
 
 
 ID = 'colons'

yamllint/rules/empty_lines.py

@@ -66,27 +66,37 @@ DEFAULT = {'max': 2,
 def check(conf, line):
     if line.start == line.end and line.end < len(line.buffer):
         # Only alert on the last blank line of a series
-        if (line.end < len(line.buffer) - 1 and
+        if (line.end + 2 <= len(line.buffer) and
-                line.buffer[line.end + 1] == '\n'):
+                line.buffer[line.end:line.end + 2] == '\n\n'):
+            return
+        elif (line.end + 4 <= len(line.buffer) and
+              line.buffer[line.end:line.end + 4] == '\r\n\r\n'):
             return
 
         blank_lines = 0
 
-        while (line.start > blank_lines and
+        start = line.start
-               line.buffer[line.start - blank_lines - 1] == '\n'):
+        while start >= 2 and line.buffer[start - 2:start] == '\r\n':
             blank_lines += 1
+            start -= 2
+        while start >= 1 and line.buffer[start - 1] == '\n':
+            blank_lines += 1
+            start -= 1
 
         max = conf['max']
 
         # Special case: start of document
-        if line.start - blank_lines == 0:
+        if start == 0:
             blank_lines += 1  # first line doesn't have a preceding \n
             max = conf['max-start']
 
         # Special case: end of document
         # NOTE: The last line of a file is always supposed to end with a new
         # line. See POSIX definition of a line at:
-        if line.end == len(line.buffer) - 1 and line.buffer[line.end] == '\n':
+        if ((line.end == len(line.buffer) - 1 and
+             line.buffer[line.end] == '\n') or
+            (line.end == len(line.buffer) - 2 and
+             line.buffer[line.end:line.end + 2] == '\r\n')):
             # Allow the exception of the one-byte file containing '\n'
             if line.end == 0:
                 return

yamllint/rules/indentation.py

@@ -193,7 +193,7 @@ Use this rule to control the indentation.
 import yaml
 
 from yamllint.linter import LintProblem
-from yamllint.rules.common import is_explicit_key, get_real_end_line
+from yamllint.rules.common import get_real_end_line, is_explicit_key
 
 
 ID = 'indentation'

yamllint/rules/new_lines.py

@@ -36,10 +36,11 @@ DEFAULT = {'type': 'unix'}
 def check(conf, line):
     if line.start == 0 and len(line.buffer) > line.end:
         if conf['type'] == 'dos':
-            if line.buffer[line.end - 1:line.end + 1] != '\r\n':
+            if (line.end + 2 > len(line.buffer) or
+                    line.buffer[line.end:line.end + 2] != '\r\n'):
                 yield LintProblem(1, line.end - line.start + 1,
                                   'wrong new line character: expected \\r\\n')
         else:
-            if line.end > 0 and line.buffer[line.end - 1] == '\r':
+            if line.buffer[line.end] == '\r':
-                yield LintProblem(1, line.end - line.start,
+                yield LintProblem(1, line.end - line.start + 1,
                                   'wrong new line character: expected \\n')

yamllint/rules/truthy.py

@@ -15,13 +15,22 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 """
-Use this rule to forbid non-explictly typed truthy values other than ``true``
+Use this rule to forbid non-explictly typed truthy values other than allowed
-and ``false``, for example ``YES``, ``False`` and ``off``.
+ones (by default: ``true`` and ``false``), for example ``YES`` or ``off``.
 
 This can be useful to prevent surprises from YAML parsers transforming
 ``[yes, FALSE, Off]`` into ``[true, false, false]`` or
 ``{y: 1, yes: 2, on: 3, true: 4, True: 5}`` into ``{y: 1, true: 5}``.
 
+.. rubric:: Options
+
+* ``allowed-values`` defines the list of truthy values which will be ignored
+  during linting. The default is ``['true', 'false']``, but can be changed to
+  any list containing: ``'TRUE'``, ``'True'``,  ``'true'``, ``'FALSE'``,
+  ``'False'``, ``'false'``, ``'YES'``, ``'Yes'``, ``'yes'``, ``'NO'``,
+  ``'No'``, ``'no'``, ``'ON'``, ``'On'``, ``'on'``, ``'OFF'``, ``'Off'``,
+  ``'off'``.
+
 .. rubric:: Examples
 
 #. With ``truthy: {}``
@@ -63,29 +72,55 @@ This can be useful to prevent surprises from YAML parsers transforming
     yes:  1
     on:   2
     True: 3
+
+#. With ``truthy: {allowed-values: ["yes", "no"]}``
+
+   the following code snippet would **PASS**:
+   ::
+
+    - yes
+    - no
+    - "true"
+    - 'false'
+    - foo
+    - bar
+
+   the following code snippet would **FAIL**:
+   ::
+
+    - true
+    - false
+    - on
+    - off
 """
 
 import yaml
 
 from yamllint.linter import LintProblem
 
-ID = 'truthy'
-TYPE = 'token'
 
 TRUTHY = ['YES', 'Yes', 'yes',
           'NO', 'No', 'no',
-          'TRUE', 'True',  # 'true' is a boolean
+          'TRUE', 'True', 'true',
-          'FALSE', 'False',  # 'false' is a boolean
+          'FALSE', 'False', 'false',
           'ON', 'On', 'on',
           'OFF', 'Off', 'off']
 
 
+ID = 'truthy'
+TYPE = 'token'
+CONF = {'allowed-values': list(TRUTHY)}
+DEFAULT = {'allowed-values': ['true', 'false']}
+
+
 def check(conf, token, prev, next, nextnext, context):
     if prev and isinstance(prev, yaml.tokens.TagToken):
         return
 
     if isinstance(token, yaml.tokens.ScalarToken):
-        if token.value in TRUTHY and token.style is None:
+        if (token.value in (set(TRUTHY) - set(conf['allowed-values'])) and
+                token.style is None):
             yield LintProblem(token.start_mark.line + 1,
                               token.start_mark.column + 1,
-                              "truthy value should be true or false")
+                              "truthy value should be one of [" +
+                              ", ".join(sorted(conf['allowed-values'])) + "]")