Bring over the 'safeyaml' from bzr

This will likely also be very useful to use since it
ensures we safely use/parse yaml.

Change-Id: Ibc0f7dee46d2f199e2d65d9bc6444bfa72383704

cloudinit/logging.py

@@ -0,0 +1,82 @@
+# Copyright 2015 Canonical Ltd.
+# This file is part of cloud-init.  See LICENCE file for license information.
+#
+# vi: ts=4 expandtab
+
+from __future__ import absolute_import
+
+import logging
+import sys
+
+_BASE = __name__.split(".", 1)[0]
+
+# Add a BLATHER level, this matches the multiprocessing utils.py module (and
+# kazoo and others) that declares a similar level, this level is for
+# information that is even lower level than regular DEBUG and gives out so
+# much runtime information that it is only useful by low-level/certain users...
+BLATHER = 5
+
+# Copy over *select* attributes to make it easy to use this module.
+CRITICAL = logging.CRITICAL
+DEBUG = logging.DEBUG
+ERROR = logging.ERROR
+FATAL = logging.FATAL
+INFO = logging.INFO
+NOTSET = logging.NOTSET
+WARN = logging.WARN
+WARNING = logging.WARNING
+
+
+class _BlatherLoggerAdapter(logging.LoggerAdapter):
+
+    def blather(self, msg, *args, **kwargs):
+        """Delegate a blather call to the underlying logger."""
+        self.log(BLATHER, msg, *args, **kwargs)
+
+    def warn(self, msg, *args, **kwargs):
+        """Delegate a warning call to the underlying logger."""
+        self.warning(msg, *args, **kwargs)
+
+
+# TODO(harlowja): we should remove when we no longer have to support 2.6...
+if sys.version_info[0:2] == (2, 6):
+
+    class _FixedBlatherLoggerAdapter(_BlatherLoggerAdapter):
+        """Ensures isEnabledFor() exists on adapters that are created."""
+
+        def isEnabledFor(self, level):
+            return self.logger.isEnabledFor(level)
+
+    _BlatherLoggerAdapter = _FixedBlatherLoggerAdapter
+
+    # Taken from python2.7 (same in python3.4)...
+    class _NullHandler(logging.Handler):
+        """This handler does nothing.
+
+        It's intended to be used to avoid the
+        "No handlers could be found for logger XXX" one-off warning. This is
+        important for library code, which may contain code to log events. If a
+        user of the library does not configure logging, the one-off warning
+        might be produced; to avoid this, the library developer simply needs
+        to instantiate a _NullHandler and add it to the top-level logger of the
+        library module or package.
+        """
+
+        def handle(self, record):
+            """Stub."""
+
+        def emit(self, record):
+            """Stub."""
+
+        def createLock(self):
+            self.lock = None
+
+else:
+    _NullHandler = logging.NullHandler
+
+
+def getLogger(name=_BASE, extra=None):
+    logger = logging.getLogger(name)
+    if not logger.handlers:
+        logger.addHandler(_NullHandler())
+    return _BlatherLoggerAdapter(logger, extra=extra)

cloudinit/safeyaml.py

@@ -0,0 +1,40 @@
+# Copyright 2015 Canonical Ltd.
+# This file is part of cloud-init.  See LICENCE file for license information.
+#
+# vi: ts=4 expandtab
+
+import yaml as _yaml
+
+from cloudinit import util
+
+
+YAMLError = _yaml.YAMLError
+
+
+def load(path):
+    """Load yaml string from a path and return the data represented.
+
+    Exception will be raised if types other than the following are found:
+        dict, int, float, string, list, unicode
+    """
+    return loads(util.load_file(path))
+
+
+def loads(blob):
+    """Load yaml string and return the data represented.
+
+    Exception will be raised if types other than the following are found:
+        dict, int, float, string, list, unicode
+    """
+    return _yaml.safe_load(blob)
+
+
+def dumps(obj):
+    """Dumps an object back into a yaml string."""
+    formatted = _yaml.safe_dump(obj,
+                                line_break="\n",
+                                indent=4,
+                                explicit_start=True,
+                                explicit_end=True,
+                                default_flow_style=False)
+    return formatted

cloudinit/shell.py

@@ -1,9 +1,12 @@
 # Copyright 2015 Canonical Ltd.
-# Copyright 2015 Cloudbase Solutions Srl
 # This file is part of cloud-init.  See LICENCE file for license information.
+#
+# vi: ts=4 expandtab
 
 
 def main():
-    print("Hello World\n")
+    print("Run cloudinit run!")
 
-# vi: ts=4 expandtab
+
+if __name__ == '__main__':
+    main()

cloudinit/tests/test_safeyaml.py

@@ -0,0 +1,29 @@
+# Copyright 2015 Canonical Ltd.
+# This file is part of cloud-init.  See LICENCE file for license information.
+#
+# vi: ts=4 expandtab
+
+from cloudinit import safeyaml as yaml
+from cloudinit import test
+
+
+class TestSafeYaml(test.TestCase):
+    def test_simple(self):
+        blob = '\nk1: one\nk2: two'
+        expected = {'k1': "one", 'k2': "two"}
+        self.assertEqual(yaml.loads(blob), expected)
+
+    def test_bogus_raises_exception(self):
+        badyaml = "1\n 2:"
+        self.assertRaises(yaml.YAMLError, yaml.loads, badyaml)
+
+    def test_unsafe_types(self):
+        # should not load complex types
+        unsafe_yaml = "!!python/object:__builtin__.object {}"
+        self.assertRaises(yaml.YAMLError, yaml.loads, unsafe_yaml)
+
+    def test_python_unicode_not_allowed(self):
+        # python/unicode is not allowed
+        # in the past this type was allowed, but not now, so explicit test.
+        blob = "{k1: !!python/unicode 'my unicode', k2: my string}"
+        self.assertRaises(yaml.YAMLError, yaml.loads, blob)

cloudinit/util.py

@@ -1,19 +1,17 @@
-# Copyright (C) 2015 Canonical Ltd.
+# Copyright 2015 Canonical Ltd.
-# Copyright (C) 2015 Cloudbase Solutions Srl
+# This file is part of cloud-init.  See LICENCE file for license information.
 #
-#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+# vi: ts=4 expandtab
-#    not use this file except in compliance with the License. You may obtain
-#    a copy of the License at
-#
-#         http://www.apache.org/licenses/LICENSE-2.0
-#
-#    Unless required by applicable law or agreed to in writing, software
-#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-#    License for the specific language governing permissions and limitations
-#    under the License.
 
-__all__ = ('abstractclassmethod', )
+from cloudinit import logging
+
+LOG = logging.getLogger(__name__)
+
+
+def load_file(path, encoding='utf8'):
+    LOG.blather("Loading file from path '%s' (%s)", path, encoding)
+    with open(path, 'rb') as fh:
+        return fh.read().decode(encoding)
 
 
 class abstractclassmethod(classmethod):