Files
deb-python-pecan/pecan/configuration.py
Ryan Petrello 063d8114d9 Fix a subtle bug in pecan.configuration.Config attribute assignment
Change-Id: Ia6d1b6a32c3c87f5ec940a48f37bfd24f3ba7196
Fixes-bug: #1476711
2015-07-30 15:57:40 -04:00

260 lines
7.1 KiB
Python

import re
import inspect
import os
import sys
import six
if six.PY3:
from importlib.machinery import SourceFileLoader
else:
import imp
IDENTIFIER = re.compile(r'[a-z_](\w)*$', re.IGNORECASE)
DEFAULT = {
# Server Specific Configurations
'server': {
'port': '8080',
'host': '0.0.0.0'
},
# Pecan Application Configurations
'app': {
'root': None,
'modules': [],
'static_root': 'public',
'template_path': '',
'force_canonical': True
}
}
class ConfigDict(dict):
pass
class Config(object):
'''
Base class for Pecan configurations.
Create a Pecan configuration object from a dictionary or a
filename.
:param conf_dict: A python dictionary to use for the configuration.
:param filename: A filename to use for the configuration.
'''
def __init__(self, conf_dict={}, filename=''):
self.__values__ = {}
self.__file__ = filename
self.update(conf_dict)
def empty(self):
self.__values__ = {}
def update(self, conf_dict):
'''
Updates this configuration with a dictionary.
:param conf_dict: A python dictionary to update this configuration
with.
'''
if isinstance(conf_dict, dict):
iterator = six.iteritems(conf_dict)
else:
iterator = iter(conf_dict)
for k, v in iterator:
if not IDENTIFIER.match(k):
raise ValueError('\'%s\' is not a valid indentifier' % k)
cur_val = self.__values__.get(k)
if isinstance(cur_val, Config):
cur_val.update(conf_dict[k])
else:
self[k] = conf_dict[k]
def get(self, attribute, default=None):
try:
return self[attribute]
except KeyError:
return default
def __dictify__(self, obj, prefix):
'''
Private helper method for to_dict.
'''
for k, v in obj.copy().items():
if prefix:
del obj[k]
k = "%s%s" % (prefix, k)
if isinstance(v, Config):
v = self.__dictify__(dict(v), prefix)
obj[k] = v
return obj
def to_dict(self, prefix=None):
'''
Converts recursively the Config object into a valid dictionary.
:param prefix: A string to optionally prefix all key elements in the
returned dictonary.
'''
conf_obj = dict(self)
return self.__dictify__(conf_obj, prefix)
def __getattr__(self, name):
try:
return self.__values__[name]
except KeyError:
msg = "'pecan.conf' object has no attribute '%s'" % name
raise AttributeError(msg)
def __setattr__(self, key, value):
if key not in ('__values__', '__file__'):
self.__setitem__(key, value)
return
super(Config, self).__setattr__(key, value)
def __getitem__(self, key):
return self.__values__[key]
def __setitem__(self, key, value):
if isinstance(value, dict) and not isinstance(value, ConfigDict):
if value.get('__force_dict__'):
del value['__force_dict__']
self.__values__[key] = ConfigDict(value)
else:
self.__values__[key] = Config(value, filename=self.__file__)
elif isinstance(value, six.string_types) and '%(confdir)s' in value:
confdir = os.path.dirname(self.__file__) or os.getcwd()
self.__values__[key] = value.replace('%(confdir)s', confdir)
else:
self.__values__[key] = value
def __iter__(self):
return six.iteritems(self.__values__)
def __dir__(self):
"""
When using dir() returns a list of the values in the config. Note:
This function only works in Python2.6 or later.
"""
return list(self.__values__.keys())
def __repr__(self):
return 'Config(%s)' % str(self.__values__)
def conf_from_file(filepath):
'''
Creates a configuration dictionary from a file.
:param filepath: The path to the file.
'''
abspath = os.path.abspath(os.path.expanduser(filepath))
conf_dict = {}
if not os.path.isfile(abspath):
raise RuntimeError('`%s` is not a file.' % abspath)
# First, make sure the code will actually compile (and has no SyntaxErrors)
with open(abspath, 'rb') as f:
compiled = compile(f.read(), abspath, 'exec')
# Next, attempt to actually import the file as a module.
# This provides more verbose import-related error reporting than exec()
absname, _ = os.path.splitext(abspath)
basepath, module_name = absname.rsplit(os.sep, 1)
if six.PY3:
SourceFileLoader(module_name, abspath).load_module(module_name)
else:
imp.load_module(
module_name,
*imp.find_module(module_name, [basepath])
)
# If we were able to import as a module, actually exec the compiled code
exec(compiled, globals(), conf_dict)
conf_dict['__file__'] = abspath
return conf_from_dict(conf_dict)
def get_conf_path_from_env():
'''
If the ``PECAN_CONFIG`` environment variable exists and it points to
a valid path it will return that, otherwise it will raise
a ``RuntimeError``.
'''
config_path = os.environ.get('PECAN_CONFIG')
if not config_path:
error = "PECAN_CONFIG is not set and " \
"no config file was passed as an argument."
elif not os.path.isfile(config_path):
error = "PECAN_CONFIG was set to an invalid path: %s" % config_path
else:
return config_path
raise RuntimeError(error)
def conf_from_dict(conf_dict):
'''
Creates a configuration dictionary from a dictionary.
:param conf_dict: The configuration dictionary.
'''
conf = Config(filename=conf_dict.get('__file__', ''))
for k, v in six.iteritems(conf_dict):
if k.startswith('__'):
continue
elif inspect.ismodule(v):
continue
conf[k] = v
return conf
def initconf():
'''
Initializes the default configuration and exposes it at
``pecan.configuration.conf``, which is also exposed at ``pecan.conf``.
'''
return conf_from_dict(DEFAULT)
def set_config(config, overwrite=False):
'''
Updates the global configuration.
:param config: Can be a dictionary containing configuration, or a string
which represents a (relative) configuration filename.
'''
if config is None:
config = get_conf_path_from_env()
# must be after the fallback other a bad fallback will incorrectly clear
if overwrite is True:
_runtime_conf.empty()
if isinstance(config, six.string_types):
config = conf_from_file(config)
_runtime_conf.update(config)
if config.__file__:
_runtime_conf.__file__ = config.__file__
elif isinstance(config, dict):
_runtime_conf.update(conf_from_dict(config))
else:
raise TypeError('%s is neither a dictionary or a string.' % config)
_runtime_conf = initconf()