mirror of
https://github.com/evilhero/mylar
synced 2024-12-26 01:26:50 +00:00
351 lines
11 KiB
Python
Executable file
351 lines
11 KiB
Python
Executable file
"""Generic configuration system using unrepr.
|
|
|
|
Configuration data may be supplied as a Python dictionary, as a filename,
|
|
or as an open file object. When you supply a filename or file, Python's
|
|
builtin ConfigParser is used (with some extensions).
|
|
|
|
Namespaces
|
|
----------
|
|
|
|
Configuration keys are separated into namespaces by the first "." in the key.
|
|
|
|
The only key that cannot exist in a namespace is the "environment" entry.
|
|
This special entry 'imports' other config entries from a template stored in
|
|
the Config.environments dict.
|
|
|
|
You can define your own namespaces to be called when new config is merged
|
|
by adding a named handler to Config.namespaces. The name can be any string,
|
|
and the handler must be either a callable or a context manager.
|
|
"""
|
|
|
|
try:
|
|
# Python 3.0+
|
|
from configparser import ConfigParser
|
|
except ImportError:
|
|
from ConfigParser import ConfigParser
|
|
|
|
try:
|
|
set
|
|
except NameError:
|
|
from sets import Set as set
|
|
import sys
|
|
|
|
def as_dict(config):
|
|
"""Return a dict from 'config' whether it is a dict, file, or filename."""
|
|
if isinstance(config, basestring):
|
|
config = Parser().dict_from_file(config)
|
|
elif hasattr(config, 'read'):
|
|
config = Parser().dict_from_file(config)
|
|
return config
|
|
|
|
|
|
class NamespaceSet(dict):
|
|
"""A dict of config namespace names and handlers.
|
|
|
|
Each config entry should begin with a namespace name; the corresponding
|
|
namespace handler will be called once for each config entry in that
|
|
namespace, and will be passed two arguments: the config key (with the
|
|
namespace removed) and the config value.
|
|
|
|
Namespace handlers may be any Python callable; they may also be
|
|
Python 2.5-style 'context managers', in which case their __enter__
|
|
method should return a callable to be used as the handler.
|
|
See cherrypy.tools (the Toolbox class) for an example.
|
|
"""
|
|
|
|
def __call__(self, config):
|
|
"""Iterate through config and pass it to each namespace handler.
|
|
|
|
config
|
|
A flat dict, where keys use dots to separate
|
|
namespaces, and values are arbitrary.
|
|
|
|
The first name in each config key is used to look up the corresponding
|
|
namespace handler. For example, a config entry of {'tools.gzip.on': v}
|
|
will call the 'tools' namespace handler with the args: ('gzip.on', v)
|
|
"""
|
|
# Separate the given config into namespaces
|
|
ns_confs = {}
|
|
for k in config:
|
|
if "." in k:
|
|
ns, name = k.split(".", 1)
|
|
bucket = ns_confs.setdefault(ns, {})
|
|
bucket[name] = config[k]
|
|
|
|
# I chose __enter__ and __exit__ so someday this could be
|
|
# rewritten using Python 2.5's 'with' statement:
|
|
# for ns, handler in self.iteritems():
|
|
# with handler as callable:
|
|
# for k, v in ns_confs.get(ns, {}).iteritems():
|
|
# callable(k, v)
|
|
for ns, handler in self.items():
|
|
exit = getattr(handler, "__exit__", None)
|
|
if exit:
|
|
callable = handler.__enter__()
|
|
no_exc = True
|
|
try:
|
|
try:
|
|
for k, v in ns_confs.get(ns, {}).items():
|
|
callable(k, v)
|
|
except:
|
|
# The exceptional case is handled here
|
|
no_exc = False
|
|
if exit is None:
|
|
raise
|
|
if not exit(*sys.exc_info()):
|
|
raise
|
|
# The exception is swallowed if exit() returns true
|
|
finally:
|
|
# The normal and non-local-goto cases are handled here
|
|
if no_exc and exit:
|
|
exit(None, None, None)
|
|
else:
|
|
for k, v in ns_confs.get(ns, {}).items():
|
|
handler(k, v)
|
|
|
|
def __repr__(self):
|
|
return "%s.%s(%s)" % (self.__module__, self.__class__.__name__,
|
|
dict.__repr__(self))
|
|
|
|
def __copy__(self):
|
|
newobj = self.__class__()
|
|
newobj.update(self)
|
|
return newobj
|
|
copy = __copy__
|
|
|
|
|
|
class Config(dict):
|
|
"""A dict-like set of configuration data, with defaults and namespaces.
|
|
|
|
May take a file, filename, or dict.
|
|
"""
|
|
|
|
defaults = {}
|
|
environments = {}
|
|
namespaces = NamespaceSet()
|
|
|
|
def __init__(self, file=None, **kwargs):
|
|
self.reset()
|
|
if file is not None:
|
|
self.update(file)
|
|
if kwargs:
|
|
self.update(kwargs)
|
|
|
|
def reset(self):
|
|
"""Reset self to default values."""
|
|
self.clear()
|
|
dict.update(self, self.defaults)
|
|
|
|
def update(self, config):
|
|
"""Update self from a dict, file or filename."""
|
|
if isinstance(config, basestring):
|
|
# Filename
|
|
config = Parser().dict_from_file(config)
|
|
elif hasattr(config, 'read'):
|
|
# Open file object
|
|
config = Parser().dict_from_file(config)
|
|
else:
|
|
config = config.copy()
|
|
self._apply(config)
|
|
|
|
def _apply(self, config):
|
|
"""Update self from a dict."""
|
|
which_env = config.get('environment')
|
|
if which_env:
|
|
env = self.environments[which_env]
|
|
for k in env:
|
|
if k not in config:
|
|
config[k] = env[k]
|
|
|
|
dict.update(self, config)
|
|
self.namespaces(config)
|
|
|
|
def __setitem__(self, k, v):
|
|
dict.__setitem__(self, k, v)
|
|
self.namespaces({k: v})
|
|
|
|
|
|
class Parser(ConfigParser):
|
|
"""Sub-class of ConfigParser that keeps the case of options and that
|
|
raises an exception if the file cannot be read.
|
|
"""
|
|
|
|
def optionxform(self, optionstr):
|
|
return optionstr
|
|
|
|
def read(self, filenames):
|
|
if isinstance(filenames, basestring):
|
|
filenames = [filenames]
|
|
for filename in filenames:
|
|
# try:
|
|
# fp = open(filename)
|
|
# except IOError:
|
|
# continue
|
|
fp = open(filename)
|
|
try:
|
|
self._read(fp, filename)
|
|
finally:
|
|
fp.close()
|
|
|
|
def as_dict(self, raw=False, vars=None):
|
|
"""Convert an INI file to a dictionary"""
|
|
# Load INI file into a dict
|
|
result = {}
|
|
for section in self.sections():
|
|
if section not in result:
|
|
result[section] = {}
|
|
for option in self.options(section):
|
|
value = self.get(section, option, raw, vars)
|
|
try:
|
|
value = unrepr(value)
|
|
except Exception, x:
|
|
msg = ("Config error in section: %r, option: %r, "
|
|
"value: %r. Config values must be valid Python." %
|
|
(section, option, value))
|
|
raise ValueError(msg, x.__class__.__name__, x.args)
|
|
result[section][option] = value
|
|
return result
|
|
|
|
def dict_from_file(self, file):
|
|
if hasattr(file, 'read'):
|
|
self.readfp(file)
|
|
else:
|
|
self.read(file)
|
|
return self.as_dict()
|
|
|
|
|
|
# public domain "unrepr" implementation, found on the web and then improved.
|
|
|
|
class _Builder:
|
|
|
|
def build(self, o):
|
|
m = getattr(self, 'build_' + o.__class__.__name__, None)
|
|
if m is None:
|
|
raise TypeError("unrepr does not recognize %s" %
|
|
repr(o.__class__.__name__))
|
|
return m(o)
|
|
|
|
def build_Subscript(self, o):
|
|
expr, flags, subs = o.getChildren()
|
|
expr = self.build(expr)
|
|
subs = self.build(subs)
|
|
return expr[subs]
|
|
|
|
def build_CallFunc(self, o):
|
|
children = map(self.build, o.getChildren())
|
|
callee = children.pop(0)
|
|
kwargs = children.pop() or {}
|
|
starargs = children.pop() or ()
|
|
args = tuple(children) + tuple(starargs)
|
|
return callee(*args, **kwargs)
|
|
|
|
def build_List(self, o):
|
|
return map(self.build, o.getChildren())
|
|
|
|
def build_Const(self, o):
|
|
return o.value
|
|
|
|
def build_Dict(self, o):
|
|
d = {}
|
|
i = iter(map(self.build, o.getChildren()))
|
|
for el in i:
|
|
d[el] = i.next()
|
|
return d
|
|
|
|
def build_Tuple(self, o):
|
|
return tuple(self.build_List(o))
|
|
|
|
def build_Name(self, o):
|
|
name = o.name
|
|
if name == 'None':
|
|
return None
|
|
if name == 'True':
|
|
return True
|
|
if name == 'False':
|
|
return False
|
|
|
|
# See if the Name is a package or module. If it is, import it.
|
|
try:
|
|
return modules(name)
|
|
except ImportError:
|
|
pass
|
|
|
|
# See if the Name is in builtins.
|
|
try:
|
|
import __builtin__
|
|
return getattr(__builtin__, name)
|
|
except AttributeError:
|
|
pass
|
|
|
|
raise TypeError("unrepr could not resolve the name %s" % repr(name))
|
|
|
|
def build_Add(self, o):
|
|
left, right = map(self.build, o.getChildren())
|
|
return left + right
|
|
|
|
def build_Getattr(self, o):
|
|
parent = self.build(o.expr)
|
|
return getattr(parent, o.attrname)
|
|
|
|
def build_NoneType(self, o):
|
|
return None
|
|
|
|
def build_UnarySub(self, o):
|
|
return -self.build(o.getChildren()[0])
|
|
|
|
def build_UnaryAdd(self, o):
|
|
return self.build(o.getChildren()[0])
|
|
|
|
|
|
def _astnode(s):
|
|
"""Return a Python ast Node compiled from a string."""
|
|
try:
|
|
import compiler
|
|
except ImportError:
|
|
# Fallback to eval when compiler package is not available,
|
|
# e.g. IronPython 1.0.
|
|
return eval(s)
|
|
|
|
p = compiler.parse("__tempvalue__ = " + s)
|
|
return p.getChildren()[1].getChildren()[0].getChildren()[1]
|
|
|
|
|
|
def unrepr(s):
|
|
"""Return a Python object compiled from a string."""
|
|
if not s:
|
|
return s
|
|
obj = _astnode(s)
|
|
return _Builder().build(obj)
|
|
|
|
|
|
def modules(modulePath):
|
|
"""Load a module and retrieve a reference to that module."""
|
|
try:
|
|
mod = sys.modules[modulePath]
|
|
if mod is None:
|
|
raise KeyError()
|
|
except KeyError:
|
|
# The last [''] is important.
|
|
mod = __import__(modulePath, globals(), locals(), [''])
|
|
return mod
|
|
|
|
def attributes(full_attribute_name):
|
|
"""Load a module and retrieve an attribute of that module."""
|
|
|
|
# Parse out the path, module, and attribute
|
|
last_dot = full_attribute_name.rfind(".")
|
|
attr_name = full_attribute_name[last_dot + 1:]
|
|
mod_path = full_attribute_name[:last_dot]
|
|
|
|
mod = modules(mod_path)
|
|
# Let an AttributeError propagate outward.
|
|
try:
|
|
attr = getattr(mod, attr_name)
|
|
except AttributeError:
|
|
raise AttributeError("'%s' object has no attribute '%s'"
|
|
% (mod_path, attr_name))
|
|
|
|
# Return a reference to the attribute.
|
|
return attr
|
|
|
|
|