deluge/deluge/config.py

536 lines
17 KiB
Python

# -*- coding: utf-8 -*-
#
# Copyright (C) 2008 Andrew Resch <andrewresch@gmail.com>
#
# This file is part of Deluge and is licensed under GNU General Public License 3.0, or later, with
# the additional special exception to link portions of this program with the OpenSSL library.
# See LICENSE for more details.
#
"""
Deluge Config Module
This module is used for loading and saving of configuration files.. or anything
really.
The format of the config file is two json encoded dicts:
<version dict>
<content dict>
The version dict contains two keys: file and format. The format version is
controlled by the Config class. It should only be changed when anything below
it is changed directly by the Config class. An example of this would be if we
changed the serializer for the content to something different.
The config file version is changed by the 'owner' of the config file. This is
to signify that there is a change in the naming of some config keys or something
similar along those lines.
The content is simply the dict to be saved and will be serialized before being
written.
Converting
Since the format of the config could change, there needs to be a way to have
the Config object convert to newer formats. To do this, you will need to
register conversion functions for various versions of the config file. Note that
this can only be done for the 'config file version' and not for the 'format'
version as this will be done internally.
"""
import cPickle as pickle
import json
import logging
import os
import shutil
from deluge.common import get_default_config_dir, utf8_encoded
log = logging.getLogger(__name__)
callLater = None # Necessary for the config tests
def prop(func):
"""Function decorator for defining property attributes
The decorated function is expected to return a dictionary
containing one or more of the following pairs:
fget - function for getting attribute value
fset - function for setting attribute value
fdel - function for deleting attribute
This can be conveniently constructed by the locals() builtin
function; see:
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/205183
"""
return property(doc=func.__doc__, **func())
def find_json_objects(s):
"""
Find json objects in a string.
:param s: the string to find json objects in
:type s: string
:returns: a list of tuples containing start and end locations of json objects in the string `s`
:rtype: [(start, end), ...]
"""
objects = []
opens = 0
start = s.find("{")
offset = start
if start < 0:
return []
for index, c in enumerate(s[offset:]):
if c == "{":
opens += 1
elif c == "}":
opens -= 1
if opens == 0:
objects.append((start, index + offset + 1))
start = index + offset + 1
return objects
class Config(object):
"""
This class is used to access/create/modify config files
:param filename: the name of the config file
:param defaults: dictionary of default values
:param config_dir: the path to the config directory
"""
def __init__(self, filename, defaults=None, config_dir=None):
self.__config = {}
self.__set_functions = {}
self.__change_callbacks = []
# These hold the version numbers and they will be set when loaded
self.__version = {
"format": 1,
"file": 1
}
# This will get set with a reactor.callLater whenever a config option
# is set.
self._save_timer = None
if defaults:
for key, value in defaults.iteritems():
self.set_item(key, value)
# Load the config from file in the config_dir
if config_dir:
self.__config_file = os.path.join(config_dir, filename)
else:
self.__config_file = get_default_config_dir(filename)
self.load()
def __contains__(self, item):
return item in self.__config
def __setitem__(self, key, value):
"""
See
:meth:`set_item`
"""
return self.set_item(key, value)
def set_item(self, key, value):
"""
Sets item 'key' to 'value' in the config dictionary, but does not allow
changing the item's type unless it is None. If the types do not match,
it will attempt to convert it to the set type before raising a ValueError.
:param key: string, item to change to change
:param value: the value to change item to, must be same type as what is currently in the config
:raises ValueError: raised when the type of value is not the same as\
what is currently in the config and it could not convert the value
**Usage**
>>> config = Config("test.conf")
>>> config["test"] = 5
>>> config["test"]
5
"""
if isinstance(value, basestring):
value = utf8_encoded(value)
if key not in self.__config:
self.__config[key] = value
log.debug("Setting '%s' to %s of %s", key, value, type(value))
return
if self.__config[key] == value:
return
# Do not allow the type to change unless it is None
if value is not None and not isinstance(
self.__config[key], type(None)) and not isinstance(self.__config[key], type(value)):
try:
oldtype = type(self.__config[key])
if isinstance(self.__config[key], unicode):
value = oldtype(value, "utf8")
else:
value = oldtype(value)
except ValueError:
log.warning("Type '%s' invalid for '%s'", type(value), key)
raise
log.debug("Setting '%s' to %s of %s", key, value, type(value))
self.__config[key] = value
global callLater
if callLater is None:
# Must import here and not at the top or it will throw ReactorAlreadyInstalledError
from twisted.internet.reactor import callLater
# Run the set_function for this key if any
try:
for func in self.__set_functions[key]:
callLater(0, func, key, value)
except KeyError:
pass
try:
def do_change_callbacks(key, value):
for func in self.__change_callbacks:
func(key, value)
callLater(0, do_change_callbacks, key, value)
except:
pass
# We set the save_timer for 5 seconds if not already set
if not self._save_timer or not self._save_timer.active():
self._save_timer = callLater(5, self.save)
def __getitem__(self, key):
"""
See
:meth:`get_item`
"""
return self.get_item(key)
def get_item(self, key):
"""
Gets the value of item 'key'
:param key: the item for which you want it's value
:return: the value of item 'key'
:raises KeyError: if 'key' is not in the config dictionary
**Usage**
>>> config = Config("test.conf", defaults={"test": 5})
>>> config["test"]
5
"""
if isinstance(self.__config[key], str):
try:
return self.__config[key].decode("utf8")
except UnicodeDecodeError:
return self.__config[key]
else:
return self.__config[key]
def get(self, key, default=None):
"""
Gets the value of item 'key' if key is in the config, else default.
If default is not given, it defaults to None, so that this method
never raises a KeyError.
:param key: the item for which you want it's value
:param default: the default value if key is missing
:return: the value of item 'key' or default
**Usage**
>>> config = Config("test.conf", defaults={"test": 5})
>>> config.get("test", 10)
5
>>> config.get("bad_key", 10)
10
"""
try:
return self.get_item(key)
except KeyError:
return default
def __delitem__(self, key):
"""
See
:meth:`del_item`
"""
self.del_item(key)
def del_item(self, key):
"""
Deletes item with a specific key from the configuration.
:param key: the item which you wish to delete.
:raises KeyError: if 'key' is not in the config dictionary
**Usage**
>>> config = Config("test.conf", defaults={"test": 5})
>>> del config["test"]
"""
del self.__config[key]
global callLater
if callLater is None:
# Must import here and not at the top or it will throw ReactorAlreadyInstalledError
from twisted.internet.reactor import callLater
# We set the save_timer for 5 seconds if not already set
if not self._save_timer or not self._save_timer.active():
self._save_timer = callLater(5, self.save)
def register_change_callback(self, callback):
"""
Registers a callback function that will be called when a value is changed in the config dictionary
:param callback: the function, callback(key, value)
**Usage**
>>> config = Config("test.conf", defaults={"test": 5})
>>> def cb(key, value):
... print key, value
...
>>> config.register_change_callback(cb)
"""
self.__change_callbacks.append(callback)
def register_set_function(self, key, function, apply_now=True):
"""
Register a function to be called when a config value changes
:param key: the item to monitor for change
:param function: the function to call when the value changes, f(key, value)
:keyword apply_now: if True, the function will be called after it's registered
**Usage**
>>> config = Config("test.conf", defaults={"test": 5})
>>> def cb(key, value):
... print key, value
...
>>> config.register_set_function("test", cb, apply_now=True)
test 5
"""
log.debug("Registering function for %s key..", key)
if key not in self.__set_functions:
self.__set_functions[key] = []
self.__set_functions[key].append(function)
# Run the function now if apply_now is set
if apply_now:
function(key, self.__config[key])
return
def apply_all(self):
"""
Calls all set functions
**Usage**
>>> config = Config("test.conf", defaults={"test": 5})
>>> def cb(key, value):
... print key, value
...
>>> config.register_set_function("test", cb, apply_now=False)
>>> config.apply_all()
test 5
"""
log.debug("Calling all set functions..")
for key, value in self.__set_functions.iteritems():
for func in value:
func(key, self.__config[key])
def apply_set_functions(self, key):
"""
Calls set functions for `:param:key`.
:param key: str, the config key
"""
log.debug("Calling set functions for key %s..", key)
if key in self.__set_functions:
for func in self.__set_functions[key]:
func(key, self.__config[key])
def load(self, filename=None):
"""
Load a config file
:param filename: if None, uses filename set in object initialization
"""
if not filename:
filename = self.__config_file
try:
data = open(filename, "rb").read()
except IOError as ex:
log.warning("Unable to open config file %s: %s", filename, ex)
return
objects = find_json_objects(data)
if not len(objects):
# No json objects found, try depickling it
try:
self.__config.update(pickle.loads(data))
except Exception as ex:
log.exception(ex)
log.warning("Unable to load config file: %s", filename)
elif len(objects) == 1:
start, end = objects[0]
try:
self.__config.update(json.loads(data[start:end]))
except Exception as ex:
log.exception(ex)
log.warning("Unable to load config file: %s", filename)
elif len(objects) == 2:
try:
start, end = objects[0]
self.__version.update(json.loads(data[start:end]))
start, end = objects[1]
self.__config.update(json.loads(data[start:end]))
except Exception as ex:
log.exception(ex)
log.warning("Unable to load config file: %s", filename)
log.debug("Config %s version: %s.%s loaded: %s", filename,
self.__version["format"], self.__version["file"], self.__config)
def save(self, filename=None):
"""
Save configuration to disk
:param filename: if None, uses filename set in object initiliazation
:rtype bool:
:return: whether or not the save succeeded.
"""
if not filename:
filename = self.__config_file
# Check to see if the current config differs from the one on disk
# We will only write a new config file if there is a difference
try:
data = open(filename, "rb").read()
objects = find_json_objects(data)
start, end = objects[0]
version = json.loads(data[start:end])
start, end = objects[1]
loaded_data = json.loads(data[start:end])
if self.__config == loaded_data and self.__version == version:
# The config has not changed so lets just return
if self._save_timer and self._save_timer.active():
self._save_timer.cancel()
return True
except (IOError, IndexError) as ex:
log.warning("Unable to open config file: %s because: %s", filename, ex)
# Save the new config and make sure it's written to disk
try:
log.debug("Saving new config file %s", filename + ".new")
f = open(filename + ".new", "wb")
json.dump(self.__version, f, indent=2)
json.dump(self.__config, f, indent=2)
f.flush()
os.fsync(f.fileno())
f.close()
except IOError as ex:
log.error("Error writing new config file: %s", ex)
return False
# Make a backup of the old config
try:
log.debug("Backing up old config file to %s.bak", filename)
shutil.move(filename, filename + ".bak")
except IOError as ex:
log.warning("Unable to backup old config: %s", ex)
# The new config file has been written successfully, so let's move it over
# the existing one.
try:
log.debug("Moving new config file %s to %s..", filename + ".new", filename)
shutil.move(filename + ".new", filename)
except IOError as ex:
log.error("Error moving new config file: %s", ex)
return False
else:
return True
finally:
if self._save_timer and self._save_timer.active():
self._save_timer.cancel()
def run_converter(self, input_range, output_version, func):
"""
Runs a function that will convert file versions in the `:param:input_range`
to the `:param:output_version`.
:param input_range: tuple, (int, int) the range of input versions this
function will accept
:param output_version: int, the version this function will return
:param func: func, the function that will do the conversion, it will take
the config dict as an argument and return the augmented dict
:raises ValueError: if the output_version is less than the input_range
"""
if output_version in input_range or output_version <= max(input_range):
raise ValueError("output_version needs to be greater than input_range")
if self.__version["file"] not in input_range:
log.debug("File version %s is not in input_range %s, ignoring converter function..",
self.__version["file"], input_range)
return
try:
self.__config = func(self.__config)
except Exception as ex:
log.exception(ex)
log.error("There was an exception try to convert config file %s %s to %s",
self.__config_file, self.__version["file"], output_version)
raise ex
else:
self.__version["file"] = output_version
self.save()
@property
def config_file(self):
return self.__config_file
@prop
def config():
"""The config dictionary"""
def fget(self):
return self.__config
def fdel(self):
return self.save()
return locals()