Files
mayan-edms/mayan/apps/smart_settings/classes.py
Roberto Rosario fa8fddb349 Add support for setting migrations
Signed-off-by: Roberto Rosario <roberto.rosario@mayan-edms.com>
2019-11-18 00:27:33 -04:00

370 lines
11 KiB
Python

from __future__ import unicode_literals
import errno
import hashlib
from importlib import import_module
import logging
import os
import sys
import yaml
from django.apps import apps
from django.conf import settings
from django.utils.functional import Promise
from django.utils.encoding import (
force_bytes, force_text, python_2_unicode_compatible
)
from mayan.apps.common.serialization import yaml_dump, yaml_load
logger = logging.getLogger(__name__)
NAMESPACE_VERSION_INITIAL = '0001'
SMART_SETTINGS_NAMESPACES_NAME = 'SMART_SETTINGS_NAMESPACES'
def read_configuration_file(filepath):
try:
with open(filepath) as file_object:
file_object.seek(0, os.SEEK_END)
if file_object.tell():
file_object.seek(0)
try:
return yaml_load(stream=file_object)
except yaml.YAMLError as exception:
exit(
'Error loading configuration file: {}; {}'.format(
filepath, exception
)
)
except IOError as exception:
if exception.errno == errno.ENOENT:
# No config file, return empty dictionary
return {}
else:
raise
@python_2_unicode_compatible
class Namespace(object):
_registry = {}
@staticmethod
def initialize():
for app in apps.get_app_configs():
try:
import_module('{}.settings'.format(app.name))
except ImportError as exception:
if force_text(exception) not in ('No module named settings', 'No module named \'{}.settings\''.format(app.name)):
logger.error(
'Error importing %s settings.py file; %s', app.name,
exception
)
@classmethod
def get(cls, name):
return cls._registry[name]
@classmethod
def get_all(cls):
return sorted(cls._registry.values(), key=lambda x: x.label)
@classmethod
def get_namespace_config(cls, name):
return cls.get_namespaces_config().get(name, {})
@classmethod
def get_namespaces_config(cls):
return getattr(settings, SMART_SETTINGS_NAMESPACES_NAME, {})
@classmethod
def invalidate_cache_all(cls):
for namespace in cls.get_all():
namespace.invalidate_cache()
def __init__(
self, name, label, migration_class=None,
version=NAMESPACE_VERSION_INITIAL
):
if name in self.__class__._registry:
raise Exception(
'Namespace names must be unique; "%s" already exists.' % name
)
self.migration_class = migration_class
self.name = name
self.label = label
self.version = version
self.__class__._registry[name] = self
self._settings = []
def __str__(self):
return force_text(self.label)
def add_setting(self, **kwargs):
return Setting(namespace=self, **kwargs)
def get_config_version(self):
return Namespace.get_namespace_config(name=self.name).get(
'version', NAMESPACE_VERSION_INITIAL
)
def invalidate_cache(self):
for setting in self._settings:
setting.invalidate_cache()
def migrate(self, setting):
if self.migration_class:
self.migration_class(namespace=self).migrate(setting=setting)
@property
def settings(self):
return sorted(self._settings, key=lambda x: x.global_name)
class NamespaceMigration(object):
def __init__(self, namespace):
self.namespace = namespace
def get_method_name(self, setting):
return setting.global_name.lower()
def get_method_name_full(self, setting, version):
return '{}_{}'.format(
self.get_method_name(setting=setting),
version
)
def migrate(self, setting):
if self.namespace.get_config_version() != self.namespace.version:
method_name = self.get_method_name(setting=setting)
# Get methods for this setting
setting_methods = [
method for method in dir(self) if method.startswith(
method_name
)
]
# Get order of execution of setting methods
versions = [
method.replace(
'{}_'.format(method_name), ''
) for method in setting_methods
]
try:
start = versions.index(self.namespace.get_config_version())
except ValueError:
start = 0
try:
end = versions.index(self.namespace.version)
except ValueError:
end = None
value = setting.raw_value
for version in versions[start:end]:
method = getattr(
self, self.get_method_name_full(
setting=setting, version=version
), None
)
if method:
value = method(value=value)
setting.raw_value = value
@python_2_unicode_compatible
class Setting(object):
_registry = {}
_cache_hash = None
_config_file_cache = None
@staticmethod
def deserialize_value(value):
return yaml_load(stream=value)
@staticmethod
def express_promises(value):
"""
Walk all the elements of a value and force promises to text
"""
if isinstance(value, (list, tuple)):
return [Setting.express_promises(item) for item in value]
elif isinstance(value, Promise):
return force_text(value)
else:
return value
@staticmethod
def serialize_value(value):
result = yaml_dump(
data=Setting.express_promises(value), allow_unicode=True,
default_flow_style=False,
)
# safe_dump returns bytestrings
# Disregard the last 3 dots that mark the end of the YAML document
if force_text(result).endswith('...\n'):
result = result[:-4]
return result
@classmethod
def check_changed(cls):
if not cls._cache_hash:
cls._cache_hash = cls.get_hash()
return cls._cache_hash != cls.get_hash()
@classmethod
def dump_data(cls, filter_term=None, namespace=None):
dictionary = {}
if not namespace:
namespace_dictionary = {}
for _namespace in Namespace.get_all():
namespace_dictionary[_namespace.name] = {
'version': _namespace.version
}
dictionary[SMART_SETTINGS_NAMESPACES_NAME] = namespace_dictionary
for setting in cls.get_all():
# If a namespace is specified, filter the list by that namespace
# otherwise return always True to include all (or not None == True)
if (namespace and setting.namespace.name == namespace) or not namespace:
if (filter_term and filter_term.lower() in setting.global_name.lower()) or not filter_term:
dictionary[setting.global_name] = Setting.express_promises(setting.value)
return yaml_dump(
data=dictionary, default_flow_style=False
)
@classmethod
def get(cls, global_name):
return cls._registry[global_name]
@classmethod
def get_all(cls):
return sorted(cls._registry.values(), key=lambda x: x.global_name)
@classmethod
def get_config_file_content(cls):
# Cache content of config file to speed up initial boot up
if not cls._config_file_cache:
cls._config_file_cache = read_configuration_file(
filepath=settings.CONFIGURATION_FILEPATH
)
return cls._config_file_cache
@classmethod
def get_hash(cls):
return force_text(
hashlib.sha256(force_bytes(cls.dump_data())).hexdigest()
)
@classmethod
def save_configuration(cls, path=None):
if not path:
path = settings.CONFIGURATION_FILEPATH
try:
with open(path, mode='w') as file_object:
file_object.write(cls.dump_data())
except IOError as exception:
if exception.errno == errno.ENOENT:
logger.warning(
'The path to the configuration file doesn\'t '
'exist. It is not possible to save the backup file.'
)
@classmethod
def save_last_known_good(cls):
# Don't write over the last good configuration if we are trying
# to restore the last good configuration
if 'revertsettings' not in sys.argv:
cls.save_configuration(
path=settings.CONFIGURATION_LAST_GOOD_FILEPATH
)
def __init__(
self, namespace, global_name, default, help_text=None, is_path=False,
post_edit_function=None
):
self.global_name = global_name
self.default = default
self.help_text = help_text
self.loaded = False
self.namespace = namespace
self.environment_variable = False
self.post_edit_function = post_edit_function
namespace._settings.append(self)
self.__class__._registry[global_name] = self
def __str__(self):
return force_text(self.global_name)
def cache_value(self):
environment_value = os.environ.get('MAYAN_{}'.format(self.global_name))
if environment_value:
self.environment_variable = True
try:
self.raw_value = yaml_load(stream=environment_value)
except yaml.YAMLError as exception:
raise type(exception)(
'Error interpreting environment variable: {} with '
'value: {}; {}'.format(
self.global_name, environment_value, exception
)
)
else:
try:
# Try the config file
self.raw_value = self.get_config_file_content()[self.global_name]
except KeyError:
try:
# Try the Django settings variable
self.raw_value = getattr(
settings, self.global_name
)
except AttributeError:
# Finally set to the default value
self.raw_value = self.default
else:
# Found in the config file, try to migrate the value
self.migrate()
self.yaml = Setting.serialize_value(self.raw_value)
self.loaded = True
def invalidate_cache(self):
self.loaded = False
def migrate(self):
self.namespace.migrate(setting=self)
@property
def serialized_value(self):
"""
YAML serialize value of the setting.
Used for UI display.
"""
if not self.loaded:
self.cache_value()
return self.yaml
@property
def value(self):
if not self.loaded:
self.cache_value()
return self.raw_value
@value.setter
def value(self, value):
# value is in YAML format
self.yaml = value
self.raw_value = Setting.deserialize_value(value)
if self.post_edit_function:
self.post_edit_function(setting=self)