241 lines
7.6 KiB
Python
241 lines
7.6 KiB
Python
from functools import partial
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from django.apps import apps
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from django.utils import timezone
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from django.utils.translation import ugettext_lazy as _
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from orchestra import plugins
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from . import methods
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def replace(context, pattern, repl):
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""" applies replace to all context str values """
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for key, value in context.items():
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if isinstance(value, str):
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context[key] = value.replace(pattern, repl)
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return context
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class ServiceMount(plugins.PluginMount):
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def __init__(cls, name, bases, attrs):
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# Make sure backends specify a model attribute
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if not (attrs.get('abstract', False) or name == 'ServiceBackend' or cls.model):
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raise AttributeError("'%s' does not have a defined model attribute." % cls)
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super(ServiceMount, cls).__init__(name, bases, attrs)
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class ServiceBackend(plugins.Plugin, metaclass=ServiceMount):
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"""
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Service management backend base class
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It uses the _unit of work_ design principle, which allows bulk operations to
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be conviniently supported. Each backend generates the configuration for all
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the changes of all modified objects, reloading the daemon just once.
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"""
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model = None
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related_models = () # ((model, accessor__attribute),)
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script_method = methods.SSH
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script_executable = '/bin/bash'
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function_method = methods.Python
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type = 'task' # 'sync'
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# Don't wait for the backend to finish before continuing with request/response
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ignore_fields = []
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actions = []
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default_route_match = 'True'
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# Force the backend manager to block in multiple backend executions executing them synchronously
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serialize = False
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doc_settings = None
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# By default backend will not run if actions do not generate insctructions,
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# If your backend uses prepare() or commit() only then you should set force_empty_action_execution = True
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force_empty_action_execution = False
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def __str__(self):
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return type(self).__name__
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def __init__(self):
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self.head = []
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self.content = []
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self.tail = []
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def __getattribute__(self, attr):
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""" Select head, content or tail section depending on the method name """
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IGNORE_ATTRS = (
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'append',
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'cmd_section',
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'head',
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'tail',
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'content',
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'script_method',
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'function_method',
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'set_head',
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'set_tail',
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'set_content',
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'actions',
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)
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if attr == 'prepare':
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self.set_head()
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elif attr == 'commit':
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self.set_tail()
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elif attr not in IGNORE_ATTRS and attr in self.actions:
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self.set_content()
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return super(ServiceBackend, self).__getattribute__(attr)
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def set_head(self):
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self.cmd_section = self.head
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def set_tail(self):
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self.cmd_section = self.tail
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def set_content(self):
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self.cmd_section = self.content
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@classmethod
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def get_actions(cls):
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return [ action for action in cls.actions if action in dir(cls) ]
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@classmethod
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def get_name(cls):
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return cls.__name__
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@classmethod
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def is_main(cls, obj):
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opts = obj._meta
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return cls.model == '%s.%s' % (opts.app_label, opts.object_name)
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@classmethod
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def get_related(cls, obj):
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opts = obj._meta
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model = '%s.%s' % (opts.app_label, opts.object_name)
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for rel_model, field in cls.related_models:
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if rel_model == model:
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related = obj
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for attribute in field.split('__'):
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related = getattr(related, attribute)
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return related
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return None
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@classmethod
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def get_backends(cls, instance=None, action=None):
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backends = cls.get_plugins()
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included = []
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# Filter for instance or action
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for backend in backends:
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include = True
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if instance:
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opts = instance._meta
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if backend.model != '.'.join((opts.app_label, opts.object_name)):
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include = False
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if include and action:
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if action not in backend.get_actions():
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include = False
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if include:
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included.append(backend)
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return included
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@classmethod
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def get_backend(cls, name):
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return cls.get(name)
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@classmethod
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def model_class(cls):
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return apps.get_model(cls.model)
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@property
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def scripts(self):
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""" group commands based on their method """
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if not self.content:
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return []
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scripts = {}
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for method, cmd in self.content:
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scripts[method] = []
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for method, commands in self.head + self.content + self.tail:
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try:
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scripts[method] += commands
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except KeyError:
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pass
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return list(scripts.items())
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def get_banner(self):
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time = timezone.now().strftime("%h %d, %Y %I:%M:%S %Z")
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return "Generated by Orchestra at %s" % time
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def create_log(self, server, **kwargs):
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from .models import BackendLog
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state = BackendLog.RECEIVED
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run = bool(self.scripts) or (self.force_empty_action_execution or bool(self.content))
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if not run:
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state = BackendLog.NOTHING
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using = kwargs.pop('using', None)
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manager = BackendLog.objects
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if using:
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manager = manager.using(using)
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log = manager.create(backend=self.get_name(), state=state, server=server)
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return log
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def execute(self, server, async=False, log=None):
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from .models import BackendLog
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if log is None:
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log = self.create_log(server)
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run = log.state != BackendLog.NOTHING
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if run:
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scripts = self.scripts
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for method, commands in scripts:
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method(log, server, commands, async)
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if log.state != BackendLog.SUCCESS:
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break
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return log
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def append(self, *cmd):
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# aggregate commands acording to its execution method
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if isinstance(cmd[0], str):
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method = self.script_method
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cmd = cmd[0]
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else:
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method = self.function_method
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cmd = partial(*cmd)
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if not self.cmd_section or self.cmd_section[-1][0] != method:
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self.cmd_section.append((method, [cmd]))
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else:
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self.cmd_section[-1][1].append(cmd)
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def get_context(self, obj):
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return {}
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def prepare(self):
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"""
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hook for executing something at the beging
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define functions or initialize state
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"""
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self.append(
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'set -e\n'
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'set -o pipefail\n'
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'exit_code=0;\n'
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)
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def commit(self):
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"""
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hook for executing something at the end
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apply the configuration, usually reloading a service
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reloading a service is done in a separated method in order to reload
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the service once in bulk operations
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"""
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self.append('exit $exit_code')
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class ServiceController(ServiceBackend):
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actions = ('save', 'delete')
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abstract = True
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@classmethod
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def get_verbose_name(cls):
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return _("[S] %s") % super(ServiceController, cls).get_verbose_name()
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@classmethod
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def get_backends(cls):
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""" filter controller classes """
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backends = super(ServiceController, cls).get_backends()
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return [
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backend for backend in backends if issubclass(backend, ServiceController)
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]
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