django-orchestra/orchestra/contrib/orchestration/__init__.py

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import copy
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from .backends import ServiceBackend, ServiceController, replace
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class Operation():
DELETE = 'delete'
SAVE = 'save'
MONITOR = 'monitor'
EXCEEDED = 'exceeded'
RECOVERY = 'recovery'
def __str__(self):
return '%s.%s(%s)' % (self.backend, self.action, self.instance)
def __hash__(self):
""" set() """
return hash(self.backend) + hash(self.instance) + hash(self.action)
def __eq__(self, operation):
""" set() """
return hash(self) == hash(operation)
def __init__(self, backend, instance, action, servers=None):
self.backend = backend
# instance should maintain any dynamic attribute until backend execution
# deep copy is prefered over copy otherwise objects will share same atributes (queryset cache)
self.instance = copy.deepcopy(instance)
self.action = action
self.servers = servers
@classmethod
def execute(cls, operations, async=False):
from . import manager
scripts, block = manager.generate(operations)
return manager.execute(scripts, block=block, async=async)
@classmethod
def execute_action(cls, instance, action):
backends = ServiceBackend.get_backends(instance=instance, action=action)
operations = [cls(backend_cls, instance, action) for backend_cls in backends]
return cls.execute(operations)
def preload_context(self):
"""
Heuristic
Running get_context will prevent most of related objects do not exist errors
"""
if self.action == self.DELETE:
if hasattr(self.backend, 'get_context'):
self.backend().get_context(self.instance)
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def store(self, log):
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from .models import BackendOperation
return BackendOperation.objects.create(
log=log,
backend=self.backend.get_name(),
instance=self.instance,
action=self.action,
)