def load_context(cls):
"""
加载context，首次加载时，新建GuardianContext对象，否则从状态服务反序列化对象
:return: context对象
:rtype: GuardianContext
"""
context_path = config.GuardianConfig.get_persistent_path("context")
data = persistence.PersistenceDriver().get_data(context_path)
log.i("load context success")
guardian_context = pickle.loads(data) if data else GuardianContext()
# load状态机信息
operations_path = config.GuardianConfig.get_persistent_path("operations")
# operations子节点名称均为operation_id
operation_ids = persistence.PersistenceDriver().get_children(operations_path)
for operation_id in operation_ids:
operation_path = operations_path + "/" + operation_id
try:
operation_data = persistence.PersistenceDriver().get_data(operation_path)
log.i("load operation[{}] success".format(operation_id))
operation = pickle.loads(operation_data)
guardian_context.operations[operation_id] = operation
except Exception as e:
log.f("load operation {} failed".format(operation_id))
cls._context = guardian_context
return guardian_context
def save_operation(self, operation):
"""
持久化状态机信息
:param operation:
:return:
"""
if not self.lock:
log.e("current guardian instance no privilege to save operation")
raise exception.EInvalidOperation(
"current guardian instance no privilege to save operation")
operation_path = config.GuardianConfig.get_persistent_path("operations") + "/" + operation.operation_id
if not persistence.PersistenceDriver().exists(operation_path):
persistence.PersistenceDriver().create_node(path=operation_path)
persistence.PersistenceDriver().save_data(operation_path, pickle.dumps(operation))
log.d("save operation_id:{} success".format(operation.operation_id))
def init_environment(cls):
"""
初始化Guardian运行环境
:return: 无返回
:rtype: None
:raises EFailedRequest: 状态服务请求异常
"""
guardian_base = config.GuardianConfig.get_persistent_path()
guardian_client_path = config.GuardianConfig.get_persistent_path("alive_clients")
context_path = config.GuardianConfig.get_persistent_path("context")
operations_path = config.GuardianConfig.get_persistent_path("operations")
pd = persistence.PersistenceDriver()
if not pd.exists(guardian_base):
pd.create_node(path=guardian_base, makepath=True)
log.d("persistent node %s created!" % guardian_base)
if not pd.exists(context_path):
pd.create_node(path=context_path)
log.d("persistent node %s created!" % context_path)
if not pd.exists(guardian_client_path):
pd.create_node(path=guardian_client_path)
log.d("persistent node %s created!" % guardian_client_path)
if not pd.exists(operations_path):
pd.create_node(path=operations_path)
log.d("persistent node %s created!" % operations_path)
def delete_operation(self, operation_id):
"""
删除一个操作，一般在一个事件操作结束时调用
:param str operation_id: 操作id
:return: 无返回
:rtype: None
"""
del self.operations[operation_id]
operation_path = config.GuardianConfig.get_persistent_path("operations") + "/" + operation_id
persistence.PersistenceDriver().delete_node(operation_path)
log.d("delete operation from context success, operation_id:{}".
format(operation_id))
def __init__(self, start_scheduler_func, stop_scheduler_func):
"""
初始化方法
:param func start_scheduler_func: 实例成为主时回调函数
:param func stop_scheduler_func: 实例成为从时回调函数
"""
self.path = config.GuardianConfig.get_persistent_path("alive_clients")
self._start_scheduler_func = start_scheduler_func
self._stop_scheduler_func = stop_scheduler_func
self._pd = persistence.PersistenceDriver()
self._pd.add_listener(self.state_listener)
self.is_leader = False
def save_context(self):
"""
运行数据持久化，当当前Guardian为主（lock属性为True）时，可持久化数据，否则失败
:return: 无返回
:rtype: None
:raises EInvalidOperation: 非法操作
"""
if not self.lock:
log.e("current guardian instance no privilege to save context")
raise exception.EInvalidOperation(
"current guardian instance no privilege to save context")
context_path = config.GuardianConfig.get_persistent_path("context")
context_to_persist = copy.deepcopy(self)
# 考虑反序列化时可能异常，不使用del删除属性operations
context_to_persist.operations = {}
persistence.PersistenceDriver().save_data(
context_path, pickle.dumps(context_to_persist))
log.i("save context success")
def save_context(self):
"""
运行数据持久化，当当前Guardian为主（lock属性为True）时，可持久化数据，否则失败
:return: 无返回
:rtype: None
:raises EInvalidOperation: 非法操作
"""
if not self.lock:
log.e("current guardian instance no privilege to save context")
raise exception.EInvalidOperation(
"current guardian instance no privilege to save context")
context_path = config.GuardianConfig.get_persistent_path("context")
context_to_persist = self
operations_tmp = self.operations
context_to_persist.operations = {}
try:
persistence.PersistenceDriver().save_data(context_path, pickle.dumps(context_to_persist))
except Exception as e:
self.operations = operations_tmp
log.r(e, "save context fail")
self.operations = operations_tmp
log.d("save context success")
