# --------------------------------------------------------------------------------------------
# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License. See License.txt in the project root for license information.
# --------------------------------------------------------------------------------------------
import logging
import datetime
from typing import TYPE_CHECKING, Union, Optional
import six
from ._common.utils import utc_from_timestamp, utc_now
from ._common.constants import (
REQUEST_RESPONSE_GET_SESSION_STATE_OPERATION,
REQUEST_RESPONSE_SET_SESSION_STATE_OPERATION,
REQUEST_RESPONSE_RENEW_SESSION_LOCK_OPERATION,
MGMT_RESPONSE_SESSION_STATE,
MGMT_RESPONSE_RECEIVER_EXPIRATION,
MGMT_REQUEST_SESSION_ID,
MGMT_REQUEST_SESSION_STATE,
)
from .exceptions import SessionLockExpired
from ._common import mgmt_handlers
if TYPE_CHECKING:
from ._servicebus_session_receiver import ServiceBusSessionReceiver
from .aio._servicebus_session_receiver_async import ServiceBusSessionReceiver as ServiceBusSessionReceiverAsync
_LOGGER = logging.getLogger(__name__)
class BaseSession(object):
def __init__(self, session_id, receiver, encoding="UTF-8"):
# type: (str, Union[ServiceBusSessionReceiver, ServiceBusSessionReceiverAsync], str) -> None
self._session_id = session_id
self._receiver = receiver
self._encoding = encoding
self._session_start = None
self._locked_until_utc = None # type: Optional[datetime.datetime]
self.auto_renew_error = None
def _check_live(self):
if self._lock_expired:
raise SessionLockExpired(inner_exception=self.auto_renew_error)
@property
def _lock_expired(self):
# type: () -> bool
"""Whether the receivers lock on a particular session has expired.
:rtype: bool
"""
return bool(self._locked_until_utc and self._locked_until_utc <= utc_now())
@property
def session_id(self):
# type: () -> str
"""
Session id of the current session.
:rtype: str
"""
return self._session_id
@property
def locked_until_utc(self):
# type: () -> Optional[datetime.datetime]
"""The time at which this session's lock will expire.
:rtype: datetime.datetime
"""
return self._locked_until_utc
[docs]class ServiceBusSession(BaseSession):
"""
The ServiceBusSession is used for manage session states and lock renewal.
**Please use the instance variable `session` on the ServiceBusReceiver to get the corresponding ServiceBusSession
object linked with the receiver instead of instantiating a ServiceBusSession object directly.**
:ivar auto_renew_error: Error when AutoLockRenew is used and it fails to renew the session lock.
:vartype auto_renew_error: ~azure.servicebus.AutoLockRenewTimeout or ~azure.servicebus.AutoLockRenewFailed
.. admonition:: Example:
.. literalinclude:: ../samples/sync_samples/sample_code_servicebus.py
:start-after: [START get_session_sync]
:end-before: [END get_session_sync]
:language: python
:dedent: 4
:caption: Get session from a receiver
"""
[docs] def get_state(self):
# type: () -> str
"""Get the session state.
Returns None if no state has been set.
:rtype: str
.. admonition:: Example:
.. literalinclude:: ../samples/sync_samples/sample_code_servicebus.py
:start-after: [START get_session_state_sync]
:end-before: [END get_session_state_sync]
:language: python
:dedent: 4
:caption: Get the session state
"""
self._check_live()
response = self._receiver._mgmt_request_response_with_retry( # pylint: disable=protected-access
REQUEST_RESPONSE_GET_SESSION_STATE_OPERATION,
{MGMT_REQUEST_SESSION_ID: self._session_id},
mgmt_handlers.default
)
session_state = response.get(MGMT_RESPONSE_SESSION_STATE)
if isinstance(session_state, six.binary_type):
session_state = session_state.decode(self._encoding)
return session_state
[docs] def set_state(self, state):
# type: (Union[str, bytes, bytearray]) -> None
"""Set the session state.
:param state: The state value.
:type state: Union[str, bytes, bytearray]
.. admonition:: Example:
.. literalinclude:: ../samples/sync_samples/sample_code_servicebus.py
:start-after: [START set_session_state_sync]
:end-before: [END set_session_state_sync]
:language: python
:dedent: 4
:caption: Set the session state
"""
self._check_live()
state = state.encode(self._encoding) if isinstance(state, six.text_type) else state
return self._receiver._mgmt_request_response_with_retry( # pylint: disable=protected-access
REQUEST_RESPONSE_SET_SESSION_STATE_OPERATION,
{MGMT_REQUEST_SESSION_ID: self._session_id, MGMT_REQUEST_SESSION_STATE: bytearray(state)},
mgmt_handlers.default
)
[docs] def renew_lock(self):
# type: () -> datetime.datetime
"""Renew the session lock.
This operation must be performed periodically in order to retain a lock on the
session to continue message processing.
Once the lock is lost the connection will be closed; an expired lock cannot be renewed.
This operation can also be performed as a threaded background task by registering the session
with an `azure.servicebus.AutoLockRenew` instance.
:returns: The utc datetime the lock is set to expire at.
:rtype: datetime.datetime
.. admonition:: Example:
.. literalinclude:: ../samples/sync_samples/sample_code_servicebus.py
:start-after: [START session_renew_lock_sync]
:end-before: [END session_renew_lock_sync]
:language: python
:dedent: 4
:caption: Renew the session lock before it expires
"""
self._check_live()
expiry = self._receiver._mgmt_request_response_with_retry( # pylint: disable=protected-access
REQUEST_RESPONSE_RENEW_SESSION_LOCK_OPERATION,
{MGMT_REQUEST_SESSION_ID: self._session_id},
mgmt_handlers.default
)
expiry_timestamp = expiry[MGMT_RESPONSE_RECEIVER_EXPIRATION]/1000.0
self._locked_until_utc = utc_from_timestamp(expiry_timestamp) # type: datetime.datetime
return self._locked_until_utc