# --------------------------------------------------------------------------------------------
# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License. See License.txt in the project root for license information.
# --------------------------------------------------------------------------------------------
import asyncio
import collections
import functools
import logging
from typing import Any, TYPE_CHECKING, List
from uamqp import ReceiveClientAsync, types
from uamqp.constants import SenderSettleMode
from ._base_handler_async import BaseHandler, ServiceBusSharedKeyCredential
from ._async_message import ReceivedMessage
from .._base_handler import _convert_connection_string_to_kwargs
from .._common.receiver_mixins import ReceiverMixin
from .._common.constants import (
REQUEST_RESPONSE_UPDATE_DISPOSTION_OPERATION,
REQUEST_RESPONSE_PEEK_OPERATION,
REQUEST_RESPONSE_RECEIVE_BY_SEQUENCE_NUMBER,
REQUEST_RESPONSE_RENEWLOCK_OPERATION,
ReceiveSettleMode,
MGMT_REQUEST_DISPOSITION_STATUS,
MGMT_REQUEST_LOCK_TOKENS,
MGMT_REQUEST_SEQUENCE_NUMBERS,
MGMT_REQUEST_RECEIVER_SETTLE_MODE,
MGMT_REQUEST_FROM_SEQUENCE_NUMBER,
MGMT_REQUEST_MESSAGE_COUNT
)
from .._common import mgmt_handlers
from ._async_utils import create_authentication
if TYPE_CHECKING:
from azure.core.credentials import TokenCredential
_LOGGER = logging.getLogger(__name__)
[docs]class ServiceBusReceiver(collections.abc.AsyncIterator, BaseHandler, ReceiverMixin):
"""The ServiceBusReceiver class defines a high level interface for
receiving messages from the Azure Service Bus Queue or Topic Subscription.
:ivar fully_qualified_namespace: The fully qualified host name for the Service Bus namespace.
The namespace format is: `<yournamespace>.servicebus.windows.net`.
:vartype fully_qualified_namespace: str
:ivar entity_path: The path of the entity that the client connects to.
:vartype entity_path: str
:param str fully_qualified_namespace: The fully qualified host name for the Service Bus namespace.
The namespace format is: `<yournamespace>.servicebus.windows.net`.
:param ~azure.core.credentials.TokenCredential credential: The credential object used for authentication which
implements a particular interface for getting tokens. It accepts
:class:`ServiceBusSharedKeyCredential<azure.servicebus.ServiceBusSharedKeyCredential>`, or credential objects
generated by the azure-identity library and objects that implement the `get_token(self, *scopes)` method.
:keyword str queue_name: The path of specific Service Bus Queue the client connects to.
:keyword str topic_name: The path of specific Service Bus Topic which contains the Subscription
the client connects to.
:keyword str subscription_name: The path of specific Service Bus Subscription under the
specified Topic the client connects to.
:keyword mode: The mode with which messages will be retrieved from the entity. The two options
are PeekLock and ReceiveAndDelete. Messages received with PeekLock must be settled within a given
lock period before they will be removed from the queue. Messages received with ReceiveAndDelete
will be immediately removed from the queue, and cannot be subsequently rejected or re-received if
the client fails to process the message. The default mode is PeekLock.
:paramtype mode: ~azure.servicebus.ReceiveSettleMode
:keyword int prefetch: The maximum number of messages to cache with each request to the service.
The default value is 0 meaning messages will be received from the service and processed
one at a time. Increasing this value will improve message throughput performance but increase
the change that messages will expire while they are cached if they're not processed fast enough.
:keyword float idle_timeout: The timeout in seconds between received messages after which the receiver will
automatically shutdown. The default value is 0, meaning no timeout.
:keyword bool logging_enable: Whether to output network trace logs to the logger. Default is `False`.
:keyword int retry_total: The total number of attempts to redo a failed operation when an error occurs.
Default value is 3.
:keyword transport_type: The type of transport protocol that will be used for communicating with
the Service Bus service. Default is `TransportType.Amqp`.
:paramtype transport_type: ~azure.servicebus.TransportType
:keyword dict http_proxy: HTTP proxy settings. This must be a dictionary with the following
keys: `'proxy_hostname'` (str value) and `'proxy_port'` (int value).
Additionally the following keys may also be present: `'username', 'password'`.
.. admonition:: Example:
.. literalinclude:: ../samples/async_samples/sample_code_servicebus_async.py
:start-after: [START create_servicebus_receiver_async]
:end-before: [END create_servicebus_receiver_async]
:language: python
:dedent: 4
:caption: Create a new instance of the ServiceBusReceiver.
"""
def __init__(
self,
fully_qualified_namespace: str,
credential: "TokenCredential",
**kwargs: Any
):
if kwargs.get("entity_name"):
super(ServiceBusReceiver, self).__init__(
fully_qualified_namespace=fully_qualified_namespace,
credential=credential,
**kwargs
)
else:
queue_name = kwargs.get("queue_name")
topic_name = kwargs.get("topic_name")
subscription_name = kwargs.get("subscription_name")
if queue_name and topic_name:
raise ValueError("Queue/Topic name can not be specified simultaneously.")
if not (queue_name or topic_name):
raise ValueError("Queue/Topic name is missing. Please specify queue_name/topic_name.")
if topic_name and not subscription_name:
raise ValueError("Subscription name is missing for the topic. Please specify subscription_name.")
entity_name = queue_name or topic_name
super(ServiceBusReceiver, self).__init__(
fully_qualified_namespace=fully_qualified_namespace,
credential=credential,
entity_name=str(entity_name),
**kwargs
)
self._populate_attributes(**kwargs)
async def __anext__(self):
self._check_live()
while True:
try:
return await self._do_retryable_operation(self._iter_next)
except StopAsyncIteration:
await self.close()
raise
async def _iter_next(self):
await self._open()
uamqp_message = await self._message_iter.__anext__()
message = self._build_message(uamqp_message, ReceivedMessage)
return message
def _create_handler(self, auth):
self._handler = ReceiveClientAsync(
self._get_source(),
auth=auth,
debug=self._config.logging_enable,
properties=self._properties,
error_policy=self._error_policy,
client_name=self._name,
on_attach=self._on_attach,
auto_complete=False,
encoding=self._config.encoding,
receive_settle_mode=self._mode.value,
send_settle_mode=SenderSettleMode.Settled if self._mode == ReceiveSettleMode.ReceiveAndDelete else None,
timeout=self._idle_timeout * 1000 if self._idle_timeout else 0,
prefetch=self._prefetch
)
async def _open(self):
if self._running:
return
if self._handler:
await self._handler.close_async()
auth = None if self._connection else (await create_authentication(self))
self._create_handler(auth)
try:
await self._handler.open_async(connection=self._connection)
self._message_iter = self._handler.receive_messages_iter_async() # pylint: disable=attribute-defined-outside-init
while not await self._handler.client_ready_async():
await asyncio.sleep(0.05)
self._running = True
except:
await self.close()
raise
async def _receive(self, max_batch_size=None, timeout=None):
await self._open()
max_batch_size = max_batch_size or self._handler._prefetch # pylint: disable=protected-access
timeout_ms = 1000 * (timeout or self._idle_timeout) if (timeout or self._idle_timeout) else 0
batch = await self._handler.receive_message_batch_async(
max_batch_size=max_batch_size,
timeout=timeout_ms
)
return [self._build_message(message, ReceivedMessage) for message in batch]
async def _settle_message(self, settlement, lock_tokens, dead_letter_details=None):
message = {
MGMT_REQUEST_DISPOSITION_STATUS: settlement,
MGMT_REQUEST_LOCK_TOKENS: types.AMQPArray(lock_tokens)}
self._populate_message_properties(message)
if dead_letter_details:
message.update(dead_letter_details)
return await self._mgmt_request_response_with_retry(
REQUEST_RESPONSE_UPDATE_DISPOSTION_OPERATION,
message,
mgmt_handlers.default
)
async def _renew_locks(self, *lock_tokens):
message = {MGMT_REQUEST_LOCK_TOKENS: types.AMQPArray(lock_tokens)}
return await self._mgmt_request_response_with_retry(
REQUEST_RESPONSE_RENEWLOCK_OPERATION,
message,
mgmt_handlers.lock_renew_op
)
[docs] @classmethod
def from_connection_string(
cls,
conn_str: str,
**kwargs: Any
) -> "ServiceBusReceiver":
"""Create a ServiceBusReceiver from a connection string.
:param conn_str: The connection string of a Service Bus.
:keyword str queue_name: The path of specific Service Bus Queue the client connects to.
:keyword str topic_name: The path of specific Service Bus Topic which contains the Subscription
the client connects to.
:keyword str subscription_name: The path of specific Service Bus Subscription under the
specified Topic the client connects to.
:keyword mode: The mode with which messages will be retrieved from the entity. The two options
are PeekLock and ReceiveAndDelete. Messages received with PeekLock must be settled within a given
lock period before they will be removed from the queue. Messages received with ReceiveAndDelete
will be immediately removed from the queue, and cannot be subsequently rejected or re-received if
the client fails to process the message. The default mode is PeekLock.
:paramtype mode: ~azure.servicebus.ReceiveSettleMode
:keyword int prefetch: The maximum number of messages to cache with each request to the service.
The default value is 0, meaning messages will be received from the service and processed
one at a time. Increasing this value will improve message throughput performance but increase
the change that messages will expire while they are cached if they're not processed fast enough.
:keyword float idle_timeout: The timeout in seconds between received messages after which the receiver will
automatically shutdown. The default value is 0, meaning no timeout.
:keyword bool logging_enable: Whether to output network trace logs to the logger. Default is `False`.
:keyword int retry_total: The total number of attempts to redo a failed operation when an error occurs.
Default value is 3.
:keyword transport_type: The type of transport protocol that will be used for communicating with
the Service Bus service. Default is `TransportType.Amqp`.
:paramtype transport_type: ~azure.servicebus.TransportType
:keyword dict http_proxy: HTTP proxy settings. This must be a dictionary with the following
keys: `'proxy_hostname'` (str value) and `'proxy_port'` (int value).
Additionally the following keys may also be present: `'username', 'password'`.
:rtype: ~azure.servicebus.aio.ServiceBusReceiver
.. admonition:: Example:
.. literalinclude:: ../samples/async_samples/sample_code_servicebus_async.py
:start-after: [START create_servicebus_receiver_from_conn_str_async]
:end-before: [END create_servicebus_receiver_from_conn_str_async]
:language: python
:dedent: 4
:caption: Create a new instance of the ServiceBusReceiver from connection string.
"""
constructor_args = _convert_connection_string_to_kwargs(
conn_str,
ServiceBusSharedKeyCredential,
**kwargs
)
if kwargs.get("queue_name") and kwargs.get("subscription_name"):
raise ValueError("Queue entity does not have subscription.")
if kwargs.get("topic_name") and not kwargs.get("subscription_name"):
raise ValueError("Subscription name is missing for the topic. Please specify subscription_name.")
return cls(**constructor_args)
[docs] async def receive(self, max_batch_size=None, max_wait_time=None):
# type: (int, float) -> List[ReceivedMessage]
"""Receive a batch of messages at once.
This approach it optimal if you wish to process multiple messages simultaneously. Note that the
number of messages retrieved in a single batch will be dependent on
whether `prefetch` was set for the receiver. This call will prioritize returning
quickly over meeting a specified batch size, and so will return as soon as at least
one message is received and there is a gap in incoming messages regardless
of the specified batch size.
:param int max_batch_size: Maximum number of messages in the batch. Actual number
returned will depend on prefetch size and incoming stream rate.
:param float max_wait_time: Maximum time to wait in seconds for the first message to arrive.
If no messages arrive, and no timeout is specified, this call will not return
until the connection is closed. If specified, an no messages arrive within the
timeout period, an empty list will be returned.
:rtype: list[~azure.servicebus.aio.ReceivedMessage]
.. admonition:: Example:
.. literalinclude:: ../samples/async_samples/sample_code_servicebus_async.py
:start-after: [START receive_async]
:end-before: [END receive_async]
:language: python
:dedent: 4
:caption: Receive messages from ServiceBus.
"""
self._check_live()
if max_batch_size and self._prefetch < max_batch_size:
raise ValueError("max_batch_size should be less than or equal to prefetch of ServiceBusReceiver, or you "
"could set a larger prefetch value when you're constructing the ServiceBusReceiver.")
return await self._do_retryable_operation(
self._receive,
max_batch_size=max_batch_size,
timeout=max_wait_time,
require_timeout=True
)
[docs] async def receive_deferred_messages(self, sequence_numbers):
# type: (List[int]) -> List[ReceivedMessage]
"""Receive messages that have previously been deferred.
When receiving deferred messages from a partitioned entity, all of the supplied
sequence numbers must be messages from the same partition.
:param list[int] sequence_numbers: A list of the sequence numbers of messages that have been
deferred.
:rtype: list[~azure.servicebus.aio.ReceivedMessage]
.. admonition:: Example:
.. literalinclude:: ../samples/async_samples/sample_code_servicebus_async.py
:start-after: [START receive_defer_async]
:end-before: [END receive_defer_async]
:language: python
:dedent: 4
:caption: Receive deferred messages from ServiceBus.
"""
self._check_live()
if not sequence_numbers:
raise ValueError("At least one sequence number must be specified.")
await self._open()
try:
receive_mode = self._mode.value.value
except AttributeError:
receive_mode = int(self._mode)
message = {
MGMT_REQUEST_SEQUENCE_NUMBERS: types.AMQPArray([types.AMQPLong(s) for s in sequence_numbers]),
MGMT_REQUEST_RECEIVER_SETTLE_MODE: types.AMQPuInt(receive_mode)
}
self._populate_message_properties(message)
handler = functools.partial(mgmt_handlers.deferred_message_op, mode=self._mode, message_type=ReceivedMessage)
messages = await self._mgmt_request_response_with_retry(
REQUEST_RESPONSE_RECEIVE_BY_SEQUENCE_NUMBER,
message,
handler
)
for m in messages:
m._receiver = self # pylint: disable=protected-access
return messages
[docs] async def peek(self, message_count=1, sequence_number=0):
"""Browse messages currently pending in the queue.
Peeked messages are not removed from queue, nor are they locked. They cannot be completed,
deferred or dead-lettered.
:param int message_count: The maximum number of messages to try and peek. The default
value is 1.
:param int sequence_number: A message sequence number from which to start browsing messages.
:rtype: list[~azure.servicebus.PeekMessage]
.. admonition:: Example:
.. literalinclude:: ../samples/async_samples/sample_code_servicebus_async.py
:start-after: [START peek_messages_async]
:end-before: [END peek_messages_async]
:language: python
:dedent: 4
:caption: Peek messages in the queue.
"""
self._check_live()
if not sequence_number:
sequence_number = self._last_received_sequenced_number or 1
if int(message_count) < 1:
raise ValueError("count must be 1 or greater.")
if int(sequence_number) < 1:
raise ValueError("start_from must be 1 or greater.")
await self._open()
message = {
MGMT_REQUEST_FROM_SEQUENCE_NUMBER: types.AMQPLong(sequence_number),
MGMT_REQUEST_MESSAGE_COUNT: message_count
}
self._populate_message_properties(message)
return await self._mgmt_request_response_with_retry(
REQUEST_RESPONSE_PEEK_OPERATION,
message,
mgmt_handlers.peek_op
)