QueueClient class
Definition
A client to interact with a specific Queue.
QueueClient(account_url, queue_name, credential=None, **kwargs)
- Inheritance
-
builtins.objectazure.storage.queue._shared.base_client_async.AsyncStorageAccountHostsMixinQueueClientazure.storage.queue._shared.base_client.StorageAccountHostsMixinazure.storage.queue._queue_client.QueueClientQueueClient
Parameters
- account_url
- str
The URL to the storage account. In order to create a client given the full URI to the queue, use the <xref:azure.storage.queue.aio.from_queue_url> classmethod.
- queue_name
- str
The name of the queue.
- credential
The credentials with which to authenticate. This is optional if the account URL already has a SAS token. The value can be a SAS token string, an account shared access key, or an instance of a TokenCredentials class from azure.identity.
Examples
Create the queue client with url and credential.
token_auth_queue = QueueClient.from_queue_url(
queue_url=queue.url,
credential=sas_token
)
Create the queue client with a connection string.
from azure.storage.queue.aio import QueueClient
queue = QueueClient.from_connection_string(self.connection_string, "myqueue1")
Methods
| clear_messages |
Deletes all messages from the specified queue. |
| create_queue |
Creates a new queue in the storage account. If a queue with the same name already exists, the operation fails with a ResourceExistsError. |
| delete_message |
Deletes the specified message. Normally after a client retrieves a message with the receive messages operation, the client is expected to process and delete the message. To delete the message, you must have the message object itself, or two items of data: id and pop_receipt. The id is returned from the previous receive_messages operation. The pop_receipt is returned from the most recent <xref:azure.storage.queue.aio.receive_messages> or <xref:azure.storage.queue.aio.update_message> operation. In order for the delete_message operation to succeed, the pop_receipt specified on the request must match the pop_receipt returned from the <xref:azure.storage.queue.aio.receive_messages> or <xref:azure.storage.queue.aio.update_message> operation. |
| delete_queue |
Deletes the specified queue and any messages it contains. When a queue is successfully deleted, it is immediately marked for deletion and is no longer accessible to clients. The queue is later removed from the Queue service during garbage collection. Note that deleting a queue is likely to take at least 40 seconds to complete. If an operation is attempted against the queue while it was being deleted, an <xref:azure.storage.queue.aio.HttpResponseError> will be thrown. |
| get_queue_access_policy |
Returns details about any stored access policies specified on the queue that may be used with Shared Access Signatures. |
| get_queue_properties |
Returns all user-defined metadata for the specified queue. The data returned does not include the queue's list of messages. |
| peek_messages |
Retrieves one or more messages from the front of the queue, but does not alter the visibility of the message. Only messages that are visible may be retrieved. When a message is retrieved for the first time with a call to <xref:azure.storage.queue.aio.receive_messages>, its dequeue_count property is set to 1. If it is not deleted and is subsequently retrieved again, the dequeue_count property is incremented. The client may use this value to determine how many times a message has been retrieved. Note that a call to peek_messages does not increment the value of dequeue_count, but returns this value for the client to read. If the key-encryption-key or resolver field is set on the local service object, the messages will be decrypted before being returned. |
| receive_messages |
Removes one or more messages from the front of the queue. When a message is retrieved from the queue, the response includes the message content and a pop_receipt value, which is required to delete the message. The message is not automatically deleted from the queue, but after it has been retrieved, it is not visible to other clients for the time interval specified by the visibility_timeout parameter. If the key-encryption-key or resolver field is set on the local service object, the messages will be decrypted before being returned. |
| send_message |
Adds a new message to the back of the message queue. The visibility timeout specifies the time that the message will be invisible. After the timeout expires, the message will become visible. If a visibility timeout is not specified, the default value of 0 is used. The message time-to-live specifies how long a message will remain in the queue. The message will be deleted from the queue when the time-to-live period expires. If the key-encryption-key field is set on the local service object, this method will encrypt the content before uploading. |
| set_queue_access_policy |
Sets stored access policies for the queue that may be used with Shared Access Signatures. When you set permissions for a queue, the existing permissions are replaced. To update the queue's permissions, call get_queue_access_policy(**kwargs) to fetch all access policies associated with the queue, modify the access policy that you wish to change, and then call this function with the complete set of data to perform the update. When you establish a stored access policy on a queue, it may take up to 30 seconds to take effect. During this interval, a shared access signature that is associated with the stored access policy will throw an <xref:azure.storage.queue.aio.HttpResponseError> until the access policy becomes active. |
| set_queue_metadata |
Sets user-defined metadata on the specified queue. Metadata is associated with the queue as name-value pairs. |
| update_message |
Updates the visibility timeout of a message. You can also use this operation to update the contents of a message. This operation can be used to continually extend the invisibility of a queue message. This functionality can be useful if you want a worker role to "lease" a queue message. For example, if a worker role calls receive_messages(**kwargs) and recognizes that it needs more time to process a message, it can continually extend the message's invisibility until it is processed. If the worker role were to fail during processing, eventually the message would become visible again and another worker role could process it. If the key-encryption-key field is set on the local service object, this method will encrypt the content before uploading. |
clear_messages
Deletes all messages from the specified queue.
clear_messages(**kwargs)
Examples
Clears all messages.
await queue.clear_messages()
create_queue
Creates a new queue in the storage account.
If a queue with the same name already exists, the operation fails with a ResourceExistsError.
create_queue(**kwargs)
Returns
None or the result of cls(response)
Return type
Examples
Create a queue.
await queue.create_queue()
delete_message
Deletes the specified message.
Normally after a client retrieves a message with the receive messages operation, the client is expected to process and delete the message. To delete the message, you must have the message object itself, or two items of data: id and pop_receipt. The id is returned from the previous receive_messages operation. The pop_receipt is returned from the most recent <xref:azure.storage.queue.aio.receive_messages> or <xref:azure.storage.queue.aio.update_message> operation. In order for the delete_message operation to succeed, the pop_receipt specified on the request must match the pop_receipt returned from the <xref:azure.storage.queue.aio.receive_messages> or <xref:azure.storage.queue.aio.update_message> operation.
delete_message(message, pop_receipt=None, **kwargs)
Parameters
- pop_receipt
- str
A valid pop receipt value returned from an earlier call to the <xref:azure.storage.queue.aio.receive_messages> or <xref:azure.storage.queue.aio.update_message>.
Examples
Delete a message.
# Get the message at the front of the queue
messages = queue.receive_messages()
async for msg in messages:
# Delete the specified message
await queue.delete_message(msg)
delete_queue
Deletes the specified queue and any messages it contains.
When a queue is successfully deleted, it is immediately marked for deletion and is no longer accessible to clients. The queue is later removed from the Queue service during garbage collection.
Note that deleting a queue is likely to take at least 40 seconds to complete. If an operation is attempted against the queue while it was being deleted, an <xref:azure.storage.queue.aio.HttpResponseError> will be thrown.
delete_queue(**kwargs)
Return type
Examples
Delete a queue.
await queue.delete_queue()
get_queue_access_policy
Returns details about any stored access policies specified on the queue that may be used with Shared Access Signatures.
get_queue_access_policy(**kwargs)
Returns
A dictionary of access policies associated with the queue.
Return type
get_queue_properties
Returns all user-defined metadata for the specified queue.
The data returned does not include the queue's list of messages.
get_queue_properties(**kwargs)
Returns
User-defined metadata for the queue.
Return type
Examples
Get the properties on the queue.
properties = await queue.get_queue_properties()
peek_messages
Retrieves one or more messages from the front of the queue, but does not alter the visibility of the message.
Only messages that are visible may be retrieved. When a message is retrieved for the first time with a call to <xref:azure.storage.queue.aio.receive_messages>, its dequeue_count property is set to 1. If it is not deleted and is subsequently retrieved again, the dequeue_count property is incremented. The client may use this value to determine how many times a message has been retrieved. Note that a call to peek_messages does not increment the value of dequeue_count, but returns this value for the client to read.
If the key-encryption-key or resolver field is set on the local service object, the messages will be decrypted before being returned.
peek_messages(max_messages=None, **kwargs)
Parameters
- max_messages
- int
A nonzero integer value that specifies the number of messages to peek from the queue, up to a maximum of 32. By default, a single message is peeked from the queue with this operation.
Returns
A list of QueueMessage objects. Note that next_visible_on and pop_receipt will not be populated as peek does not pop the message and can only retrieve already visible messages.
Return type
Examples
Peek messages.
# Peek at one message at the front of the queue
msg = await queue.peek_messages()
# Peek at the last 5 messages
messages = await queue.peek_messages(max_messages=5)
# Print the last 5 messages
for message in messages:
print(message.content)
receive_messages
Removes one or more messages from the front of the queue.
When a message is retrieved from the queue, the response includes the message content and a pop_receipt value, which is required to delete the message. The message is not automatically deleted from the queue, but after it has been retrieved, it is not visible to other clients for the time interval specified by the visibility_timeout parameter.
If the key-encryption-key or resolver field is set on the local service object, the messages will be decrypted before being returned.
receive_messages(**kwargs)
Returns
Returns a message iterator of dict-like Message objects.
Return type
Examples
Receive messages from the queue.
# Receive messages one-by-one
messages = queue.receive_messages()
async for msg in messages:
print(msg.content)
# Receive messages by batch
messages = queue.receive_messages(messages_per_page=5)
async for msg_batch in messages.by_page():
for msg in msg_batch:
print(msg.content)
await queue.delete_message(msg)
send_message
Adds a new message to the back of the message queue.
The visibility timeout specifies the time that the message will be invisible. After the timeout expires, the message will become visible. If a visibility timeout is not specified, the default value of 0 is used.
The message time-to-live specifies how long a message will remain in the queue. The message will be deleted from the queue when the time-to-live period expires.
If the key-encryption-key field is set on the local service object, this method will encrypt the content before uploading.
send_message(content, **kwargs)
Parameters
- content
- obj
Message content. Allowed type is determined by the encode_function set on the service. Default is str. The encoded message can be up to 64KB in size.
Returns
A QueueMessage object. This object is also populated with the content although it is not returned from the service.
Return type
Examples
Send messages.
await asyncio.gather(
queue.send_message(u"message1"),
queue.send_message(u"message2", visibility_timeout=30), # wait 30s before becoming visible
queue.send_message(u"message3"),
queue.send_message(u"message4"),
queue.send_message(u"message5")
)
set_queue_access_policy
Sets stored access policies for the queue that may be used with Shared Access Signatures.
When you set permissions for a queue, the existing permissions are replaced. To update the queue's permissions, call get_queue_access_policy(**kwargs) to fetch all access policies associated with the queue, modify the access policy that you wish to change, and then call this function with the complete set of data to perform the update.
When you establish a stored access policy on a queue, it may take up to 30 seconds to take effect. During this interval, a shared access signature that is associated with the stored access policy will throw an <xref:azure.storage.queue.aio.HttpResponseError> until the access policy becomes active.
set_queue_access_policy(signed_identifiers, **kwargs)
Parameters
- signed_identifiers
- dict(str, AccessPolicy)
SignedIdentifier access policies to associate with the queue. This may contain up to 5 elements. An empty dict will clear the access policies set on the service.
Examples
Set an access policy on the queue.
# Create an access policy
from azure.storage.queue import AccessPolicy, QueueSasPermissions
access_policy = AccessPolicy()
access_policy.start = datetime.utcnow() - timedelta(hours=1)
access_policy.expiry = datetime.utcnow() + timedelta(hours=1)
access_policy.permission = QueueSasPermissions(read=True)
identifiers = {'my-access-policy-id': access_policy}
# Set the access policy
await queue.set_queue_access_policy(identifiers)
set_queue_metadata
Sets user-defined metadata on the specified queue.
Metadata is associated with the queue as name-value pairs.
set_queue_metadata(metadata=None, **kwargs)
Parameters
- metadata
- dict(str, str)
A dict containing name-value pairs to associate with the queue as metadata.
Examples
Set metadata on the queue.
metadata = {'foo': 'val1', 'bar': 'val2', 'baz': 'val3'}
await queue.set_queue_metadata(metadata=metadata)
update_message
Updates the visibility timeout of a message. You can also use this operation to update the contents of a message.
This operation can be used to continually extend the invisibility of a queue message. This functionality can be useful if you want a worker role to "lease" a queue message. For example, if a worker role calls receive_messages(**kwargs) and recognizes that it needs more time to process a message, it can continually extend the message's invisibility until it is processed. If the worker role were to fail during processing, eventually the message would become visible again and another worker role could process it.
If the key-encryption-key field is set on the local service object, this method will encrypt the content before uploading.
update_message(message, pop_receipt=None, content=None, **kwargs)
Parameters
- pop_receipt
- str
A valid pop receipt value returned from an earlier call to the receive_messages(**kwargs) or update_message(message, pop_receipt=None, content=None, **kwargs) operation.
- content
- obj
Message content. Allowed type is determined by the encode_function set on the service. Default is str.
Returns
A QueueMessage object. For convenience, this object is also populated with the content, although it is not returned by the service.
Return type
Examples
Update a message.
# Send a message
await queue.send_message(u"update me")
# Receive the message
messages = queue.receive_messages()
# Update the message
async for message in messages:
message = await queue.update_message(
message,
visibility_timeout=0,
content=u"updated")