slimta.cloudstorage

Package containing a module for the different cloud service providers along with any necessary helper modules.

exception slimta.cloudstorage.CloudStorageError([*args[, **kwargs]])

Bases: slimta.queue.QueueError

Base exception for all exceptions in the package.

class slimta.cloudstorage.CloudStorage(object_store[, message_queue=None])

Bases: slimta.queue.QueueStorage

This class implements a QueueStorage backend that uses cloud services to store messages. It coordinates the storage of messages and metadata (using S3) with the optional message queue mechanisms (using SQS) that can alert other slimta processes that a new message is available in the object store.

Parameters

  • object_store – The object used as the backend for storing message contents and metadata in the cloud. Currently this can be an instance of SimpleStorageService.

  • message_queue – The optional object used as the backend for alerting other processes that a new message is in the object store. Currently this can be an instance of SimpleQueueService.

write(envelope, timestamp)

Writes the given envelope to storage, along with the timestamp of its next delivery attempt. The number of delivery attempts asociated with the message should start at zero.

Parameters

  • envelope – Envelope object to write.

  • timestamp – Timestamp of message’s next delivery attempt.

Returns

Unique identifier string for the message in queue.

Raises

QueueError

set_timestamp(id, timestamp)

Sets a new timestamp for the message’s next delivery attempt.

Parameters

  • id – The unique identifier string for the message.

  • timestamp – The new delivery attempt timestamp.

Raises

QueueError

increment_attempts(id)

Increments the number of delivery attempts associated with the message.

Parameters

id – The unique identifier string for the message.

Returns

The new number of message delivery attempts.

Raises

QueueError

set_recipients_delivered(id, rcpt_indexes)

New in version 1.1.0.

Marks the given recipients from the original envelope as already-delivered, meaning they will be skipped by future relay attempts.

Parameters

  • id – The unique identifier string for the message.

  • rcpt_indexes – List of indexes in the original envelope’s recipients list to mark as delivered.

Raises

QueueError

load()

Loads all queued messages from the storage engine, such that the Queue can be aware of all upcoming delivery attempts.

Returns

Iterable that yields tuples of the form (timestamp, id) for each message in storage.

Raises

QueueError

get(id)

Returns the Envelope object associated with the given unique identifier sring.

The envelope’s recipients should not include those marked as delivered by set_recipients_delivered().

Parameters

id – The unique identifier string of the requested Envelope.

Returns

Tuple with the Envelope object and number of attempts.

Raises

KeyError, QueueError

remove(id)

Removes the Envelope associated with the given unique identifier string from queue storage. This is typically used when the message has been successfully delivered or delivery has permanently failed.

Parameters

id – The unique identifier string of the Envelope to remove.

Raises

QueueError

wait()

If messages are not being delivered from the same process in which they were received, the storage mechanism needs a way to wait until it is notified that a new message has been stored.

Returns

An iterable or generator producing tuples with the timestamp and unique identifier string of a new message in storage. When the iterable or generator is exhausted, wait() is simply called again.

Sub-Modules: