This feature prevents applications from sending guaranteed messages that exceed the maximum message size configured in the PubSub+ Event Broker to prevent erroneous states in the API and save on bandwidth usage.

The API now supports TLS 1.3. This feature requires an Event Broker that also supports TLS 1.3.

The Solace Python API now supports Alpine Linux, allowing developers to build and deploy applications using the API on this platform.

The Messaging API for Python now supports message NACK.

The Python API now supports development and deployment on platforms that use ARM processors.

The Python API now supports end-to-end payload compression. Sessions can now be optionally configured to compress the payload of every message on a message-by-message basis. While enabling this feature severely impacts API performance for small messages and significantly impacts API performance for larger messages, it has a positive impact on Event Broker performance and message-spool usage.

Enables adding and extracting tracing metadata attached to events published and received by the Solace Python API.

The Python API now supports development and deployment on platforms that use MAC M-series processors.

We have simplified the API license text and clarified that distributing works containing the Solace APIs is allowed.

This enhancement adds PubSub+ Cache support in the Python API. This allows applications using the Python API to interact with PubSub+ Cache.

This enhancement adds support for Partitioned Queues to the API. Partitioned Queues expand PubSub+ to provide deterministic, ordered, and non-exclusive message delivery for customers to scale the number of consumers when publishing ordered datasets. The ordered datasets are keyed to ensure all events in the dataset are sent to the same consumer without mis-ordering events. This feature requires PubSub+ Event Broker support. Support for this feature is planned to be introduced to the Event Broker around April 30, 2023 in release 10.4.0.

This feature allows an application to automatically update the OAuth token without the need to create a new session the next time the API tries to reconnect.

This feature adds support for Transacted Sessions in the API. This will enable client applications to group multiple message send and/or receive operations together in single, atomic units known as local transactions. Each transacted Session can support a single series of transactions.

The API will be able to handle unsolicited service interruption for receiving or publishing situations where there are permanent or long ongoing network interruptions. The API will now handle these scenarios more gracefully by notifying the application when this occurs.

OAuth / OpenID Connect has been added as a method of authenticating and authorizing clients connecting to the PubSub+ Event Broker using the SMF protocol. Clients using Solace APIs will be able to present a token as a credential during client login. This enables clients to integrate with modern identity and access management systems.

Changed tagging procedure to properly package for PyPi.

Added Kerberos as a client authentication scheme.

Added "drop latest" and "drop oldest" strategies to the Direct Receiver Backpressure buffer. This gives more options for what to do with messages received when the message buffer fills.

Applications can now replay messages following the message-ID of the last message which they successfully processed. The feature uses "replication group message ID", which uniquely identifies messages within an HA group and Replication/DR group of brokers. The broker includes this ID in all guaranteed messages it delivers to the consumer. Consuming applications can extract and save this ID along with the message payload, and then use it later to initiate a replay. This is a more "fine-grained" way to start a replay than from date-and-time, and is ideal in cases where the last message-ID successfully processed is known by the application (e.g. recovery from a database crash). To initiate replay after message-ID from an application, both the PubSub+ Event Broker and PubSub+ Event API must be upgraded. The following versions introduce support for replay after message-ID: Broker: • PubSub+ Event Broker version 9.9.0 Messaging API: • PubSub+ Messaging API for Java(JCSMP) version 10.11.0 • PubSub+ Messaging API for Java version 1.0.0 • PubSub+ Messaging API for C version 7.18.0 • PubSub+ Messaging API for JavaRTO version 7.18.0 • PubSub+ Messaging API for .NET version 10.12.0 • PubSub+ Messaging API for JavaScript version 10.7.0 • PubSub+ Messaging API for Python version 1.2.0

The API now supports the request/reply messaging pattern with synchronous and asynchronous functions.

The API can now consume messages published with SDTMap and SDTStream and publish messages setting SDTMap and SDTStream.

The replay of messages from the replay log is now possible via the API. This is for temporal replay only. Replay from the replication group ID will be included in a future release.

Messages published with other Solace APIs populating XMLContent are now consumable by this API.

This is the initial release of the PubSub+ Messaging API for Python. Solace created this API to support the rich Python ecosystem and help developers create applications in Python that take advantage of the broad features of PubSub+. This version contains a feature set that allows for common messaging patterns like publish/subscribe using Direct Messaging and Guaranteed Messaging. This API provides support for all deployments of PubSub+ across software, appliance, and cloud. Future versions of the Python API will introduce more features as Solace builds out the roadmap for this API. The Python API 1.0.0 supports: • Connection management to PubSub+ event brokers • Addition and removal of topic subscriptions • Sending and receiving Direct and Guaranteed Messages • Message compression • Use of Selectors The Python API 1.0.0 does not support the following features: • Request/Reply message exchange pattern • Message Replay • Structured data types that allow interoperability between various architectures and programming languages • PubSub+ Cache Client API support • Session Transactions • XA Transactions • Queue browsing • Kerberos authentication

The API uses deprecated method datetime.utcnow().

The PublishReceipt method is_persisted() always returns true, whether or not the message was persisted by the Solace Broker. workaround: applications may check that exception is NONE to be sure the message was successfully published and persisted.

PublishReceipt.message returns the wrong object. It incorrectly returns _SolaceMessage instead of OutboundMessage.

In rare cases, Python applications that use guaranteed messaging with significant session creation may experience an increase in memory usage over time.

When a persistent publisher terminates it may block for 10 minutes before receiving pending publisher receipts.

When the endpoint is configured with max-delivered-unacked-msgs-per-flow less than 255, the Messaging API performance may be degraded. This is particularly noticeable when max-delivered-unacked-msgs-per-flow is 1, as acknowledgements will only be sent once per second. Workaround: Messaging API for C: set SOLCLIENT_FLOW_PROP_MAX_UNACKED_MESSAGES equal to the value configured on the endpoint. Messaging API for .NET: set FlowProperties.MaxUnackedMessages equal to the value configured on the endpoint. Messaging API for Python and Go: No workaround is available.

Attempting to canonicalize very large messages on non-Linux platforms (1MB+) via print or other means that invoke __str__() may not complete. When this occurs, the MessagingService will become unresponsive.

After a service is disconnected, calling is_running(), is_terminating(), or is_terminated() may return the incorrect state for the Publisher or Receiver.

The default value for PERSISTENT_DMQ_ELIGIBLE should be 'true', to be consistent with other Solace Messaging APIs.

In rare cases, a persistent receiver may suddenly stop receiving messages. The receiver will not recover on its own and must be terminated.

The Class of Service feature is not supported in the Solace PubSub+ Messaging API for Python.

The Python API fails to automatically re-bind to endpoints after reconnecting.

The API has been updated to decode “400 Invalid Queue or Topic Endpoint Durability” broker response. For more information, see: C API .Net API JavaRTO API Go API Python API Javascript API JCSMP API JMS API

The C, .Net, JavaRTO, Go, and Python APIs no longer bundle OpenSSL libraries on Linux platforms. For all other platforms, the bundled OpenSSL libraries have been updated to OpenSSL 3.0. For more information, refer to the [Supported Environments|https://docs.solace.com/API/API-Developer-Guide/Supported-Environments.htm] page in our customer documentation.

The Python API now requires macOS 11(Big Sur) or newer.

Setting basic-username (via solace.messaging.authentication.scheme.basic.username) will no longer set the client username used for client-certificate authentication. Applications are now required to set client-certificate-username using solace.messaging.authentication.client-cert.username.

A large number of overlapping subscriptions in a single messaging service with a high rate of incoming matching messages from the broker may result in degraded performance.

Attempting to disconnect the messaging service while it is in connecting state will cause the Python API to ungracefully shut down.

RequestReplyMessagePublisher.terminate() waits until all Future objects created by RequestReplyMessagePublisher.publish() are complete. All Future objects created and returned by RequestReplyMessagePublisher.publish() must be completed before terminate() can finish. Even if terminate has a shorter or zero time, it will block until the outstanding Futures are complete after the time has elapsed. Workaround: The application may choose to implement its own executor to call publish_await_response() for asynchronous publish. This will return a failure, as expected, on terminate.

In rare cases, a transacted receiver may suddenly stop receiving messages. The transacted service will not recover and the process will need to be terminated.

Messaging metrics within the Python API may be slightly out of sync (delayed) compared to the actual number of messages sent and received.