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AMQ Clients 2.2 Release Notes

Red Hat AMQ 7.2

Release Notes for Red Hat AMQ Clients


These release notes contain the latest information about new features, enhancements, fixes, and issues contained in the AMQ Clients 2.2 release.

Chapter 1. Features

  • A new library for using AMQ with the Spring framework, AMQ Spring Boot Starter, is now available.
  • AMQ JMS can now optionally use native OpenSSL libraries for improved SSL/TLS performance.
  • This release improves the overall performance of AMQ JMS.

Chapter 2. Enhancements

2.1. AMQ C++

  • ENTMQCL-727 - Add a thread-safe wake operation

    The client library now provides a wake() method on connection and a new on_connection_wake() event. These serve as thread-handling primitives for use in more advanced multithreaded programs.

Chapter 3. Resolved issues

3.1. AMQ C++, AMQ Python, AMQ Ruby

  • ENTMQCL-943 - Normalize encoding of AMQP "multiple" fields

    In earlier releases of the product, the encoding of AMQP fields such as source and target capabilities was incompatible with some AMQP implementations.

    In this release, the encoding is normalized for improved interoperability.

3.2. AMQ C++

  • ENTMQCL-693 - Cannot receive message properties with null values

    In earlier releases of the product, the client library threw a conversion_error if a null value was decoded into a proton::scalar. This occurred when decoding application properties that contained null values.

    In this release, the library accepts null values in message properties.

3.3. AMQ JMS

  • ENTMQCL-923 - Stop further reconnection attempts after an unrecoverable authentication error

    In earlier releases of the product, a client library configured to reconnect continued to attempt new connections after unrecoverable SASL errors such as invalid user credentials.

    In this release, the library stops the reconnection process after an unrecoverable authentication error.

3.4. AMQ .NET

  • ENTMQCL-903 - Incorrect default message priority

    In earlier releases of the product, the client library reported the priority of a message as 0 if it was not explicitly set. The AMQP specification requires the default be 4.

    In this release, the library returns the correct default priority.

  • ENTMQCL-874 - Cannot reuse TCP socket on Unix

    In previous releases of the product, the client library failed when attempting to reuse a TCP socket after it was recently closed.

    In this release, the library can reuse recently closed sockets without error.

Chapter 4. Known issues

4.1. AMQ Python

  • ENTMQCL-483 - Selectors with backslashes are invalid in non-Unicode strings

    The Selector option on Container.create_receiver() accepts a string. If the string is not supplied as Unicode (in Python 2, u"somestring"), any elements escaped with backslashes might not be processed correctly.

    Workaround: Users of Python 2 should use an explicit Unicode string in filter declarations to avoid the problem.

  • ENTMQCL-546 - Transactions introduce unexpected link events

    Starting a transaction internally opens a sending link for controlling the transaction. This special link can trigger extra application events.

    Workaround: Code using transactions should ensure link handler functions are processing the link they expect.

4.2. AMQ .NET

  • ENTMQCL-794 - Transactions do not work with .NET Core

    Rolling back transactions when using AMQ .NET on .NET Core is not working as expected.

    Workaround: Use .NET Framework 4.5 instead of .NET Core if you require transactions.

Chapter 5. Important notes

5.1. AMQ C++

  • Unsettled interfaces

    The AMQ C++ messaging API includes classes and methods that are not yet proven and can change in future releases. Be aware that use of these interfaces might require changes to your application code in the future.

    These interfaces are marked Unsettled API in the API reference. They include the interfaces in the proton::codec and proton::io namespaces and the following interfaces in the proton namespace.

    • listen_handler
    • reconnect_options
    • ssl_certificate, ssl_client_options, and ssl_server_options
    • work_queue and work
    • The on_connection_wake method on messaging_handler
    • The wake method on connection
    • The on_sender_drain_start and on_sender_drain_finish methods on messaging_handler
    • The draining and return_credit methods on sender
    • The draining and drain methods on receiver

    API elements present in header files but not yet documented are considered unsettled and are subject to change.

  • Deprecated interfaces

    Interfaces marked Deprecated in the API reference are scheduled for removal in a future release.

    This release deprecates the following interfaces in the proton namespace.

    • void_function0 - Use the work class or C++11 lambdas instead.
    • default_container - Use the container class instead.
    • url and url_error - Use a third-party URL library instead.

5.2. Preferred clients

In general, AMQ clients that support the AMQP 1.0 standard are preferred for new application development. However, the following exceptions apply:

  • If your implementation requires distributed transactions, use the AMQ Core Protocol JMS client.
  • If you require MQTT or STOMP in your domain (for IoT applications, for instance), use community-supported MQTT or STOMP clients.

The considerations above do not necessarily apply if you are already using:

  • The AMQ OpenWire JMS client (the JMS implementation previously provided in A-MQ 6)
  • The AMQ Core Protocol JMS client (the JMS implementation previously provided with HornetQ)

5.3. Legacy clients

  • Deprecation of the CMS and NMS APIs

    The ActiveMQ CMS and NMS messaging APIs are deprecated in AMQ 7. It is recommended that users of the CMS API migrate to AMQ C++, and users of the NMS API migrate to AMQ .NET. The CMS and NMS APIs might have reduced functionality in AMQ 7.

  • The Core API is unsupported

    The Artemis Core API client is not supported. This client is distinct from the AMQ Core Protocol JMS client, which is supported.

5.4. Upstream versions

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