[ARTEMIS-4200] Allow configuring link-stealing behavior for MQTT

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.29.0
• Assignee: Justin Bertram
• Reporter: Justin Bertram
• Created: 08/Mar/23 18:40
• Updated: 15/Jun/23 20:31
• Resolved: 03/May/23 18:13

Description

The MQTT specifications define a behavior often referred to as "link stealing." This means that whenever a new client connects with the same client ID as another existing client then the existing client's session will be closed and its network connection will be terminated.

In certain use-cases this behavior is not desired so it is configurable. The URL parameter allowLinkStealing can be configured on the MQTT acceptor to modify this behavior. By default allowLinkStealing is true. If it is set to false then whenever a new client connects with the same client ID as another existing client then the new client's session will be closed and its network connection will be terminated. In the case of MQTT 5 clients they will receive a disconnect reason code of 0x80 (i.e. "Unspecified error").