On SOW Message Expiration

AMPS provides a module to run an action when a message expires from a topic in the SOW.

The amps-action-on-sow-expire-message module monitors a topic for expirations. The action runs once for each message that expires in the matching topic. Notice, in particular, that this includes monitoring messages that expire from the queue, which are presented as SOW expirations to this module.

This action requires the following parameters. In addition to that, this module also accepts an optional parameter listed below:

Parameter	Description
Topic (required)	The name of the topic to monitor for messages. This parameter does not support regular expressions. The topic name must be either a SOW topic, a view, a conflated topic or a queue. There is no default for this parameter.
MessageType (required)	The message type of the topic to monitor for messages. There is no default for this parameter.
Reason	An optional comma-delimited string indicating the expiration reasons to monitor for. For example, setting this to time_limit,forced_expire will cause this action to be invoked only when the expiration reason includes one of time_limit or forced_expire. For more information on the allowed values and definitions, see the documentation for AMPS_REASON below.

The module adds the following variables to the AMPS context:

Variable	Description
AMPS_TOPIC	The topic of the message that expired.
AMPS_DATA	The current data of the message.
AMPS_DATA_LENGTH	The length of the current data of the message, in bytes.
AMPS_REASON	A comma-delimited string indicating one or more reason(s) the message was expired. This string contains one or more of the following values: time_limit - the expiration time for this message or topic has passed. forced_expire - this queue message was acknowledged with an expire option resulting in the message's immediate removal. max_cancels - this queue message was acknowledged with a cancel option and the number of cancels exceeded the queue's configured MaxCancels limit. max_deliveries - this queue message was not successfully acknowledged by a subscriber and the number of deliveries has exceeded the queue's MaxDeliveries limit.
AMPS_CORRELATION_ID	The correlation ID set on the publish command if one was set.