If there are few data power boxes (say 5) and we have logging common logging machanism where all the errors is logged in same place. While logging errors we need to log errors along with datapower box name (say xi52xxxx) so that it will be easy to identify in which box we have errors/which box is behaving abnormally.
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I realize var://service/system/ident or serviceVars.systemIdent nodeset which contains e.g. configured system "name" is what you look for (https://www.ibm.com/support/knowledgecenter/en/SS9H2Y_7.7.0/com.ibm.dp.doc/var-service-system-ident_reference.html).
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I've been thinking var://service/system/status could have been your friend, but playing with it e.g. as per https://www.ibm.com/developerworks/community/blogs/HermannSW/entry/var_service_system_status_xsl51 I realize DP doesn't expose the "show system" status provider through SOMA (XML Mgmt / REST Mgmt) (as in contrast to e.g. DateTimeStatus or FirmwareStatus), but only wraps the SystemSettings config/modify options in CLI and GUI.
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However is this really needed to be set in each custom log message?
I'm thinking most of your log traffic will be sent using a DP log target of type syslog if you send to Splunk, right? Note that for each such log target you typically set the Local Identifier which determines what identifier the sending system uses.
So the question is do you want to set the identifier statically or dynamically (while operating one permanent set of configuration). I think it is static, so you set it in the log target, which is a DP config object. These get configured on e.g. config import, and so are ideally adjusted using e.g. Deployment Policies.
I hope this helps a bit.