meta

The meta library provides information about the running ruleset. The following are available (notice that these are values, not functions):

  • meta:eci - the event channel identifier on which the current event was raised

  • meta:host - the public DNS name of the machine running the engine, including port number. Does not include the trailing "/". ex. http://localhost:8080 You may configure this value when starting your pico engine. See the developer tips page to see why and how.

  • meta:inEvent - Boolean value true if the engine is evaluating an event for this pico, false otherwise

  • meta:inQuery - Boolean value true if the engine is evaluating a query for this pico, false otherwise

  • meta:picoId - the ID of the currently running pico

  • meta:rid - the ruleset ID of the currently running ruleset

  • meta:ruleName - the name of the rule currently being evaluated

  • meta:rulesetURI - the URL from which the currently running ruleset was registered/installed

  • meta:txnId - the transaction ID for the current evaluation. This is mostly useful for debugging or as a correlation identifier

  • meta:rulesetConfig - the configuration Map given when the ruleset was installed in the pico

Wrangler and Meta

Some of the data in the meta block is also available through Wrangler:

wrangler:rulesetMeta(meta:rid){"author"} - the author from the meta section of the current ruleset

wrangler:rulesetMeta(meta:rid){"description"} - the description from the meta section of the current ruleset

wrangler:rulesetMeta(meta:rid){"name"} - the name from the meta section of the current ruleset

 

Not Supported
The following are not yet available:

  • meta:callingRID() - returns the RID of the calling ruleset if running in a module, or the current ruleset ID otherwise.

  • meta:callingVersion() - returns the version of the calling ruleset if running in a module, or the current ruleset version otherwise.

  • meta:errorCount() - returns the number of errors for current rule execution. Reset to 0 for each new rule execution.

  • meta:inModule() - returns a Boolean value indicating whether the current code is running in a module.

  • meta:moduleRID() - returns the RID of the module if running in a module, or the current ruleset ID otherwise.

  • meta:moduleVersion() - returns the version of the module if running in a module, or the current ruleset version otherwise.

  • meta:version() - returns the version of the currently running ruleset.

Note, in the case of meta:moduleRID(), meta:moduleVersion(), and meta:inModule(), care has been taken to preserve static behavior. So, for example, if you do the following, you should get the result you expect based on static function semantics:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 ruleset my_module {   ... global { myRid = function() { meta:rid } } }   ruleset use_my_module { meta { use module my_module } global { x = my_module:myRid(); // x = my_module, not use_my_module } }