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 raisedmeta: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 valuetrue
if the engine is evaluating an event for this pico,false
otherwisemeta:inQuery
- Boolean valuetrue
if the engine is evaluating a query for this pico,false
otherwisemeta:picoId
- the ID of the currently running picometa:rid -
the ruleset ID of the currently running rulesetmeta:ruleName
- the name of the rule currently being evaluatedmeta:rulesetURI
- the URL from which the currently running ruleset was registered/installedmeta:txnId
- the transaction ID for the current evaluation. This is mostly useful for debugging or as a correlation identifiermeta: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:
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
}
}
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