Value Functions
Overview
Value functions provide access to metric values received in the same series command.
series e:entity-1 m:metric-1=3.0 m:metric-2=20.0 m:metric-3=91.5
In the example above, a metric-1 window can access the remaining values in the command using value('metric-2') and value('metric-3') functions.
value > 5 && value('metric-2') > 10
Compared to the db_last function, the value() function retrieves metric values from the underlying command, without querying the database.
Related functions:
value
value(string metric [, number default_value]) number
Retrieves the value for the specified metric received in the same series command or parsed from the same row in the CSV file.
Example:
value > 1.5 && value('temperature') > 50
series e:sensor01 m:pressure=3.5 m:temperature=80
If the default is specified and the requested metric is not present in the command, the function returns the default value without raising a processing error.
value > 10 && value('pressure', 0.0) > 50
Assuming the rule is created for the pressure metric, the above condition resolves fields and evaluates to true.
// returns true
3.5 > 1.5 && 80 > 50
If the value of the pressure metric is less than 50 the condition evaluates to false.
series e:sensor01 m:pressure=3.5 m:temperature=33
// returns false
3.5 > 1.5 && 33 > 50