Rule Syntax

require 'openhab'

rule 'name' do |<rule>|
   <zero or more triggers>
   <zero or more execution blocks>
   <zero or more guards>
end

All of the properties that are available to the rule resource are

Property	Type	Last/Multiple	Options	Default	Description	Examples
description	String	Single			Set the rule description
tags	String or Array of String or Semantics class	Single			Set the rule tags	tags ‘lighting’, ‘security’
every	Symbol or Duration	Multiple	at: String or TimeOfDay		When to execute rule	Symbol (:second, :minute, :hour, :day, :week, :month, :year, :monday, :tuesday, :wednesday, :thursday, :friday, :saturday, :sunday) or duration (5.minutes, 20.seconds, 14.hours), at: ‘5:15’ or TimeOfDay(h:5, m:15)
cron	String	Multiple			OpenHAB Style Cron Expression	’* * * * * * ?’
changed	Item or Item Array[] or Group or Group.members or Thing or Thing Array []	Multiple	from: State, to: State, for: Duration		Execute rule on item state change	BedroomLightSwitch, from: OFF to ON
updated	Item or Item Array[] or Group or Group.members or Thing or Thing Array []	Multiple	to: State		Execute rule on item update	BedroomLightSwitch, to: ON
received_command	Item or Item Array[] or Group or Group.members	Multiple	command:		Execute rule on item command	BedroomLightSwitch command: ON
channel	Channel	Multiple	triggered:		Execute rule on channel trigger	`'astro:sun:home:rise#event', triggered: 'START'`
on_start	Boolean	Single		false	Execute rule on system start	on_start
run	Block passed event	Multiple			Code to execute on rule trigger
triggered	Block passed item	Multiple			Code with triggering item to execute on rule trigger
delay	Duration	Multiple			Duration to wait between or after run blocks	delay 5.seconds
otherwise	Block passed event	Multiple			Code to execute on rule trigger if guards are not satisfied
between	Range of TimeOfDay or String Objects	Single			Only execute rule if current time is between supplied time ranges	‘6:05’..’14:05:05’ (Include end) or ‘6:05’…‘14:05:05’ (Excludes end second) or TimeOfDay.new(h:6,m:5)..TimeOfDay.new(h:14,m:15,s:5)
only_if	Item or Item Array, or Block	Multiple			Only execute rule if all supplied items are “On” and/or block returns true	BedroomLightSwitch, BackyardLightSwitch or {BedroomLightSwitch.state == ON}
not_if	Item or Item Array, or Block	Multiple			Do NOT execute rule if any of the supplied items or blocks returns true	BedroomLightSwitch
enabled	Boolean	Single		true	Enable or disable the rule from executing

Last means that last value for the property is used
Multiple indicates that multiple entries of the same property can be used in aggregate

An optional variable can be provided to the block to access the rule configuration from within execution blocks and guards.

Terse Rules

If you have a single trigger and execution block, you can use a terse rule:

changed TestSwitch do |event|
  logger.info("TestSwitch changed to #{event.state}")
end

All parameters to the trigger are passed through, and an optional name: parameter is added:

received_command TestSwitch, name: "My Test Switch Rule", command: ON do
  loogger.info("TestSwitch received command ON")
end