Workflow modifiers

Workflow modifiers define the behaviors of a workflow.

Construct	Modifier	Domain	Description	Default
Workflow			`Examples:` `<Workflow` `Limit="1"` `Live="1"` `Timeout="-1">...</Workflow>` `<Workflow` `Limit="5"` `Live="2"` `Timeout="PT3M">...</Workflow>`
	Limit	-1..n	The maximum number of workflow instances of the same model waiting at any given time (they are pre-created instances existing in the buffer)	10
	Live	-1..n	The maximum number of workflow instances of the same model allowed to run (in parallel) at the same time. (For example, a workflow receives inputs of X value and Y value and calculates X+Y=Z. When the first X and Y values are received, a workflow instance starts the process of calculation. While the calculation is taking 1 second to complete, a new set of X and Y values are received before the current instance is completed. Therefore a new workflow instance will start calculating X+Y from the new values. These two instances are running in parallel	10
	Timeout	-1..n	The period of time of inactivity after which a workflow instance is considered dead and removed from the buffer. Both XSD time period format and plain number of milliseconds are allowed. Timeout = "-1" means the workflow will never time out.	PT1M

Task			`Examples:` `<Task` `name="Main"` `while="true">...</Task>`
	While	true, false	Logical expression for repeatable tasks (only true/false is currently supported) (if false use variable not streams)	false

Invoke			`Examples:` `<Invoke` `name="InvokeSerialRead"` `waitFor="Argument"` `get="perif://">...</Invoke>` `<Invoke name="SetState" Skipif="[%:[:AA:].State/no-value(Value):%]" WaitFor="ActionArgument" Delay="PT5S">...</Invoke>`
	SkipIf (skip-if)	true, false	A logical expression to skip the invoke execution (mutually exclusive with OnlyIf) - the output will be Null `<Invoke` `name="SetPreset"` `waitFor="Argument"` `skip-if="[%:[:AD:].Preset/no-value(Value):%]"` `delayAfter="PT5S"` `get="[%:[:AA:].URL.Value:%]/cgi-bin/decoder_control.cgi?[:UP:][%:amp:%]command=15[%:amp:%]sit=[%:[:AD:].Preset.Value:%]"/>`
	OnlyIf (only-if)	true, false	A logical expression to execute invoke conditionally (mutually exclusive with SkipIf)
	Delay	Duration	Synonym of DelayBefore (mutually exclusive with DelayUntil, Timeout) `<Invoke` `name="GetImage"` `waitFor="Argument"` `delay="PT1S"` `get="[%:[:AA:].URL.Value:%]/cgi-bin/video_snapshot.cgi?[:UP:]"/>`
	DelayBefore	Duration	Invoke execution delay interval (delay before invoke starts executing) - Mutually exclusive with Timeout and DelayUntil
	DelayAfter	Duration	Time to wait after invoke is completed before the next invoke in the same task starts `<Invoke` `name="SetPreset"` `waitFor="Argument"` `skip-if="[%:[:AD:].Preset/no-value(Value):%]"` `delayAfter="PT5S"` `get="[%:[:AA:].URL.Value:%]/cgi-bin/decoder_control.cgi?[:UP:][%:amp:%]command=15[%:amp:%]sit=[%:[:AD:].Preset.Value:%]"/>`
	DelayUntil	DateTime	Absolute invoke execution time (Mutually exclusive with DelayBefore and Timeout)
	WaitFor		The output(s)/event(s) that will allow the Invoke to continue. Until the WaitFor is met, the Invoke will be suspended `<Invoke` `name="GetImage"` `waitFor="Argument"` `delay="PT1S"` `get="[%:[:AA:].URL.Value:%]/cgi-bin/video_snapshot.cgi?[:UP:]"/>`
	Unless		Usually used with delay. The output/event will terminate the delay and start the Invoke. This can be an event or the output from another task.