Zero, Unset, Boolean, Drop, Null and Exists Functions

Function	Description	Example	Output or Result
fn.zero	Return a zero value.	{{fn.zero}}	0
fn.unset	Return an empty string.	{{fn.unset}}	''
fn.true	Return a boolean True.	{{fn.true}}	true
fn.false	Return a boolean False.	{{fn.false}}	false

Given input context:

1. {"input": {"field1": {"key1": "value1"}}}
2. {"input": {"field1": None}}
3. {"input": {"field1": ""}}

Function	Description	Example	Input and Result
fn.is_none_or_empty	Return a boolean if the argument is None or an empty string	{{fn.is_none_or_empty input.field1}}	input 1. false input 2. true input 3. true

Given input context:

{
 "input": {
   "test": null
 }
}

Function	Description	Example	Output or Result
fn.null	Returns Null. Useful in comparison tests.	(( input.test == fn.null ))	true

Useful in Configuration Templates:

Function	Description	Example	Output or Result
fn.drop	Removes the attribute	{'name': '{{fn.drop}}'}	Attribute dropped
fn.force_null	Attribute has Null value	{'name': '{{fn.force_null}}'}	{'name': None}

Example of fn.drop in an if-then-else test from a Configuration Template of a workflow. the attribute is dropped if not entered as input:

"ldapDirectoryName": "(( input.cucm_user_ldapDirectoryName != '' ))
  <{{ input.cucm_user_ldapDirectoryName }}>
  <{{ fn.drop }}"

Given input context:

1. {"input": {"field1": {"key1": "value1"}}}
2. {"input": {"field1": {"key1": null}}}
3. {"input": {"field1": ""}}

Function	Description	Example	Input and Result
fn.exists	Return a boolean true if the argument is exits and has a non-null value.	{{ fn.exists input.field1.key1 }}	input 1. true input 2. false input 3. false
fn.exists	If the argument does not exist, it is interpreted as a string - which is interpretable, so the function returns true.	{{ fn.exists field.key }}	input 1, 2, 3 true