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:

{"input": {"field1": {"key1": "value1"}}}
{"input": {"field1": None}}
{"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

Function	Description	Example	Output or Result
fn.drop	Removes the attribute from CFT	{'name': '{{fn.drop}}'}	Attribute as in existing data
fn.force_null	Attribute has Null value	{'name': '{{fn.force_null}}'}	{'name': None}

Useful in Configuration Templates (CFT):

Function fn.drop in a CFT will drop a value from the input data when it is processed through a CFT. Input data without the dropped field is then overlaid onto the existing model data by the workflow code. The final payload data for the value will thus remain the same as in the existing model data.

Example of fn.drop in an if-then-else test from a CFT of a workflow:

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

Function	Description	Example	Output or Result
fn.drop_from_payload	Removes the attribute from payload	{'name': '{{fn.drop_from_payload}}'}	Attribute “blank”

Useful in Configuration Templates (CFT):

Function fn.drop_from_payload forces a field to not be present in the final payload data. Used in a CFT, it will drop a value from the existing model data after the input data is overlaid onto the existing model data. The value is then not present, i.e. “blanked”.

Example of fn.drop_from_payload in a CFT so that attributes are blanked:

{
  "meta": {},
  "resources": [
    {
      "data": {
        "name": "ConvertCUCUserCFT",
        "target_model_type": "device/cuc/User",
        "template": {
          "LdapType": "0",
          "LdapCcmUserId": "{{ fn.drop_from_payload }}",
          "LdapCcmPkid": "{{ fn.drop_from_payload }}"
        }
      },
      "meta": {
        "model_type": "data/ConfigurationTemplate",
        "system_resource": true,
        "tags": [
          "convertusertype"
        ]
      }
    }
  ]
}

Given input context:

{"input": {"field1": {"key1": "value1"}}}
{"input": {"field1": {"key1": null}}}
{"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

VOSS Automate 21.2

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