Added strict option for JSON validation

Ticket: CFE-4163
Signed-off-by: Victor Moene <victor.moene@northern.tech>

Author: victormlg

reference/functions/validdata.markdown

@@ -4,16 +4,23 @@ title: validdata
 published: true
 ---
 
-[%CFEngine_function_prototype(data_container, type)%]
+[%CFEngine_function_prototype(data_container, type, strict)%]
 
 **Description:** Validates a JSON container from `data_container` and returns
-`true` if the contents are valid JSON.
+`"true"` if the contents are valid JSON.
+An optional second argument `strict` may be used to enable strict validation.
+When set to `"true"` the function will not evaluate to true for JSON primitives.
+The default value of `strict`is `"false"`.
+
+The strict behavior matches the expectations in other parts of policy language.
+Notably, `data` containers and functions like `readjson()` and `parsejson()` expect JSON containers (arrays and objects) not primitives.
+Thus, using `validdata()` with `strict` set to `"true"` is an effective way to check if something can be parsed by those functions.
 
 This function is intended to be expanded with functionality for validating
 CSV and YAML files eventually, mirroring `readdata()`. If `type` is `JSON`,
 it behaves the same as `validjson()`.
 
-[%CFEngine_function_attributes(data_container, type)%]
+[%CFEngine_function_attributes(data_container, type, strict)%]
 
 **Example:**
 

reference/functions/validjson.markdown

@@ -4,12 +4,19 @@ title: validjson
 published: true
 ---
 
-[%CFEngine_function_prototype(string)%]
+[%CFEngine_function_prototype(string, strict)%]
 
 **Description:** Validates a JSON container from `string` and returns
-`true` if the contents are valid JSON.
+`"true"` if the contents are valid JSON.
+An optional second argument `strict` may be used to enable strict validation.
+When set to `"true"` the function will not evaluate to true for JSON primitives.
+The default value of `strict`is `"false"`.
 
-[%CFEngine_function_attributes(string)%]
+The strict behavior matches the expectations in other parts of policy language.
+Notably, `data` containers and functions like `readjson()` and `parsejson()` expect JSON containers (arrays and objects) not primitives.
+Thus, using `validjson()` with `strict` set to `"true"` is an effective way to check if something can be parsed by those functions.
+
+[%CFEngine_function_attributes(string, strict)%]
 
 **Example:**