DMN module returns the history of a decision evaluation

[saig0]

Description

The DMN module should return the history/audit of a decision evaluation together with the EvaluationResult. The history should include all relevant data from the evaluation, like the decision result, the intermediate results from required decisions, and the inputs and outputs of evaluated decision tables. The history will be used by the engine to write a history event on the log stream that can be consumed by Operate/Optimize.

• add the history/audit to the EvaluationResult
• the history should include the result from the evaluated decision
  • as the last item in the list of results
• it should include the result from all required decisions that were evaluated
• if the decision is a decision table then it should include the input values and the matched rules
• if the decision is a literal expression then it should include only the result

The structure of the history could like this:

{
  "decisionResults": [
    {
      "decisionId": "x",
      "decisionName": "x",
      "decisionType": "x",
      "result": "x" (JSON),  
      "evaluatedInputs": [ (for decision tables) 
      	{
      	  "inputId": "x",
      	  "inputName": "x",
      	  "inputValue": "x" (JSON) 
      	}
      ],
      "matchedRules": [ (for decision tables)
      	{
      	  "ruleId": "x",
      	  "ruleIndex:": x,
      	  "evaluatedOutputs": [
  	    {
  	      "outputId": "x",
  	      "outputName": "x",
  	      "outputValue": "x" (JSON)
  	    } 
      	  ] 
      	}
      ]
    }
  ]  
}

blocked by #8082

[saig0]

Alternatives

• serialize the decision returns in a tree structure that represents the evaluation order (i.e. required decisions are child elements)
  • could be more complicated to deserialize
  • if needed, the structure could be constructed using the data of the DMN
• reference to the parent decision
  • this relationship is currently not required
  • if needed, the structure could be constructed using the data of the DMN