rule.md

Rule

A rule is a group of conditions that will output a list of actions after processing. A unique id identifies each rule.
The default action types and their object structure definitions can be found in structure definition file. To see more about conditions, have a look at nested conditions example.

It contains at root level the information needed to optimize the reevaluation of this rule :

• inputRuntimeFacts : the input runtime facts the rule is based on
• inputFacts : the facts that are used by the rule
• outputRuntimeFacts : the runtime facts that are updated/set by the rule This allows to refresh only the needed rule when a fact changes. In case a fact used in a rule is not part of this inputFacts list it will just be considered undefined.

During the rules execution if an error is thrown (for example by an operator validator) then all the actions resulting from the associated ruleset will be ignored. It ensures atomicity at ruleset level (all or nothing).

The following examples contain details about the rule object structure in different contexts.

Sequential rules

Example:

• the first rule is updating a runtime (temporary) fact used by the second one

  ...
  "rules": [
    {
      "id": "6e8t54h6s4e-6erth46sre8th4-d46t8s13t5j1",
      "name": "the first rule",
      "inputRuntimeFacts": [], // list of runtime fact ids updated by previous rules
      "inputFacts": ["isMobileDevice"], // list of base facts used at rule execution
      "outputRuntimeFacts": ["UI_FACT_2"], // list of runtime facts ids modified by this rule
      "rootElement": {  // Q: TODO can it be smth else?
        "elementType": "RULE_BLOCK", // type of the element, in this case a RULE_BLOCK.
        "blockType": "IF_ELSE", // defines a structure with a condition and a list of success elements plus a list of failure elements
        "condition": { // rule condition object. See `nested-conditions.ts` for object structure details
          "any": [
            {
              "lhs": {
                "type": "FACT",
                "value": "isMobileDevice"
              },
              "operator": "equals",  // see all default operators in [engine operators section](https://github.com/AmadeusITGroup/otter/blob/main/packages/%40o3r/rules-engine/src/engine/operator/operators/index.ts)
              "rhs": {
                "type": "LITERAL",
                "value": true
              }
            }
          ]
        },
        "successElements": [ // list of actions executed in case of condition evaluation as success
          {
            "elementType":"ACTION", // type of the element, in this case an ACTION
            "actionType":"SET_FACT",
            "fact":"UI_FACT_2",
            "value":true
          }
        ],
        "failureElements":[ // list of actions executed in case of condition evaluation as failure
          {
            "elementType":"ACTION",
            "actionType":"SET_FACT",
            "fact":"UI_FACT_2",
            "value":false
          }
        ]
      }
    },
    {
      "id": "6e8t54h6s4e-6erth46sre8th4-d46t8s13t5j2",
      "name": "the second rule",
      "inputRuntimeFacts": ["UI_FACT_2"],
      "inputFacts": [],
      "outputRuntimeFacts": [],
      "rootElement": {
        "elementType": "RULE_BLOCK",
        "blockType": "IF_ELSE",
        "condition": {
          "any": [
            {
              "lhs": {
                "type": "RUNTIME_FACT",
                "value": "UI_FACT_2"
              },
              "operator": "equals",
              "rhs": {
                "type": "LITERAL",
                "value": false
              }
            }
          ]
        },
        "successElements": [
          { // update config for `MyComponent` in case of condition valid output
            "actionType": "UPDATE_CONFIG",
            "elementType": "ACTION",
            "property": "testConfig",
            "library": "@scope/components",
            "component": "MyComponent",
            "value": "value"
          }
        ],
        "failureElements": [
          // Any actions
        ]
      }
    }
  ]

No condition rules

In this case the successElements will always be executed

Example:

  ...
  "rules": [
    {
      "id": "6e8t54h6s4e-6erth46sre8th4-d46t8s13t5j1",
      "name": "the first rule",
      "inputRuntimeFacts": [], // list of runtime fact ids updated by previous rules
      "inputFacts": ["isMobileDevice"], // list of base facts used at rule execution
      "outputRuntimeFacts": ["UI_FACT_2"], // list of runtime facts ids modified by this rule
      "rootElement": {
        "elementType": "RULE_BLOCK", // type of the element, in this case a RULE_BLOCK.
        "blockType": "IF_ELSE", // TODO check if this field still exists
        "successElements": [ // always executed
          {
            "elementType":"ACTION", // type of the element, in this case an ACTION
            "actionType":"SET_FACT",
            "fact":"UI_FACT_2",
            "value":true
          }
        ],
        "failureElements":[ // never executed
          {
            "elementType":"ACTION",
            "actionType":"SET_FACT",
            "fact":"UI_FACT_2",
            "value":false
          }
        ]
      }
    },
    ...
  ]