gojsonlogicmongodb

go-jsonlogic-mongodb

Convert JsonLogic into a MongoDB aggregate query.

How to use

Use the Convert() function with your jsonLogic as parameter and get your mongo pipeline generated.

func Convert(rules io.Reader) (bson.D, error)

Examples

Equal operator

Json Logic input

{"==": [1, 1]}

Mongo output

bson.D{{
  Key: "$eq",
  Value: bson.A{
    Key: "1",
    Value: 1.0
  }
}}

Not Equal operator

Json Logic input

{"!=": ["Hello", "Bonjour"]}

Mongo output

bson.D{{
  Key: "$ne", 
  Value: bson.A{"Hello", "Bonjour"}
}}

Not operator

Json Logic input

{"!": "true"}

Mongo output

bson.D{{
  Key: "$not", 
  Value: "true"
}}

Var operator

Json Logic input

{"==": ["kube-system", {"var": ".metadata.namespace"}]}

Mongo output

bson.D{{
  Key: "$eq",
  Value: bson.A{
    "kube-system",
    "$metadata.namespace"
  }
}}

And & Or operators

And & Or operators work the same way, just specify what operator is needed it will result in a mongo $and or $or.

Json Logic input

{
  "and": [
    {
      "==": [
        1,
        1
      ]
    },
    {
      "!=": [
        "Hello",
        "Bonjour"
      ]
    }
  ]
}

Mongo output

bson.D{{
  Key: "$and",
  Value: bson.A{
    bson.D{{
      Key: "$eq",
      Value: bson.A{
        1.0,
        1.0
      }
    }}, 
    bson.D{{
      Key: "$ne",
      Value: bson.A{
        "Hello", 
        "Bonjour"
      }
    }}
  }
}}

Custom operator

In order to add a custom operator, you need to use the AddOperator function.
To make it work, it is mandatory to add your custom operator on the jsonlogic library side too, otherwise, go-jsonlogic-mongodb will not validate it.

Example :

Create your custom function

func isKeyValue(value interface{}) (primitive.D, error) {
	parsed, _ := value.([]interface{})

	key := parsed[1].(string)
	val := parsed[2].(string)

	firstArgument, internalError := InternalConvert(value.([]interface{})[0])
	if internalError != nil {
		return nil, internalError
	}

	return bson.D{{
		Key: "$match",
		Value: bson.D{{
			Key: "$expr", Value: bson.D{{
				Key: "$eq", Value: bson.A{
					bson.D{{
						Key: "$getField", Value: bson.D{
							{Key: "field", Value: bson.D{{Key: "$literal", Value: key}}},
							{Key: "input", Value: firstArgument},
						},
					}},
					val,
				},
			}},
		}},
	}}, nil
}

Add go-jsonlogic-mongodb custom operator

AddOperator("is_key_value", isKeyValue)

Override the jsonlogic operator, if you are not interested in applying the jsonlogic with your custom operator in the future, you can override it with an empty function like following :

	jsonlogic.AddOperator(name, func(values interface{}, data interface{}) (result interface{}) { return })

This way, you can achieve this :

{
  "is_key_value": [
    {
      "var":".metadata.labels"
    },
    "app.kubernetes.io/name",
    "kubees"
  ]
}

Mongo output

bson.D{{
  Key: "$match", Value: bson.D{{
    Key: "$expr", Value: bson.D{{
      Key: "$eq", Value: bson.A{
        bson.D{{
          Key: "$getField", Value: bson.D{
            {
              Key: "field", Value: bson.D{{
                Key: "$literal", Value: "app.kubernetes.io/name"
              }}
            },
            {
              Key: "input", Value: "$metadata.labels"
            }
          }}
        },
        "kubees"
      }
    }}
  }}
}}