add in operator conversion

internal/opatranslator/mongo.go

@@ -30,6 +30,7 @@ const (
 	EqOp    = "eq"
 	EqualOp = "equal"
 	NeqOp   = "neq"
+	InOp    = "internal.member_2"
 )
 
 var rangeOperatorStrategies = map[string]func(pipeline *[]bson.M, fieldName string, fieldValue interface{}){
@@ -40,6 +41,7 @@ var rangeOperatorStrategies = map[string]func(pipeline *[]bson.M, fieldName stri
 	EqOp:    HandleEquals,
 	EqualOp: HandleEquals,
 	NeqOp:   HandleNotEquals,
+	InOp:    HandleIn,
 }
 
 func HandleOperations(operation string, pipeline *[]bson.M, fieldName string, fieldValue interface{}) bool {
@@ -56,6 +58,12 @@ func HandleEquals(pipeline *[]bson.M, fieldName string, fieldValue interface{})
 	*pipeline = append(*pipeline, filter)
 }
 
+// Parse the in operator into equivalent mongo query.
+func HandleIn(pipeline *[]bson.M, fieldName string, fieldValue interface{}) {
+	filter := bson.M{fieldName: bson.M{"$in": fieldValue}}
+	*pipeline = append(*pipeline, filter)
+}
+
 // Parse the != into equivalent mongo query.
 func HandleNotEquals(pipeline *[]bson.M, fieldName string, fieldValue interface{}) {
 	filter := bson.M{fieldName: bson.M{"$ne": fieldValue}}

service/handler_test.go

@@ -818,6 +818,9 @@ allow {
 
 	t.Run("sends filter query with $in", func(t *testing.T) {
 		policy := `package policies
+
+		import future.keywords.in
+
 allow {
 	input.request.method == "GET"
 
@@ -860,7 +863,7 @@ allow {
 
 		require.Equal(t, http.StatusOK, w.Result().StatusCode, "Unexpected status code.")
 		filterQuery := r.Header.Get("rowfilterquery")
-		expectedQuery := `{"$or":[{"$and":[{"membership":{"$in":["manager_test"]}}]},{"$and":[{"salary":{"$gt":0}}]}]}`
+		expectedQuery := `{"$or":[{"$and":[{"membership":{"$in":"member_test"}}]},{"$and":[{"salary":{"$gt":0}}]}]}`
 		require.Equal(t, expectedQuery, filterQuery)
 	})