fix: validating cookie parameter for req-validator

At the moment, we do not support cookie parameters in request-validator
plugin. However, `deck file openapi2kong` command generates the yaml file
even if it is present in the parameter schema. Thus, adding a validation
layer over it to ensure deck does not create invalid specs.

For: #223

openapi2kong/oas3_testfiles/13-request-validator-plugin.expected.json

@@ -190,14 +190,6 @@
                     "schema": "{\"type\":\"integer\"}",
                     "style": "simple"
                   },
-                  {
-                    "explode": true,
-                    "in": "cookie",
-                    "name": "cookieid",
-                    "required": true,
-                    "schema": "{\"type\":\"integer\"}",
-                    "style": "form"
-                  },
                   {
                     "explode": false,
                     "in": "path",

openapi2kong/oas3_testfiles/13-request-validator-plugin.yaml

@@ -40,6 +40,9 @@ paths:
           schema:
             type: integer
           required: true
+        # This would not be added to the req-validator plugin config
+        # as cookie type is not supported yet.
+        # A warning would be logged and this parameter would be ignored.
         - in: cookie
           name: cookieid
           schema:

openapi2kong/validator.go

@@ -65,9 +65,19 @@ func generateParameterSchema(operation *v3.Operation, path *v3.PathItem,
 
 	result := make([]map[string]interface{}, len(combinedParameters))
 	i := 0
+	invalidParamCounts := 0
 
 	for _, parameter := range combinedParameters {
 		if parameter != nil {
+			if parameter.In == "cookie" {
+				logbasics.Info(`cookie parameters are not supported for request-validator plugin; 
+					choose either path, query or header`)
+
+				invalidParamCounts++
+
+				continue
+			}
+
 			style := getDefaultParamStyle(parameter.Style, parameter.In)
 
 			var explode bool
@@ -82,11 +92,6 @@ func generateParameterSchema(operation *v3.Operation, path *v3.PathItem,
 			paramConf["explode"] = explode
 			paramConf["in"] = parameter.In
 
-			if parameter.In == "cookie" {
-				return nil, fmt.Errorf(`cookie parameters are not supported for request-validator plugin; 
-				choose either path, query or header`)
-			}
-
 			if parameter.In == "path" {
 				paramConf["name"] = sanitizeRegexCapture(parameter.Name, insoCompat)
 			} else {
@@ -115,7 +120,9 @@ func generateParameterSchema(operation *v3.Operation, path *v3.PathItem,
 		}
 	}
 
-	return result, nil
+	// This ensures that we don't return nulls in the map, in case of invalid parameters
+	// indexing makes sure that order is maintained and nulls are in the end
+	return result[:len(result)-invalidParamCounts], nil
 }
 
 func parseMediaType(mediaType string) (string, string, error) {