OAS server path as base path for matchers

examples/oas3/petstore-with-kuadrant-extensions.yaml

@@ -13,7 +13,7 @@ info:
         - name: istio-ingressgateway
           namespace: istio-system
 servers:
-  - url: https://example.io/v1
+  - url: https://example.io/api/v1
 paths:
   /cat:
     x-kuadrant:  ## Path level Kuadrant Extension

pkg/gatewayapi/http_route.go

@@ -77,6 +77,11 @@ func HTTPRouteRulesFromOAS(doc *openapi3.T) []gatewayapiv1beta1.HTTPRouteRule {
 	// TODO(eguzki): consider about grouping operations as HTTPRouteMatch objects in fewer HTTPRouteRule objects
 	rules := make([]gatewayapiv1beta1.HTTPRouteRule, 0)
 
+	basePath, err := utils.BasePathFromOpenAPI(doc)
+	if err != nil {
+		panic(err)
+	}
+
 	// Paths
 	for path, pathItem := range doc.Paths {
 		kuadrantPathExtension, err := utils.NewKuadrantOASPathExtension(pathItem)
@@ -104,7 +109,7 @@ func HTTPRouteRulesFromOAS(doc *openapi3.T) []gatewayapiv1beta1.HTTPRouteRule {
 				backendRefs = kuadrantOperationExtension.BackendRefs
 			}
 
-			rules = append(rules, buildHTTPRouteRule(path, pathItem, verb, operation, backendRefs))
+			rules = append(rules, buildHTTPRouteRule(basePath, path, pathItem, verb, operation, backendRefs))
 		}
 	}
 
@@ -137,8 +142,8 @@ func ExtractLabelsFromOAS(doc *openapi3.T) (map[string]string, bool) {
 	return nil, false
 }
 
-func buildHTTPRouteRule(path string, pathItem *openapi3.PathItem, verb string, op *openapi3.Operation, backendRefs []gatewayapiv1beta1.HTTPBackendRef) gatewayapiv1beta1.HTTPRouteRule {
-	match := utils.OpenAPIMatcherFromOASOperations(path, pathItem, verb, op)
+func buildHTTPRouteRule(basePath, path string, pathItem *openapi3.PathItem, verb string, op *openapi3.Operation, backendRefs []gatewayapiv1beta1.HTTPBackendRef) gatewayapiv1beta1.HTTPRouteRule {
+	match := utils.OpenAPIMatcherFromOASOperations(basePath, path, pathItem, verb, op)
 
 	return gatewayapiv1beta1.HTTPRouteRule{
 		BackendRefs: backendRefs,

pkg/kuadrantapi/rate_limit_policy.go

@@ -21,6 +21,11 @@ func RateLimitPolicyLimitsFromOAS(doc *openapi3.T) map[string]kuadrantapiv1beta2
 
 	limits := make(map[string]kuadrantapiv1beta2.Limit)
 
+	basePath, err := utils.BasePathFromOpenAPI(doc)
+	if err != nil {
+		panic(err)
+	}
+
 	// Paths
 	for path, pathItem := range doc.Paths {
 		kuadrantPathExtension, err := utils.NewKuadrantOASPathExtension(pathItem)
@@ -57,7 +62,12 @@ func RateLimitPolicyLimitsFromOAS(doc *openapi3.T) map[string]kuadrantapiv1beta2
 
 			limitName := utils.OpenAPIOperationName(path, verb, operation)
 
-			limits[limitName] = buildRateLimitPolicyLimit(path, pathItem, verb, operation, rateLimit)
+			limits[limitName] = kuadrantapiv1beta2.Limit{
+				RouteSelectors: buildLimitRouteSelectors(basePath, path, pathItem, verb, operation),
+				When:           rateLimit.When,
+				Counters:       rateLimit.Counters,
+				Rates:          rateLimit.Rates,
+			}
 		}
 	}
 
@@ -68,17 +78,8 @@ func RateLimitPolicyLimitsFromOAS(doc *openapi3.T) map[string]kuadrantapiv1beta2
 	return limits
 }
 
-func buildRateLimitPolicyLimit(path string, pathItem *openapi3.PathItem, verb string, op *openapi3.Operation, rateLimit *utils.KuadrantRateLimitExtension) kuadrantapiv1beta2.Limit {
-	return kuadrantapiv1beta2.Limit{
-		RouteSelectors: buildLimitRouteSelectors(path, pathItem, verb, op),
-		When:           rateLimit.When,
-		Counters:       rateLimit.Counters,
-		Rates:          rateLimit.Rates,
-	}
-}
-
-func buildLimitRouteSelectors(path string, pathItem *openapi3.PathItem, verb string, op *openapi3.Operation) []kuadrantapiv1beta2.RouteSelector {
-	match := utils.OpenAPIMatcherFromOASOperations(path, pathItem, verb, op)
+func buildLimitRouteSelectors(basePath, path string, pathItem *openapi3.PathItem, verb string, op *openapi3.Operation) []kuadrantapiv1beta2.RouteSelector {
+	match := utils.OpenAPIMatcherFromOASOperations(basePath, path, pathItem, verb, op)
 
 	return []kuadrantapiv1beta2.RouteSelector{
 		{

pkg/utils/oas_utils.go

@@ -1,7 +1,10 @@
 package utils
 
 import (
+	"bytes"
 	"fmt"
+	"html/template"
+	"net/url"
 	"regexp"
 
 	"github.com/getkin/kin-openapi/openapi3"
@@ -11,9 +14,97 @@ import (
 var (
 	// NonWordCharRegexp not word characters (== [^0-9A-Za-z_])
 	NonWordCharRegexp = regexp.MustCompile(`\W`)
+	// TemplateRegexp used to render openapi server URLs
+	TemplateRegexp = regexp.MustCompile(`{([\w]+)}`)
+	// LastSlashRegexp matches the last slash
+	LastSlashRegexp = regexp.MustCompile(`/$`)
 )
 
-func OpenAPIMatcherFromOASOperations(path string, pathItem *openapi3.PathItem, verb string, op *openapi3.Operation) gatewayapiv1beta1.HTTPRouteMatch {
+func FirstServerFromOpenAPI(obj *openapi3.T) *openapi3.Server {
+	if obj == nil {
+		return nil
+	}
+
+	// take only first server
+	// From https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.3.md
+	//   If the servers property is not provided, or is an empty array, the default value would be a Server Object with a url value of /.
+	server := &openapi3.Server{
+		URL:       `/`,
+		Variables: map[string]*openapi3.ServerVariable{},
+	}
+
+	// Current constraint: only read the first item when there are multiple servers
+	// Maybe this should be user provided setting
+	if len(obj.Servers) > 0 {
+		server = obj.Servers[0]
+	}
+
+	return server
+}
+
+func RenderOpenAPIServerURLStr(server *openapi3.Server) (string, error) {
+	if server == nil {
+		return "", nil
+	}
+
+	data := &struct {
+		Data map[string]string
+	}{
+		map[string]string{},
+	}
+
+	for variableName, variable := range server.Variables {
+		data.Data[variableName] = variable.Default
+	}
+
+	urlTemplate := TemplateRegexp.ReplaceAllString(server.URL, `{{ index .Data "$1" }}`)
+
+	tObj, err := template.New(server.URL).Parse(urlTemplate)
+	if err != nil {
+		return "", err
+	}
+
+	var tpl bytes.Buffer
+	err = tObj.Execute(&tpl, data)
+	if err != nil {
+		return "", err
+	}
+
+	return tpl.String(), nil
+}
+
+func RenderOpenAPIServerURL(server *openapi3.Server) (*url.URL, error) {
+	serverURLStr, err := RenderOpenAPIServerURLStr(server)
+	if err != nil {
+		return nil, err
+	}
+
+	serverURL, err := url.Parse(serverURLStr)
+	if err != nil {
+		return nil, err
+	}
+
+	return serverURL, nil
+}
+
+func BasePathFromOpenAPI(obj *openapi3.T) (string, error) {
+	server := FirstServerFromOpenAPI(obj)
+	serverURL, err := RenderOpenAPIServerURL(server)
+	if err != nil {
+		return "", err
+	}
+
+	return serverURL.Path, nil
+}
+
+func OpenAPIMatcherFromOASOperations(basePath, path string, pathItem *openapi3.PathItem, verb string, op *openapi3.Operation) gatewayapiv1beta1.HTTPRouteMatch {
+
+	// remove the last slash of the Base Path
+	sanitizedBasePath := LastSlashRegexp.ReplaceAllString(basePath, "")
+
+	//  According OAS 3.0: path MUST begin with a slash
+	matchPath := fmt.Sprintf("%s%s", sanitizedBasePath, path)
+
 	pathHeadersMatch := headersMatchFromParams(pathItem.Parameters)
 	operationHeadersMatch := headersMatchFromParams(op.Parameters)
 
@@ -37,7 +128,7 @@ func OpenAPIMatcherFromOASOperations(path string, pathItem *openapi3.PathItem, v
 		Path: &gatewayapiv1beta1.HTTPPathMatch{
 			// TODO(eguzki): consider other path match types like PathPrefix
 			Type:  &[]gatewayapiv1beta1.PathMatchType{gatewayapiv1beta1.PathMatchExact}[0],
-			Value: &[]string{path}[0],
+			Value: &[]string{matchPath}[0],
 		},
 		Headers:     headersMatch,
 		QueryParams: queryParams,