comments

staging/src/k8s.io/client-go/applyconfigurations/meta/v1/unstructured.go

@@ -19,14 +19,8 @@ type UnstructuredExtractor interface {
 	ExtractUnstructuredStatus(object *unstructured.Unstructured, fieldManager string) (*unstructured.Unstructured, error)
 }
 
-//// objectTypeCache is a cache of typed.ParseableTypes
+// objectTypeCache caches the GVKParser in order to prevent from having to repeatedly
-//type objectTypeCache interface {
+// parse the models from the open API schema when the schema itself changes infrequently.
-//	objectTypeForGVK(gvk schema.GroupVersionKind) (*typed.ParseableType, error)
-//}
-
-// objectTypeCache is a objectTypeCache that does no caching
-// (i.e. it downloads the OpenAPISchema every time)
-// Useful during the proof-of-concept stage until we agree on a caching solution.
 type objectTypeCache struct {
 	// TODO: lock this?
 	discoveryClient discovery.DiscoveryInterface
@@ -35,7 +29,6 @@ type objectTypeCache struct {
 
 // objectTypeForGVK retrieves the typed.ParseableType for a given gvk from the cache
 func (c *objectTypeCache) objectTypeForGVK(gvk schema.GroupVersionKind) (*typed.ParseableType, error) {
-
 	if !c.discoveryClient.HasOpenAPISchemaChanged() && c.gvkParser != nil {
 		// cache hit
 		fmt.Println("cache hit")

staging/src/k8s.io/client-go/discovery/cached/disk/cached_discovery.go

@@ -240,6 +240,7 @@ func (d *CachedDiscoveryClient) OpenAPISchema() (*openapi_v2.Document, error) {
 	return d.delegate.OpenAPISchema()
 }
 
+// HasOpenAPISchemaChanged checks wether the open API schema being served is cached or not.
 func (d *CachedDiscoveryClient) HasOpenAPISchemaChanged() bool {
 	return d.delegate.HasOpenAPISchemaChanged()
 }

staging/src/k8s.io/client-go/discovery/discovery_client.go

@@ -122,11 +122,14 @@ type ServerVersionInterface interface {
 	ServerVersion() (*version.Info, error)
 }
 
-// OpenAPISchemaInterface has a method to retrieve the open API schema.
+// OpenAPISchemaInterface has a method to retrieve the open API schema
+// and a method to check whether the open API schema has changed.
 type OpenAPISchemaInterface interface {
 	// OpenAPISchema retrieves and parses the swagger API schema the server supports.
 	OpenAPISchema() (*openapi_v2.Document, error)
 
+	// HasOpenAPISchema changed checks whether the API schema being served
+	// by the apiserver is cached (and thus has not changed).
 	HasOpenAPISchemaChanged() bool
 }
 
@@ -423,6 +426,8 @@ func (d *DiscoveryClient) ServerVersion() (*version.Info, error) {
 	return &info, nil
 }
 
+// HasOpenAPISchemaChanged checks whether a HEAD request to openapi endpoint returns
+// a 304 StatusNotModified meaning it has not changed.
 func (d *DiscoveryClient) HasOpenAPISchemaChanged() bool {
 	result := d.restClient.Verb("HEAD").AbsPath("/openapi/v2").SetHeader("If-None-Match", d.etag).SetHeader("Accept", mimePb).Do(context.TODO())
 	var status int

staging/src/k8s.io/client-go/discovery/fake/discovery.go

@@ -153,6 +153,7 @@ func (c *FakeDiscovery) OpenAPISchema() (*openapi_v2.Document, error) {
 	return &openapi_v2.Document{}, nil
 }
 
+// HasOpenAPISchemaChanged checks wether the open API schema being served is cached or not.
 func (c *FakeDiscovery) HasOpenAPISchemaChanged() bool {
 	return true
 }

staging/src/k8s.io/client-go/rest/request.go

@@ -1062,12 +1062,6 @@ func (r *Request) DoRaw(ctx context.Context) ([]byte, error) {
 
 // transformResponse converts an API response into a structured API object
 func (r *Request) transformResponse(resp *http.Response, req *http.Request) Result {
-	var etag string
-	etagHeader, ok := resp.Header["Etag"]
-	if ok && len(etagHeader) == 1 {
-		etag = etagHeader[0]
-	}
-
 	var body []byte
 	if resp.Body != nil {
 		data, err := ioutil.ReadAll(resp.Body)
@@ -1146,6 +1140,14 @@ func (r *Request) transformResponse(resp *http.Response, req *http.Request) Resu
 		}
 	}
 
+	// store the etag header so that we can check whether the document
+	// has changed or not.
+	var etag string
+	etagHeader, ok := resp.Header["Etag"]
+	if ok && len(etagHeader) == 1 {
+		etag = etagHeader[0]
+	}
+
 	return Result{
 		body:        body,
 		contentType: contentType,