make kubectl explain work for extensions API

Author: Chao Xu

pkg/client/unversioned/client.go

@@ -26,7 +26,6 @@ import (
 	"github.com/emicklei/go-restful/swagger"
 
 	"k8s.io/kubernetes/pkg/api"
-	"k8s.io/kubernetes/pkg/api/latest"
 	"k8s.io/kubernetes/pkg/api/unversioned"
 	"k8s.io/kubernetes/pkg/version"
 )
@@ -184,26 +183,32 @@ func (c *Client) ValidateComponents() (*api.ComponentStatusList, error) {
 // SwaggerSchemaInterface has a method to retrieve the swagger schema. Used in
 // client.Interface
 type SwaggerSchemaInterface interface {
-	SwaggerSchema(version string) (*swagger.ApiDeclaration, error)
+	SwaggerSchema(groupVersion string) (*swagger.ApiDeclaration, error)
 }
 
 // SwaggerSchema retrieves and parses the swagger API schema the server supports.
-func (c *Client) SwaggerSchema(version string) (*swagger.ApiDeclaration, error) {
-	if version == "" {
-		version = latest.GroupOrDie("").Version
+func (c *Client) SwaggerSchema(groupVersion string) (*swagger.ApiDeclaration, error) {
+	if groupVersion == "" {
+		return nil, fmt.Errorf("groupVersion cannot be empty")
 	}
 
-	vers, err := c.ServerAPIVersions()
+	groupList, err := c.Discovery().ServerGroups()
 	if err != nil {
 		return nil, err
 	}
-
+	groupVersions := extractGroupVersions(groupList)
 	// This check also takes care the case that kubectl is newer than the running endpoint
-	if stringDoesntExistIn(version, vers.Versions) {
-		return nil, fmt.Errorf("API version: %s is not supported by the server. Use one of: %v", version, vers.Versions)
+	if stringDoesntExistIn(groupVersion, groupVersions) {
+		return nil, fmt.Errorf("API version: %s is not supported by the server. Use one of: %v", groupVersion, groupVersions)
+	}
+	var path string
+	if groupVersion == "v1" {
+		path = "/swaggerapi/api/" + groupVersion
+	} else {
+		path = "/swaggerapi/apis/" + groupVersion
 	}
 
-	body, err := c.Get().AbsPath("/swaggerapi/api/" + version).Do().Raw()
+	body, err := c.Get().AbsPath(path).Do().Raw()
 	if err != nil {
 		return nil, err
 	}

pkg/kubectl/cmd/explain.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/spf13/cobra"
 
+	"k8s.io/kubernetes/pkg/api/latest"
 	"k8s.io/kubernetes/pkg/kubectl"
 	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
 )
@@ -70,13 +71,28 @@ func RunExplain(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, args []st
 	recursive := cmdutil.GetFlagBool(cmd, "recursive")
 	apiV := cmdutil.GetFlagString(cmd, "api-version")
 
-	swagSchema, err := kubectl.GetSwaggerSchema(apiV, client)
+	mapper, _ := f.Object()
+	group, inModel, fieldsPath, err := kubectl.SplitAndParseResourceRequest(args[0], mapper)
 	if err != nil {
 		return err
 	}
 
-	mapper, _ := f.Object()
-	inModel, fieldsPath, err := kubectl.SplitAndParseResourceRequest(args[0], mapper)
+	if len(group) == 0 {
+		// TODO: We should deduce the group for a resource by discovering the supported resources at server.
+		group, err = mapper.GroupForResource(inModel)
+		if err != nil {
+			return err
+		}
+	}
+
+	if len(apiV) == 0 {
+		groupMeta, err := latest.Group(group)
+		if err != nil {
+			return err
+		}
+		apiV = groupMeta.GroupVersion
+	}
+	swagSchema, err := kubectl.GetSwaggerSchema(apiV, client)
 	if err != nil {
 		return err
 	}

pkg/kubectl/explain.go

@@ -24,6 +24,7 @@ import (
 	"github.com/emicklei/go-restful/swagger"
 
 	"k8s.io/kubernetes/pkg/api/meta"
+	apiutil "k8s.io/kubernetes/pkg/api/util"
 	client "k8s.io/kubernetes/pkg/client/unversioned"
 )
 
@@ -40,16 +41,17 @@ func GetSwaggerSchema(apiVer string, kubeClient client.Interface) (*swagger.ApiD
 }
 
 // SplitAndParseResourceRequest separates the users input into a model and fields
-func SplitAndParseResourceRequest(inResource string, mapper meta.RESTMapper) (string, []string, error) {
+func SplitAndParseResourceRequest(inResource string, mapper meta.RESTMapper) (string, string, []string, error) {
 	inResource, fieldsPath := splitDotNotation(inResource)
+	group, inResource := splitGroupFromResource(inResource)
 	inResource, _ = mapper.ResourceSingularizer(expandResourceShortcut(inResource))
-	return inResource, fieldsPath, nil
+	return group, inResource, fieldsPath, nil
 }
 
 // PrintModelDescription prints the description of a specific model or dot path
 func PrintModelDescription(inModel string, fieldsPath []string, w io.Writer, swaggerSchema *swagger.ApiDeclaration, r bool) error {
 	recursive = r // this is global for convenience
-	apiVer := swaggerSchema.ApiVersion + "."
+	apiVer := apiutil.GetVersion(swaggerSchema.ApiVersion) + "."
 
 	var pointedModel *swagger.NamedModel
 	for i := range swaggerSchema.Models.List {
@@ -61,7 +63,7 @@ func PrintModelDescription(inModel string, fieldsPath []string, w io.Writer, swa
 		}
 	}
 	if pointedModel == nil {
-		return fmt.Errorf("Requested resourse: %s doesn't exit", inModel)
+		return fmt.Errorf("Requested resource: %s doesn't exist", inModel)
 	}
 
 	if len(fieldsPath) == 0 {
@@ -84,6 +86,15 @@ func PrintModelDescription(inModel string, fieldsPath []string, w io.Writer, swa
 	return printModelInfo(w, pointedModel, pointedModelAsProp)
 }
 
+func splitGroupFromResource(resource string) (string, string) {
+	seg := strings.SplitN(resource, "/", 2)
+	if len(seg) == 1 {
+		return "", seg[0]
+	} else {
+		return seg[0], seg[1]
+	}
+}
+
 func splitDotNotation(model string) (string, []string) {
 	var fieldsPath []string
 	dotModel := strings.Split(model, ".")