client can return swagger schema

pkg/client/unversioned/client.go

@@ -23,7 +23,10 @@ import (
 	"net/url"
 	"strings"
 
+	"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"
 )
@@ -47,6 +50,7 @@ type Interface interface {
 	PersistentVolumesInterface
 	PersistentVolumeClaimsNamespacer
 	ComponentStatusesInterface
+	SwaggerSchemaInterface
 	Experimental() ExperimentalInterface
 }
 
@@ -174,6 +178,49 @@ func (c *Client) ValidateComponents() (*api.ComponentStatusList, error) {
 	return &api.ComponentStatusList{Items: statuses}, nil
 }
 
+// SwaggerSchemaInterface has a method to retrieve the swagger schema. Used in
+// client.Interface
+type SwaggerSchemaInterface interface {
+	SwaggerSchema(version 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
+	}
+
+	vers, err := c.ServerAPIVersions()
+	if err != nil {
+		return nil, err
+	}
+
+	// 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)
+	}
+
+	body, err := c.Get().AbsPath("/swaggerapi/api/" + version).Do().Raw()
+	if err != nil {
+		return nil, err
+	}
+	var schema swagger.ApiDeclaration
+	err = json.Unmarshal(body, &schema)
+	if err != nil {
+		return nil, fmt.Errorf("got '%s': %v", string(body), err)
+	}
+	return &schema, nil
+}
+
+func stringDoesntExistIn(str string, slice []string) bool {
+	for _, s := range slice {
+		if s == str {
+			return false
+		}
+	}
+	return true
+}
+
 // IsTimeout tests if this is a timeout error in the underlying transport.
 // This is unbelievably ugly.
 // See: http://stackoverflow.com/questions/23494950/specifically-check-for-timeout-error for details

pkg/client/unversioned/client_test.go

@@ -26,6 +26,8 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/emicklei/go-restful/swagger"
+
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/api/testapi"
 	"k8s.io/kubernetes/pkg/fields"
@@ -290,3 +292,63 @@ func TestGetServerAPIVersions(t *testing.T) {
 		t.Errorf("expected %v, got %v", e, a)
 	}
 }
+
+func swaggerSchemaFakeServer() (*httptest.Server, error) {
+	request := 1
+	var sErr error
+
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+		var resp interface{}
+		if request == 1 {
+			resp = api.APIVersions{Versions: []string{"v1", "v2", "v3"}}
+			request++
+		} else {
+			resp = swagger.ApiDeclaration{}
+		}
+		output, err := json.Marshal(resp)
+		if err != nil {
+			sErr = err
+			return
+		}
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusOK)
+		w.Write(output)
+	}))
+	return server, sErr
+}
+
+func TestGetSwaggerSchema(t *testing.T) {
+	expect := swagger.ApiDeclaration{}
+
+	server, err := swaggerSchemaFakeServer()
+	if err != nil {
+		t.Errorf("unexpected encoding error: %v", err)
+	}
+
+	client := NewOrDie(&Config{Host: server.URL})
+	got, err := client.SwaggerSchema("v1")
+	if err != nil {
+		t.Fatalf("unexpected encoding error: %v", err)
+	}
+	if e, a := expect, *got; !reflect.DeepEqual(e, a) {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+}
+
+func TestGetSwaggerSchemaFail(t *testing.T) {
+	expErr := "API version: v4 is not supported by the server. Use one of: [v1 v2 v3]"
+
+	server, err := swaggerSchemaFakeServer()
+	if err != nil {
+		t.Errorf("unexpected encoding error: %v", err)
+	}
+
+	client := NewOrDie(&Config{Host: server.URL})
+	got, err := client.SwaggerSchema("v4")
+	if got != nil {
+		t.Fatalf("unexpected response: %v", got)
+	}
+	if err.Error() != expErr {
+		t.Errorf("expected an error, got %v", err)
+	}
+}

pkg/client/unversioned/testclient/testclient.go

@@ -20,6 +20,8 @@ import (
 	"fmt"
 	"sync"
 
+	"github.com/emicklei/go-restful/swagger"
+
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/api/registered"
 	client "k8s.io/kubernetes/pkg/client/unversioned"
@@ -282,6 +284,16 @@ func (c *Fake) ComponentStatuses() client.ComponentStatusInterface {
 	return &FakeComponentStatuses{Fake: c}
 }
 
+// SwaggerSchema returns an empty swagger.ApiDeclaration for testing
+func (c *Fake) SwaggerSchema(version string) (*swagger.ApiDeclaration, error) {
+	action := ActionImpl{}
+	action.Verb = "get"
+	action.Resource = "/swaggerapi/api/" + version
+
+	c.Invokes(action, nil)
+	return &swagger.ApiDeclaration{}, nil
+}
+
 type FakeExperimental struct {
 	*Fake
 }