Refactor Get and Describe to allow extension of types

Get should use ResourceMapper, allow Printer to be abstracted,
and extract Describe as *Describer types.

Author: smarterclayton

cmd/kubectl/kubectl.go

@@ -23,5 +23,5 @@ import (
 )
 
 func main() {
-	cmd.RunKubectl(os.Stdout)
+	cmd.NewFactory().Run(os.Stdout)
 }

pkg/client/fake_pods.go

@@ -35,7 +35,7 @@ func (c *FakePods) List(selector labels.Selector) (*api.PodList, error) {
 
 func (c *FakePods) Get(name string) (*api.Pod, error) {
 	c.Fake.Actions = append(c.Fake.Actions, FakeAction{Action: "get-pod", Value: name})
-	return &api.Pod{}, nil
+	return &api.Pod{ObjectMeta: api.ObjectMeta{Name: name, Namespace: c.Namespace}}, nil
 }
 
 func (c *FakePods) Delete(name string) error {

pkg/client/fake_services.go

@@ -36,7 +36,7 @@ func (c *FakeServices) List(selector labels.Selector) (*api.ServiceList, error)
 
 func (c *FakeServices) Get(name string) (*api.Service, error) {
 	c.Fake.Actions = append(c.Fake.Actions, FakeAction{Action: "get-service", Value: name})
-	return &api.Service{}, nil
+	return &api.Service{ObjectMeta: api.ObjectMeta{Name: name, Namespace: c.Namespace}}, nil
 }
 
 func (c *FakeServices) Create(service *api.Service) (*api.Service, error) {

pkg/kubectl/cmd/cmd.go

@@ -35,13 +35,38 @@ import (
 	"github.com/spf13/cobra"
 )
 
+// Factory provides abstractions that allow the Kubectl command to be extended across multiple types
+// of resources and different API sets.
 type Factory struct {
-	Mapper meta.RESTMapper
-	Typer  runtime.ObjectTyper
-	Client func(*cobra.Command, *meta.RESTMapping) (kubectl.RESTClient, error)
+	Mapper    meta.RESTMapper
+	Typer     runtime.ObjectTyper
+	Client    func(*cobra.Command, *meta.RESTMapping) (kubectl.RESTClient, error)
+	Describer func(*cobra.Command, *meta.RESTMapping) (kubectl.Describer, error)
+	Printer   func(cmd *cobra.Command, mapping *meta.RESTMapping, noHeaders bool) (kubectl.ResourcePrinter, error)
 }
 
-func RunKubectl(out io.Writer) {
+// NewFactory creates a factory with the default Kubernetes resources defined
+func NewFactory() *Factory {
+	return &Factory{
+		Mapper: latest.RESTMapper,
+		Typer:  api.Scheme,
+		Client: func(cmd *cobra.Command, mapping *meta.RESTMapping) (kubectl.RESTClient, error) {
+			return getKubeClient(cmd), nil
+		},
+		Describer: func(cmd *cobra.Command, mapping *meta.RESTMapping) (kubectl.Describer, error) {
+			describer, ok := kubectl.DescriberFor(mapping.Kind, getKubeClient(cmd))
+			if !ok {
+				return nil, fmt.Errorf("No description has been implemented for %q", mapping.Kind)
+			}
+			return describer, nil
+		},
+		Printer: func(cmd *cobra.Command, mapping *meta.RESTMapping, noHeaders bool) (kubectl.ResourcePrinter, error) {
+			return kubectl.NewHumanReadablePrinter(noHeaders), nil
+		},
+	}
+}
+
+func (f *Factory) Run(out io.Writer) {
 	// Parent command to which all subcommands are added.
 	cmds := &cobra.Command{
 		Use:   "kubectl",
@@ -52,15 +77,6 @@ Find more information at https://github.com/GoogleCloudPlatform/kubernetes.`,
 		Run: runHelp,
 	}
 
-	factory := &Factory{
-		Mapper: latest.NewDefaultRESTMapper(),
-		Typer:  api.Scheme,
-		Client: func(cmd *cobra.Command, mapping *meta.RESTMapping) (kubectl.RESTClient, error) {
-			// Will handle all resources defined by the command
-			return getKubeClient(cmd), nil
-		},
-	}
-
 	// Globally persistent flags across all subcommands.
 	// TODO Change flag names to consts to allow safer lookup from subcommands.
 	// TODO Add a verbose flag that turns on glog logging. Probably need a way
@@ -78,12 +94,12 @@ Find more information at https://github.com/GoogleCloudPlatform/kubernetes.`,
 
 	cmds.AddCommand(NewCmdVersion(out))
 	cmds.AddCommand(NewCmdProxy(out))
-	cmds.AddCommand(NewCmdGet(out))
-	cmds.AddCommand(NewCmdDescribe(out))
 
-	cmds.AddCommand(factory.NewCmdCreate(out))
-	cmds.AddCommand(factory.NewCmdUpdate(out))
-	cmds.AddCommand(factory.NewCmdDelete(out))
+	cmds.AddCommand(f.NewCmdGet(out))
+	cmds.AddCommand(f.NewCmdDescribe(out))
+	cmds.AddCommand(f.NewCmdCreate(out))
+	cmds.AddCommand(f.NewCmdUpdate(out))
+	cmds.AddCommand(f.NewCmdDelete(out))
 
 	cmds.AddCommand(NewCmdNamespace(out))
 	cmds.AddCommand(NewCmdLog(out))

pkg/kubectl/cmd/create.go

@@ -47,7 +47,7 @@ Examples:
 			client, err := f.Client(cmd, mapping)
 			checkErr(err)
 
-			err = kubectl.NewRESTModifier(client, mapping).Create(namespace, data)
+			err = kubectl.NewRESTHelper(client, mapping).Create(namespace, data)
 			checkErr(err)
 			fmt.Fprintf(out, "%s\n", name)
 		},

pkg/kubectl/cmd/delete.go

@@ -54,7 +54,7 @@ Examples:
 			client, err := f.Client(cmd, mapping)
 			checkErr(err)
 
-			err = kubectl.NewRESTModifier(client, mapping).Delete(namespace, name)
+			err = kubectl.NewRESTHelper(client, mapping).Delete(namespace, name)
 			checkErr(err)
 			fmt.Fprintf(out, "%s\n", name)
 		},

pkg/kubectl/cmd/describe.go

@@ -17,13 +17,13 @@ limitations under the License.
 package cmd
 
 import (
+	"fmt"
 	"io"
 
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl"
 	"github.com/spf13/cobra"
 )
 
-func NewCmdDescribe(out io.Writer) *cobra.Command {
+func (f *Factory) NewCmdDescribe(out io.Writer) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "describe <resource> <id>",
 		Short: "Show details of a specific resource",
@@ -32,13 +32,14 @@ func NewCmdDescribe(out io.Writer) *cobra.Command {
 This command joins many API calls together to form a detailed description of a
 given resource.`,
 		Run: func(cmd *cobra.Command, args []string) {
-			if len(args) < 2 {
-				usageError(cmd, "Need to supply a resource and an ID")
-			}
-			resource := args[0]
-			id := args[1]
-			err := kubectl.Describe(out, getKubeClient(cmd), resource, id)
+			mapping, namespace, name := ResourceFromArgs(cmd, args, f.Mapper)
+
+			describer, err := f.Describer(cmd, mapping)
+			checkErr(err)
+
+			s, err := describer.Describe(namespace, name)
 			checkErr(err)
+			fmt.Fprintf(out, "%s\n", s)
 		},
 	}
 	return cmd

pkg/kubectl/cmd/get.go

@@ -20,12 +20,13 @@ import (
 	"io"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
 	"github.com/spf13/cobra"
 )
 
-func NewCmdGet(out io.Writer) *cobra.Command {
+func (f *Factory) NewCmdGet(out io.Writer) *cobra.Command {
 	cmd := &cobra.Command{
-		Use:   "get [(-o|--output=)table|json|yaml|template] [-t <file>|--template=<file>] <resource> [<id>]",
+		Use:   "get [(-o|--output=)console|json|yaml|...] <resource> [<id>]",
 		Short: "Display one or many resources",
 		Long: `Display one or many resources.
 
@@ -44,20 +45,24 @@ Examples:
   $ kubectl get -f json pod 1234-56-7890-234234-456456
   <list single pod in json output format>`,
 		Run: func(cmd *cobra.Command, args []string) {
-			var resource, id string
-			if len(args) == 0 {
-				usageError(cmd, "Need to supply a resource.")
-			}
-			if len(args) >= 1 {
-				resource = args[0]
-			}
-			if len(args) >= 2 {
-				id = args[1]
-			}
+			mapping, namespace, name := ResourceOrTypeFromArgs(cmd, args, f.Mapper)
+
+			selector := getFlagString(cmd, "selector")
+			labels, err := labels.ParseSelector(selector)
+			checkErr(err)
+
+			client, err := f.Client(cmd, mapping)
+			checkErr(err)
+
+			obj, err := kubectl.NewRESTHelper(client, mapping).Get(namespace, name, labels)
+			checkErr(err)
+
 			outputFormat := getFlagString(cmd, "output")
 			templateFile := getFlagString(cmd, "template")
-			selector := getFlagString(cmd, "selector")
-			err := kubectl.Get(out, getKubeClient(cmd).RESTClient, getKubeNamespace(cmd), resource, id, selector, outputFormat, getFlagBool(cmd, "no-headers"), templateFile)
+			defaultPrinter, err := f.Printer(cmd, mapping, getFlagBool(cmd, "no-headers"))
+			checkErr(err)
+
+			err = kubectl.Print(out, obj, outputFormat, templateFile, defaultPrinter)
 			checkErr(err)
 		},
 	}

pkg/kubectl/cmd/resource.go

@@ -21,7 +21,6 @@ import (
 
 	"github.com/spf13/cobra"
 
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/meta"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
 )
@@ -37,7 +36,7 @@ func ResourceFromArgsOrFile(cmd *cobra.Command, args []string, filename string,
 
 	if len(args) == 2 {
 		resource := args[0]
-		namespace = api.NamespaceDefault
+		namespace = getKubeNamespace(cmd)
 		name = args[1]
 		if len(name) == 0 || len(resource) == 0 {
 			usageError(cmd, "Must specify filename or command line params")
@@ -63,6 +62,62 @@ func ResourceFromArgsOrFile(cmd *cobra.Command, args []string, filename string,
 	return
 }
 
+// ResourceFromArgs expects two arguments with a given type, and extracts the fields necessary
+// to uniquely locate a resource. Displays a usageError if that contract is not satisfied, or
+// a generic error if any other problems occur.
+func ResourceFromArgs(cmd *cobra.Command, args []string, mapper meta.RESTMapper) (mapping *meta.RESTMapping, namespace, name string) {
+	if len(args) != 2 {
+		usageError(cmd, "Must provide resource and name command line params")
+	}
+
+	resource := args[0]
+	namespace = getKubeNamespace(cmd)
+	name = args[1]
+	if len(name) == 0 || len(resource) == 0 {
+		usageError(cmd, "Must provide resource and name command line params")
+	}
+
+	version, kind, err := mapper.VersionAndKindForResource(resource)
+	checkErr(err)
+
+	mapping, err = mapper.RESTMapping(version, kind)
+	checkErr(err)
+	return
+}
+
+// ResourceFromArgs expects two arguments with a given type, and extracts the fields necessary
+// to uniquely locate a resource. Displays a usageError if that contract is not satisfied, or
+// a generic error if any other problems occur.
+func ResourceOrTypeFromArgs(cmd *cobra.Command, args []string, mapper meta.RESTMapper) (mapping *meta.RESTMapping, namespace, name string) {
+	if len(args) == 0 || len(args) > 2 {
+		usageError(cmd, "Must provide resource or a resource and name as command line params")
+	}
+
+	resource := args[0]
+	if len(resource) == 0 {
+		usageError(cmd, "Must provide resource or a resource and name as command line params")
+	}
+
+	namespace = getKubeNamespace(cmd)
+	if len(args) == 2 {
+		name = args[1]
+		if len(name) == 0 {
+			usageError(cmd, "Must provide resource or a resource and name as command line params")
+		}
+	}
+
+	version, kind, err := mapper.VersionAndKindForResource(resource)
+	checkErr(err)
+
+	mapping, err = mapper.RESTMapping(version, kind)
+	checkErr(err)
+
+	return
+}
+
+// ResourceFromFile retrieves the name and namespace from a valid file. If the file does not
+// resolve to a known type an error is returned. The returned mapping can be used to determine
+// the correct REST endpoint to modify this resource with.
 func ResourceFromFile(filename string, typer runtime.ObjectTyper, mapper meta.RESTMapper) (mapping *meta.RESTMapping, namespace, name string, data []byte) {
 	configData, err := readConfigData(filename)
 	checkErr(err)

pkg/kubectl/cmd/update.go

@@ -47,7 +47,7 @@ Examples:
 			client, err := f.Client(cmd, mapping)
 			checkErr(err)
 
-			err = kubectl.NewRESTModifier(client, mapping).Update(namespace, name, true, data)
+			err = kubectl.NewRESTHelper(client, mapping).Update(namespace, name, true, data)
 			checkErr(err)
 			fmt.Fprintf(out, "%s\n", name)
 		},