Add a resize command to kubectl.

docs/kubectl.md

@@ -388,6 +388,7 @@ Additional help topics:
   kubectl namespace     Set and view the current Kubernetes namespace
   kubectl log           Print the logs for a container in a pod.
   kubectl rollingupdate Perform a rolling update of the given ReplicationController
+  kubectl resize        Set a new size for a resizable resource (currently only Replication Controllers)
   kubectl run-container Run a particular image on the cluster.
 
 Use "kubectl help [command]" for more information about that command.
@@ -815,6 +816,59 @@ Usage:
 
 ```
 
+#### resize
+Set a new size for a resizable resource (currently only Replication Controllers)
+
+Resize also allows users to specify one or more preconditions for the resize action.
+The new size is specified by --replicas=<n>. You can also specify an optional precondition. 
+The two currently supported options are --current-replicas or --resource-version.
+If a precondition is specified, it is validated before the resize is attempted, and it is 
+guaranteed that the precondition holds true when the resize is sent to the server.
+
+Examples:
+  $ kubectl resize replicationcontrollers foo 3
+  resized
+
+  # will only execute if the current size is 3
+  $ kubectl resize --current-replicas=2 replicationcontrollers foo 3
+
+
+Usage:
+```
+  kubectl resize [---resource-version=<version>] [--current-replicas=<count>] --replicas=<count> <resource> <id> [flags]
+
+ Available Flags:
+      --alsologtostderr=false: log to standard error as well as files
+      --api-version="": The API version to use when talking to the server
+  -a, --auth-path="": Path to the auth info file. If missing, prompt the user. Only used if using https.
+      --certificate-authority="": Path to a cert. file for the certificate authority.
+      --client-certificate="": Path to a client key file for TLS.
+      --client-key="": Path to a client key file for TLS.
+      --cluster="": The name of the kubeconfig cluster to use
+      --context="": The name of the kubeconfig context to use
+      --current-replicas=-1: Precondition for current size. Requires that the current size of the replication controller match this value in order to resize
+  -h, --help=false: help for resize
+      --insecure-skip-tls-verify=false: If true, the server's certificate will not be checked for validity. This will make your HTTPS connections insecure.
+      --kubeconfig="": Path to the kubeconfig file to use for CLI requests.
+      --log_backtrace_at=:0: when logging hits line file:N, emit a stack trace
+      --log_dir=: If non-empty, write log files in this directory
+      --log_flush_frequency=5s: Maximum number of seconds between log flushes
+      --logtostderr=true: log to standard error instead of files
+      --match-server-version=false: Require server version to match client version
+  -n, --namespace="": If present, the namespace scope for this CLI request.
+      --ns-path="/home/username/.kubernetes_ns": Path to the namespace info file that holds the namespace context to use for CLI requests.
+      --replicas=-1: The new number desired number of replicas.  Required.
+      --resource-version="": Precondition for resource version. Requires that the current resource version match this value in order to resize
+  -s, --server="": The address of the Kubernetes API server
+      --stderrthreshold=2: logs at or above this threshold go to stderr
+      --token="": Bearer token for authentication to the API server.
+      --user="": The name of the kubeconfig user to use
+      --v=0: log level for V logs
+      --validate=false: If true, use a schema to validate the input before sending it
+      --vmodule=: comma-separated list of pattern=N settings for file-filtered logging
+
+```
+
 #### run-container
 Create and run a particular image, possibly replicated.
 Creates a replication controller to manage the created container(s)

pkg/kubectl/cmd/cmd.go

@@ -62,6 +62,8 @@ type Factory struct {
 	Describer func(cmd *cobra.Command, mapping *meta.RESTMapping) (kubectl.Describer, error)
 	// Returns a Printer for formatting objects of the given type or an error.
 	Printer func(cmd *cobra.Command, mapping *meta.RESTMapping, noHeaders bool) (kubectl.ResourcePrinter, error)
+	// Returns a Resizer for changing the size of the specified RESTMapping type or an error
+	Resizer func(cmd *cobra.Command, mapping *meta.RESTMapping) (kubectl.Resizer, error)
 	// Returns a schema that can validate objects stored on disk.
 	Validator func(*cobra.Command) (validation.Schema, error)
 }
@@ -112,6 +114,17 @@ func NewFactory() *Factory {
 		Printer: func(cmd *cobra.Command, mapping *meta.RESTMapping, noHeaders bool) (kubectl.ResourcePrinter, error) {
 			return kubectl.NewHumanReadablePrinter(noHeaders), nil
 		},
+		Resizer: func(cmd *cobra.Command, mapping *meta.RESTMapping) (kubectl.Resizer, error) {
+			client, err := clients.ClientForVersion(mapping.APIVersion)
+			if err != nil {
+				return nil, err
+			}
+			resizer, ok := kubectl.ResizerFor(mapping.Kind, client)
+			if !ok {
+				return nil, fmt.Errorf("no resizer has been implemented for %q", mapping.Kind)
+			}
+			return resizer, nil
+		},
 		Validator: func(cmd *cobra.Command) (validation.Schema, error) {
 			if GetFlagBool(cmd, "validate") {
 				client, err := clients.ClientForVersion("")
@@ -173,6 +186,7 @@ Find more information at https://github.com/GoogleCloudPlatform/kubernetes.`,
 	cmds.AddCommand(NewCmdNamespace(out))
 	cmds.AddCommand(f.NewCmdLog(out))
 	cmds.AddCommand(f.NewCmdRollingUpdate(out))
+	cmds.AddCommand(f.NewCmdResize(out))
 
 	cmds.AddCommand(f.NewCmdRunContainer(out))
 

pkg/kubectl/cmd/resize.go

@@ -0,0 +1,68 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cmd
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl"
+	"github.com/spf13/cobra"
+)
+
+func (f *Factory) NewCmdResize(out io.Writer) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "resize [---resource-version=<version>] [--current-replicas=<count>] --replicas=<count> <resource> <id>",
+		Short: "Set a new size for a resizable resource (currently only Replication Controllers)",
+		Long: `Set a new size for a resizable resource (currently only Replication Controllers)
+
+Resize also allows users to specify one or more preconditions for the resize action.
+The new size is specified by --replicas=<n>. You can also specify an optional precondition. 
+The two currently supported options are --current-replicas or --resource-version.
+If a precondition is specified, it is validated before the resize is attempted, and it is 
+guaranteed that the precondition holds true when the resize is sent to the server.
+
+Examples:
+  $ kubectl resize replicationcontrollers foo 3
+  resized
+
+  # will only execute if the current size is 3
+  $ kubectl resize --current-replicas=2 replicationcontrollers foo 3
+`,
+		Run: func(cmd *cobra.Command, args []string) {
+			count := GetFlagInt(cmd, "replicas")
+			if len(args) != 2 || count < 0 {
+				usageError(cmd, "--replicas=<count> <resource> <id>")
+			}
+			mapper, _ := f.Object(cmd)
+			mapping, namespace, name := ResourceFromArgs(cmd, args, mapper)
+
+			resizer, err := f.Resizer(cmd, mapping)
+			checkErr(err)
+
+			resourceVersion := GetFlagString(cmd, "resource-version")
+			currentSize := GetFlagInt(cmd, "current-replicas")
+			s, err := resizer.Resize(namespace, name, &kubectl.ResizePrecondition{currentSize, resourceVersion}, uint(count))
+			checkErr(err)
+			fmt.Fprintf(out, "%s\n", s)
+		},
+	}
+	cmd.Flags().String("resource-version", "", "Precondition for resource version. Requires that the current resource version match this value in order to resize")
+	cmd.Flags().Int("current-replicas", -1, "Precondition for current size. Requires that the current size of the replication controller match this value in order to resize")
+	cmd.Flags().Int("replicas", -1, "The new number desired number of replicas.  Required.")
+	return cmd
+}

pkg/kubectl/resize.go

@@ -0,0 +1,93 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kubectl
+
+import (
+	"fmt"
+	"strconv"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
+)
+
+// ResizePrecondition describes a condition that must be true for the resize to take place
+// If CurrentSize == -1, it is ignored.
+// If CurrentResourceVersion is the empty string, it is ignored.
+// Otherwise they must equal the values in the replication controller for it to be valid.
+type ResizePrecondition struct {
+	Size            int
+	ResourceVersion string
+}
+
+type PreconditionError struct {
+	Precondition  string
+	ExpectedValue string
+	ActualValue   string
+}
+
+func (pe *PreconditionError) Error() string {
+	return fmt.Sprintf("Expected %s to be %s, was %s", pe.Precondition, pe.ExpectedValue, pe.ActualValue)
+}
+
+// Validate ensures that the preconditions match.  Returns nil if they are valid, an error otherwise
+func (precondition *ResizePrecondition) Validate(controller *api.ReplicationController) error {
+	if precondition.Size != -1 && controller.Spec.Replicas != precondition.Size {
+		return &PreconditionError{"replicas", strconv.Itoa(precondition.Size), strconv.Itoa(controller.Spec.Replicas)}
+	}
+	if precondition.ResourceVersion != "" && controller.ResourceVersion != precondition.ResourceVersion {
+		return &PreconditionError{"resource version", precondition.ResourceVersion, controller.ResourceVersion}
+	}
+	return nil
+}
+
+type Resizer interface {
+	Resize(namespace, name string, preconditions *ResizePrecondition, newSize uint) (string, error)
+}
+
+func ResizerFor(kind string, c *client.Client) (Resizer, bool) {
+	switch kind {
+	case "ReplicationController":
+		return &ReplicationControllerResizer{c}, true
+	}
+	return nil, false
+}
+
+type ReplicationControllerResizer struct {
+	client.Interface
+}
+
+func (resize *ReplicationControllerResizer) Resize(namespace, name string, preconditions *ResizePrecondition, newSize uint) (string, error) {
+	rc := resize.ReplicationControllers(namespace)
+	controller, err := rc.Get(name)
+	if err != nil {
+		return "", err
+	}
+
+	if preconditions != nil {
+		if err := preconditions.Validate(controller); err != nil {
+			return "", err
+		}
+	}
+
+	controller.Spec.Replicas = int(newSize)
+	// TODO: do retry on 409 errors here?
+	if _, err := rc.Update(controller); err != nil {
+		return "", err
+	}
+	// TODO: do a better job of printing objects here.
+	return "resized", nil
+}

pkg/kubectl/resize_test.go

@@ -0,0 +1,182 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kubectl
+
+import (
+	//	"strings"
+	"testing"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
+	//	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+)
+
+func TestReplicationControllerResize(t *testing.T) {
+	fake := &client.Fake{}
+	resizer := ReplicationControllerResizer{fake}
+	preconditions := ResizePrecondition{-1, ""}
+	count := uint(3)
+	name := "foo"
+	resizer.Resize("default", name, &preconditions, count)
+
+	if len(fake.Actions) != 2 {
+		t.Errorf("unexpected actions: %v, expected 2 actions (get, update)", fake.Actions)
+	}
+	if fake.Actions[0].Action != "get-controller" || fake.Actions[0].Value != name {
+		t.Errorf("unexpected action: %v, expected get-controller %s", fake.Actions[0], name)
+	}
+	if fake.Actions[1].Action != "update-controller" || fake.Actions[1].Value.(*api.ReplicationController).Spec.Replicas != int(count) {
+		t.Errorf("unexpected action %v, expected update-controller with replicas = %d", count)
+	}
+}
+
+func TestReplicationControllerResizeFailsPreconditions(t *testing.T) {
+	fake := &client.Fake{
+		Ctrl: api.ReplicationController{
+			Spec: api.ReplicationControllerSpec{
+				Replicas: 10,
+			},
+		},
+	}
+	resizer := ReplicationControllerResizer{fake}
+	preconditions := ResizePrecondition{2, ""}
+	count := uint(3)
+	name := "foo"
+	resizer.Resize("default", name, &preconditions, count)
+
+	if len(fake.Actions) != 1 {
+		t.Errorf("unexpected actions: %v, expected 2 actions (get, update)", fake.Actions)
+	}
+	if fake.Actions[0].Action != "get-controller" || fake.Actions[0].Value != name {
+		t.Errorf("unexpected action: %v, expected get-controller %s", fake.Actions[0], name)
+	}
+}
+
+func TestPreconditionValidate(t *testing.T) {
+	tests := []struct {
+		preconditions ResizePrecondition
+		controller    api.ReplicationController
+		expectError   bool
+		test          string
+	}{
+		{
+			preconditions: ResizePrecondition{-1, ""},
+			expectError:   false,
+			test:          "defaults",
+		},
+		{
+			preconditions: ResizePrecondition{-1, ""},
+			controller: api.ReplicationController{
+				ObjectMeta: api.ObjectMeta{
+					ResourceVersion: "foo",
+				},
+				Spec: api.ReplicationControllerSpec{
+					Replicas: 10,
+				},
+			},
+			expectError: false,
+			test:        "defaults 2",
+		},
+		{
+			preconditions: ResizePrecondition{0, ""},
+			controller: api.ReplicationController{
+				ObjectMeta: api.ObjectMeta{
+					ResourceVersion: "foo",
+				},
+				Spec: api.ReplicationControllerSpec{
+					Replicas: 0,
+				},
+			},
+			expectError: false,
+			test:        "size matches",
+		},
+		{
+			preconditions: ResizePrecondition{-1, "foo"},
+			controller: api.ReplicationController{
+				ObjectMeta: api.ObjectMeta{
+					ResourceVersion: "foo",
+				},
+				Spec: api.ReplicationControllerSpec{
+					Replicas: 10,
+				},
+			},
+			expectError: false,
+			test:        "resource version matches",
+		},
+		{
+			preconditions: ResizePrecondition{10, "foo"},
+			controller: api.ReplicationController{
+				ObjectMeta: api.ObjectMeta{
+					ResourceVersion: "foo",
+				},
+				Spec: api.ReplicationControllerSpec{
+					Replicas: 10,
+				},
+			},
+			expectError: false,
+			test:        "both match",
+		},
+		{
+			preconditions: ResizePrecondition{10, "foo"},
+			controller: api.ReplicationController{
+				ObjectMeta: api.ObjectMeta{
+					ResourceVersion: "foo",
+				},
+				Spec: api.ReplicationControllerSpec{
+					Replicas: 20,
+				},
+			},
+			expectError: true,
+			test:        "size different",
+		},
+		{
+			preconditions: ResizePrecondition{10, "foo"},
+			controller: api.ReplicationController{
+				ObjectMeta: api.ObjectMeta{
+					ResourceVersion: "bar",
+				},
+				Spec: api.ReplicationControllerSpec{
+					Replicas: 10,
+				},
+			},
+			expectError: true,
+			test:        "version different",
+		},
+		{
+			preconditions: ResizePrecondition{10, "foo"},
+			controller: api.ReplicationController{
+				ObjectMeta: api.ObjectMeta{
+					ResourceVersion: "bar",
+				},
+				Spec: api.ReplicationControllerSpec{
+					Replicas: 20,
+				},
+			},
+			expectError: true,
+			test:        "both different",
+		},
+	}
+	for _, test := range tests {
+		err := test.preconditions.Validate(&test.controller)
+		if err != nil && !test.expectError {
+			t.Errorf("unexpected error: %v (%s)", err, test.test)
+		}
+		if err == nil && test.expectError {
+			t.Errorf("unexpected non-error: %v (%s)", err, test.test)
+		}
+	}
+}