Add command "kubectl config get-contexts"

Note: Context is not a runtime object (doesn't have Kind and Version) so
      we can't use the resource_printer

.generated_docs

@@ -15,6 +15,7 @@ docs/man/man1/kubectl-cluster-info-dump.1
 docs/man/man1/kubectl-cluster-info.1
 docs/man/man1/kubectl-completion.1
 docs/man/man1/kubectl-config-current-context.1
+docs/man/man1/kubectl-config-get-contexts.1
 docs/man/man1/kubectl-config-set-cluster.1
 docs/man/man1/kubectl-config-set-context.1
 docs/man/man1/kubectl-config-set-credentials.1
@@ -75,6 +76,7 @@ docs/user-guide/kubectl/kubectl_cluster-info_dump.md
 docs/user-guide/kubectl/kubectl_completion.md
 docs/user-guide/kubectl/kubectl_config.md
 docs/user-guide/kubectl/kubectl_config_current-context.md
+docs/user-guide/kubectl/kubectl_config_get-contexts.md
 docs/user-guide/kubectl/kubectl_config_set-cluster.md
 docs/user-guide/kubectl/kubectl_config_set-context.md
 docs/user-guide/kubectl/kubectl_config_set-credentials.md

CHANGELOG.md

@@ -2,11 +2,9 @@
 
 - [v1.3.0](#v130)
   - [Downloads](#downloads)
-  - [Major Themes](#major-themes)
-  - [Other notable improvements](#other-notable-improvements)
-  - [Known Issues](#known-issues)
+  - [Highlights](#highlights)
+  - [Known Issues and Important Steps before Upgrading](#known-issues-and-important-steps-before-upgrading)
   - [Provider-specific Notes](#provider-specific-notes)
-  - [Changelog since v1.3.0-beta.3](#changelog-since-v130-beta3)
     - [Previous Releases Included in v1.3.0](#previous-releases-included-in-v130)
 - [v1.3.0-beta.3](#v130-beta3)
   - [Downloads](#downloads)
@@ -102,7 +100,7 @@ binary | sha1 hash | md5 hash
 
 * Authorization:
   * **Alpha** RBAC authorization API group
-* Federation 
+* Federation
   * federation api group is now **beta**
   * Services from all federated clusters are now registered in Cloud DNS (AWS and GCP).
 * Stateful Apps:
@@ -139,7 +137,7 @@ binary | sha1 hash | md5 hash
   * ARP caching fix
   * Use /dev/xvdXX names
   * ELB:
-    * ELB proxy protocol support 
+    * ELB proxy protocol support
     * mixed plaintext/encrypted ports support in ELBs
     * SSL support for ELB listeners
   * Allow VPC CIDR to be specified (experimental)

docs/man/man1/kubectl-config-get-contexts.1

@@ -0,0 +1,3 @@
+This file is autogenerated, but we've stopped checking such files into the
+repository to reduce the need for rebases. Please run hack/generate-docs.sh to
+populate this file.

docs/user-guide/kubectl/kubectl_config_get-contexts.md

@@ -0,0 +1,36 @@
+<!-- BEGIN MUNGE: UNVERSIONED_WARNING -->
+
+<!-- BEGIN STRIP_FOR_RELEASE -->
+
+<img src="http://kubernetes.io/img/warning.png" alt="WARNING"
+     width="25" height="25">
+<img src="http://kubernetes.io/img/warning.png" alt="WARNING"
+     width="25" height="25">
+<img src="http://kubernetes.io/img/warning.png" alt="WARNING"
+     width="25" height="25">
+<img src="http://kubernetes.io/img/warning.png" alt="WARNING"
+     width="25" height="25">
+<img src="http://kubernetes.io/img/warning.png" alt="WARNING"
+     width="25" height="25">
+
+<h2>PLEASE NOTE: This document applies to the HEAD of the source tree</h2>
+
+If you are using a released version of Kubernetes, you should
+refer to the docs that go with that version.
+
+Documentation for other releases can be found at
+[releases.k8s.io](http://releases.k8s.io).
+</strong>
+--
+
+<!-- END STRIP_FOR_RELEASE -->
+
+<!-- END MUNGE: UNVERSIONED_WARNING -->
+
+This file is autogenerated, but we've stopped checking such files into the
+repository to reduce the need for rebases. Please run hack/generate-docs.sh to
+populate this file.
+
+<!-- BEGIN MUNGE: GENERATED_ANALYTICS -->
+[![Analytics](https://kubernetes-site.appspot.com/UA-36037335-10/GitHub/docs/user-guide/kubectl/kubectl_config_get-contexts.md?pixel)]()
+<!-- END MUNGE: GENERATED_ANALYTICS -->

pkg/kubectl/cmd/config/config.go

@@ -57,6 +57,7 @@ The loading order follows these rules:
 	cmd.AddCommand(NewCmdConfigUnset(out, pathOptions))
 	cmd.AddCommand(NewCmdConfigCurrentContext(out, pathOptions))
 	cmd.AddCommand(NewCmdConfigUseContext(out, pathOptions))
+	cmd.AddCommand(NewCmdConfigGetContexts(out, pathOptions))
 
 	return cmd
 }

pkg/kubectl/cmd/config/get_contexts.go

@@ -0,0 +1,168 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+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 config
+
+import (
+	"fmt"
+	"io"
+	"strings"
+	"text/tabwriter"
+
+	"github.com/spf13/cobra"
+	"k8s.io/kubernetes/pkg/client/unversioned/clientcmd"
+	clientcmdapi "k8s.io/kubernetes/pkg/client/unversioned/clientcmd/api"
+	"k8s.io/kubernetes/pkg/kubectl"
+
+	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
+	utilerrors "k8s.io/kubernetes/pkg/util/errors"
+	"k8s.io/kubernetes/pkg/util/sets"
+)
+
+// GetContextsOptions contains the assignable options from the args.
+type GetContextsOptions struct {
+	configAccess clientcmd.ConfigAccess
+	nameOnly     bool
+	showHeaders  bool
+	contextNames []string
+	out          io.Writer
+}
+
+const (
+	getContextsLong = `Displays one or many contexts from the kubeconfig file.`
+
+	getContextsExample = `# List all the contexts in your kubeconfig file
+kubectl config get-contexts
+
+# Describe one context in your kubeconfig file.
+kubectl config get-contexts my-context`
+)
+
+// NewCmdConfigGetContexts creates a command object for the "get-contexts" action, which
+// retrieves one or more contexts from a kubeconfig.
+func NewCmdConfigGetContexts(out io.Writer, configAccess clientcmd.ConfigAccess) *cobra.Command {
+	options := &GetContextsOptions{configAccess: configAccess}
+
+	cmd := &cobra.Command{
+		Use:     "get-contexts [(-o|--output=)name)]",
+		Short:   "Describe one or many contexts",
+		Long:    getContextsLong,
+		Example: getContextsExample,
+		Run: func(cmd *cobra.Command, args []string) {
+			validOutputTypes := sets.NewString("", "json", "yaml", "wide", "name", "go-template", "go-template-file", "jsonpath", "jsonpath-file")
+			supportedOutputTypes := sets.NewString("", "name")
+			outputFormat := cmdutil.GetFlagString(cmd, "output")
+			if !validOutputTypes.Has(outputFormat) {
+				cmdutil.CheckErr(fmt.Errorf("output must be one of '' or 'name': %v", outputFormat))
+			}
+			if !supportedOutputTypes.Has(outputFormat) {
+				fmt.Fprintf(out, "--output %v is not available in kubectl config get-contexts; reseting to default output format", outputFormat)
+				cmd.Flags().Set("output", "")
+			}
+			cmdutil.CheckErr(options.Complete(cmd, args, out))
+			cmdutil.CheckErr(options.RunGetContexts())
+		},
+	}
+	cmdutil.AddOutputFlags(cmd)
+	cmdutil.AddNoHeadersFlags(cmd)
+	return cmd
+}
+
+// Complete assigns GetContextsOptions from the args.
+func (o *GetContextsOptions) Complete(cmd *cobra.Command, args []string, out io.Writer) error {
+	o.contextNames = args
+	o.out = out
+	o.nameOnly = false
+	if cmdutil.GetFlagString(cmd, "output") == "name" {
+		o.nameOnly = true
+	}
+	o.showHeaders = true
+	if cmdutil.GetFlagBool(cmd, "no-headers") || o.nameOnly {
+		o.showHeaders = false
+	}
+
+	return nil
+}
+
+// RunGetContexts implements all the necessary functionality for context retrieval.
+func (o GetContextsOptions) RunGetContexts() error {
+	config, err := o.configAccess.GetStartingConfig()
+	if err != nil {
+		return err
+	}
+
+	out, found := o.out.(*tabwriter.Writer)
+	if !found {
+		out = kubectl.GetNewTabWriter(o.out)
+		defer out.Flush()
+	}
+
+	// Build a list of context names to print, and warn if any requested contexts are not found.
+	// Do this before printing the headers so it doesn't look ugly.
+	allErrs := []error{}
+	toPrint := []string{}
+	if len(o.contextNames) == 0 {
+		for name := range config.Contexts {
+			toPrint = append(toPrint, name)
+		}
+	} else {
+		for _, name := range o.contextNames {
+			_, ok := config.Contexts[name]
+			if ok {
+				toPrint = append(toPrint, name)
+			} else {
+				allErrs = append(allErrs, fmt.Errorf("context %v not found", name))
+			}
+		}
+	}
+	if o.showHeaders {
+		err = printContextHeaders(out, o.nameOnly)
+		if err != nil {
+			allErrs = append(allErrs, err)
+		}
+	}
+
+	for _, name := range toPrint {
+		err = printContext(name, config.Contexts[name], out, o.nameOnly, config.CurrentContext == name)
+		if err != nil {
+			allErrs = append(allErrs, err)
+		}
+	}
+
+	return utilerrors.NewAggregate(allErrs)
+}
+
+func printContextHeaders(out io.Writer, nameOnly bool) error {
+	columnNames := []string{"CURRENT", "NAME", "CLUSTER", "AUTHINFO", "NAMESPACE"}
+	if nameOnly {
+		columnNames = columnNames[:1]
+	}
+	_, err := fmt.Fprintf(out, "%s\n", strings.Join(columnNames, "\t"))
+	return err
+}
+
+func printContext(name string, context *clientcmdapi.Context, w io.Writer, nameOnly, current bool) error {
+	if nameOnly {
+		_, err := fmt.Fprintf(w, "%s\n", name)
+		return err
+	}
+	prefix := " "
+	if current {
+		prefix = "*"
+	}
+	_, err := fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\n", prefix, name, context.Cluster, context.AuthInfo, context.Namespace)
+	return err
+}

pkg/kubectl/cmd/config/get_contexts_test.go

@@ -0,0 +1,158 @@
+/*
+Copyright 2014 The Kubernetes Authors.
+
+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 config
+
+import (
+	"bytes"
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"k8s.io/kubernetes/pkg/client/unversioned/clientcmd"
+	clientcmdapi "k8s.io/kubernetes/pkg/client/unversioned/clientcmd/api"
+)
+
+type getContextsTest struct {
+	startingConfig clientcmdapi.Config
+	names          []string
+	noHeader       bool
+	nameOnly       bool
+	expectedOut    string
+}
+
+func TestGetContextsAll(t *testing.T) {
+	tconf := clientcmdapi.Config{
+		CurrentContext: "shaker-context",
+		Contexts: map[string]*clientcmdapi.Context{
+			"shaker-context": {AuthInfo: "blue-user", Cluster: "big-cluster", Namespace: "saw-ns"}}}
+	test := getContextsTest{
+		startingConfig: tconf,
+		names:          []string{},
+		noHeader:       false,
+		nameOnly:       false,
+		expectedOut: `CURRENT   NAME             CLUSTER       AUTHINFO    NAMESPACE
+*         shaker-context   big-cluster   blue-user   saw-ns
+`,
+	}
+	test.run(t)
+}
+
+func TestGetContextsAllNoHeader(t *testing.T) {
+	tconf := clientcmdapi.Config{
+		CurrentContext: "shaker-context",
+		Contexts: map[string]*clientcmdapi.Context{
+			"shaker-context": {AuthInfo: "blue-user", Cluster: "big-cluster", Namespace: "saw-ns"}}}
+	test := getContextsTest{
+		startingConfig: tconf,
+		names:          []string{},
+		noHeader:       true,
+		nameOnly:       false,
+		expectedOut:    "*         shaker-context   big-cluster   blue-user   saw-ns\n",
+	}
+	test.run(t)
+}
+
+func TestGetContextsAllName(t *testing.T) {
+	tconf := clientcmdapi.Config{
+		Contexts: map[string]*clientcmdapi.Context{
+			"shaker-context": {AuthInfo: "blue-user", Cluster: "big-cluster", Namespace: "saw-ns"}}}
+	test := getContextsTest{
+		startingConfig: tconf,
+		names:          []string{},
+		noHeader:       false,
+		nameOnly:       true,
+		expectedOut:    "shaker-context\n",
+	}
+	test.run(t)
+}
+
+func TestGetContextsAllNameNoHeader(t *testing.T) {
+	tconf := clientcmdapi.Config{
+		CurrentContext: "shaker-context",
+		Contexts: map[string]*clientcmdapi.Context{
+			"shaker-context": {AuthInfo: "blue-user", Cluster: "big-cluster", Namespace: "saw-ns"}}}
+	test := getContextsTest{
+		startingConfig: tconf,
+		names:          []string{},
+		noHeader:       true,
+		nameOnly:       true,
+		expectedOut:    "shaker-context\n",
+	}
+	test.run(t)
+}
+
+func TestGetContextsAllNone(t *testing.T) {
+	test := getContextsTest{
+		startingConfig: *clientcmdapi.NewConfig(),
+		names:          []string{},
+		noHeader:       true,
+		nameOnly:       false,
+		expectedOut:    "",
+	}
+	test.run(t)
+}
+
+func TestGetContextsSelectOneOfTwo(t *testing.T) {
+	tconf := clientcmdapi.Config{
+		CurrentContext: "shaker-context",
+		Contexts: map[string]*clientcmdapi.Context{
+			"shaker-context": {AuthInfo: "blue-user", Cluster: "big-cluster", Namespace: "saw-ns"},
+			"not-this":       {AuthInfo: "blue-user", Cluster: "big-cluster", Namespace: "saw-ns"}}}
+	test := getContextsTest{
+		startingConfig: tconf,
+		names:          []string{"shaker-context"},
+		noHeader:       true,
+		nameOnly:       true,
+		expectedOut:    "shaker-context\n",
+	}
+	test.run(t)
+}
+
+func (test getContextsTest) run(t *testing.T) {
+	fakeKubeFile, _ := ioutil.TempFile("", "")
+	defer os.Remove(fakeKubeFile.Name())
+	err := clientcmd.WriteToFile(test.startingConfig, fakeKubeFile.Name())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	pathOptions := clientcmd.NewDefaultPathOptions()
+	pathOptions.GlobalFile = fakeKubeFile.Name()
+	pathOptions.EnvVar = ""
+	buf := bytes.NewBuffer([]byte{})
+	options := GetContextsOptions{
+		configAccess: pathOptions,
+	}
+	cmd := NewCmdConfigGetContexts(buf, options.configAccess)
+	if test.nameOnly {
+		cmd.Flags().Set("output", "name")
+	}
+	if test.noHeader {
+		cmd.Flags().Set("no-headers", "true")
+	}
+	cmd.Run(cmd, test.names)
+	if len(test.expectedOut) != 0 {
+		if buf.String() != test.expectedOut {
+			t.Errorf("Expected %v, but got %v", test.expectedOut, buf.String())
+		}
+		return
+	}
+
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+}

pkg/kubectl/cmd/util/printing.go

@@ -30,9 +30,9 @@ import (
 
 // AddPrinterFlags adds printing related flags to a command (e.g. output format, no headers, template path)
 func AddPrinterFlags(cmd *cobra.Command) {
-	cmd.Flags().StringP("output", "o", "", "Output format. One of: json|yaml|wide|name|go-template=...|go-template-file=...|jsonpath=...|jsonpath-file=... See golang template [http://golang.org/pkg/text/template/#pkg-overview] and jsonpath template [http://kubernetes.io/docs/user-guide/jsonpath].")
+	AddOutputFlags(cmd)
 	cmd.Flags().String("output-version", "", "Output the formatted object with the given group version (for ex: 'extensions/v1beta1').")
-	cmd.Flags().Bool("no-headers", false, "When using the default output, don't print headers.")
+	AddNoHeadersFlags(cmd)
 	cmd.Flags().Bool("show-labels", false, "When printing, show all labels as the last column (default hide labels column)")
 	cmd.Flags().String("template", "", "Template string or path to template file to use when -o=go-template, -o=go-template-file. The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview].")
 	cmd.MarkFlagFilename("template")
@@ -45,6 +45,16 @@ func AddOutputFlagsForMutation(cmd *cobra.Command) {
 	cmd.Flags().StringP("output", "o", "", "Output mode. Use \"-o name\" for shorter output (resource/name).")
 }
 
+// AddOutputFlags adds output related flags to a command.
+func AddOutputFlags(cmd *cobra.Command) {
+	cmd.Flags().StringP("output", "o", "", "Output format. One of: json|yaml|wide|name|go-template=...|go-template-file=...|jsonpath=...|jsonpath-file=... See golang template [http://golang.org/pkg/text/template/#pkg-overview] and jsonpath template [http://kubernetes.io/docs/user-guide/jsonpath].")
+}
+
+// AddNoHeadersFlags adds no-headers flags to a command.
+func AddNoHeadersFlags(cmd *cobra.Command) {
+	cmd.Flags().Bool("no-headers", false, "When using the default output, don't print headers.")
+}
+
 // PrintSuccess prints message after finishing mutating operations
 func PrintSuccess(mapper meta.RESTMapper, shortOutput bool, out io.Writer, resource string, name string, operation string) {
 	resource, _ = mapper.ResourceSingularizer(resource)