Merge pull request #96087 from VilledeMontreal/feat/goComp

Move all bash custom completions to Go

Kubernetes-commit: f7d2ecdc3e52b408833aa6269c57ad9ef408467e

pkg/cmd/annotate/annotate.go

@@ -38,6 +38,7 @@ import (
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/polymorphichelpers"
 	"k8s.io/kubectl/pkg/scheme"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -134,6 +135,7 @@ func NewCmdAnnotate(parent string, f cmdutil.Factory, ioStreams genericclioption
 		Short:                 i18n.T("Update the annotations on a resource"),
 		Long:                  annotateLong + "\n\n" + cmdutil.SuggestAPIResources(parent),
 		Example:               annotateExample,
+		ValidArgsFunction:     util.ResourceTypeAndNameCompletionFunc(f),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Validate())

pkg/cmd/apiresources/apiresources.go

@@ -17,8 +17,11 @@ limitations under the License.
 package apiresources
 
 import (
+	"bytes"
 	"fmt"
 	"io"
+	"io/ioutil"
+	"os"
 	"sort"
 	"strings"
 
@@ -275,3 +278,38 @@ func (s sortableResource) compareValues(i, j int) (string, string) {
 	}
 	return s.resources[i].APIGroup, s.resources[j].APIGroup
 }
+
+// CompGetResourceList returns the list of api resources which begin with `toComplete`.
+func CompGetResourceList(f cmdutil.Factory, cmd *cobra.Command, toComplete string) []string {
+	buf := new(bytes.Buffer)
+	streams := genericclioptions.IOStreams{In: os.Stdin, Out: buf, ErrOut: ioutil.Discard}
+	o := NewAPIResourceOptions(streams)
+
+	// Get the list of resources
+	o.Output = "name"
+	o.Cached = true
+	o.Verbs = []string{"get"}
+	// TODO:Should set --request-timeout=5s
+
+	// Ignore errors as the output may still be valid
+	o.RunAPIResources(cmd, f)
+
+	// Resources can be a comma-separated list.  The last element is then
+	// the one we should complete.  For example if toComplete=="pods,secre"
+	// we should return "pods,secrets"
+	prefix := ""
+	suffix := toComplete
+	lastIdx := strings.LastIndex(toComplete, ",")
+	if lastIdx != -1 {
+		prefix = toComplete[0 : lastIdx+1]
+		suffix = toComplete[lastIdx+1:]
+	}
+	var comps []string
+	resources := strings.Split(buf.String(), "\n")
+	for _, res := range resources {
+		if res != "" && strings.HasPrefix(res, suffix) {
+			comps = append(comps, fmt.Sprintf("%s%s", prefix, res))
+		}
+	}
+	return comps
+}

pkg/cmd/apply/apply_edit_last_applied.go

@@ -22,6 +22,7 @@ import (
 	"k8s.io/cli-runtime/pkg/genericclioptions"
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/cmd/util/editor"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -66,6 +67,7 @@ func NewCmdApplyEditLastApplied(f cmdutil.Factory, ioStreams genericclioptions.I
 		Short:                 i18n.T("Edit latest last-applied-configuration annotations of a resource/object"),
 		Long:                  applyEditLastAppliedLong,
 		Example:               applyEditLastAppliedExample,
+		ValidArgsFunction:     util.ResourceTypeAndNameCompletionFunc(f),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, args, cmd))
 			cmdutil.CheckErr(o.Run())

pkg/cmd/apply/apply_view_last_applied.go

@@ -77,6 +77,7 @@ func NewCmdApplyViewLastApplied(f cmdutil.Factory, ioStreams genericclioptions.I
 		Short:                 i18n.T("View latest last-applied-configuration annotations of a resource/object"),
 		Long:                  applyViewLastAppliedLong,
 		Example:               applyViewLastAppliedExample,
+		ValidArgsFunction:     util.ResourceTypeAndNameCompletionFunc(f),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(options.Complete(cmd, f, args))
 			cmdutil.CheckErr(options.Validate(cmd))

pkg/cmd/attach/attach.go

@@ -35,6 +35,7 @@ import (
 	"k8s.io/kubectl/pkg/cmd/util/podcmd"
 	"k8s.io/kubectl/pkg/polymorphichelpers"
 	"k8s.io/kubectl/pkg/scheme"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -104,6 +105,7 @@ func NewCmdAttach(f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra
 		Short:                 i18n.T("Attach to a running container"),
 		Long:                  i18n.T("Attach to a process that is already running inside an existing container."),
 		Example:               attachExample,
+		ValidArgsFunction:     util.ResourceNameCompletionFunc(f, "pod"),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Validate())

pkg/cmd/autoscale/autoscale.go

@@ -107,12 +107,12 @@ func NewCmdAutoscale(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *
 		Short:                 i18n.T("Auto-scale a Deployment, ReplicaSet, StatefulSet, or ReplicationController"),
 		Long:                  autoscaleLong,
 		Example:               autoscaleExample,
+		ValidArgsFunction:     util.SpecifiedResourceTypeAndNameCompletionFunc(f, validArgs),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Validate())
 			cmdutil.CheckErr(o.Run())
 		},
-		ValidArgs: validArgs,
 	}
 
 	// bind flag structs

pkg/cmd/cmd.go

@@ -71,6 +71,7 @@ import (
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/cmd/version"
 	"k8s.io/kubectl/pkg/cmd/wait"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 	"k8s.io/kubectl/pkg/util/term"
@@ -79,261 +80,8 @@ import (
 	"k8s.io/kubectl/pkg/cmd/kustomize"
 )
 
-const (
-	bashCompletionFunc = `# call kubectl get $1,
-__kubectl_debug_out()
-{
-    local cmd="$1"
-    __kubectl_debug "${FUNCNAME[1]}: get completion by ${cmd}"
-    eval "${cmd} 2>/dev/null"
-}
-
-__kubectl_override_flag_list=(--kubeconfig --cluster --user --context --namespace --server -n -s)
-__kubectl_override_flags()
-{
-    local ${__kubectl_override_flag_list[*]##*-} two_word_of of var
-    for w in "${words[@]}"; do
-        if [ -n "${two_word_of}" ]; then
-            eval "${two_word_of##*-}=\"${two_word_of}=\${w}\""
-            two_word_of=
-            continue
-        fi
-        for of in "${__kubectl_override_flag_list[@]}"; do
-            case "${w}" in
-                ${of}=*)
-                    eval "${of##*-}=\"${w}\""
-                    ;;
-                ${of})
-                    two_word_of="${of}"
-                    ;;
-            esac
-        done
-    done
-    for var in "${__kubectl_override_flag_list[@]##*-}"; do
-        if eval "test -n \"\$${var}\""; then
-            eval "echo -n \${${var}}' '"
-        fi
-    done
-}
-
-__kubectl_config_get_contexts()
-{
-    __kubectl_parse_config "contexts"
-}
-
-__kubectl_config_get_clusters()
-{
-    __kubectl_parse_config "clusters"
-}
-
-__kubectl_config_get_users()
-{
-    __kubectl_parse_config "users"
-}
-
-# $1 has to be "contexts", "clusters" or "users"
-__kubectl_parse_config()
-{
-    local template kubectl_out
-    template="{{ range .$1  }}{{ .name }} {{ end }}"
-    if kubectl_out=$(__kubectl_debug_out "kubectl config $(__kubectl_override_flags) -o template --template=\"${template}\" view"); then
-        COMPREPLY=( $( compgen -W "${kubectl_out[*]}" -- "$cur" ) )
-    fi
-}
-
-# $1 is the name of resource (required)
-# $2 is template string for kubectl get (optional)
-__kubectl_parse_get()
-{
-    local template
-    template="${2:-"{{ range .items  }}{{ .metadata.name }} {{ end }}"}"
-    local kubectl_out
-    if kubectl_out=$(__kubectl_debug_out "kubectl get $(__kubectl_override_flags) -o template --template=\"${template}\" \"$1\""); then
-        COMPREPLY+=( $( compgen -W "${kubectl_out[*]}" -- "$cur" ) )
-    fi
-}
-
-# Same as __kubectl_get_resources (with s) but allows completion for only one resource name.
-__kubectl_get_resource()
-{
-    if [[ ${#nouns[@]} -eq 0 ]]; then
-      __kubectl_get_resource_helper "" "$cur"
-      return # the return status is that of the last command executed in the function body
-    fi
-    __kubectl_parse_get "${nouns[${#nouns[@]} -1]}"
-}
-
-# Same as __kubectl_get_resource (without s) but allows completion for multiple, comma-separated resource names.
-__kubectl_get_resources()
-{
-    local SEPARATOR=','
-    if [[ ${#nouns[@]} -eq 0 ]]; then
-      local kubectl_out HEAD TAIL
-      HEAD=""
-      TAIL="$cur"
-      # if SEPARATOR is contained in $cur, e.g. "pod,sec"
-      if [[ "$cur" = *${SEPARATOR}* ]] ; then
-        # set HEAD to "pod,"
-        HEAD="${cur%${SEPARATOR}*}${SEPARATOR}"
-        # set TAIL to "sec"
-        TAIL="${cur##*${SEPARATOR}}"
-      fi
-      __kubectl_get_resource_helper "$HEAD" "$TAIL"
-      return # the return status is that of the last command executed in the function body
-    fi
-    __kubectl_parse_get "${nouns[${#nouns[@]} -1]}"
-}
-
-__kubectl_get_resource_helper()
-{
-    local kubectl_out HEAD TAIL
-    HEAD="$1"
-    TAIL="$2"
-    if kubectl_out=$(__kubectl_debug_out "kubectl api-resources $(__kubectl_override_flags) -o name --cached --request-timeout=5s --verbs=get"); then
-        COMPREPLY=( $( compgen -P "$HEAD" -W "${kubectl_out[*]}" -- "$TAIL" ) )
-        return 0
-    fi
-    return 1
-}
-
-__kubectl_get_resource_namespace()
-{
-    __kubectl_parse_get "namespace"
-}
-
-__kubectl_get_resource_pod()
-{
-    __kubectl_parse_get "pod"
-}
-
-__kubectl_get_resource_rc()
-{
-    __kubectl_parse_get "rc"
-}
-
-__kubectl_get_resource_node()
-{
-    __kubectl_parse_get "node"
-}
-
-__kubectl_get_resource_clusterrole()
-{
-    __kubectl_parse_get "clusterrole"
-}
-
-# $1 is the name of the pod we want to get the list of containers inside
-__kubectl_get_containers()
-{
-    local template
-    template="{{ range .spec.initContainers }}{{ .name }} {{end}}{{ range .spec.containers  }}{{ .name }} {{ end }}"
-    __kubectl_debug "${FUNCNAME} nouns are ${nouns[*]}"
-
-    local len="${#nouns[@]}"
-    if [[ ${len} -ne 1 ]]; then
-        return
-    fi
-    local last=${nouns[${len} -1]}
-    local kubectl_out
-    if kubectl_out=$(__kubectl_debug_out "kubectl get $(__kubectl_override_flags) -o template --template=\"${template}\" pods \"${last}\""); then
-        COMPREPLY=( $( compgen -W "${kubectl_out[*]}" -- "$cur" ) )
-    fi
-}
-
-# Require both a pod and a container to be specified
-__kubectl_require_pod_and_container()
-{
-    if [[ ${#nouns[@]} -eq 0 ]]; then
-        __kubectl_parse_get pods
-        return 0
-    fi;
-    __kubectl_get_containers
-    return 0
-}
-
-__kubectl_cp()
-{
-    if [[ $(type -t compopt) = "builtin" ]]; then
-        compopt -o nospace
-    fi
-
-    case "$cur" in
-        /*|[.~]*) # looks like a path
-            return
-            ;;
-        *:*) # TODO: complete remote files in the pod
-            return
-            ;;
-        */*) # complete <namespace>/<pod>
-            local template namespace kubectl_out
-            template="{{ range .items }}{{ .metadata.namespace }}/{{ .metadata.name }}: {{ end }}"
-            namespace="${cur%%/*}"
-            if kubectl_out=$(__kubectl_debug_out "kubectl get $(__kubectl_override_flags) --namespace \"${namespace}\" -o template --template=\"${template}\" pods"); then
-                COMPREPLY=( $(compgen -W "${kubectl_out[*]}" -- "${cur}") )
-            fi
-            return
-            ;;
-        *) # complete namespaces, pods, and filedirs
-            __kubectl_parse_get "namespace" "{{ range .items  }}{{ .metadata.name }}/ {{ end }}"
-            __kubectl_parse_get "pod" "{{ range .items  }}{{ .metadata.name }}: {{ end }}"
-            _filedir
-            ;;
-    esac
-}
-
-__kubectl_custom_func() {
-    case ${last_command} in
-        kubectl_get)
-            __kubectl_get_resources
-            return
-            ;;
-        kubectl_describe | kubectl_delete | kubectl_label | kubectl_edit | kubectl_patch |\
-        kubectl_annotate | kubectl_expose | kubectl_scale | kubectl_autoscale | kubectl_taint | kubectl_rollout_* |\
-        kubectl_apply_edit-last-applied | kubectl_apply_view-last-applied)
-            __kubectl_get_resource
-            return
-            ;;
-        kubectl_logs)
-            __kubectl_require_pod_and_container
-            return
-            ;;
-        kubectl_exec | kubectl_port-forward | kubectl_top_pod | kubectl_attach)
-            __kubectl_get_resource_pod
-            return
-            ;;
-        kubectl_cordon | kubectl_uncordon | kubectl_drain | kubectl_top_node)
-            __kubectl_get_resource_node
-            return
-            ;;
-        kubectl_config_use-context | kubectl_config_rename-context | kubectl_config_delete-context)
-            __kubectl_config_get_contexts
-            return
-            ;;
-        kubectl_config_delete-cluster)
-            __kubectl_config_get_clusters
-            return
-            ;;
-        kubectl_cp)
-            __kubectl_cp
-            return
-            ;;
-        *)
-            ;;
-    esac
-}
-`
-)
-
 const kubectlCmdHeaders = "KUBECTL_COMMAND_HEADERS"
 
-var (
-	bashCompletionFlags = map[string]string{
-		"namespace": "__kubectl_get_resource_namespace",
-		"context":   "__kubectl_config_get_contexts",
-		"cluster":   "__kubectl_config_get_clusters",
-		"user":      "__kubectl_config_get_users",
-	}
-)
-
 // NewDefaultKubectlCommand creates the `kubectl` command with default arguments
 func NewDefaultKubectlCommand() *cobra.Command {
 	return NewDefaultKubectlCommandWithArgs(NewDefaultPluginHandler(plugin.ValidPluginFilenamePrefixes), os.Args, os.Stdin, os.Stdout, os.Stderr)
@@ -505,7 +253,6 @@ func NewKubectlCommand(in io.Reader, out, err io.Writer) *cobra.Command {
 			}
 			return nil
 		},
-		BashCompletionFunction: bashCompletionFunc,
 	}
 
 	flags := cmds.PersistentFlags()
@@ -633,17 +380,8 @@ func NewKubectlCommand(in io.Reader, out, err io.Writer) *cobra.Command {
 
 	templates.ActsAsRootCommand(cmds, filters, groups...)
 
-	for name, completion := range bashCompletionFlags {
+	util.SetFactoryForCompletion(f)
-		if cmds.Flag(name) != nil {
+	registerCompletionFuncForGlobalFlags(cmds, f)
-			if cmds.Flag(name).Annotations == nil {
-				cmds.Flag(name).Annotations = map[string][]string{}
-			}
-			cmds.Flag(name).Annotations[cobra.BashCompCustom] = append(
-				cmds.Flag(name).Annotations[cobra.BashCompCustom],
-				completion,
-			)
-		}
-	}
 
 	cmds.AddCommand(alpha)
 	cmds.AddCommand(cmdconfig.NewCmdConfig(f, clientcmd.NewDefaultPathOptions(), ioStreams))
@@ -691,3 +429,26 @@ func addCmdHeaderHooks(cmds *cobra.Command, kubeConfigFlags *genericclioptions.C
 func runHelp(cmd *cobra.Command, args []string) {
 	cmd.Help()
 }
+
+func registerCompletionFuncForGlobalFlags(cmd *cobra.Command, f cmdutil.Factory) {
+	cmdutil.CheckErr(cmd.RegisterFlagCompletionFunc(
+		"namespace",
+		func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+			return get.CompGetResource(f, cmd, "namespace", toComplete), cobra.ShellCompDirectiveNoFileComp
+		}))
+	cmdutil.CheckErr(cmd.RegisterFlagCompletionFunc(
+		"context",
+		func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+			return util.ListContextsInConfig(toComplete), cobra.ShellCompDirectiveNoFileComp
+		}))
+	cmdutil.CheckErr(cmd.RegisterFlagCompletionFunc(
+		"cluster",
+		func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+			return util.ListClustersInConfig(toComplete), cobra.ShellCompDirectiveNoFileComp
+		}))
+	cmdutil.CheckErr(cmd.RegisterFlagCompletionFunc(
+		"user",
+		func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+			return util.ListUsersInConfig(toComplete), cobra.ShellCompDirectiveNoFileComp
+		}))
+}

pkg/cmd/completion/completion.go

@@ -17,7 +17,6 @@ limitations under the License.
 package completion
 
 import (
-	"bytes"
 	"io"
 
 	"github.com/spf13/cobra"
@@ -150,8 +149,7 @@ func runCompletionBash(out io.Writer, boilerPlate string, kubectl *cobra.Command
 }
 
 func runCompletionZsh(out io.Writer, boilerPlate string, kubectl *cobra.Command) error {
-	zshHead := "#compdef kubectl\n"
+	zshHead := "#compdef kubectl\ncompdef _kubectl kubectl\n"
-
 	out.Write([]byte(zshHead))
 
 	if len(boilerPlate) == 0 {
@@ -161,118 +159,5 @@ func runCompletionZsh(out io.Writer, boilerPlate string, kubectl *cobra.Command)
 		return err
 	}
 
-	zshInitialization := `
+	return kubectl.GenZshCompletion(out)
-__kubectl_bash_source() {
-	alias shopt=':'
-	emulate -L sh
-	setopt kshglob noshglob braceexpand
-
-	source "$@"
-}
-
-__kubectl_type() {
-	# -t is not supported by zsh
-	if [ "$1" == "-t" ]; then
-		shift
-
-		# fake Bash 4 to disable "complete -o nospace". Instead
-		# "compopt +-o nospace" is used in the code to toggle trailing
-		# spaces. We don't support that, but leave trailing spaces on
-		# all the time
-		if [ "$1" = "__kubectl_compopt" ]; then
-			echo builtin
-			return 0
-		fi
-	fi
-	type "$@"
-}
-
-__kubectl_compgen() {
-	local completions w
-	completions=( $(compgen "$@") ) || return $?
-
-	# filter by given word as prefix
-	while [[ "$1" = -* && "$1" != -- ]]; do
-		shift
-		shift
-	done
-	if [[ "$1" == -- ]]; then
-		shift
-	fi
-	for w in "${completions[@]}"; do
-		if [[ "${w}" = "$1"* ]]; then
-			echo "${w}"
-		fi
-	done
-}
-
-__kubectl_compopt() {
-	true # don't do anything. Not supported by bashcompinit in zsh
-}
-
-__kubectl_ltrim_colon_completions()
-{
-	if [[ "$1" == *:* && "$COMP_WORDBREAKS" == *:* ]]; then
-		# Remove colon-word prefix from COMPREPLY items
-		local colon_word=${1%${1##*:}}
-		local i=${#COMPREPLY[*]}
-		while [[ $((--i)) -ge 0 ]]; do
-			COMPREPLY[$i]=${COMPREPLY[$i]#"$colon_word"}
-		done
-	fi
-}
-
-__kubectl_get_comp_words_by_ref() {
-	cur="${COMP_WORDS[COMP_CWORD]}"
-	prev="${COMP_WORDS[${COMP_CWORD}-1]}"
-	words=("${COMP_WORDS[@]}")
-	cword=("${COMP_CWORD[@]}")
-}
-
-__kubectl_filedir() {
-	# Don't need to do anything here.
-	# Otherwise we will get trailing space without "compopt -o nospace"
-	true
-}
-
-autoload -U +X bashcompinit && bashcompinit
-
-# use word boundary patterns for BSD or GNU sed
-LWORD='[[:<:]]'
-RWORD='[[:>:]]'
-if sed --version 2>&1 | grep -q GNU; then
-	LWORD='\<'
-	RWORD='\>'
-fi
-
-__kubectl_convert_bash_to_zsh() {
-	sed \
-	-e 's/declare -F/whence -w/' \
-	-e 's/_get_comp_words_by_ref "\$@"/_get_comp_words_by_ref "\$*"/' \
-	-e 's/local \([a-zA-Z0-9_]*\)=/local \1; \1=/' \
-	-e 's/flags+=("\(--.*\)=")/flags+=("\1"); two_word_flags+=("\1")/' \
-	-e 's/must_have_one_flag+=("\(--.*\)=")/must_have_one_flag+=("\1")/' \
-	-e "s/${LWORD}_filedir${RWORD}/__kubectl_filedir/g" \
-	-e "s/${LWORD}_get_comp_words_by_ref${RWORD}/__kubectl_get_comp_words_by_ref/g" \
-	-e "s/${LWORD}__ltrim_colon_completions${RWORD}/__kubectl_ltrim_colon_completions/g" \
-	-e "s/${LWORD}compgen${RWORD}/__kubectl_compgen/g" \
-	-e "s/${LWORD}compopt${RWORD}/__kubectl_compopt/g" \
-	-e "s/${LWORD}declare${RWORD}/builtin declare/g" \
-	-e "s/\\\$(type${RWORD}/\$(__kubectl_type/g" \
-	<<'BASH_COMPLETION_EOF'
-`
-	out.Write([]byte(zshInitialization))
-
-	buf := new(bytes.Buffer)
-	kubectl.GenBashCompletion(buf)
-	out.Write(buf.Bytes())
-
-	zshTail := `
-BASH_COMPLETION_EOF
-}
-
-__kubectl_bash_source <(__kubectl_convert_bash_to_zsh)
-`
-	out.Write([]byte(zshTail))
-	return nil
 }

pkg/cmd/config/delete_cluster.go

@@ -23,6 +23,7 @@ import (
 	"github.com/spf13/cobra"
 	"k8s.io/client-go/tools/clientcmd"
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -41,6 +42,7 @@ func NewCmdConfigDeleteCluster(out io.Writer, configAccess clientcmd.ConfigAcces
 		Short:                 i18n.T("Delete the specified cluster from the kubeconfig"),
 		Long:                  i18n.T("Delete the specified cluster from the kubeconfig"),
 		Example:               deleteClusterExample,
+		ValidArgsFunction:     util.ClusterCompletionFunc,
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(runDeleteCluster(out, configAccess, cmd))
 		},

pkg/cmd/config/delete_context.go

@@ -23,6 +23,7 @@ import (
 	"github.com/spf13/cobra"
 	"k8s.io/client-go/tools/clientcmd"
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -41,6 +42,7 @@ func NewCmdConfigDeleteContext(out, errOut io.Writer, configAccess clientcmd.Con
 		Short:                 i18n.T("Delete the specified context from the kubeconfig"),
 		Long:                  i18n.T("Delete the specified context from the kubeconfig"),
 		Example:               deleteContextExample,
+		ValidArgsFunction:     util.ContextCompletionFunc,
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(runDeleteContext(out, errOut, configAccess, cmd))
 		},

pkg/cmd/config/rename_context.go

@@ -25,6 +25,7 @@ import (
 
 	"k8s.io/client-go/tools/clientcmd"
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -67,6 +68,7 @@ func NewCmdConfigRenameContext(out io.Writer, configAccess clientcmd.ConfigAcces
 		Short:                 renameContextShort,
 		Long:                  renameContextLong,
 		Example:               renameContextExample,
+		ValidArgsFunction:     util.ContextCompletionFunc,
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(options.Complete(cmd, args, out))
 			cmdutil.CheckErr(options.Validate())

pkg/cmd/config/use_context.go

@@ -26,6 +26,7 @@ import (
 	"k8s.io/client-go/tools/clientcmd"
 	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -52,6 +53,7 @@ func NewCmdConfigUseContext(out io.Writer, configAccess clientcmd.ConfigAccess)
 		Aliases:               []string{"use"},
 		Long:                  `Sets the current-context in a kubeconfig file`,
 		Example:               useContextExample,
+		ValidArgsFunction:     util.ContextCompletionFunc,
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(options.complete(cmd))
 			cmdutil.CheckErr(options.run())

pkg/cmd/cp/cp.go

@@ -35,6 +35,7 @@ import (
 	"k8s.io/client-go/kubernetes"
 	restclient "k8s.io/client-go/rest"
 	"k8s.io/kubectl/pkg/cmd/exec"
+	"k8s.io/kubectl/pkg/cmd/get"
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
@@ -104,6 +105,57 @@ func NewCmdCp(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *cobra.C
 		Short:                 i18n.T("Copy files and directories to and from containers."),
 		Long:                  i18n.T("Copy files and directories to and from containers."),
 		Example:               cpExample,
+		ValidArgsFunction: func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+			var comps []string
+			if len(args) == 0 {
+				if strings.IndexAny(toComplete, "/.~") == 0 {
+					// Looks like a path, do nothing
+				} else if strings.Index(toComplete, ":") != -1 {
+					// TODO: complete remote files in the pod
+				} else if idx := strings.Index(toComplete, "/"); idx > 0 {
+					// complete <namespace>/<pod>
+					namespace := toComplete[:idx]
+					template := "{{ range .items }}{{ .metadata.namespace }}/{{ .metadata.name }}: {{ end }}"
+					comps = get.CompGetFromTemplate(&template, f, namespace, cmd, []string{"pod"}, toComplete)
+				} else {
+					// Complete namespaces followed by a /
+					for _, ns := range get.CompGetResource(f, cmd, "namespace", toComplete) {
+						comps = append(comps, fmt.Sprintf("%s/", ns))
+					}
+					// Complete pod names followed by a :
+					for _, pod := range get.CompGetResource(f, cmd, "pod", toComplete) {
+						comps = append(comps, fmt.Sprintf("%s:", pod))
+					}
+
+					// Finally, provide file completion if we need to.
+					// We only do this if:
+					// 1- There are other completions found (if there are no completions,
+					//    the shell will do file completion itself)
+					// 2- If there is some input from the user (or else we will end up
+					//    listing the entire content of the current directory which could
+					//    be too many choices for the user)
+					if len(comps) > 0 && len(toComplete) > 0 {
+						if files, err := ioutil.ReadDir("."); err == nil {
+							for _, file := range files {
+								filename := file.Name()
+								if strings.HasPrefix(filename, toComplete) {
+									if file.IsDir() {
+										filename = fmt.Sprintf("%s/", filename)
+									}
+									// We are completing a file prefix
+									comps = append(comps, filename)
+								}
+							}
+						}
+					} else if len(toComplete) == 0 {
+						// If the user didn't provide any input to complete,
+						// we provide a hint that a path can also be used
+						comps = append(comps, "./", "/")
+					}
+				}
+			}
+			return comps, cobra.ShellCompDirectiveNoSpace
+		},
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd))
 			cmdutil.CheckErr(o.Run(args))

pkg/cmd/create/create_clusterrolebinding.go

@@ -29,6 +29,7 @@ import (
 	"k8s.io/cli-runtime/pkg/genericclioptions"
 	"k8s.io/cli-runtime/pkg/resource"
 	rbacclientv1 "k8s.io/client-go/kubernetes/typed/rbac/v1"
+	"k8s.io/kubectl/pkg/cmd/get"
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/scheme"
 	"k8s.io/kubectl/pkg/util"
@@ -99,11 +100,18 @@ func NewCmdCreateClusterRoleBinding(f cmdutil.Factory, ioStreams genericclioptio
 	cmdutil.AddDryRunFlag(cmd)
 	cmd.Flags().StringVar(&o.ClusterRole, "clusterrole", "", i18n.T("ClusterRole this ClusterRoleBinding should reference"))
 	cmd.MarkFlagRequired("clusterrole")
-	cmd.MarkFlagCustom("clusterrole", "__kubectl_get_resource_clusterrole")
 	cmd.Flags().StringArrayVar(&o.Users, "user", o.Users, "Usernames to bind to the clusterrole")
 	cmd.Flags().StringArrayVar(&o.Groups, "group", o.Groups, "Groups to bind to the clusterrole")
 	cmd.Flags().StringArrayVar(&o.ServiceAccounts, "serviceaccount", o.ServiceAccounts, "Service accounts to bind to the clusterrole, in the format <namespace>:<name>")
 	cmdutil.AddFieldManagerFlagVar(cmd, &o.FieldManager, "kubectl-create")
+
+	// Completion for relevant flags
+	cmdutil.CheckErr(cmd.RegisterFlagCompletionFunc(
+		"clusterrole",
+		func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+			return get.CompGetResource(f, cmd, "clusterrole", toComplete), cobra.ShellCompDirectiveNoFileComp
+		}))
+
 	return cmd
 }
 

pkg/cmd/delete/delete.go

@@ -36,6 +36,7 @@ import (
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	cmdwait "k8s.io/kubectl/pkg/cmd/wait"
 	"k8s.io/kubectl/pkg/rawhttp"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -135,6 +136,7 @@ func NewCmdDelete(f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra
 		Short:                 i18n.T("Delete resources by filenames, stdin, resources and names, or by resources and label selector"),
 		Long:                  deleteLong,
 		Example:               deleteExample,
+		ValidArgsFunction:     util.ResourceTypeAndNameCompletionFunc(f),
 		Run: func(cmd *cobra.Command, args []string) {
 			o, err := deleteFlags.ToOptions(nil, streams)
 			cmdutil.CheckErr(err)

pkg/cmd/describe/describe.go

@@ -30,6 +30,7 @@ import (
 	"k8s.io/cli-runtime/pkg/resource"
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/describe"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -106,6 +107,7 @@ func NewCmdDescribe(parent string, f cmdutil.Factory, streams genericclioptions.
 		Short:                 i18n.T("Show details of a specific resource or group of resources"),
 		Long:                  describeLong + "\n\n" + cmdutil.SuggestAPIResources(parent),
 		Example:               describeExample,
+		ValidArgsFunction:     util.ResourceTypeAndNameCompletionFunc(f),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Run())

pkg/cmd/drain/drain.go

@@ -34,6 +34,7 @@ import (
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/drain"
 	"k8s.io/kubectl/pkg/scheme"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -68,6 +69,7 @@ func NewCmdCordon(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *cob
 		Short:                 i18n.T("Mark node as unschedulable"),
 		Long:                  cordonLong,
 		Example:               cordonExample,
+		ValidArgsFunction:     util.ResourceNameCompletionFunc(f, "node"),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.RunCordonOrUncordon(true))
@@ -96,6 +98,7 @@ func NewCmdUncordon(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *c
 		Short:                 i18n.T("Mark node as schedulable"),
 		Long:                  uncordonLong,
 		Example:               uncordonExample,
+		ValidArgsFunction:     util.ResourceNameCompletionFunc(f, "node"),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.RunCordonOrUncordon(false))
@@ -181,6 +184,7 @@ func NewCmdDrain(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *cobr
 		Short:                 i18n.T("Drain node in preparation for maintenance"),
 		Long:                  drainLong,
 		Example:               drainExample,
+		ValidArgsFunction:     util.ResourceNameCompletionFunc(f, "node"),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.RunDrain())

pkg/cmd/edit/edit.go

@@ -22,6 +22,7 @@ import (
 	"k8s.io/cli-runtime/pkg/genericclioptions"
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/cmd/util/editor"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -76,6 +77,7 @@ func NewCmdEdit(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *cobra
 		Short:                 i18n.T("Edit a resource on the server"),
 		Long:                  editLong,
 		Example:               editExample,
+		ValidArgsFunction:     util.ResourceTypeAndNameCompletionFunc(f),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, args, cmd))
 			cmdutil.CheckErr(o.Run())

pkg/cmd/exec/exec.go

@@ -37,6 +37,7 @@ import (
 	"k8s.io/kubectl/pkg/cmd/util/podcmd"
 	"k8s.io/kubectl/pkg/polymorphichelpers"
 	"k8s.io/kubectl/pkg/scheme"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/interrupt"
 	"k8s.io/kubectl/pkg/util/templates"
@@ -88,6 +89,7 @@ func NewCmdExec(f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra.C
 		Short:                 i18n.T("Execute a command in a container"),
 		Long:                  i18n.T("Execute a command in a container."),
 		Example:               execExample,
+		ValidArgsFunction:     util.ResourceNameCompletionFunc(f, "pod"),
 		Run: func(cmd *cobra.Command, args []string) {
 			argsLenAtDash := cmd.ArgsLenAtDash()
 			cmdutil.CheckErr(options.Complete(f, cmd, args, argsLenAtDash))

pkg/cmd/expose/expose.go

@@ -134,11 +134,11 @@ func NewCmdExposeService(f cmdutil.Factory, streams genericclioptions.IOStreams)
 		Short:                 i18n.T("Take a replication controller, service, deployment or pod and expose it as a new Kubernetes Service"),
 		Long:                  exposeLong,
 		Example:               exposeExample,
+		ValidArgsFunction:     util.SpecifiedResourceTypeAndNameCompletionFunc(f, validArgs),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd))
 			cmdutil.CheckErr(o.RunExpose(cmd, args))
 		},
-		ValidArgs: validArgs,
 	}
 
 	o.RecordFlags.AddFlags(cmd)

pkg/cmd/get/get.go

@@ -17,11 +17,14 @@ limitations under the License.
 package get
 
 import (
+	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"net/url"
+	"os"
 	"strings"
 
 	"github.com/spf13/cobra"
@@ -42,6 +45,7 @@ import (
 	kubernetesscheme "k8s.io/client-go/kubernetes/scheme"
 	"k8s.io/client-go/rest"
 	watchtools "k8s.io/client-go/tools/watch"
+	"k8s.io/kubectl/pkg/cmd/apiresources"
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/rawhttp"
 	"k8s.io/kubectl/pkg/scheme"
@@ -161,6 +165,15 @@ func NewCmdGet(parent string, f cmdutil.Factory, streams genericclioptions.IOStr
 		Short:                 i18n.T("Display one or many resources"),
 		Long:                  getLong + "\n\n" + cmdutil.SuggestAPIResources(parent),
 		Example:               getExample,
+		ValidArgsFunction: func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+			var comps []string
+			if len(args) == 0 {
+				comps = apiresources.CompGetResourceList(f, cmd, toComplete)
+			} else if len(args) == 1 {
+				comps = CompGetResource(f, cmd, args[0], toComplete)
+			}
+			return comps, cobra.ShellCompDirectiveNoFileComp
+		},
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Validate(cmd))
@@ -849,3 +862,61 @@ func multipleGVKsRequested(infos []*resource.Info) bool {
 	}
 	return false
 }
+
+// CompGetResource gets the list of the resource specified which begin with `toComplete`.
+func CompGetResource(f cmdutil.Factory, cmd *cobra.Command, resourceName string, toComplete string) []string {
+	template := "{{ range .items  }}{{ .metadata.name }} {{ end }}"
+	return CompGetFromTemplate(&template, f, "", cmd, []string{resourceName}, toComplete)
+}
+
+// CompGetContainers gets the list of containers of the specified pod which begin with `toComplete`.
+func CompGetContainers(f cmdutil.Factory, cmd *cobra.Command, podName string, toComplete string) []string {
+	template := "{{ range .spec.initContainers }}{{ .name }} {{end}}{{ range .spec.containers  }}{{ .name }} {{ end }}"
+	return CompGetFromTemplate(&template, f, "", cmd, []string{"pod", podName}, toComplete)
+}
+
+// CompGetFromTemplate executes a Get operation using the specified template and args and returns the results
+// which begin with `toComplete`.
+func CompGetFromTemplate(template *string, f cmdutil.Factory, namespace string, cmd *cobra.Command, args []string, toComplete string) []string {
+	buf := new(bytes.Buffer)
+	streams := genericclioptions.IOStreams{In: os.Stdin, Out: buf, ErrOut: ioutil.Discard}
+	o := NewGetOptions("kubectl", streams)
+
+	// Get the list of names of the specified resource
+	o.PrintFlags.TemplateFlags.GoTemplatePrintFlags.TemplateArgument = template
+	format := "go-template"
+	o.PrintFlags.OutputFormat = &format
+
+	// Do the steps Complete() would have done.
+	// We cannot actually call Complete() or Validate() as these function check for
+	// the presence of flags, which, in our case won't be there
+	if namespace != "" {
+		o.Namespace = namespace
+		o.ExplicitNamespace = true
+	} else {
+		var err error
+		o.Namespace, o.ExplicitNamespace, err = f.ToRawKubeConfigLoader().Namespace()
+		if err != nil {
+			return nil
+		}
+	}
+
+	o.ToPrinter = func(mapping *meta.RESTMapping, outputObjects *bool, withNamespace bool, withKind bool) (printers.ResourcePrinterFunc, error) {
+		printer, err := o.PrintFlags.ToPrinter()
+		if err != nil {
+			return nil, err
+		}
+		return printer.PrintObj, nil
+	}
+
+	o.Run(f, cmd, args)
+
+	var comps []string
+	resources := strings.Split(buf.String(), " ")
+	for _, res := range resources {
+		if res != "" && strings.HasPrefix(res, toComplete) {
+			comps = append(comps, res)
+		}
+	}
+	return comps
+}

pkg/cmd/label/label.go

@@ -39,6 +39,7 @@ import (
 	"k8s.io/cli-runtime/pkg/resource"
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/scheme"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -132,6 +133,7 @@ func NewCmdLabel(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *cobr
 		Short:                 i18n.T("Update the labels on a resource"),
 		Long:                  fmt.Sprintf(labelLong, validation.LabelValueMaxLength),
 		Example:               labelExample,
+		ValidArgsFunction:     util.ResourceTypeAndNameCompletionFunc(f),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Validate())

pkg/cmd/logs/logs.go

@@ -152,6 +152,7 @@ func NewCmdLogs(f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra.C
 		Short:                 i18n.T("Print the logs for a container in a pod"),
 		Long:                  logsLong,
 		Example:               logsExample,
+		ValidArgsFunction:     util.PodResourceNameAndContainerCompletionFunc(f),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Validate())

pkg/cmd/patch/patch.go

@@ -39,6 +39,7 @@ import (
 	"k8s.io/cli-runtime/pkg/resource"
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/scheme"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -114,6 +115,7 @@ func NewCmdPatch(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *cobr
 		Short:                 i18n.T("Update field(s) of a resource"),
 		Long:                  patchLong,
 		Example:               patchExample,
+		ValidArgsFunction:     util.ResourceTypeAndNameCompletionFunc(f),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Validate())

pkg/cmd/portforward/portforward.go

@@ -109,6 +109,7 @@ func NewCmdPortForward(f cmdutil.Factory, streams genericclioptions.IOStreams) *
 		Short:                 i18n.T("Forward one or more local ports to a pod"),
 		Long:                  portforwardLong,
 		Example:               portforwardExample,
+		ValidArgsFunction:     util.ResourceNameCompletionFunc(f, "pod"),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(opts.Complete(f, cmd, args))
 			cmdutil.CheckErr(opts.Validate())

pkg/cmd/rollout/rollout_history.go

@@ -27,6 +27,7 @@ import (
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/polymorphichelpers"
 	"k8s.io/kubectl/pkg/scheme"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -82,12 +83,12 @@ func NewCmdRolloutHistory(f cmdutil.Factory, streams genericclioptions.IOStreams
 		Short:                 i18n.T("View rollout history"),
 		Long:                  historyLong,
 		Example:               historyExample,
+		ValidArgsFunction:     util.SpecifiedResourceTypeAndNameCompletionFunc(f, validArgs),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Validate())
 			cmdutil.CheckErr(o.Run())
 		},
-		ValidArgs: validArgs,
 	}
 
 	cmd.Flags().Int64Var(&o.Revision, "revision", o.Revision, "See the details, including podTemplate of the revision specified")

pkg/cmd/rollout/rollout_pause.go

@@ -30,6 +30,7 @@ import (
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/polymorphichelpers"
 	"k8s.io/kubectl/pkg/scheme"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -82,12 +83,12 @@ func NewCmdRolloutPause(f cmdutil.Factory, streams genericclioptions.IOStreams)
 		Short:                 i18n.T("Mark the provided resource as paused"),
 		Long:                  pauseLong,
 		Example:               pauseExample,
+		ValidArgsFunction:     util.SpecifiedResourceTypeAndNameCompletionFunc(f, validArgs),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Validate())
 			cmdutil.CheckErr(o.RunPause())
 		},
-		ValidArgs: validArgs,
 	}
 
 	o.PrintFlags.AddFlags(cmd)

pkg/cmd/rollout/rollout_restart.go

@@ -29,6 +29,7 @@ import (
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/polymorphichelpers"
 	"k8s.io/kubectl/pkg/scheme"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -86,12 +87,12 @@ func NewCmdRolloutRestart(f cmdutil.Factory, streams genericclioptions.IOStreams
 		Short:                 i18n.T("Restart a resource"),
 		Long:                  restartLong,
 		Example:               restartExample,
+		ValidArgsFunction:     util.SpecifiedResourceTypeAndNameCompletionFunc(f, validArgs),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Validate())
 			cmdutil.CheckErr(o.RunRestart())
 		},
-		ValidArgs: validArgs,
 	}
 
 	usage := "identifying the resource to get from a server."

pkg/cmd/rollout/rollout_resume.go

@@ -30,6 +30,7 @@ import (
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/polymorphichelpers"
 	"k8s.io/kubectl/pkg/scheme"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -86,12 +87,12 @@ func NewCmdRolloutResume(f cmdutil.Factory, streams genericclioptions.IOStreams)
 		Short:                 i18n.T("Resume a paused resource"),
 		Long:                  resumeLong,
 		Example:               resumeExample,
+		ValidArgsFunction:     util.SpecifiedResourceTypeAndNameCompletionFunc(f, validArgs),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Validate())
 			cmdutil.CheckErr(o.RunResume())
 		},
-		ValidArgs: validArgs,
 	}
 
 	usage := "identifying the resource to get from a server."

pkg/cmd/rollout/rollout_status.go

@@ -37,6 +37,7 @@ import (
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/polymorphichelpers"
 	"k8s.io/kubectl/pkg/scheme"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/interrupt"
 	"k8s.io/kubectl/pkg/util/templates"
@@ -101,12 +102,12 @@ func NewCmdRolloutStatus(f cmdutil.Factory, streams genericclioptions.IOStreams)
 		Short:                 i18n.T("Show the status of the rollout"),
 		Long:                  statusLong,
 		Example:               statusExample,
+		ValidArgsFunction:     util.SpecifiedResourceTypeAndNameCompletionFunc(f, validArgs),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, args))
 			cmdutil.CheckErr(o.Validate())
 			cmdutil.CheckErr(o.Run())
 		},
-		ValidArgs: validArgs,
 	}
 
 	usage := "identifying the resource to get from a server."

pkg/cmd/rollout/rollout_undo.go

@@ -27,6 +27,7 @@ import (
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/polymorphichelpers"
 	"k8s.io/kubectl/pkg/scheme"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -86,12 +87,12 @@ func NewCmdRolloutUndo(f cmdutil.Factory, streams genericclioptions.IOStreams) *
 		Short:                 i18n.T("Undo a previous rollout"),
 		Long:                  undoLong,
 		Example:               undoExample,
+		ValidArgsFunction:     util.SpecifiedResourceTypeAndNameCompletionFunc(f, validArgs),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Validate())
 			cmdutil.CheckErr(o.RunUndo())
 		},
-		ValidArgs: validArgs,
 	}
 
 	cmd.Flags().Int64Var(&o.ToRevision, "to-revision", o.ToRevision, "The revision to rollback to. Default to 0 (last revision).")

pkg/cmd/scale/scale.go

@@ -31,6 +31,7 @@ import (
 	"k8s.io/client-go/kubernetes"
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/scale"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 )
@@ -113,12 +114,12 @@ func NewCmdScale(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *cobr
 		Short:                 i18n.T("Set a new size for a Deployment, ReplicaSet or Replication Controller"),
 		Long:                  scaleLong,
 		Example:               scaleExample,
+		ValidArgsFunction:     util.SpecifiedResourceTypeAndNameCompletionFunc(f, validArgs),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Validate(cmd))
 			cmdutil.CheckErr(o.RunScale())
 		},
-		ValidArgs: validArgs,
 	}
 
 	o.RecordFlags.AddFlags(cmd)

pkg/cmd/taint/taint.go

@@ -24,6 +24,7 @@ import (
 	"github.com/spf13/cobra"
 	"k8s.io/klog/v2"
 	"k8s.io/kubectl/pkg/explain"
+	"k8s.io/kubectl/pkg/util"
 
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/meta"
@@ -108,12 +109,12 @@ func NewCmdTaint(f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra.
 		Short:                 i18n.T("Update the taints on one or more nodes"),
 		Long:                  fmt.Sprintf(taintLong, validation.DNS1123SubdomainMaxLength, validation.LabelValueMaxLength),
 		Example:               taintExample,
+		ValidArgsFunction:     util.SpecifiedResourceTypeAndNameCompletionFunc(f, validArgs),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(options.Complete(f, cmd, args))
 			cmdutil.CheckErr(options.Validate())
 			cmdutil.CheckErr(options.RunTaint())
 		},
-		ValidArgs: validArgs,
 	}
 
 	options.PrintFlags.AddFlags(cmd)

pkg/cmd/top/top_node.go

@@ -29,6 +29,7 @@ import (
 	corev1client "k8s.io/client-go/kubernetes/typed/core/v1"
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/metricsutil"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 	metricsapi "k8s.io/metrics/pkg/apis/metrics"
@@ -80,6 +81,7 @@ func NewCmdTopNode(f cmdutil.Factory, o *TopNodeOptions, streams genericclioptio
 		Short:                 i18n.T("Display Resource (CPU/Memory) usage of nodes"),
 		Long:                  topNodeLong,
 		Example:               topNodeExample,
+		ValidArgsFunction:     util.ResourceNameCompletionFunc(f, "node"),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Validate())

pkg/cmd/top/top_pod.go

@@ -29,6 +29,7 @@ import (
 	corev1client "k8s.io/client-go/kubernetes/typed/core/v1"
 	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/metricsutil"
+	"k8s.io/kubectl/pkg/util"
 	"k8s.io/kubectl/pkg/util/i18n"
 	"k8s.io/kubectl/pkg/util/templates"
 	metricsapi "k8s.io/metrics/pkg/apis/metrics"
@@ -97,6 +98,7 @@ func NewCmdTopPod(f cmdutil.Factory, o *TopPodOptions, streams genericclioptions
 		Short:                 i18n.T("Display Resource (CPU/Memory) usage of pods"),
 		Long:                  topPodLong,
 		Example:               topPodExample,
+		ValidArgsFunction:     util.ResourceNameCompletionFunc(f, "pod"),
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(o.Complete(f, cmd, args))
 			cmdutil.CheckErr(o.Validate())

pkg/util/completion.go

@@ -0,0 +1,158 @@
+/*
+Copyright 2021 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 util
+
+import (
+	"strings"
+
+	"github.com/spf13/cobra"
+	"k8s.io/kubectl/pkg/cmd/apiresources"
+	"k8s.io/kubectl/pkg/cmd/get"
+	cmdutil "k8s.io/kubectl/pkg/cmd/util"
+)
+
+var factory cmdutil.Factory
+
+// SetFactoryForCompletion Store the factory which is needed by the completion functions
+// Not all commands have access to the factory, so cannot pass it to the completion functions.
+func SetFactoryForCompletion(f cmdutil.Factory) {
+	factory = f
+}
+
+// ResourceTypeAndNameCompletionFunc Returns a completion function that completes as a first argument
+// the resource types that match the toComplete prefix, and as a second argument the resource names that match
+// the toComplete prefix.
+func ResourceTypeAndNameCompletionFunc(f cmdutil.Factory) func(*cobra.Command, []string, string) ([]string, cobra.ShellCompDirective) {
+	return func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+		var comps []string
+		if len(args) == 0 {
+			comps = apiresources.CompGetResourceList(f, cmd, toComplete)
+		} else if len(args) == 1 {
+			comps = get.CompGetResource(f, cmd, args[0], toComplete)
+		}
+		return comps, cobra.ShellCompDirectiveNoFileComp
+	}
+}
+
+// SpecifiedResourceTypeAndNameCompletionFunc Returns a completion function that completes as a first
+// argument the resource types that match the toComplete prefix and are limited to the allowedTypes,
+// and as a second argument the specified resource names that match the toComplete prefix.
+func SpecifiedResourceTypeAndNameCompletionFunc(f cmdutil.Factory, allowedTypes []string) func(*cobra.Command, []string, string) ([]string, cobra.ShellCompDirective) {
+	return func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+		var comps []string
+		if len(args) == 0 {
+			for _, comp := range allowedTypes {
+				if strings.HasPrefix(comp, toComplete) {
+					comps = append(comps, comp)
+				}
+			}
+		} else if len(args) == 1 {
+			comps = get.CompGetResource(f, cmd, args[0], toComplete)
+		}
+		return comps, cobra.ShellCompDirectiveNoFileComp
+	}
+}
+
+// ResourceNameCompletionFunc Returns a completion function that completes as a first argument
+// the resource names specified by the resourceType parameter, and which match the toComplete prefix.
+func ResourceNameCompletionFunc(f cmdutil.Factory, resourceType string) func(*cobra.Command, []string, string) ([]string, cobra.ShellCompDirective) {
+	return func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+		var comps []string
+		if len(args) == 0 {
+			comps = get.CompGetResource(f, cmd, resourceType, toComplete)
+		}
+		return comps, cobra.ShellCompDirectiveNoFileComp
+	}
+}
+
+// PodResourceNameAndContainerCompletionFunc Returns a completion function that completes as a first
+// argument pod names that match the toComplete prefix, and as a second argument the containers
+// within the specified pod.
+func PodResourceNameAndContainerCompletionFunc(f cmdutil.Factory) func(*cobra.Command, []string, string) ([]string, cobra.ShellCompDirective) {
+	return func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+		var comps []string
+		if len(args) == 0 {
+			comps = get.CompGetResource(f, cmd, "pod", toComplete)
+		} else if len(args) == 1 {
+			comps = get.CompGetContainers(f, cmd, args[0], toComplete)
+		}
+		return comps, cobra.ShellCompDirectiveNoFileComp
+	}
+}
+
+// ContextCompletionFunc is a completion function that completes as a first argument the
+// context names that match the toComplete prefix
+func ContextCompletionFunc(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+	if len(args) == 0 {
+		return ListContextsInConfig(toComplete), cobra.ShellCompDirectiveNoFileComp
+	}
+	return nil, cobra.ShellCompDirectiveNoFileComp
+}
+
+// ClusterCompletionFunc is a completion function that completes as a first argument the
+// cluster names that match the toComplete prefix
+func ClusterCompletionFunc(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+	if len(args) == 0 {
+		return ListClustersInConfig(toComplete), cobra.ShellCompDirectiveNoFileComp
+	}
+	return nil, cobra.ShellCompDirectiveNoFileComp
+}
+
+// ListContextsInConfig returns a list of context names which begin with `toComplete`
+func ListContextsInConfig(toComplete string) []string {
+	config, err := factory.ToRawKubeConfigLoader().RawConfig()
+	if err != nil {
+		return nil
+	}
+	var ret []string
+	for name := range config.Contexts {
+		if strings.HasPrefix(name, toComplete) {
+			ret = append(ret, name)
+		}
+	}
+	return ret
+}
+
+// ListClustersInConfig returns a list of cluster names which begin with `toComplete`
+func ListClustersInConfig(toComplete string) []string {
+	config, err := factory.ToRawKubeConfigLoader().RawConfig()
+	if err != nil {
+		return nil
+	}
+	var ret []string
+	for name := range config.Clusters {
+		if strings.HasPrefix(name, toComplete) {
+			ret = append(ret, name)
+		}
+	}
+	return ret
+}
+
+// ListUsersInConfig returns a list of user names which begin with `toComplete`
+func ListUsersInConfig(toComplete string) []string {
+	config, err := factory.ToRawKubeConfigLoader().RawConfig()
+	if err != nil {
+		return nil
+	}
+	var ret []string
+	for name := range config.AuthInfos {
+		if strings.HasPrefix(name, toComplete) {
+			ret = append(ret, name)
+		}
+	}
+	return ret
+}

pkg/util/completion_test.go

@@ -0,0 +1,188 @@
+/*
+Copyright 2021 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 util
+
+import (
+	"net/http"
+	"sort"
+	"testing"
+
+	"github.com/spf13/cobra"
+	"k8s.io/cli-runtime/pkg/genericclioptions"
+	"k8s.io/cli-runtime/pkg/resource"
+	"k8s.io/client-go/rest/fake"
+	"k8s.io/kubectl/pkg/cmd/get"
+	cmdtesting "k8s.io/kubectl/pkg/cmd/testing"
+
+	// cmdutil "k8s.io/kubectl/pkg/cmd/util"
+	"k8s.io/kubectl/pkg/scheme"
+)
+
+func TestResourceTypeAndNameCompletionFuncOneArg(t *testing.T) {
+	tf, cmd := prepareCompletionTest()
+	addPodsToFactory(tf)
+	compFunc := ResourceTypeAndNameCompletionFunc(tf)
+	comps, directive := compFunc(cmd, []string{"pod"}, "b")
+	checkCompletion(t, comps, []string{"bar"}, directive, cobra.ShellCompDirectiveNoFileComp)
+}
+
+func TestResourceTypeAndNameCompletionFuncTooManyArgs(t *testing.T) {
+	tf := cmdtesting.NewTestFactory()
+	defer tf.Cleanup()
+
+	streams, _, _, _ := genericclioptions.NewTestIOStreams()
+	cmd := get.NewCmdGet("kubectl", tf, streams)
+	compFunc := ResourceTypeAndNameCompletionFunc(tf)
+	comps, directive := compFunc(cmd, []string{"pod", "pod-name"}, "")
+	checkCompletion(t, comps, []string{}, directive, cobra.ShellCompDirectiveNoFileComp)
+}
+
+func TestSpecifiedResourceTypeAndNameCompletionFuncNoArgs(t *testing.T) {
+	tf := cmdtesting.NewTestFactory()
+	defer tf.Cleanup()
+
+	streams, _, _, _ := genericclioptions.NewTestIOStreams()
+	cmd := get.NewCmdGet("kubectl", tf, streams)
+	compFunc := SpecifiedResourceTypeAndNameCompletionFunc(tf, []string{"pod", "service", "statefulset"})
+	comps, directive := compFunc(cmd, []string{}, "s")
+	checkCompletion(t, comps, []string{"service", "statefulset"}, directive, cobra.ShellCompDirectiveNoFileComp)
+}
+
+func TestSpecifiedResourceTypeAndNameCompletionFuncOneArg(t *testing.T) {
+	tf := cmdtesting.NewTestFactory().WithNamespace("test")
+	defer tf.Cleanup()
+
+	pods, _, _ := cmdtesting.TestData()
+	codec := scheme.Codecs.LegacyCodec(scheme.Scheme.PrioritizedVersionsAllGroups()...)
+	tf.UnstructuredClient = &fake.RESTClient{
+		NegotiatedSerializer: resource.UnstructuredPlusDefaultContentConfig().NegotiatedSerializer,
+		Resp:                 &http.Response{StatusCode: http.StatusOK, Header: cmdtesting.DefaultHeader(), Body: cmdtesting.ObjBody(codec, pods)},
+	}
+
+	streams, _, _, _ := genericclioptions.NewTestIOStreams()
+	cmd := get.NewCmdGet("kubectl", tf, streams)
+	compFunc := SpecifiedResourceTypeAndNameCompletionFunc(tf, []string{"pod"})
+	comps, directive := compFunc(cmd, []string{"pod"}, "b")
+	checkCompletion(t, comps, []string{"bar"}, directive, cobra.ShellCompDirectiveNoFileComp)
+}
+
+func TestSpecifiedResourceTypeAndNameCompletionFuncTooManyArgs(t *testing.T) {
+	tf := cmdtesting.NewTestFactory()
+	defer tf.Cleanup()
+
+	streams, _, _, _ := genericclioptions.NewTestIOStreams()
+	cmd := get.NewCmdGet("kubectl", tf, streams)
+	compFunc := SpecifiedResourceTypeAndNameCompletionFunc(tf, []string{"pod"})
+	comps, directive := compFunc(cmd, []string{"pod", "pod-name"}, "")
+	checkCompletion(t, comps, []string{}, directive, cobra.ShellCompDirectiveNoFileComp)
+}
+
+func TestResourceNameCompletionFuncNoArgs(t *testing.T) {
+	tf := cmdtesting.NewTestFactory().WithNamespace("test")
+	defer tf.Cleanup()
+
+	pods, _, _ := cmdtesting.TestData()
+	codec := scheme.Codecs.LegacyCodec(scheme.Scheme.PrioritizedVersionsAllGroups()...)
+	tf.UnstructuredClient = &fake.RESTClient{
+		NegotiatedSerializer: resource.UnstructuredPlusDefaultContentConfig().NegotiatedSerializer,
+		Resp:                 &http.Response{StatusCode: http.StatusOK, Header: cmdtesting.DefaultHeader(), Body: cmdtesting.ObjBody(codec, pods)},
+	}
+
+	streams, _, _, _ := genericclioptions.NewTestIOStreams()
+	cmd := get.NewCmdGet("kubectl", tf, streams)
+	compFunc := ResourceNameCompletionFunc(tf, "pod")
+	comps, directive := compFunc(cmd, []string{}, "b")
+	checkCompletion(t, comps, []string{"bar"}, directive, cobra.ShellCompDirectiveNoFileComp)
+}
+
+func TestResourceNameCompletionFuncTooManyArgs(t *testing.T) {
+	tf := cmdtesting.NewTestFactory()
+	defer tf.Cleanup()
+
+	streams, _, _, _ := genericclioptions.NewTestIOStreams()
+	cmd := get.NewCmdGet("kubectl", tf, streams)
+	compFunc := ResourceNameCompletionFunc(tf, "pod")
+	comps, directive := compFunc(cmd, []string{"pod-name"}, "")
+	checkCompletion(t, comps, []string{}, directive, cobra.ShellCompDirectiveNoFileComp)
+}
+
+func TestPodResourceNameAndContainerCompletionFuncNoArgs(t *testing.T) {
+	tf := cmdtesting.NewTestFactory().WithNamespace("test")
+	defer tf.Cleanup()
+
+	pods, _, _ := cmdtesting.TestData()
+	codec := scheme.Codecs.LegacyCodec(scheme.Scheme.PrioritizedVersionsAllGroups()...)
+	tf.UnstructuredClient = &fake.RESTClient{
+		NegotiatedSerializer: resource.UnstructuredPlusDefaultContentConfig().NegotiatedSerializer,
+		Resp:                 &http.Response{StatusCode: http.StatusOK, Header: cmdtesting.DefaultHeader(), Body: cmdtesting.ObjBody(codec, pods)},
+	}
+
+	streams, _, _, _ := genericclioptions.NewTestIOStreams()
+	cmd := get.NewCmdGet("kubectl", tf, streams)
+	compFunc := PodResourceNameAndContainerCompletionFunc(tf)
+	comps, directive := compFunc(cmd, []string{}, "b")
+	checkCompletion(t, comps, []string{"bar"}, directive, cobra.ShellCompDirectiveNoFileComp)
+}
+
+func TestPodResourceNameAndContainerCompletionFuncTooManyArgs(t *testing.T) {
+	tf := cmdtesting.NewTestFactory().WithNamespace("test")
+	defer tf.Cleanup()
+
+	streams, _, _, _ := genericclioptions.NewTestIOStreams()
+	cmd := get.NewCmdGet("kubectl", tf, streams)
+	compFunc := PodResourceNameAndContainerCompletionFunc(tf)
+	comps, directive := compFunc(cmd, []string{"pod-name", "container-name"}, "")
+	checkCompletion(t, comps, []string{}, directive, cobra.ShellCompDirectiveNoFileComp)
+}
+
+func prepareCompletionTest() (*cmdtesting.TestFactory, *cobra.Command) {
+	tf := cmdtesting.NewTestFactory().WithNamespace("test")
+	defer tf.Cleanup()
+
+	streams, _, _, _ := genericclioptions.NewTestIOStreams()
+	cmd := get.NewCmdGet("kubectl", tf, streams)
+	return tf, cmd
+}
+
+func addPodsToFactory(tf *cmdtesting.TestFactory) {
+	pods, _, _ := cmdtesting.TestData()
+	codec := scheme.Codecs.LegacyCodec(scheme.Scheme.PrioritizedVersionsAllGroups()...)
+	tf.UnstructuredClient = &fake.RESTClient{
+		NegotiatedSerializer: resource.UnstructuredPlusDefaultContentConfig().NegotiatedSerializer,
+		Resp:                 &http.Response{StatusCode: http.StatusOK, Header: cmdtesting.DefaultHeader(), Body: cmdtesting.ObjBody(codec, pods)},
+	}
+}
+
+func checkCompletion(t *testing.T, comps, expectedComps []string, directive, expectedDirective cobra.ShellCompDirective) {
+	if e, d := expectedDirective, directive; e != d {
+		t.Errorf("expected directive\n%v\nbut got\n%v", e, d)
+	}
+
+	sort.Strings(comps)
+	sort.Strings(expectedComps)
+
+	if len(expectedComps) != len(comps) {
+		t.Fatalf("expected completions\n%v\nbut got\n%v", expectedComps, comps)
+	}
+
+	for i := range comps {
+		if expectedComps[i] != comps[i] {
+			t.Errorf("expected completions\n%v\nbut got\n%v", expectedComps, comps)
+			break
+		}
+	}
+}