kubernetes/pkg/kubectl/cmd/cmd.go
Kubernetes Submit Queue d4ece0abc3 Merge pull request #37499 from fabianofranz/kubectl_plugins
Automatic merge from submit-queue

kubectl binary plugins

**What this PR does / why we need it**:

Introduces the ability to extend `kubectl` by adding third-party plugins that will be exposed through `kubectl`.

Plugins are executable commands written in any language. To be included as a plugin, a binary or script file has to

1. be located under one of the supported plugin path locations:
1.1 `~/.kubectl/plugins` dir
1.2. one or more directory set in the `KUBECTL_PLUGINS_PATH` env var
1.3. the `kubectl/plugins` dir under one or more directory set in the `XDG_DATA_DIRS` env var, which defaults to `/usr/local/share:/usr/share`
2. in any of the plugin path above, have a subfolder with the plugin file(s)
3. in the subfolder, contain at least a `plugin.yaml` file that describes the plugin

Example:

```
$ cat ~/.kube/plugins/myplugin/plugin.yaml
name: "myplugin"
shortDesc: "My plugin's short description"
command: "echo Hello plugins!"

$ kubectl myplugin
Hello plugins!
```

~~In case the plugin declares `tunnel: true`, the plugin engine will pass the `KUBECTL_PLUGIN_API_HOST` env var when calling the plugin binary. Plugins can then access the Kube REST API in "http://$KUBECTL_PLUGIN_API_HOST/api" using the same context currently in use by `kubectl`.~~

Test plugins are provided in `pkg/kubectl/plugins/examples`. Just copy (or symlink) the files to `~/.kube/plugins` to test.

**Which issue this PR fixes**:

Related to the discussions in the proposal document: https://github.com/kubernetes/kubernetes/pull/30086 and https://github.com/kubernetes/community/pull/122.

**Release note**:
```release-note
Introduces the ability to extend kubectl by adding third-party plugins. Developer preview, please refer to the documentation for instructions about how to use it.
```
2017-04-28 12:23:59 -07:00

393 lines
11 KiB
Go

/*
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 cmd
import (
"fmt"
"io"
"k8s.io/apiserver/pkg/util/flag"
"k8s.io/client-go/tools/clientcmd"
"k8s.io/kubernetes/pkg/kubectl/cmd/auth"
cmdconfig "k8s.io/kubernetes/pkg/kubectl/cmd/config"
"k8s.io/kubernetes/pkg/kubectl/cmd/rollout"
"k8s.io/kubernetes/pkg/kubectl/cmd/set"
"k8s.io/kubernetes/pkg/kubectl/cmd/templates"
cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
"k8s.io/kubernetes/pkg/util/i18n"
"github.com/golang/glog"
"github.com/spf13/cobra"
)
const (
bashCompletionFunc = `# call kubectl get $1,
__kubectl_override_flag_list=(kubeconfig cluster user context namespace server)
__kubectl_override_flags()
{
local ${__kubectl_override_flag_list[*]} two_word_of of
for w in "${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
if [ "${w}" == "--all-namespaces" ]; then
namespace="--all-namespaces"
fi
done
for of in "${__kubectl_override_flag_list[@]}"; do
if eval "test -n \"\$${of}\""; then
eval "echo \${${of}}"
fi
done
}
__kubectl_get_namespaces()
{
local template kubectl_out
template="{{ range .items }}{{ .metadata.name }} {{ end }}"
if kubectl_out=$(kubectl get -o template --template="${template}" namespace 2>/dev/null); then
COMPREPLY=( $( compgen -W "${kubectl_out[*]}" -- "$cur" ) )
fi
}
__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_config_get()
{
local template kubectl_out
template="{{ range .$1 }}{{ .name }} {{ end }}"
if kubectl_out=$(kubectl config $(__kubectl_override_flags) -o template --template="${template}" view 2>/dev/null); then
COMPREPLY=( $( compgen -W "${kubectl_out[*]}" -- "$cur" ) )
fi
}
__kubectl_parse_get()
{
local template
template="{{ range .items }}{{ .metadata.name }} {{ end }}"
local kubectl_out
if kubectl_out=$(kubectl get $(__kubectl_override_flags) -o template --template="${template}" "$1" 2>/dev/null); then
COMPREPLY=( $( compgen -W "${kubectl_out[*]}" -- "$cur" ) )
fi
}
__kubectl_get_resource()
{
if [[ ${#nouns[@]} -eq 0 ]]; then
return 1
fi
__kubectl_parse_get "${nouns[${#nouns[@]} -1]}"
}
__kubectl_get_resource_pod()
{
__kubectl_parse_get "pod"
}
__kubectl_get_resource_rc()
{
__kubectl_parse_get "rc"
}
__kubectl_get_resource_node()
{
__kubectl_parse_get "node"
}
# $1 is the name of the pod we want to get the list of containers inside
__kubectl_get_containers()
{
local template
template="{{ range .spec.containers }}{{ .name }} {{ end }}"
__debug "${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 get $(__kubectl_override_flags) -o template --template="${template}" pods "${last}" 2>/dev/null); 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
}
__custom_func() {
case ${last_command} in
kubectl_get | kubectl_describe | kubectl_delete | kubectl_label | kubectl_stop | kubectl_edit | kubectl_patch |\
kubectl_annotate | kubectl_expose | kubectl_scale | kubectl_autoscale | kubectl_taint | kubectl_rollout_*)
__kubectl_get_resource
return
;;
kubectl_logs | kubectl_attach)
__kubectl_require_pod_and_container
return
;;
kubectl_exec | kubectl_port-forward | kubectl_top_pod)
__kubectl_get_resource_pod
return
;;
kubectl_rolling-update)
__kubectl_get_resource_rc
return
;;
kubectl_cordon | kubectl_uncordon | kubectl_drain | kubectl_top_node)
__kubectl_get_resource_node
return
;;
kubectl_config_use-context)
__kubectl_config_get_contexts
return
;;
*)
;;
esac
}
`
// If you add a resource to this list, please also take a look at pkg/kubectl/kubectl.go
// and add a short forms entry in expandResourceShortcut() when appropriate.
// TODO: This should be populated using the discovery information from apiserver.
validResources = `Valid resource types include:
* all
* certificatesigningrequests (aka 'csr')
* clusterrolebindings
* clusterroles
* clusters (valid only for federation apiservers)
* componentstatuses (aka 'cs')
* configmaps (aka 'cm')
* cronjobs
* daemonsets (aka 'ds')
* deployments (aka 'deploy')
* endpoints (aka 'ep')
* events (aka 'ev')
* horizontalpodautoscalers (aka 'hpa')
* ingresses (aka 'ing')
* jobs
* limitranges (aka 'limits')
* namespaces (aka 'ns')
* networkpolicies (aka 'netpol')
* nodes (aka 'no')
* persistentvolumeclaims (aka 'pvc')
* persistentvolumes (aka 'pv')
* poddisruptionbudgets (aka 'pdb')
* pods (aka 'po')
* podsecuritypolicies (aka 'psp')
* podtemplates
* replicasets (aka 'rs')
* replicationcontrollers (aka 'rc')
* resourcequotas (aka 'quota')
* rolebindings
* roles
* secrets
* serviceaccounts (aka 'sa')
* services (aka 'svc')
* statefulsets
* storageclasses
* thirdpartyresources
`
)
var (
bash_completion_flags = map[string]string{
"namespace": "__kubectl_get_namespaces",
"context": "__kubectl_config_get_contexts",
"cluster": "__kubectl_config_get_clusters",
"user": "__kubectl_config_get_users",
}
)
// NewKubectlCommand creates the `kubectl` command and its nested children.
func NewKubectlCommand(f cmdutil.Factory, in io.Reader, out, err io.Writer) *cobra.Command {
// Parent command to which all subcommands are added.
cmds := &cobra.Command{
Use: "kubectl",
Short: i18n.T("kubectl controls the Kubernetes cluster manager"),
Long: templates.LongDesc(`
kubectl controls the Kubernetes cluster manager.
Find more information at https://github.com/kubernetes/kubernetes.`),
Run: runHelp,
BashCompletionFunction: bashCompletionFunc,
}
f.BindFlags(cmds.PersistentFlags())
f.BindExternalFlags(cmds.PersistentFlags())
// Sending in 'nil' for the getLanguageFn() results in using
// the LANG environment variable.
//
// TODO: Consider adding a flag or file preference for setting
// the language, instead of just loading from the LANG env. variable.
i18n.LoadTranslations("kubectl", nil)
// From this point and forward we get warnings on flags that contain "_" separators
cmds.SetGlobalNormalizationFunc(flag.WarnWordSepNormalizeFunc)
groups := templates.CommandGroups{
{
Message: "Basic Commands (Beginner):",
Commands: []*cobra.Command{
NewCmdCreate(f, out, err),
NewCmdExposeService(f, out),
NewCmdRun(f, in, out, err),
set.NewCmdSet(f, out, err),
},
},
{
Message: "Basic Commands (Intermediate):",
Commands: []*cobra.Command{
NewCmdGet(f, out, err),
NewCmdExplain(f, out, err),
NewCmdEdit(f, out, err),
NewCmdDelete(f, out, err),
},
},
{
Message: "Deploy Commands:",
Commands: []*cobra.Command{
rollout.NewCmdRollout(f, out, err),
NewCmdRollingUpdate(f, out),
NewCmdScale(f, out),
NewCmdAutoscale(f, out),
},
},
{
Message: "Cluster Management Commands:",
Commands: []*cobra.Command{
NewCmdCertificate(f, out),
NewCmdClusterInfo(f, out),
NewCmdTop(f, out, err),
NewCmdCordon(f, out),
NewCmdUncordon(f, out),
NewCmdDrain(f, out, err),
NewCmdTaint(f, out),
},
},
{
Message: "Troubleshooting and Debugging Commands:",
Commands: []*cobra.Command{
NewCmdDescribe(f, out, err),
NewCmdLogs(f, out),
NewCmdAttach(f, in, out, err),
NewCmdExec(f, in, out, err),
NewCmdPortForward(f, out, err),
NewCmdProxy(f, out),
NewCmdCp(f, out, err),
auth.NewCmdAuth(f, out, err),
},
},
{
Message: "Advanced Commands:",
Commands: []*cobra.Command{
NewCmdApply(f, out, err),
NewCmdPatch(f, out),
NewCmdReplace(f, out),
NewCmdConvert(f, out),
},
},
{
Message: "Settings Commands:",
Commands: []*cobra.Command{
NewCmdLabel(f, out),
NewCmdAnnotate(f, out),
NewCmdCompletion(out, ""),
},
},
}
groups.Add(cmds)
filters := []string{
"options",
Deprecated("kubectl", "delete", cmds, NewCmdStop(f, out)),
}
templates.ActsAsRootCommand(cmds, filters, groups...)
for name, completion := range bash_completion_flags {
if cmds.Flag(name) != nil {
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(cmdconfig.NewCmdConfig(clientcmd.NewDefaultPathOptions(), out, err))
cmds.AddCommand(NewCmdPlugin(f, in, out, err))
cmds.AddCommand(NewCmdVersion(f, out))
cmds.AddCommand(NewCmdApiVersions(f, out))
cmds.AddCommand(NewCmdOptions())
return cmds
}
func runHelp(cmd *cobra.Command, args []string) {
cmd.Help()
}
func printDeprecationWarning(command, alias string) {
glog.Warningf("%s is DEPRECATED and will be removed in a future version. Use %s instead.", alias, command)
}
func Deprecated(baseName, to string, parent, cmd *cobra.Command) string {
cmd.Long = fmt.Sprintf("Deprecated: This command is deprecated, all its functionalities are covered by \"%s %s\"", baseName, to)
cmd.Short = fmt.Sprintf("Deprecated: %s", to)
parent.AddCommand(cmd)
return cmd.Name()
}