add nerdctl completion bash

Usage: add `source <(nerdctl completion bash)` to `~/.bash_profile`.

Similar to `kubectl completion bash`.

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

Author: AkihiroSuda

README.md

@@ -194,6 +194,8 @@ It does not necessarily mean that the corresponding features are missing in cont
     - [:whale: nerdctl events](#whale-nerdctl-events)
     - [:whale: nerdctl info](#whale-nerdctl-info)
     - [:whale: nerdctl version](#whale-nerdctl-version)
+  - [Shell completion](#shell-completion)
+    - [:nerd_face: nerdctl completion bash](#nerd_face-nerdctl-completion-bash)
   - [Global flags](#global-flags)
   - [Unimplemented Docker commands](#unimplemented-docker-commands)
 - [Additional documents](#additional-documents)
@@ -454,6 +456,17 @@ Display system-wide information
 ### :whale: nerdctl version
 Show the nerdctl version information
 
+## Shell completion
+
+### :nerd_face: nerdctl completion bash
+
+Show bash completion.
+
+Usage: add the following line to `~/.bash_profile`:
+```bash
+source <(nerdctl completion bash)>
+```
+
 ## Global flags
 - :nerd_face: `-a`, `--address`:  containerd address, optionally with "unix://" prefix
 - :whale:     `-H`, `--host`: Docker-compatible alias for `-a`, `--address`

commit.go

@@ -30,10 +30,11 @@ import (
 
 var (
 	commitCommand = &cli.Command{
-		Name:        "commit",
-		Usage:       "[flags] CONTAINER REPOSITORY[:TAG]",
-		Description: "Create a new image from a container's changes",
-		Action:      commitAction,
+		Name:         "commit",
+		Usage:        "[flags] CONTAINER REPOSITORY[:TAG]",
+		Description:  "Create a new image from a container's changes",
+		Action:       commitAction,
+		BashComplete: commitBashComplete,
 		Flags: []cli.Flag{
 			&cli.StringFlag{
 				Name:    "author",
@@ -103,3 +104,12 @@ func newCommitOpts(clicontext *cli.Context) (*commit.Opts, error) {
 		Ref:     named.String(),
 	}, nil
 }
+
+func commitBashComplete(clicontext *cli.Context) {
+	if _, ok := isFlagCompletionContext(); ok {
+		defaultBashComplete(clicontext)
+		return
+	}
+	// show container names
+	bashCompleteContainerNames(clicontext)
+}

completion.go

@@ -0,0 +1,86 @@
+/*
+   Copyright (C) nerdctl authors.
+   Copyright (C) containerd 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 main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/urfave/cli/v2"
+)
+
+var completionCommand = &cli.Command{
+	Name:  "completion",
+	Usage: "Show shell completion",
+	Subcommands: []*cli.Command{
+		completionBashCommand,
+	},
+}
+
+var completionBashCommand = &cli.Command{
+	Name:        "bash",
+	Usage:       "Show bash completion (use with `source <(nerdctl completion bash)`)",
+	Description: "Usage: add `source <(nerdctl completion bash)` to ~/.bash_profile",
+	Action:      completionBashAction,
+}
+
+func completionBashAction(clicontext *cli.Context) error {
+	tmpl := `#!/bin/bash
+# Autocompletion enabler for nerdctl.
+# Usage: add 'source <(nerdctl completion bash)' to ~/.bash_profile
+
+# _cli_bash_autocomplete is from https://github.com/urfave/cli/blob/v2.3.0/autocomplete/bash_autocomplete (MIT License)
+_cli_bash_autocomplete() {
+  if [[ "${COMP_WORDS[0]}" != "source" ]]; then
+    local cur opts base
+    COMPREPLY=()
+    cur="${COMP_WORDS[COMP_CWORD]}"
+    if [[ "$cur" == "-"* ]]; then
+      opts=$( ${COMP_WORDS[@]:0:$COMP_CWORD} ${cur} --generate-bash-completion )
+    else
+      opts=$( ${COMP_WORDS[@]:0:$COMP_CWORD} --generate-bash-completion )
+    fi
+    COMPREPLY=( $(compgen -W "${opts}" -- ${cur}) )
+    return 0
+  fi
+}
+
+complete -o bashdefault -o default -o nospace -F _cli_bash_autocomplete nerdctl
+`
+	_, err := fmt.Fprint(clicontext.App.Writer, tmpl)
+	return err
+}
+
+func isFlagCompletionContext() (string, bool) {
+	args := os.Args
+	// args[len(args)-1] == "--generate-bash-completion"
+	// args[len(args)-2] == the current key stroke, e.g. "--ne" for "--net"
+	if len(args) <= 2 {
+		return "", false
+	}
+	userTyping := args[len(args)-2]
+	if strings.HasPrefix(userTyping, "-") {
+		return userTyping, true
+	}
+	return "", false
+}
+
+func defaultBashComplete(clicontext *cli.Context) {
+	cli.DefaultCompleteWithFlags(clicontext.Command)(clicontext)
+}

container_inspect.go

@@ -31,11 +31,12 @@ import (
 )
 
 var containerInspectCommand = &cli.Command{
-	Name:        "inspect",
-	Usage:       "Display detailed information on one or more containers.",
-	ArgsUsage:   "[flags] CONTAINER [CONTAINER, ...]",
-	Description: "Hint: set `--mode=native` for showing the full output",
-	Action:      containerInspectAction,
+	Name:         "inspect",
+	Usage:        "Display detailed information on one or more containers.",
+	ArgsUsage:    "[flags] CONTAINER [CONTAINER, ...]",
+	Description:  "Hint: set `--mode=native` for showing the full output",
+	Action:       containerInspectAction,
+	BashComplete: containerInspectBashComplete,
 	Flags: []cli.Flag{
 		&cli.StringFlag{
 			Name:  "mode",
@@ -113,3 +114,12 @@ func (x *containerInspector) Handler(ctx context.Context, found containerwalker.
 	}
 	return nil
 }
+
+func containerInspectBashComplete(clicontext *cli.Context) {
+	if _, ok := isFlagCompletionContext(); ok {
+		defaultBashComplete(clicontext)
+		return
+	}
+	// show container names
+	bashCompleteContainerNames(clicontext)
+}

exec.go

@@ -71,7 +71,8 @@ var execCommand = &cli.Command{
 			Usage: "Give extended privileges to the command",
 		},
 	},
-	Action: execAction,
+	Action:       execAction,
+	BashComplete: execBashComplete,
 }
 
 func execAction(clicontext *cli.Context) error {
@@ -241,3 +242,12 @@ func generateExecProcessSpec(ctx context.Context, clicontext *cli.Context, conta
 
 	return pspec, nil
 }
+
+func execBashComplete(clicontext *cli.Context) {
+	if _, ok := isFlagCompletionContext(); ok {
+		defaultBashComplete(clicontext)
+		return
+	}
+	// show container names
+	bashCompleteContainerNames(clicontext)
+}

image_convert.go

@@ -162,6 +162,7 @@ When '--all-platforms' is given all images in a manifest list must be available.
 		fmt.Fprintln(context.App.Writer, newImg.Target.Digest.String())
 		return nil
 	},
+	BashComplete: imageConvertBashComplete,
 }
 
 func getESGZConvertOpts(context *cli.Context) ([]estargz.Option, error) {
@@ -203,3 +204,12 @@ func readPathsFromRecordFile(filename string) ([]string, error) {
 	}
 	return paths, nil
 }
+
+func imageConvertBashComplete(clicontext *cli.Context) {
+	if _, ok := isFlagCompletionContext(); ok {
+		defaultBashComplete(clicontext)
+		return
+	}
+	// show image names
+	bashCompleteImageNames(clicontext)
+}

inspect.go

@@ -22,9 +22,10 @@ import (
 )
 
 var inspectCommand = &cli.Command{
-	Name:        "inspect",
-	Usage:       "Return low-level information on objects. Currently, only supports container objects.",
-	Description: containerInspectCommand.Description,
-	Action:      containerInspectAction,
-	Flags:       containerInspectCommand.Flags,
+	Name:         "inspect",
+	Usage:        "Return low-level information on objects. Currently, only supports container objects.",
+	Description:  containerInspectCommand.Description,
+	Action:       containerInspectAction,
+	BashComplete: containerInspectBashComplete,
+	Flags:        containerInspectCommand.Flags,
 }

kill.go

@@ -34,10 +34,11 @@ import (
 )
 
 var killCommand = &cli.Command{
-	Name:      "kill",
-	Usage:     "Kill one or more running containers",
-	ArgsUsage: "[flags] CONTAINER [CONTAINER, ...]",
-	Action:    killAction,
+	Name:         "kill",
+	Usage:        "Kill one or more running containers",
+	ArgsUsage:    "[flags] CONTAINER [CONTAINER, ...]",
+	Action:       killAction,
+	BashComplete: killBashComplete,
 	Flags: []cli.Flag{
 		&cli.StringFlag{
 			Name:    "signal",
@@ -127,3 +128,12 @@ func killContainer(ctx context.Context, container containerd.Container, signal s
 	}
 	return nil
 }
+
+func killBashComplete(clicontext *cli.Context) {
+	if _, ok := isFlagCompletionContext(); ok {
+		defaultBashComplete(clicontext)
+		return
+	}
+	// show container names (TODO: filter already stopped containers)
+	bashCompleteContainerNames(clicontext)
+}

logs.go

@@ -29,10 +29,11 @@ import (
 )
 
 var logsCommand = &cli.Command{
-	Name:      "logs",
-	Usage:     "Fetch the logs of a container. Currently, only containers created with `nerdctl run -d` are supported.",
-	ArgsUsage: "[flags] CONTAINER",
-	Action:    logsAction,
+	Name:         "logs",
+	Usage:        "Fetch the logs of a container. Currently, only containers created with `nerdctl run -d` are supported.",
+	ArgsUsage:    "[flags] CONTAINER",
+	Action:       logsAction,
+	BashComplete: logsBashComplete,
 }
 
 func logsAction(clicontext *cli.Context) error {
@@ -81,3 +82,12 @@ func logsAction(clicontext *cli.Context) error {
 	}
 	return nil
 }
+
+func logsBashComplete(clicontext *cli.Context) {
+	if _, ok := isFlagCompletionContext(); ok {
+		defaultBashComplete(clicontext)
+		return
+	}
+	// show container names (TODO: only show containers with logs)
+	bashCompleteContainerNames(clicontext)
+}

main.go

@@ -55,6 +55,7 @@ func newApp() *cli.App {
 	app.Name = "nerdctl"
 	app.Usage = "Docker-compatible CLI for containerd"
 	app.UseShortOptionHandling = true
+	app.EnableBashCompletion = true
 	app.Version = strings.TrimPrefix(version.Version, "v")
 	app.Flags = []cli.Flag{
 		&cli.BoolFlag{
@@ -176,6 +177,8 @@ func newApp() *cli.App {
 		loginCommand,
 		// Logout
 		logoutCommand,
+		// Completion
+		completionCommand,
 	}
 	return app
 }

network_inspect.go

@@ -28,11 +28,12 @@ import (
 )
 
 var networkInspectCommand = &cli.Command{
-	Name:        "inspect",
-	Usage:       "Display detailed information on one or more networks",
-	ArgsUsage:   "[flags] NETWORK [NETWORK, ...]",
-	Description: "NOTE: The output format is not compatible with Docker.",
-	Action:      networkInspectAction,
+	Name:         "inspect",
+	Usage:        "Display detailed information on one or more networks",
+	ArgsUsage:    "[flags] NETWORK [NETWORK, ...]",
+	Description:  "NOTE: The output format is not compatible with Docker.",
+	Action:       networkInspectAction,
+	BashComplete: networkInspectBashComplete,
 }
 
 func networkInspectAction(clicontext *cli.Context) error {
@@ -78,3 +79,16 @@ func networkInspectAction(clicontext *cli.Context) error {
 	fmt.Fprintln(clicontext.App.Writer, string(b))
 	return nil
 }
+
+func networkInspectBashComplete(clicontext *cli.Context) {
+	if _, ok := isFlagCompletionContext(); ok {
+		defaultBashComplete(clicontext)
+		return
+	}
+	// show network names
+	bashCompleteNetworkNames(clicontext)
+
+	// For `nerdctl network inspect`, print built-in "bridge" as well
+	w := clicontext.App.Writer
+	fmt.Fprintln(w, "bridge")
+}

network_rm.go

@@ -28,12 +28,13 @@ import (
 )
 
 var networkRmCommand = &cli.Command{
-	Name:        "rm",
-	Aliases:     []string{"remove"},
-	Usage:       "Remove one or more networks",
-	ArgsUsage:   "[flags] NETWORK [NETWORK, ...]",
-	Description: "NOTE: network in use is deleted without caution",
-	Action:      networkRmAction,
+	Name:         "rm",
+	Aliases:      []string{"remove"},
+	Usage:        "Remove one or more networks",
+	ArgsUsage:    "[flags] NETWORK [NETWORK, ...]",
+	Description:  "NOTE: network in use is deleted without caution",
+	Action:       networkRmAction,
+	BashComplete: networkRmBashComplete,
 }
 
 func networkRmAction(clicontext *cli.Context) error {
@@ -79,3 +80,27 @@ func networkRmAction(clicontext *cli.Context) error {
 	}
 	return lockutil.WithDirLock(netconfpath, fn)
 }
+
+func networkRmBashComplete(clicontext *cli.Context) {
+	if _, ok := isFlagCompletionContext(); ok {
+		defaultBashComplete(clicontext)
+		return
+	}
+	// show network names
+	bashCompleteNetworkNames(clicontext)
+}
+
+func bashCompleteNetworkNames(clicontext *cli.Context) {
+	w := clicontext.App.Writer
+	e := &netutil.CNIEnv{
+		Path:        clicontext.String("cni-path"),
+		NetconfPath: clicontext.String("cni-netconfpath"),
+	}
+	ll, err := netutil.ConfigLists(e)
+	if err != nil {
+		return
+	}
+	for _, l := range ll {
+		fmt.Fprintln(w, l.Name)
+	}
+}