Merge pull request #319 from AkihiroSuda/more-format

nerdctl (ps|images|volume ls|network ls|version) --format

Author: AkihiroSuda

README.md

@@ -480,8 +480,9 @@ Flags:
 - :whale: `-a, --all`: Show all containers (default shows just running)
 - :whale: `--no-trunc`: Don't truncate output
 - :whale: `-q, --quiet`: Only display container IDs
+- :whale: `--format`: Format the output using the given Go template, e.g, `{{json .}}`
 
-Unimplemented `docker ps` flags: `--filter`, `--format`, `--last`, `--size`
+Unimplemented `docker ps` flags: `--filter`, `--last`, `--size`
 
 ### :whale: nerdctl inspect
 Display detailed information on one or more containers.
@@ -604,8 +605,9 @@ Usage: `nerdctl images [OPTIONS] [REPOSITORY[:TAG]]`
 Flags:
 - :whale: `-q, --quiet`: Only show numeric IDs
 - :whale: `--no-trunc`: Don't truncate output
+- :whale: `--format`: Format the output using the given Go template, e.g, `{{json .}}`
 
-Unimplemented `docker images` flags: `--all`, `--digests`, `--filter`, `--format`
+Unimplemented `docker images` flags: `--all`, `--digests`, `--filter`
 
 ### :whale: nerdctl pull
 Pull an image from a registry.
@@ -717,7 +719,11 @@ List networks
 
 Usage: `nerdctl network ls [OPTIONS]`
 
-Unimplemented `docker network ls` flags: `--filter`, `--format`, `--no-trunc`, `--quiet`
+Flags:
+- :whale: `-q, --quiet`: Only display network IDs
+- :whale: `--format`: Format the output using the given Go template, e.g, `{{json .}}`
+
+Unimplemented `docker network ls` flags: `--filter`, `--no-trunc`
 
 ### :whale: nerdctl network inspect
 Display detailed information on one or more networks
@@ -749,8 +755,9 @@ Usage: `nerdctl volume ls [OPTIONS]`
 
 Flags:
 - :whale: `-q, --quiet`: Only display volume names
+- :whale: `--format`: Format the output using the given Go template, e.g, `{{json .}}`
 
-Unimplemented `docker volume ls` flags: `--filter`, `--format`
+Unimplemented `docker volume ls` flags: `--filter`
 
 ### :whale: nerdctl volume inspect
 Display detailed information on one or more volumes
@@ -800,7 +807,8 @@ Show the nerdctl version information
 
 Usage: `nerdctl version [OPTIONS]`
 
-Unimplemented `docker version` flags: `--format`
+Flags:
+- :whale: `-f, --format`: Format the output using the given Go template, e.g, `{{json .}}`
 
 ## Stats
 ### :whale: nerdctl top

cmd/nerdctl/fmtutil.go

@@ -0,0 +1,35 @@
+/*
+   Copyright The 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
+
+// Flusher is implemented by text/tabwriter.Writer
+type Flusher interface {
+	Flush() error
+}
+
+func formatLabels(labels map[string]string) string {
+	var res string
+	for k, v := range labels {
+		s := k + "=" + v
+		if res == "" {
+			res = s
+		} else {
+			res += "," + s
+		}
+	}
+	return res
+}

cmd/nerdctl/images.go

@@ -17,10 +17,13 @@
 package main
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"strings"
 	"text/tabwriter"
+	"text/template"
+	"time"
 
 	"github.com/containerd/containerd"
 	"github.com/containerd/containerd/content"
@@ -29,6 +32,7 @@ import (
 	refdocker "github.com/containerd/containerd/reference/docker"
 	"github.com/containerd/containerd/snapshots"
 	"github.com/containerd/nerdctl/pkg/imgutil"
+	"github.com/docker/cli/templates"
 	"github.com/opencontainers/image-spec/identity"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -50,6 +54,11 @@ var imagesCommand = &cli.Command{
 			Name:  "no-trunc",
 			Usage: "Don't truncate output",
 		},
+		&cli.StringFlag{
+			Name: "format",
+			// Alias "-f" is reserved for "--filter"
+			Usage: "Format the output using the given Go template, e.g, '{{json .}}'",
+		},
 	},
 }
 
@@ -87,13 +96,40 @@ func imagesAction(clicontext *cli.Context) error {
 	return printImages(ctx, clicontext, client, imageList, cs)
 }
 
+type imagePrintable struct {
+	// TODO: "Containers"
+	CreatedAt    string
+	CreatedSince string
+	// TODO: "Digest" (only when --digests is set)
+	ID         string
+	Repository string
+	Tag        string
+	Size       string
+	// TODO: "SharedSize", "UniqueSize", "VirtualSize"
+}
+
 func printImages(ctx context.Context, clicontext *cli.Context, client *containerd.Client, imageList []images.Image, cs content.Store) error {
 	quiet := clicontext.Bool("quiet")
 	noTrunc := clicontext.Bool("no-trunc")
-
-	w := tabwriter.NewWriter(clicontext.App.Writer, 4, 8, 4, ' ', 0)
-	if !quiet {
-		fmt.Fprintln(w, "REPOSITORY\tTAG\tIMAGE ID\tCREATED\tSIZE")
+	w := clicontext.App.Writer
+	var tmpl *template.Template
+	switch format := clicontext.String("format"); format {
+	case "", "table":
+		w = tabwriter.NewWriter(clicontext.App.Writer, 4, 8, 4, ' ', 0)
+		if !quiet {
+			fmt.Fprintln(w, "REPOSITORY\tTAG\tIMAGE ID\tCREATED\tSIZE")
+		}
+	case "raw":
+		return errors.New("unsupported format: \"raw\"")
+	default:
+		if quiet {
+			return errors.New("format and quiet must not be specified together")
+		}
+		var err error
+		tmpl, err = templates.Parse(format)
+		if err != nil {
+			return err
+		}
 	}
 
 	s := client.SnapshotService(clicontext.String("snapshotter"))
@@ -106,34 +142,48 @@ func printImages(ctx context.Context, clicontext *cli.Context, client *container
 		}
 		repository, tag := imgutil.ParseRepoTag(img.Name)
 
-		var digest string
+		p := imagePrintable{
+			CreatedAt:    img.CreatedAt.Round(time.Second).Local().String(), // format like "2021-08-07 02:19:45 +0900 JST"
+			CreatedSince: timeSinceInHuman(img.CreatedAt),
+			ID:           img.Target.Digest.String(),
+			Repository:   repository,
+			Tag:          tag,
+			Size:         progress.Bytes(size).String(),
+		}
 		if !noTrunc {
-			digest = strings.Split(img.Target.Digest.String(), ":")[1][:12]
-		} else {
-			digest = img.Target.Digest.String()
+			p.ID = strings.Split(img.Target.Digest.String(), ":")[1][:12]
 		}
-
-		if quiet {
-			if _, err := fmt.Fprintf(w, "%s\n", digest); err != nil {
+		if tmpl != nil {
+			var b bytes.Buffer
+			if err := tmpl.Execute(&b, p); err != nil {
+				return err
+			}
+			if _, err = fmt.Fprintf(w, b.String()+"\n"); err != nil {
+				return err
+			}
+		} else if quiet {
+			if _, err := fmt.Fprintf(w, "%s\n", p.ID); err != nil {
+				return err
+			}
+		} else {
+			if _, err := fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\n",
+				repository,
+				tag,
+				p.ID,
+				p.CreatedSince,
+				p.Size,
+			); err != nil {
 				return err
 			}
-			continue
-		}
-
-		if _, err := fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\n",
-			repository,
-			tag,
-			digest,
-			timeSinceInHuman(img.CreatedAt),
-			progress.Bytes(size),
-		); err != nil {
-			return err
 		}
 	}
 	if len(errs) > 0 {
 		logrus.Warn("failed to compute image(s) size")
 	}
-	return w.Flush()
+	if f, ok := w.(Flusher); ok {
+		return f.Flush()
+	}
+	return nil
 }
 
 func imagesBashComplete(clicontext *cli.Context) {

cmd/nerdctl/network_ls.go

@@ -17,11 +17,15 @@
 package main
 
 import (
+	"bytes"
 	"fmt"
 	"strconv"
 	"text/tabwriter"
+	"text/template"
 
 	"github.com/containerd/nerdctl/pkg/netutil"
+	"github.com/docker/cli/templates"
+	"github.com/pkg/errors"
 	"github.com/urfave/cli/v2"
 )
 
@@ -30,9 +34,51 @@ var networkLsCommand = &cli.Command{
 	Aliases: []string{"list"},
 	Usage:   "List networks",
 	Action:  networkLsAction,
+	Flags: []cli.Flag{
+		&cli.BoolFlag{
+			Name:    "quiet",
+			Aliases: []string{"q"},
+			Usage:   "Only display network IDs",
+		},
+		&cli.StringFlag{
+			Name: "format",
+			// Alias "-f" is reserved for "--filter"
+			Usage: "Format the output using the given Go template, e.g, '{{json .}}'",
+		},
+	},
+}
+
+type networkPrintable struct {
+	ID     string // empty for non-nerdctl networks
+	Name   string
+	Labels string
+	// TODO: "CreatedAt", "Driver", "IPv6", "Internal", "Scope"
+	file string `json:"-"`
 }
 
 func networkLsAction(clicontext *cli.Context) error {
+	quiet := clicontext.Bool("quiet")
+	w := clicontext.App.Writer
+	var tmpl *template.Template
+	switch format := clicontext.String("format"); format {
+	case "", "table":
+		w = tabwriter.NewWriter(clicontext.App.Writer, 4, 8, 4, ' ', 0)
+		if !quiet {
+			fmt.Fprintln(w, "NETWORK ID\tNAME\tFILE")
+		}
+	case "raw":
+		return errors.New("unsupported format: \"raw\"")
+	default:
+		if quiet {
+			return errors.New("format and quiet must not be specified together")
+		}
+		var err error
+		tmpl, err = templates.Parse(format)
+		if err != nil {
+			return err
+		}
+	}
+
 	e := &netutil.CNIEnv{
 		Path:        clicontext.String("cni-path"),
 		NetconfPath: clicontext.String("cni-netconfpath"),
@@ -41,17 +87,50 @@ func networkLsAction(clicontext *cli.Context) error {
 	if err != nil {
 		return err
 	}
-	w := tabwriter.NewWriter(clicontext.App.Writer, 4, 8, 4, ' ', 0)
-	fmt.Fprintln(w, "NETWORK ID\tNAME\tFILE")
-	for _, l := range ll {
-		var idStr string
+	pp := make([]networkPrintable, len(ll))
+	for i, l := range ll {
+		p := networkPrintable{
+			Name: l.Name,
+			file: l.File,
+		}
 		if l.NerdctlID != nil {
-			idStr = strconv.Itoa(*l.NerdctlID)
+			p.ID = strconv.Itoa(*l.NerdctlID)
+		}
+		if l.NerdctlLabels != nil {
+			p.Labels = formatLabels(*l.NerdctlLabels)
 		}
-		fmt.Fprintf(w, "%s\t%s\t%s\n", idStr, l.Name, l.File)
+		pp[i] = p
+	}
+
+	// append pseudo networks
+	pp = append(pp, []networkPrintable{
+		{
+			Name: "host",
+		},
+		{
+			Name: "none",
+		},
+	}...)
+
+	for _, p := range pp {
+		if tmpl != nil {
+			var b bytes.Buffer
+			if err := tmpl.Execute(&b, p); err != nil {
+				return err
+			}
+			if _, err = fmt.Fprintf(w, b.String()+"\n"); err != nil {
+				return err
+			}
+		} else if quiet {
+			if p.ID != "" {
+				fmt.Fprintln(w, p.ID)
+			}
+		} else {
+			fmt.Fprintf(w, "%s\t%s\t%s\n", p.ID, p.Name, p.file)
+		}
+	}
+	if f, ok := w.(Flusher); ok {
+		return f.Flush()
 	}
-	// pseudo networks
-	fmt.Fprintf(w, "\thost\t\n")
-	fmt.Fprintf(w, "\tnone\t\n")
-	return w.Flush()
+	return nil
 }