cmd: json format support for du command in verbose mode

Signed-off-by: CrazyMax <[email protected]>

Author: crazy-max

commands/diskusage.go

@@ -2,9 +2,11 @@ package commands
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"io"
 	"os"
+	"slices"
 	"strings"
 	"text/tabwriter"
 	"time"
@@ -13,9 +15,11 @@ import (
 	"github.com/docker/buildx/util/cobrautil/completion"
 	"github.com/docker/cli/cli"
 	"github.com/docker/cli/cli/command"
+	"github.com/docker/cli/cli/command/formatter"
 	"github.com/docker/cli/opts"
 	"github.com/docker/go-units"
 	"github.com/moby/buildkit/client"
+	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 	"golang.org/x/sync/errgroup"
 )
@@ -24,9 +28,19 @@ type duOptions struct {
 	builder string
 	filter  opts.FilterOpt
 	verbose bool
+	format  string
 }
 
 func runDiskUsage(ctx context.Context, dockerCli command.Cli, opts duOptions) error {
+	if opts.format != "" {
+		if !opts.verbose {
+			return errors.New("cannot use --format without --verbose")
+		}
+		if !slices.Contains([]string{formatter.RawFormatKey, formatter.JSONFormatKey}, opts.format) {
+			return errors.Errorf("unsupported format: %q", opts.format)
+		}
+	}
+
 	pi, err := toBuildkitPruneInfo(opts.filter.Value())
 	if err != nil {
 		return err
@@ -74,6 +88,18 @@ func runDiskUsage(ctx context.Context, dockerCli command.Cli, opts duOptions) er
 		return err
 	}
 
+	if opts.verbose && opts.format == formatter.JSONFormatKey {
+		var dus []*client.UsageInfo
+		for _, du := range out {
+			if du != nil {
+				dus = append(dus, du...)
+			}
+		}
+		enc := json.NewEncoder(dockerCli.Out())
+		enc.SetIndent("", "  ")
+		return enc.Encode(dus)
+	}
+
 	tw := tabwriter.NewWriter(os.Stdout, 1, 8, 1, '\t', 0)
 	first := true
 	for _, du := range out {
@@ -120,6 +146,7 @@ func duCmd(dockerCli command.Cli, rootOpts *rootOptions) *cobra.Command {
 	flags := cmd.Flags()
 	flags.Var(&options.filter, "filter", "Provide filter values")
 	flags.BoolVar(&options.verbose, "verbose", false, "Provide a more verbose output")
+	flags.StringVar(&options.format, "format", "", "Format the output in verbose mode")
 
 	return cmd
 }

docs/reference/buildx_du.md

@@ -14,6 +14,7 @@ Disk usage
 | [`--builder`](#builder) | `string` |         | Override the configured builder instance |
 | `-D`, `--debug`         | `bool`   |         | Enable debug logging                     |
 | `--filter`              | `filter` |         | Provide filter values                    |
+| [`--format`](#format)   | `string` |         | Format the output in verbose mode        |
 | [`--verbose`](#verbose) | `bool`   |         | Provide a more verbose output            |
 
 
@@ -117,3 +118,41 @@ uj802yxtvkcjysnjb4kgwvn2v         true           11.68MB       45 hours ago
 Reclaimable:    2.627GB
 Total:          2.627GB
 ```
+
+### <a name="format"></a> Format the output in verbose mode (--format)
+
+The formatting options (`--format`) can be used with [`--verbose` flag](#verbose)
+to print the output in `raw` (default) or `json`:
+
+```console
+$ docker buildx du --verbose --format=json
+[
+  ...
+  {
+    "id": "4m8061kctvjyh9qleus8rgpgx",
+    "mutable": true,
+    "inUse": false,
+    "size": 1723305984,
+    "createdAt": "2025-06-19T21:00:41.53563755Z",
+    "lastUsedAt": "2025-08-11T09:20:22.598927091Z",
+    "usageCount": 25,
+    "parents": null,
+    "description": "cached mount /root/.cache/go-build from exec /bin/sh -c   set -ex\n  go test -v -coverprofile=/tmp/coverage.txt -covermode=atomic -race ./...\n  go tool cover -func=/tmp/coverage.txt\n with id \"//root/.cache/go-build\"",
+    "recordType": "exec.cachemount",
+    "shared": false
+  },
+  {
+    "id": "fcm9mlz2641u8r5eicjqdhy1l",
+    "mutable": false,
+    "inUse": false,
+    "size": 1840796514,
+    "createdAt": "2025-06-21T12:45:07.224976569Z",
+    "lastUsedAt": "2025-06-21T12:45:59.043699703Z",
+    "usageCount": 1,
+    "parents": null,
+    "description": "[stage-35 1/1] COPY --link --from=build /out /",
+    "recordType": "regular",
+    "shared": true
+  }
+]
+```