feat(system): add nerdctl system df

cmd/nerdctl/image/image_list_test.go

@@ -38,6 +38,17 @@ import (
 	"github.com/containerd/nerdctl/v2/pkg/testutil/nerdtest"
 )
 
+// padRow widens a row of a table back to the width of its header, so that its last column can be
+// read. tabutil indexes the columns by byte offset and slices without checking the bounds, and a
+// row can be shorter than the header in two ways: the trailing column is empty, and the padding of
+// the very last line is gone once the output has been trimmed.
+func padRow(header, row string) string {
+	if pad := len(header) - len(row); pad > 0 {
+		return row + strings.Repeat(" ", pad)
+	}
+	return row
+}
+
 // TestNameFilterFor is a regression test for
 // https://github.com/containerd/nerdctl/issues/5113: `nerdctl image ls
 // myapp`, where myapp is a bare repository name, returned nothing unless
@@ -207,6 +218,57 @@ func TestImages(t *testing.T) {
 					}
 				},
 			},
+			{
+				Description: "In use survives a retag",
+				Setup: func(data test.Data, helpers test.Helpers) {
+					// Run a container off a private tag, then move that tag onto another image.
+					// The container still runs the original image, so that is the one that must
+					// stay marked as in use.
+					helpers.Ensure("tag", commonImage.String(), data.Identifier()+":moving")
+					helpers.Ensure("run", "-d", "--quiet", "--name", data.Identifier(),
+						data.Identifier()+":moving", "sleep", nerdtest.Infinity)
+					helpers.Ensure("tag", testutil.NginxAlpineImage, data.Identifier()+":moving")
+
+					nginx, _ := referenceutil.Parse(testutil.NginxAlpineImage)
+					data.Labels().Set("retaggedTo", nginx.FamiliarName()+":"+nginx.Tag)
+				},
+				Cleanup: func(data test.Data, helpers test.Helpers) {
+					helpers.Anyhow("rm", "-f", data.Identifier())
+					helpers.Anyhow("rmi", "-f", data.Identifier()+":moving")
+				},
+				Command: test.Command("images"),
+				Expected: func(data test.Data, helpers test.Helpers) *test.Expected {
+					return &test.Expected{
+						Output: func(stdout string, t tig.T) {
+							lines := strings.Split(strings.TrimSpace(stdout), "\n")
+							assert.Assert(t, len(lines) >= 2, "there should be at least two lines\n")
+							tab := tabutil.NewReader("IMAGE\tID\tDISK USAGE\tCONTENT SIZE\tEXTRA")
+							err := tab.ParseHeader(lines[0])
+							assert.NilError(t, err, "ParseHeader should not fail\n")
+
+							original := commonImage.FamiliarName() + ":" + commonImage.Tag
+							retagged := data.Labels().Get("retaggedTo")
+							seen := 0
+							for _, line := range lines[1:] {
+								line = padRow(lines[0], line)
+								image, _ := tab.ReadRow(line, "IMAGE")
+								extra, _ := tab.ReadRow(line, "EXTRA")
+								switch image {
+								case original:
+									assert.Equal(t, extra, "U",
+										"the image the container runs must stay in use: "+image)
+									seen++
+								case retagged:
+									assert.Equal(t, extra, "",
+										"the image the tag now points at is not in use: "+image)
+									seen++
+								}
+							}
+							assert.Equal(t, seen, 2, "both images should be listed\n")
+						},
+					}
+				},
+			},
 		},
 	}
 

cmd/nerdctl/system/system.go

@@ -33,6 +33,7 @@ func Command() *cobra.Command {
 	}
 	// versionCommand is not here
 	cmd.AddCommand(
+		dfCommand(),
 		EventsCommand(),
 		InfoCommand(),
 		pruneCommand(),

cmd/nerdctl/system/system_df.go

@@ -0,0 +1,90 @@
+/*
+   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 system
+
+import (
+	"github.com/spf13/cobra"
+
+	"github.com/containerd/log"
+
+	"github.com/containerd/nerdctl/v2/cmd/nerdctl/builder"
+	"github.com/containerd/nerdctl/v2/cmd/nerdctl/helpers"
+	"github.com/containerd/nerdctl/v2/pkg/api/types"
+	"github.com/containerd/nerdctl/v2/pkg/clientutil"
+	"github.com/containerd/nerdctl/v2/pkg/cmd/system"
+)
+
+func dfCommand() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:           "df [flags]",
+		Short:         "Show nerdctl disk usage",
+		Args:          cobra.NoArgs,
+		RunE:          dfAction,
+		SilenceUsage:  true,
+		SilenceErrors: true,
+	}
+	cmd.Flags().BoolP("verbose", "v", false, "Show detailed information on space usage")
+	cmd.Flags().String("format", "", "Format the output using the given Go template, e.g, '{{json .}}'")
+	return cmd
+}
+
+func dfOptions(cmd *cobra.Command) (types.SystemDfOptions, error) {
+	globalOptions, err := helpers.ProcessRootCmdFlags(cmd)
+	if err != nil {
+		return types.SystemDfOptions{}, err
+	}
+
+	verbose, err := cmd.Flags().GetBool("verbose")
+	if err != nil {
+		return types.SystemDfOptions{}, err
+	}
+
+	format, err := cmd.Flags().GetString("format")
+	if err != nil {
+		return types.SystemDfOptions{}, err
+	}
+
+	buildkitHost, err := builder.GetBuildkitHost(cmd, globalOptions.Namespace)
+	if err != nil {
+		log.L.WithError(err).Warn("BuildKit is not running. The build cache usage will be reported as empty.")
+		buildkitHost = ""
+	}
+
+	return types.SystemDfOptions{
+		Stdout:       cmd.OutOrStdout(),
+		Stderr:       cmd.ErrOrStderr(),
+		GOptions:     globalOptions,
+		Format:       format,
+		Verbose:      verbose,
+		BuildKitHost: buildkitHost,
+	}, nil
+}
+
+func dfAction(cmd *cobra.Command, _ []string) error {
+	options, err := dfOptions(cmd)
+	if err != nil {
+		return err
+	}
+
+	client, ctx, cancel, err := clientutil.NewClient(cmd.Context(), options.GOptions.Namespace, options.GOptions.Address)
+	if err != nil {
+		return err
+	}
+	defer cancel()
+
+	return system.Df(ctx, client, options)
+}

cmd/nerdctl/system/system_df_linux_test.go

@@ -0,0 +1,70 @@
+/*
+   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 system
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/containerd/nerdctl/mod/tigron/test"
+	"github.com/containerd/nerdctl/mod/tigron/tig"
+
+	"github.com/containerd/nerdctl/v2/pkg/testutil"
+	"github.com/containerd/nerdctl/v2/pkg/testutil/nerdtest"
+)
+
+// TestSystemDfVolumes covers the Local Volumes row, which the rest of TestSystemDf cannot: a volume
+// is only counted once a container mounts it, and the target of a mount is written differently on
+// each platform.
+func TestSystemDfVolumes(t *testing.T) {
+	testCase := nerdtest.Setup()
+
+	// The counts are only meaningful when nothing else is running against the same namespace.
+	testCase.NoParallel = true
+
+	testCase.SubTests = []*test.Case{
+		{
+			Description: "mounted volume is active",
+			Require:     nerdtest.Private,
+			Setup: func(data test.Data, helpers test.Helpers) {
+				data.Labels().Set(baselineLabel, helpers.Capture("system", "df"))
+				helpers.Ensure("volume", "create", data.Identifier())
+				helpers.Ensure("run", "-d", "--name", data.Identifier(),
+					"-v", fmt.Sprintf("%s:/volume", data.Identifier()),
+					testutil.CommonImage, "sleep", nerdtest.Infinity)
+			},
+			Cleanup: func(data test.Data, helpers test.Helpers) {
+				helpers.Anyhow("rm", "-f", data.Identifier())
+				helpers.Anyhow("volume", "rm", "-f", data.Identifier())
+			},
+			Command: test.Command("system", "df"),
+			Expected: func(data test.Data, helpers test.Helpers) *test.Expected {
+				return &test.Expected{
+					ExitCode: 0,
+					Output: func(stdout string, t tig.T) {
+						// The volume is created by this test and the container it runs mounts it,
+						// so both counts went up by it.
+						dfGrewBy(t, data, stdout, "Local Volumes", totalColumn, 1)
+						dfGrewBy(t, data, stdout, "Local Volumes", activeColumn, 1)
+					},
+				}
+			},
+		},
+	}
+
+	testCase.Run(t)
+}