Builder disk usage and clean

We use dedicated docker container as builder and we are able to clean
data inside only by re-creating of it. Let's add disk usage and clean
commands for builder.

Signed-off-by: Petr Fedchenkov <giggsoff@gmail.com>

src/cmd/linuxkit/pkg.go

@@ -12,6 +12,7 @@ func pkgUsage() {
 
 	fmt.Printf("'subcommand' is one of:\n")
 	fmt.Printf("  build\n")
+	fmt.Printf("  builder\n")
 	fmt.Printf("  push\n")
 	fmt.Printf("  show-tag\n")
 	fmt.Printf("\n")
@@ -28,6 +29,8 @@ func pkg(args []string) {
 	switch args[0] {
 	case "build":
 		pkgBuild(args[1:])
+	case "builder":
+		pkgBuilder(args[1:])
 	case "push":
 		pkgPush(args[1:])
 	case "show-tag":

src/cmd/linuxkit/pkg_builder.go

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+
+	"github.com/linuxkit/linuxkit/src/cmd/linuxkit/pkglib"
+	log "github.com/sirupsen/logrus"
+)
+
+func pkgBuilderUsage() {
+	invoked := filepath.Base(os.Args[0])
+	fmt.Printf("USAGE: %s builder command [options]\n\n", invoked)
+	fmt.Printf("Supported commands are\n")
+	// Please keep these in alphabetical order
+	fmt.Printf("  du\n")
+	fmt.Printf("  prune\n")
+	fmt.Printf("\n")
+	fmt.Printf("'options' are the backend specific options.\n")
+	fmt.Printf("See '%s builder [command] --help' for details.\n\n", invoked)
+}
+
+// Process the builder
+func pkgBuilder(args []string) {
+	if len(args) < 1 {
+		pkgBuilderUsage()
+		os.Exit(1)
+	}
+	switch args[0] {
+	// Please keep cases in alphabetical order
+	case "du":
+		pkgBuilderCommands(args[0], args[1:])
+	case "prune":
+		pkgBuilderCommands(args[0], args[1:])
+	case "help", "-h", "-help", "--help":
+		pkgBuilderUsage()
+		os.Exit(0)
+	default:
+		log.Errorf("No 'builder' command specified.")
+	}
+}
+
+func pkgBuilderCommands(command string, args []string) {
+	flags := flag.NewFlagSet(command, flag.ExitOnError)
+	builders := flags.String("builders", "", "Which builders to use for which platforms, e.g. linux/arm64=docker-context-arm64, overrides defaults and environment variables, see https://github.com/linuxkit/linuxkit/blob/master/docs/packages.md#Providing-native-builder-nodes")
+	platforms := flags.String("platforms", fmt.Sprintf("linux/%s", runtime.GOARCH), "Which platforms we built images for")
+	builderImage := flags.String("builder-image", defaultBuilderImage, "buildkit builder container image to use")
+	verbose := flags.Bool("v", false, "Verbose output")
+	if err := flags.Parse(args); err != nil {
+		log.Fatal("Unable to parse args")
+	}
+	// build the builders map
+	buildersMap := make(map[string]string)
+	// look for builders env var
+	buildersMap, err := buildPlatformBuildersMap(os.Getenv(buildersEnvVar), buildersMap)
+	if err != nil {
+		log.Fatalf("%s in environment variable %s\n", err.Error(), buildersEnvVar)
+	}
+	// any CLI options override env var
+	buildersMap, err = buildPlatformBuildersMap(*builders, buildersMap)
+	if err != nil {
+		log.Fatalf("%s in --builders flag\n", err.Error())
+	}
+
+	platformsToClean := strings.Split(*platforms, ",")
+	switch command {
+	case "du":
+		if err := pkglib.DiskUsage(buildersMap, *builderImage, platformsToClean, *verbose); err != nil {
+			log.Fatalf("Unable to print disk usage of builder: %v", err)
+		}
+	case "prune":
+		if err := pkglib.PruneBuilder(buildersMap, *builderImage, platformsToClean, *verbose); err != nil {
+			log.Fatalf("Unable to prune builder: %v", err)
+		}
+	default:
+		log.Errorf("unexpected command %s", command)
+		pkgBuilderUsage()
+		os.Exit(1)
+	}
+}

src/cmd/linuxkit/pkglib/build_test.go

@@ -19,6 +19,7 @@ import (
 	"github.com/google/go-containerregistry/pkg/v1/types"
 	"github.com/linuxkit/linuxkit/src/cmd/linuxkit/spec"
 	lktspec "github.com/linuxkit/linuxkit/src/cmd/linuxkit/spec"
+	buildkitClient "github.com/moby/buildkit/client"
 	imagespec "github.com/opencontainers/image-spec/specs-go/v1"
 )
 
@@ -52,7 +53,9 @@ func (d *dockerMocker) contextSupportCheck() error {
 	}
 	return errors.New("contexts not supported")
 }
-
+func (d *dockerMocker) builder(_ context.Context, _, _, _ string, _ bool) (*buildkitClient.Client, error) {
+	return nil, fmt.Errorf("not implemented")
+}
 func (d *dockerMocker) build(ctx context.Context, tag, pkg, dockerContext, builderImage, platform string, builderRestart bool, c spec.CacheProvider, r io.Reader, stdout io.Writer, imageBuildOpts dockertypes.ImageBuildOptions) error {
 	if !d.enableBuild {
 		return errors.New("build disabled")

src/cmd/linuxkit/pkglib/docker.go

@@ -57,6 +57,7 @@ type dockerRunner interface {
 	load(src io.Reader) error
 	pull(img string) (bool, error)
 	contextSupportCheck() error
+	builder(ctx context.Context, dockerContext, builderImage, platform string, restart bool) (*buildkitClient.Client, error)
 }
 
 type dockerRunnerImpl struct {

src/cmd/linuxkit/pkglib/utils.go

@@ -0,0 +1,183 @@
+package pkglib
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+	"text/tabwriter"
+	"time"
+
+	"github.com/containerd/containerd/platforms"
+	"github.com/docker/go-units"
+	buildkitClient "github.com/moby/buildkit/client"
+)
+
+func printTableHeader(tw *tabwriter.Writer) {
+	fmt.Fprintln(tw, "ID\tRECLAIMABLE\tSIZE\tLAST ACCESSED")
+}
+
+func printTableRow(tw *tabwriter.Writer, di *buildkitClient.UsageInfo) {
+	id := di.ID
+	if di.Mutable {
+		id += "*"
+	}
+	size := units.HumanSize(float64(di.Size))
+	if di.Shared {
+		size += "*"
+	}
+	lastAccessed := ""
+	if di.LastUsedAt != nil {
+		lastAccessed = units.HumanDuration(time.Since(*di.LastUsedAt)) + " ago"
+	}
+	fmt.Fprintf(tw, "%-40s\t%-5v\t%-10s\t%s\n", id, !di.InUse, size, lastAccessed)
+}
+
+func printSummary(tw *tabwriter.Writer, du []*buildkitClient.UsageInfo) {
+	total := int64(0)
+	reclaimable := int64(0)
+	shared := int64(0)
+
+	for _, di := range du {
+		if di.Size > 0 {
+			total += di.Size
+			if !di.InUse {
+				reclaimable += di.Size
+			}
+		}
+		if di.Shared {
+			shared += di.Size
+		}
+	}
+
+	if shared > 0 {
+		fmt.Fprintf(tw, "Shared:\t%s\n", units.HumanSize(float64(shared)))
+		fmt.Fprintf(tw, "Private:\t%s\n", units.HumanSize(float64(total-shared)))
+	}
+
+	fmt.Fprintf(tw, "Reclaimable:\t%s\n", units.HumanSize(float64(reclaimable)))
+	fmt.Fprintf(tw, "Total:\t%s\n", units.HumanSize(float64(total)))
+	tw.Flush()
+}
+
+func printKV(w io.Writer, k string, v interface{}) {
+	fmt.Fprintf(w, "%s:\t%v\n", k, v)
+}
+
+func printVerbose(tw *tabwriter.Writer, du []*buildkitClient.UsageInfo) {
+	for _, di := range du {
+		printKV(tw, "ID", di.ID)
+		if len(di.Parents) != 0 {
+			printKV(tw, "Parent", strings.Join(di.Parents, ","))
+		}
+		printKV(tw, "Created at", di.CreatedAt)
+		printKV(tw, "Mutable", di.Mutable)
+		printKV(tw, "Reclaimable", !di.InUse)
+		printKV(tw, "Shared", di.Shared)
+		printKV(tw, "Size", units.HumanSize(float64(di.Size)))
+		if di.Description != "" {
+			printKV(tw, "Description", di.Description)
+		}
+		printKV(tw, "Usage count", di.UsageCount)
+		if di.LastUsedAt != nil {
+			printKV(tw, "Last used", units.HumanDuration(time.Since(*di.LastUsedAt))+" ago")
+		}
+		if di.RecordType != "" {
+			printKV(tw, "Type", di.RecordType)
+		}
+
+		fmt.Fprintf(tw, "\n")
+	}
+
+	tw.Flush()
+}
+
+func getClientForPlatform(ctx context.Context, buildersMap map[string]string, builderImage, platform string) (*buildkitClient.Client, error) {
+	p, err := platforms.Parse(platform)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse platform: %s", err)
+	}
+	dr := newDockerRunner(false)
+	builderName := getBuilderForPlatform(p.Architecture, buildersMap)
+	client, err := dr.builder(ctx, builderName, builderImage, platform, false)
+	if err != nil {
+		return nil, fmt.Errorf("unable to ensure builder container: %v", err)
+	}
+	return client, nil
+}
+
+// DiskUsage of builder
+func DiskUsage(buildersMap map[string]string, builderImage string, platformsToClean []string, verbose bool) error {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	for _, platform := range platformsToClean {
+		client, err := getClientForPlatform(ctx, buildersMap, builderImage, platform)
+		if err != nil {
+			return fmt.Errorf("cannot get client: %s", err)
+		}
+
+		du, err := client.DiskUsage(ctx)
+		if err != nil {
+			_ = client.Close()
+			return err
+		}
+		err = client.Close()
+		if err != nil {
+			return fmt.Errorf("cannot close client: %s", err)
+		}
+		tw := tabwriter.NewWriter(os.Stdout, 1, 8, 1, '\t', 0)
+		if len(du) > 0 {
+			if verbose {
+				printVerbose(tw, du)
+			} else {
+				printTableHeader(tw)
+				for _, di := range du {
+					printTableRow(tw, di)
+				}
+			}
+		}
+		printSummary(tw, du)
+	}
+	return nil
+}
+
+// PruneBuilder clean build cache of builder
+func PruneBuilder(buildersMap map[string]string, builderImage string, platformsToClean []string, verbose bool) error {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	total := int64(0)
+	for _, platform := range platformsToClean {
+		client, err := getClientForPlatform(ctx, buildersMap, builderImage, platform)
+		if err != nil {
+			return fmt.Errorf("cannot get client: %s", err)
+		}
+
+		ch := make(chan buildkitClient.UsageInfo)
+		processed := make(chan struct{})
+
+		go func() {
+			defer close(processed)
+			for du := range ch {
+				if verbose {
+					fmt.Printf("%s\t%s\tremoved\n", du.ID, units.HumanSize(float64(du.Size)))
+				}
+				total += du.Size
+			}
+		}()
+		err = client.Prune(ctx, ch)
+		if err != nil {
+			_ = client.Close()
+			close(ch)
+			return err
+		}
+		err = client.Close()
+		if err != nil {
+			return fmt.Errorf("cannot close client: %s", err)
+		}
+		close(ch)
+		<-processed
+	}
+	fmt.Printf("Reclaimed:\t%s\n", units.BytesSize(float64(total)))
+	return nil
+}