limactl prune: add --keep-referred option to keep objects that ar…

…e referred by some instances or templates

Signed-off-by: Norio Nomura <[email protected]>

cmd/limactl/prune.go

@@ -1,9 +1,14 @@
 package main
 
 import (
+	"crypto/sha256"
+	"fmt"
 	"os"
 	"path/filepath"
 
+	"github.com/lima-vm/lima/pkg/limayaml"
+	"github.com/lima-vm/lima/pkg/store"
+	"github.com/lima-vm/lima/pkg/templatestore"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 )
@@ -17,15 +22,115 @@ func newPruneCommand() *cobra.Command {
 		ValidArgsFunction: cobra.NoFileCompletions,
 		GroupID:           advancedCommand,
 	}
+	pruneCommand.Flags().Bool("keep-referred", false, "Keep objects that are referred by some instances or templates")
 	return pruneCommand
 }
 
-func pruneAction(_ *cobra.Command, _ []string) error {
+func pruneAction(cmd *cobra.Command, _ []string) error {
+	keepReferred, err := cmd.Flags().GetBool("keep-referred")
+	if err != nil {
+		return err
+	}
 	ucd, err := os.UserCacheDir()
 	if err != nil {
 		return err
 	}
 	cacheDir := filepath.Join(ucd, "lima")
 	logrus.Infof("Pruning %q", cacheDir)
-	return os.RemoveAll(cacheDir)
+	if !keepReferred {
+		return os.RemoveAll(cacheDir)
+	}
+
+	// Prune downloads that are not used by any instances or templates
+	downloadDir := filepath.Join(cacheDir, "download", "by-url-sha256")
+	_, err = os.Stat(downloadDir)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil
+		}
+		return err
+	}
+	cacheEntries, err := os.ReadDir(downloadDir)
+	if err != nil {
+		return err
+	}
+	knownLocations, err := knownLocations()
+	if err != nil {
+		return err
+	}
+	for _, entry := range cacheEntries {
+		if file, exists := knownLocations[entry.Name()]; exists {
+			logrus.Debugf("Keep %q caching %q", entry.Name(), file.Location)
+		} else {
+			logrus.Debug("Deleting ", entry.Name())
+			if err := os.RemoveAll(filepath.Join(downloadDir, entry.Name())); err != nil {
+				logrus.Warnf("Failed to delete %q: %v", entry.Name(), err)
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func knownLocations() (map[string]limayaml.File, error) {
+	locations := make(map[string]limayaml.File)
+
+	// Collect locations from instances
+	instances, err := store.Instances()
+	if err != nil {
+		return nil, err
+	}
+	for _, instanceName := range instances {
+		instance, err := store.Inspect(instanceName)
+		if err != nil {
+			return nil, err
+		}
+		for k, v := range locationsFromLimaYAML(instance.Config) {
+			locations[k] = v
+		}
+	}
+
+	// Collect locations from templates
+	templates, err := templatestore.Templates()
+	if err != nil {
+		return nil, err
+	}
+	for _, t := range templates {
+		b, err := templatestore.Read(t.Name)
+		if err != nil {
+			return nil, err
+		}
+		y, err := limayaml.Load(b, t.Name)
+		if err != nil {
+			return nil, err
+		}
+		for k, v := range locationsFromLimaYAML(y) {
+			locations[k] = v
+		}
+	}
+	return locations, nil
+}
+
+func locationsFromLimaYAML(y *limayaml.LimaYAML) map[string]limayaml.File {
+	locations := make(map[string]limayaml.File)
+	for _, f := range y.Images {
+		locations[sha256OfURL(f.Location)] = f.File
+		if f.Kernel != nil {
+			locations[sha256OfURL(f.Kernel.Location)] = f.Kernel.File
+		}
+		if f.Initrd != nil {
+			locations[sha256OfURL(f.Initrd.Location)] = *f.Initrd
+		}
+	}
+	for _, f := range y.Containerd.Archives {
+		locations[sha256OfURL(f.Location)] = f
+	}
+	for _, f := range y.Firmware.Images {
+		locations[sha256OfURL(f.Location)] = f.File
+	}
+	return locations
+}
+
+func sha256OfURL(url string) string {
+	return fmt.Sprintf("%x", sha256.Sum256([]byte(url)))
 }