Allow adding CID to existing files

Signed-off-by: Anders F Björklund <anders.f.bjorklund@gmail.com>

pkg/downloader/downloader.go

@@ -40,6 +40,7 @@ const (
 	StatusDownloaded Status = "downloaded"
 	StatusSkipped    Status = "skipped"
 	StatusUsedCache  Status = "used-cache"
+	StatusUsedIPFS   Status = "used-ipfs"
 )
 
 type Result struct {
@@ -55,6 +56,7 @@ type options struct {
 	decompress     bool   // default: false (keep compression)
 	description    string // default: url
 	expectedDigest digest.Digest
+	cid            string
 }
 
 type Opt func(*options) error
@@ -121,6 +123,13 @@ func WithExpectedDigest(expectedDigest digest.Digest) Opt {
 	}
 }
 
+func WithContentIdentifier(cid string) Opt {
+	return func(o *options) error {
+		o.cid = cid
+		return nil
+	}
+}
+
 func readFile(path string) string {
 	if path == "" {
 		return ""
@@ -273,11 +282,17 @@ func Download(ctx context.Context, local, remote string, opts ...Opt) (*Result,
 	if err := os.WriteFile(shadURL, []byte(remote), 0o644); err != nil {
 		return nil, err
 	}
+	status := StatusDownloaded
+	if o.cid != "" {
+		if err := downloadIPFS(ctx, shadData, fmt.Sprintf("ipfs://%s", o.cid), o.description, o.expectedDigest); err == nil {
+			status = StatusUsedIPFS
+		}
+	}
 	if IsIPFS(remote) {
 		if err := downloadIPFS(ctx, shadData, remote, o.description, o.expectedDigest); err != nil {
 			return nil, err
 		}
-	} else {
+	} else if status != StatusUsedIPFS {
 		if err := downloadHTTP(ctx, shadData, shadTime, shadType, remote, o.description, o.expectedDigest); err != nil {
 			return nil, err
 		}
@@ -292,7 +307,7 @@ func Download(ctx context.Context, local, remote string, opts ...Opt) (*Result,
 		}
 	}
 	res := &Result{
-		Status:          StatusDownloaded,
+		Status:          status,
 		CachePath:       shadData,
 		LastModified:    readTime(shadTime),
 		ContentType:     readFile(shadType),

pkg/fileutils/download.go

@@ -26,6 +26,7 @@ func DownloadFile(ctx context.Context, dest string, f limayaml.File, decompress
 		downloader.WithDecompress(decompress),
 		downloader.WithDescription(fmt.Sprintf("%s (%s)", description, path.Base(f.Location))),
 		downloader.WithExpectedDigest(f.Digest),
+		downloader.WithContentIdentifier(f.Cid),
 	)
 	if err != nil {
 		return "", fmt.Errorf("failed to download %q: %w", f.Location, err)
@@ -36,6 +37,8 @@ func DownloadFile(ctx context.Context, dest string, f limayaml.File, decompress
 		logrus.Infof("Downloaded %s from %q", description, f.Location)
 	case downloader.StatusUsedCache:
 		logrus.Infof("Using cache %q", res.CachePath)
+	case downloader.StatusUsedIPFS:
+		logrus.Infof("Used ipfs %q", f.Cid)
 	default:
 		logrus.Warnf("Unexpected result from downloader.Download(): %+v", res)
 	}

pkg/limayaml/limayaml.go

@@ -81,6 +81,7 @@ type File struct {
 	Location string        `yaml:"location" json:"location"` // REQUIRED
 	Arch     Arch          `yaml:"arch,omitempty" json:"arch,omitempty"`
 	Digest   digest.Digest `yaml:"digest,omitempty" json:"digest,omitempty"`
+	Cid      string        `yaml:"cid,omitempty" json:"cid,omitempty"`
 }
 
 type FileWithVMType struct {

pkg/limayaml/validate.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net"
 	"os"
+	"os/exec"
 	"path"
 	"path/filepath"
 	"regexp"
@@ -39,6 +40,18 @@ func validateFileObject(f File, fieldName string) error {
 			return fmt.Errorf("field `%s.digest` is invalid: %s: %w", fieldName, f.Digest.String(), err)
 		}
 	}
+	if f.Cid != "" {
+		if _, err := exec.LookPath("ipfs"); err == nil {
+			cmd := exec.Command("ipfs", "cid", "format", f.Cid)
+			if cid, err := cmd.CombinedOutput(); err != nil || strings.TrimSuffix(string(cid), "\n") != f.Cid {
+				// unfortunately, the `ipfs cid` command does not return any proper exit codes
+				if err == nil {
+					return fmt.Errorf("field `%s.cid` is invalid: %s", fieldName, string(cid))
+				}
+				return fmt.Errorf("field `%s.cid` is invalid: %s: %w", fieldName, f.Cid, err)
+			}
+		}
+	}
 	return nil
 }