refactor: split function

pkg/installpackage/checksum.go

@@ -55,14 +55,16 @@ func (is *Installer) dlAndExtractChecksum(ctx context.Context, logE *logrus.Entr
 		}
 	}
 
-	if err := is.verifyChecksumWithMinisign(ctx, logE, pkg, assetName, tempFilePath, b); err != nil {
+	if err := is.verifyChecksumWithMinisign(ctx, logE, pkg, tempFilePath, b); err != nil {
 		return "", err
 	}
 
 	return checksum.GetChecksum(logE, assetName, string(b), pkg.PackageInfo.Checksum) //nolint:wrapcheck
 }
 
-func (is *Installer) verifyChecksumWithMinisign(ctx context.Context, logE *logrus.Entry, pkg *config.Package, assetName, tempFilePath string, b []byte) error {
+// b is a content of the checksum file.
+// tempFilePath is a path of the checksum file.
+func (is *Installer) verifyChecksumWithMinisign(ctx context.Context, logE *logrus.Entry, pkg *config.Package, tempFilePath string, b []byte) error {
 	ms := pkg.PackageInfo.Checksum.GetMinisign()
 	if !ms.GetEnabled() {
 		return nil
@@ -88,7 +90,8 @@ func (is *Installer) verifyChecksumWithMinisign(ctx context.Context, logE *logru
 			return fmt.Errorf("write a checksum to a temporary file: %w", err)
 		}
 	}
-	art := pkg.TemplateArtifact(is.runtime, assetName)
+
+	art := pkg.TemplateArtifact(is.runtime, "")
 	logE.Info("verifing a checksum file with Minisign")
 	if err := is.minisignInstaller.install(ctx, logE); err != nil {
 		return err

pkg/minisign/verifier.go

@@ -33,25 +33,33 @@ type ParamVerify struct {
 }
 
 func (v *Verifier) Verify(ctx context.Context, logE *logrus.Entry, rt *runtime.Runtime, m *registry.Minisign, art *template.Artifact, file *download.File, param *ParamVerify) error {
+	sigFile, err := v.downloadSignature(ctx, logE, rt, m, art, file)
+	if err != nil {
+		return err
+	}
+	defer v.fs.Remove(sigFile)                     //nolint:errcheck
+	return v.exe.Verify(ctx, logE, param, sigFile) //nolint:wrapcheck
+}
+
+func (v *Verifier) downloadSignature(ctx context.Context, logE *logrus.Entry, rt *runtime.Runtime, m *registry.Minisign, art *template.Artifact, file *download.File) (string, error) {
 	f, err := download.ConvertDownloadedFileToFile(m.ToDownloadedFile(), file, rt, art)
 	if err != nil {
-		return err //nolint:wrapcheck
+		return "", err //nolint:wrapcheck
 	}
+
 	rc, _, err := v.downloader.ReadCloser(ctx, logE, f)
 	if err != nil {
-		return fmt.Errorf("download a Minisign signature: %w", err)
+		return "", fmt.Errorf("download a Minisign signature: %w", err)
 	}
 	defer rc.Close()
 
 	signatureFile, err := afero.TempFile(v.fs, "", "")
 	if err != nil {
-		return fmt.Errorf("create a temporary file: %w", err)
+		return "", fmt.Errorf("create a temporary file: %w", err)
 	}
-	defer signatureFile.Close()
-	defer v.fs.Remove(signatureFile.Name()) //nolint:errcheck
+	defer signatureFile.Close() //nolint:errcheck
 	if _, err := io.Copy(signatureFile, rc); err != nil {
-		return fmt.Errorf("copy a signature to a temporary file: %w", err)
+		return signatureFile.Name(), fmt.Errorf("copy a signature to a temporary file: %w", err)
 	}
-
-	return v.exe.Verify(ctx, logE, param, signatureFile.Name()) //nolint:wrapcheck
+	return signatureFile.Name(), nil
 }