GoogleContainerTools/skaffold · error

error opening file: %w

Error message

error opening file: %w

What it means

UploadFile wraps os.Open failures for the local source file before uploading it to GCS. It means the src path could not be opened for reading: it does not exist, is a directory, or the process lacks read permission. The OS error is wrapped with %w so errors.Is/As still work.

Source

Thrown at pkg/skaffold/gcs/client/native.go:102

		if _, err := os.Stat(dir); os.IsNotExist(err) {
			if err := os.MkdirAll(dir, os.ModePerm); err != nil {
				return fmt.Errorf("failed to create directory: %v", err)
			}
		}

		if err := bucket.DownloadObject(ctx, fullPath, uri); err != nil {
			return err
		}
	}

	return nil
}

// Uploads a single file to the given dst.
func (n *Native) UploadFile(ctx context.Context, src, dst string) error {
	f, err := os.Open(src)
	if err != nil {
		return fmt.Errorf("error opening file: %w", err)
	}
	defer f.Close()

	urinfo, err := n.parseGCSURI(dst)
	if err != nil {
		return err
	}

	bucket, err := GetBucketManager(ctx, urinfo.Bucket)
	if err != nil {
		return err
	}

	isDirectory, err := n.isGCSDirectory(ctx, bucket, urinfo)
	if err != nil {
		return err
	}

View on GitHub (pinned to a1189de023)

Solutions

1. Verify the src path exists and is a regular file (os.Stat) before calling UploadFile; the wrapped error usually says 'no such file or directory'
2. Fix the path (use an absolute path or ensure the expected working directory)
3. Grant the process read permission on the file (chmod/chown or run as the owning user)
4. Check that the build/generation step that produces the file ran before the upload

Example fix

// before
n.UploadFile(ctx, "./out/app.tar.gz", "gs://bucket/artifacts/") // file not built yet
// after
if _, err := os.Stat("./out/app.tar.gz"); err != nil {
    return fmt.Errorf("artifact missing, run build first: %w", err)
}
if err := n.UploadFile(ctx, "./out/app.tar.gz", "gs://bucket/artifacts/"); err != nil { /* handle */ }

func ensureReadableFile(path string) error {
	fi, err := os.Stat(path)
	if err != nil {
		return fmt.Errorf("source missing: %w", err)
	}
	if fi.IsDir() {
		return fmt.Errorf("%s is a directory, need a file", path)
	}
	f, err := os.Open(path)
	if err != nil {
		return fmt.Errorf("%s not readable: %w", path, err)
	}
	return f.Close()
}
// call ensureReadableFile(src) before UploadFile

When it happens

Trigger: Calling Native.UploadFile(ctx, src, dst) where src is missing, is a directory, is a broken symlink, or is unreadable by the current user (e.g. src="./config.yaml" when the file was never created).

Common situations: Uploading a generated artifact before the build step produced it; typo in the source path; file deleted by a cleanup step; running with a different working directory than expected; container user lacks read permission on a mounted file.

Understand the failure class

Background: "File not found" and ENOENT errors: why libraries can't find a file that should exist — this error's family across 50 libraries.

Related errors

• failed to create directory: %v
• failed to create file: %v
• failed creating Google Cloud Storage cache directory for %q:
• failed to create the tmp directory: %w
• failed to create the tmp directory: %w

AI-assisted analysis of GoogleContainerTools/skaffold@a1189de023 (2026-09-05). Data as JSON: /api/errors/f8fb3207fa0a43e9. Report an issue: GitHub.