gofiber/fiber · error · ErrFileStore

file: failed to store file: %q to %q: %w

Error message

file: failed to store file: %q to %q: %w

What it means

Returned by Ctx.SaveFileToStorage when the external Storage backend's SetWithContext fails to persist the uploaded file. It wraps ErrFileStore with the source filename, destination path, and the storage layer's error. This is the final step after the file was successfully read into memory.

Source

Thrown at ctx.go:600

		return fmt.Errorf("%w: %q: %w", ErrFileRead, fileheader.Filename, fasthttp.ErrBodyTooLarge)
	}

	buf := bytebufferpool.Get()
	defer bytebufferpool.Put(buf)

	limitedReader := io.LimitReader(file, int64(maxUploadSize)+1)
	if _, err = buf.ReadFrom(limitedReader); err != nil {
		return fmt.Errorf("%w: %q: %w", ErrFileRead, fileheader.Filename, err)
	}

	if buf.Len() > maxUploadSize {
		return fmt.Errorf("%w: %q: %w", ErrFileRead, fileheader.Filename, fasthttp.ErrBodyTooLarge)
	}

	data := append([]byte(nil), buf.Bytes()...)

	if err := storage.SetWithContext(c.Context(), path, data, 0); err != nil {
		return fmt.Errorf("%w: %q to %q: %w", ErrFileStore, fileheader.Filename, path, err)
	}

	return nil
}

// Secure returns whether a secure connection was established.
func (c *DefaultCtx) Secure() bool {
	return c.Scheme() == schemeHTTPS
}

// Status sets the HTTP status for the response.
// This method is chainable.
func (c *DefaultCtx) Status(status int) Ctx {
	c.fasthttp.Response.SetStatusCode(status)
	return c
}

// String returns unique string representation of the ctx.

View on GitHub (pinned to 9a4c7e57fe)

Solutions

1. Inspect the wrapped storage error to determine if it is auth, quota, network, or context-cancellation.
2. Verify storage backend connectivity and credentials independently.
3. Use a retry-with-backoff for transient storage failures (network, throttling).
4. Check the destination path is valid for the storage scheme (e.g. no leading slash for some S3 keys).

Example fix

// before
err := c.SaveFileToStorage(fh, path, storage)

// after
err := c.SaveFileToStorage(fh, path, storage)
if err != nil {
    if errors.Is(err, fiber.ErrFileStore) {
        log.Errorf("storage write failed for %q: %v", fh.Filename, err)
        return c.Status(fiber.StatusBadGateway).
            SendString("storage unavailable")
    }
    return err
}

// Verify storage connectivity before the upload handler
if err := storage.SetWithContext(ctx, "healthcheck", []byte("ok"), time.Second); err != nil {
    return fmt.Errorf("storage unreachable: %w", err)
}

if err := c.SaveFileToStorage(fh, path, storage); err != nil {
    if errors.Is(err, fiber.ErrFileStore) {
        // retry transient backend errors, else 502
        return c.Status(fiber.StatusBadGateway).SendString("storage error")
    }
    return err
}

When it happens

Trigger: Calling c.SaveFileToStorage(fh, path, storage) where storage.SetWithContext returns an error: the remote store (S3, Redis, etc.) is unreachable, returns a permission/quota error, or the request context was cancelled before the write completed.

Common situations: Misconfigured storage backend credentials, network outage to the storage service, expired storage session, the destination path/key is invalid or already exists in a write-once bucket, or the client cancelled the request mid-store.

Related errors

• file: failed to open file: %q: %w
• file: failed to read file: %q: %w
• file: failed to store file
• memory storage %s: %w
• failed to listen: %w

AI-assisted analysis of gofiber/fiber@9a4c7e57fe (2026-08-04). Data as JSON: /data/errors/cd6998448e6dd871.json. Report an issue: GitHub.