gofiber/fiber · error · ErrFileStore

file: failed to store file

Error message

file: failed to store file

What it means

ErrFileStore ('file: failed to store file', error.go:100) is wrapped and returned by ctx.SaveFileToStorage (ctx.go:600) when the Storage backend's SetWithContext call fails after the file was successfully read. It indicates the destination (S3, Redis, filesystem abstraction, etc.) rejected the write, not that the upload itself was malformed. The error includes the filename and target path.

Source

Thrown at error.go:99

	SyntaxError = json.SyntaxError

	// UnmarshalTypeError describes a JSON value that was
	// not appropriate for a value of a specific Go type.
	UnmarshalTypeError = json.UnmarshalTypeError

	// UnsupportedTypeError is returned by Marshal when attempting
	// to encode an unsupported value type.
	UnsupportedTypeError = json.UnsupportedTypeError

	// UnsupportedValueError exposes json.UnsupportedValueError to describe unsupported values encountered during encoding.
	UnsupportedValueError = json.UnsupportedValueError
)

// File errors
var (
	ErrFileHeaderNil = errors.New("file: file header is nil")
	ErrFileOpen      = errors.New("file: failed to open file")
	ErrFileRead      = errors.New("file: failed to read file")
	ErrFileStore     = errors.New("file: failed to store file")
)

View on GitHub (pinned to 9a4c7e57fe)

Solutions

1. Inspect the wrapped error to identify the storage-specific cause (e.g. AWS S3 error codes) and fix credentials/config.
2. Implement retries with backoff for transient storage failures before returning to the client.
3. Validate the destination path/key format before calling SetWithContext, and ensure the storage client is initialized and reachable.

Example fix

// before
if err := c.SaveFileToStorage(fh, key, storage); err != nil {
    return err // generic 500, no diagnosis
}

// after
if err := c.SaveFileToStorage(fh, key, storage); err != nil {
    if errors.Is(err, fiber.ErrFileStore) {
        log.Printf("storage write failed for %q: %v", key, err)
        return fiber.NewError(fiber.StatusBadGateway, "could not store file, please retry")
    }
    return err
}

// Verify storage connectivity before serving uploads.
if err := storage.SetWithContext(ctx, "__healthcheck", []byte("ok"), 0); err != nil {
    log.Fatalf("storage unreachable: %v", err)
}

if err := c.SaveFileToStorage(fh, key, storage); err != nil {
    if errors.Is(err, fiber.ErrFileStore) {
        log.Printf("store failed for %q: %v", key, err)
        return fiber.NewError(fiber.StatusBadGateway, "storage unavailable, please retry")
    }
    return err
}

When it happens

Trigger: c.SaveFileToStorage(fh, "uploads/x", storage) where storage.SetWithContext returns an error: network/credential failure against S3, Redis connection lost, disk full for a filesystem storage, or an invalid path/key. Triggered after the body was read successfully, so the upload was valid.

Common situations: Expired or wrong cloud-storage credentials, transient network blips to the object store, full disk, path/key validation failures in a custom Storage implementation, or a misconfigured storage client (wrong region/endpoint).

Related errors

• file: file header is nil
• file: failed to read file
• file: failed to open file: %q: %w
• file: failed to read file: %q: %w
• file: failed to store file: %q to %q: %w

AI-assisted analysis of gofiber/fiber@9a4c7e57fe (2026-08-04). Data as JSON: /data/errors/5a2caf0e7e8916be.json. Report an issue: GitHub.