//
// Note that returning an error here will cause the Metrics handler to return a
// 500 Internal Server Error.
type MetricsLoaderFn func(context.Context, MetricValues, *metricsCache) error

// JoinLoaders - joins multiple loaders into a single loader. The returned
// loader will call each of the given loaders in order. If any of the loaders
// return an error, the returned loader will return that error.

func generateCredentialStr(accessKey, date, region, service, requestVersion string) string {
	return "Credential=" + joinWithSlash(accessKey, date, region, service, requestVersion)
}

// joins the argument strings with a '/' and returns it.
func joinWithSlash(accessKey, date, region, service, requestVersion string) string {
	return strings.Join([]string{
		accessKey,
		date,
		region,
		service,