func getResourceGroups(client *autorest.Client) (*string, error) {
	var p map[string]interface{}
	var req *http.Request
	p = map[string]interface{}{
		"subscription-id": subscriptionID,
	}
	q := map[string]interface{}{
		"api-version": apiVersion,
	}

	req, _ = autorest.Prepare(&http.Request{},
		autorest.AsGet(),
		autorest.WithBaseURL(resourceGroupURLTemplate),
		autorest.WithPathParameters(p),
		autorest.WithQueryParameters(q))

	resp, err := client.Send(req, http.StatusOK)
	if err != nil {
		return nil, err
	}

	defer resp.Body.Close()
	contents, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	contentsString := string(contents)

	return &contentsString, nil
}

// pollIndefinitelyAsNeeded is a terrible hack which is necessary because the Azure
// Storage API (and perhaps others) can have response times way beyond the default
// retry timeouts, with no apparent upper bound. This effectively causes the client
// to continue polling when it reaches the configured timeout. My investigations
// suggest that this is neccesary when deleting and recreating a storage account with
// the same name in a short (though undetermined) time period.
//
// It is possible that this will give Terraform the appearance of being slow in
// future: I have attempted to mitigate this by logging whenever this happens. We
// may want to revisit this with configurable timeouts in the future as clearly
// unbounded wait loops is not ideal. It does seem preferable to the current situation
// where our polling loop will time out _with an operation in progress_, but no ID
// for the resource - so the state will not know about it, and conflicts will occur
// on the next run.
func pollIndefinitelyAsNeeded(client autorest.Client, response *http.Response, acceptableCodes ...int) (*http.Response, error) {
	var resp *http.Response
	var err error

	for {
		resp, err = client.PollAsNeeded(response, acceptableCodes...)
		if err != nil {
			if resp.StatusCode != http.StatusAccepted {
				log.Printf("[DEBUG] Starting new polling loop for %q", response.Request.URL.Path)
				continue
			}

			return resp, err
		}

		return resp, nil
	}
}

func setUserAgent(client *autorest.Client) {
	var version string
	if terraform.VersionPrerelease != "" {
		version = fmt.Sprintf("%s-%s", terraform.Version, terraform.VersionPrerelease)
	} else {
		version = terraform.Version
	}

	client.UserAgent = fmt.Sprintf("HashiCorp-Terraform-v%s", version)
}