func (b *instanceLoginRequestBuilder) BuildLoginRequest(host string) (*http.Request, error) {
	if host == "" {
		host = "us-3.rightscale.com"
	}
	accountHref := fmt.Sprintf("/api/accounts/%d", b.accountID)
	jsonStr := fmt.Sprintf(`{"instance_token":"%s","account_href":"%s"}`, b.token, accountHref)
	authReq, err := http.NewRequest("POST", buildURL(host, "api/session/instance"),
		bytes.NewBufferString(jsonStr))
	if err != nil {
		return nil, fmt.Errorf("Authentication failed (failed to build request): %s", err)
	}
	authReq.Header.Set("X-API-Version", "1.5")
	authReq.Header.Set("Content-Type", "application/json")
	return authReq, nil
}
func (b *instanceLoginRequestBuilder) BuildLoginRequest(host string) (*http.Request, error) {
	if host == "" {
		host = "us-3.rightscale.com"
	}
	accountHref := fmt.Sprintf("/api/accounts/%d", b.accountID)
	jsonStr := fmt.Sprintf(`{"instance_token":"%s","account_href":"%s"}`, b.token, accountHref)
	authReq, err := http.NewRequest("POST", buildURL(host, "api/session/instance"),
		bytes.NewBufferString(jsonStr))
	if err != nil {
		return nil, fmt.Errorf("Authentication failed (failed to build request): %s", err)
	}
	authReq.Header.Set("X-API-Version", "1.5")
	authReq.Header.Set("Content-Type", "application/json")
	return authReq, nil
}
// BuildLoginRequest builds session create requests from users email and password.