func showHelp(meta *ec2metadata.EC2Metadata) {

	fmt.Printf("usage: meta ATTRIBUTE\n\nValid attributes are:\n")
	categories, _ := meta.GetMetadata("/")
	fmt.Println(categories)
	fmt.Println("region")
}

// requestCredList requests a list of credentials from the EC2 service.
// If there are no credentials, or there is an error making or receiving the request
func requestCredList(client *ec2metadata.EC2Metadata) ([]string, error) {
	resp, err := client.GetMetadata(iamSecurityCredsPath)
	if err != nil {
		return nil, awserr.New("EC2RoleRequestError", "failed to list EC2 Roles", err)
	}

	credsList := []string{}
	s := bufio.NewScanner(strings.NewReader(resp))
	for s.Scan() {
		credsList = append(credsList, s.Text())
	}

	if err := s.Err(); err != nil {
		return nil, awserr.New("SerializationError", "failed to read list of EC2 Roles", err)
	}

	return credsList, nil
}

// requestCred requests the credentials for a specific credentials from the EC2 service.
//
// If the credentials cannot be found, or there is an error reading the response
// and error will be returned.
func requestCred(client *ec2metadata.EC2Metadata, credsName string) (ec2RoleCredRespBody, error) {
	resp, err := client.GetMetadata(path.Join(iamSecurityCredsPath, credsName))
	if err != nil {
		return ec2RoleCredRespBody{},
			awserr.New("EC2RoleRequestError",
				fmt.Sprintf("failed to get %s EC2 Role credentials", credsName),
				err)
	}

	respCreds := ec2RoleCredRespBody{}
	if err := json.NewDecoder(strings.NewReader(resp)).Decode(&respCreds); err != nil {
		return ec2RoleCredRespBody{},
			awserr.New("SerializationError",
				fmt.Sprintf("failed to decode %s EC2 Role credentials", credsName),
				err)
	}

	if respCreds.Code != "Success" {
		// If an error code was returned something failed requesting the role.
		return ec2RoleCredRespBody{}, awserr.New(respCreds.Code, respCreds.Message, nil)
	}

	return respCreds, nil
}