libmachine/check/check.go
func parseSwarm(hostURL string, h *host.Host) (string, error) {
	swarmOptions := h.HostOptions.SwarmOptions

	if !swarmOptions.Master {
		return "", fmt.Errorf("%q is not a swarm master. The --swarm flag is intended for use with swarm masters", h.Name)
	}

	u, err := url.Parse(swarmOptions.Host)
	if err != nil {
		return "", fmt.Errorf("There was an error parsing the url: %s", err)
	}
	parts := strings.Split(u.Host, ":")
	swarmPort := parts[1]

	// get IP of machine to replace in case swarm host is 0.0.0.0
	mURL, err := url.Parse(hostURL)
	if err != nil {
		return "", fmt.Errorf("There was an error parsing the url: %s", err)
	}

	mParts := strings.Split(mURL.Host, ":")
	machineIP := mParts[0]

	hostURL = fmt.Sprintf("tcp://%s:%s", machineIP, swarmPort)

	return hostURL, nil
}
func parseSwarm(hostURL string, h *host.Host) (string, error) {
	swarmOptions := h.HostOptions.SwarmOptions

	if !swarmOptions.Master {
		return "", fmt.Errorf("%q is not a swarm master. The --swarm flag is intended for use with swarm masters", h.Name)
	}

	u, err := url.Parse(swarmOptions.Host)
	if err != nil {
		return "", fmt.Errorf("There was an error parsing the url: %s", err)
	}
	parts := strings.Split(u.Host, ":")
	swarmPort := parts[1]

	// get IP of machine to replace in case swarm host is 0.0.0.0
	mURL, err := url.Parse(hostURL)
	if err != nil {
		return "", fmt.Errorf("There was an error parsing the url: %s", err)
	}

	mParts := strings.Split(mURL.Host, ":")
	machineIP := mParts[0]

	hostURL = fmt.Sprintf("tcp://%s:%s", machineIP, swarmPort)

	return hostURL, nil
}
// TODO: This could use a unit test.