code: func getHardwareId() (string, error) {
  	inters, err := net.Interfaces()
  	if err != nil {
  		return "", fmt.Errorf("jobs: Unable to get network interfaces via net.Interfaces(). Does this machine have any network interfaces?\n%s", err.Error())
  	}
  	address := ""
  	for _, inter := range inters {
  		if inter.HardwareAddr.String() != "" {
  			address = inter.HardwareAddr.String()
  			break
  		}
  	}
  	if address == "" {
  		return "", fmt.Errorf("jobs: Unable to find a network interface with a non-empty hardware (MAC) address. Does this machine have any valid network interfaces?\n%s", err.Error())
  	}
  	return address, nil
  }
docs: // getHardwareId returns a unique identifier for the current machine. It does this
  // by iterating through the network interfaces of the machine and picking the first
  // one that has a non-empty hardware (MAC) address. MAC Addresses are guaranteed by
  // IEEE to be unique, however, they are also sometimes spoofable. Spoofed MAC addresses
  // are fine as long as no two machines in the job pool have the same MAC address.