Golang Env.WriteTo方法代碼示例

// Allocate a network interface
func Allocate(job *engine.Job) engine.Status {
	var (
		ip          *net.IP
		err         error
		id          = job.Args[0]
		requestedIP = net.ParseIP(job.Getenv("RequestedIP"))
	)

	if requestedIP != nil {
		ip, err = ipallocator.RequestIP(bridgeNetwork, &requestedIP)
	} else {
		ip, err = ipallocator.RequestIP(bridgeNetwork, nil)
	}
	if err != nil {
		return job.Error(err)
	}

	out := engine.Env{}
	out.Set("IP", ip.String())
	out.Set("Mask", bridgeNetwork.Mask.String())
	out.Set("Gateway", bridgeNetwork.IP.String())
	out.Set("Bridge", bridgeIface)

	size, _ := bridgeNetwork.Mask.Size()
	out.SetInt("IPPrefixLen", size)

	currentInterfaces.Set(id, &networkInterface{
		IP: *ip,
	})

	out.WriteTo(job.Stdout)

	return engine.StatusOK
}

// Allocate an external port and map it to the interface
func AllocatePort(job *engine.Job) engine.Status {
	var (
		err error

		ip            = defaultBindingIP
		id            = job.Args[0]
		hostIP        = job.Getenv("HostIP")
		hostPort      = job.GetenvInt("HostPort")
		containerPort = job.GetenvInt("ContainerPort")
		proto         = job.Getenv("Proto")
		network       = currentInterfaces.Get(id)
	)

	if hostIP != "" {
		ip = net.ParseIP(hostIP)
	}

	// host ip, proto, and host port
	var container net.Addr
	switch proto {
	case "tcp":
		container = &net.TCPAddr{IP: network.IP, Port: containerPort}
	case "udp":
		container = &net.UDPAddr{IP: network.IP, Port: containerPort}
	default:
		return job.Errorf("unsupported address type %s", proto)
	}

	//
	// Try up to 10 times to get a port that's not already allocated.
	//
	// In the event of failure to bind, return the error that portmapper.Map
	// yields.
	//

	var host net.Addr
	for i := 0; i < MaxAllocatedPortAttempts; i++ {
		if host, err = portmapper.Map(container, ip, hostPort); err == nil {
			break
		}

		if allocerr, ok := err.(portallocator.ErrPortAlreadyAllocated); ok {
			// There is no point in immediately retrying to map an explicitly
			// chosen port.
			if hostPort != 0 {
				job.Logf("Failed to bind %s for container address %s: %s", allocerr.IPPort(), container.String(), allocerr.Error())
				break
			}

			// Automatically chosen 'free' port failed to bind: move on the next.
			job.Logf("Failed to bind %s for container address %s. Trying another port.", allocerr.IPPort(), container.String())
		} else {
			// some other error during mapping
			job.Logf("Received an unexpected error during port allocation: %s", err.Error())
			break
		}
	}

	if err != nil {
		return job.Error(err)
	}

	network.PortMappings = append(network.PortMappings, host)

	out := engine.Env{}
	switch netAddr := host.(type) {
	case *net.TCPAddr:
		out.Set("HostIP", netAddr.IP.String())
		out.SetInt("HostPort", netAddr.Port)
	case *net.UDPAddr:
		out.Set("HostIP", netAddr.IP.String())
		out.SetInt("HostPort", netAddr.Port)
	}
	if _, err := out.WriteTo(job.Stdout); err != nil {
		return job.Error(err)
	}

	return engine.StatusOK
}