//This file was modified from the original work, https://github.com/xenserver/docker-machine-driver-xenserver

package xenserver

import (
	"archive/tar"
	"bytes"
	"crypto/rand"
	"crypto/tls"
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"os"
	"strings"
	"time"
	"path"

	"github.com/docker/machine/libmachine/drivers"
	"github.com/docker/machine/libmachine/log"
	"github.com/docker/machine/libmachine/mcnflag"
	"github.com/docker/machine/libmachine/mcnutils"
	"github.com/docker/machine/libmachine/ssh"
	"github.com/docker/machine/libmachine/state"
	"github.com/nilshell/xmlrpc"
	xsclient "github.com/xenserver/go-xenserver-client"
	"golang.org/x/net/context"

        diskfs "github.com/diskfs/go-diskfs"
        "github.com/diskfs/go-diskfs/disk"
        "github.com/diskfs/go-diskfs/filesystem"
        "github.com/diskfs/go-diskfs/filesystem/iso9660"
)

const (
	isoFilename = "boot2docker.iso"
	tarFilename = "boot2docker.tar"
	B2D_USER    = "docker"
	B2D_PASS    = "tcuser"
)

type Driver struct {
	*drivers.BaseDriver

	Server              string
	Username            string
	Password            string
	Boot2DockerURL      string
	CPU                 uint
	Memory              uint
	DiskSize            uint
	SR                  string
	Network             string
	Host                string
	ISO                 string
	TAR                 string
	UploadTimeout       uint
	WaitTimeout         uint
	CaCertPath          string
	PrivateKeyPath      string
	osTemplateLabelName string
	CoreosConfigDrive   bool

	xenAPIClient *XenAPIClient
}

// GetCreateFlags registers the flags this driver adds to
// "docker hosts create"
func (d *Driver) GetCreateFlags() []mcnflag.Flag {
	return []mcnflag.Flag{
		mcnflag.StringFlag{
			EnvVar: "XENSERVER_SERVER",
			Name:   "xenserver-server",
			Usage:  "XENSERVER server hostname/IP for docker VM",
		},
		mcnflag.StringFlag{
			EnvVar: "XENSERVER_USERNAME",
			Name:   "xenserver-username",
			Usage:  "XENSERVER username",
		},
		mcnflag.StringFlag{
			EnvVar: "XENSERVER_PASSWORD",
			Name:   "xenserver-password",
			Usage:  "XENSERVER password",
		},
		mcnflag.StringFlag{
			EnvVar: "XENSERVER_BOOT2DOCKER_URL",
			Name:   "xenserver-boot2docker-url",
			Usage:  "XENSERVER URL for boot2docker image",
		},
		mcnflag.IntFlag{
			EnvVar: "XENSERVER_VCPU_COUNT",
			Name:   "xenserver-vcpu-count",
			Usage:  "XENSERVER vCPU number for docker VM",
			Value:  1,
		},
		mcnflag.IntFlag{
			EnvVar: "XENSERVER_MEMORY_SIZE",
			Name:   "xenserver-memory-size",
			Usage:  "XENSERVER size of memory for docker VM (in MB)",
			Value:  1024,
		},
		mcnflag.IntFlag{
			EnvVar: "XENSERVER_DISK_SIZE",
			Name:   "xenserver-disk-size",
			Usage:  "XENSERVER size of disk for docker VM (in MB)",
			Value:  5120,
		},
		mcnflag.StringFlag{
			EnvVar: "XENSERVER_SR_LABEL",
			Name:   "xenserver-sr-label",
			Usage:  "XENSERVER SR label where the docker VM will be attached",
		},
		mcnflag.StringFlag{
			EnvVar: "XENSERVER_NETWORK_LABEL",
			Name:   "xenserver-network-label",
			Usage:  "XENSERVER network label where the docker VM will be attached",
		},
		mcnflag.StringFlag{
			EnvVar: "XENSERVER_HOST_LABEL",
			Name:   "xenserver-host-label",
			Usage:  "XENSERVER host label where the docker VM will be run",
		},
		mcnflag.IntFlag{
			EnvVar: "XENSERVER_UPLOAD_TIMEOUT",
			Name:   "xenserver-upload-timeout",
			Usage:  "XENSERVER upload VDI timeout(seconds)",
			Value:  5 * 60,
		},
		mcnflag.IntFlag{
			EnvVar: "XENSERVER_WAIT_TIMEOUT",
			Name:   "xenserver-wait-timeout",
			Usage:  "XENSERVER wait VM start timeout(seconds)",
			Value:  30 * 60,
		},
		mcnflag.StringFlag{
			EnvVar: "XENSERVER_OS_TEMPLATE",
			Name:   "xenserver-os-template",
			Usage:  "XENSERVER OS Template Label Name",
			Value:  "Other install media",
		},
		mcnflag.StringFlag{
			EnvVar: "XENSERVER_OS_USERNAME",
			Name:   "xenserver-os-username",
			Usage:  "XENSERVER Username used to SSH into guest OS",
			Value:  B2D_USER,
		},
		mcnflag.BoolFlag{
			EnvVar: "XENSERVER_COREOS_CONFIGDRIVE",
			Name:   "xenserver-coreos-configdrive",
			Usage:  "XENSERVER Enable CoreOS specific ConfigDrive (requires xscontainer supplemental pack)",
		},
	}
}

func NewDriver() *Driver {
	return &Driver{}
}

func (d *Driver) GetMachineName() string {
	return d.MachineName
}

func (d *Driver) GetSSHHostname() (string, error) {
	return d.GetIP()
}

func (d *Driver) GetSSHPort() (int, error) {
	if d.SSHPort == 0 {
		d.SSHPort = 22
	}

	return d.SSHPort, nil
}

func (d *Driver) GetSSHUsername() string {
	if d.SSHUser == "" {
		d.SSHUser = B2D_USER
	}

	return d.SSHUser
}

func (d *Driver) DriverName() string {
	return "xenserver"
}

func (d *Driver) SetConfigFromFlags(flags drivers.DriverOptions) error {
	d.SSHUser = flags.String("xenserver-os-username")
	d.SSHPort = 22
	d.Server = flags.String("xenserver-server")
	d.Username = flags.String("xenserver-username")
	d.Password = flags.String("xenserver-password")
	d.Boot2DockerURL = flags.String("xenserver-boot2docker-url")
	d.CPU = uint(flags.Int("xenserver-vcpu-count"))
	d.Memory = uint(flags.Int("xenserver-memory-size"))
	d.DiskSize = uint(flags.Int("xenserver-disk-size"))
	d.SR = flags.String("xenserver-sr-label")
	d.Network = flags.String("xenserver-network-label")
	d.Host = flags.String("xenserver-host-label")
	d.UploadTimeout = uint(flags.Int("xenserver-upload-timeout"))
	d.WaitTimeout = uint(flags.Int("xenserver-wait-timeout"))
	d.SwarmMaster = flags.Bool("swarm-master")
	d.SwarmHost = flags.String("swarm-host")
	d.SwarmDiscovery = flags.String("swarm-discovery")
	d.ISO = d.ResolveStorePath(isoFilename)
	d.TAR = d.ResolveStorePath(tarFilename)
	d.osTemplateLabelName = flags.String("xenserver-os-template")
	d.CoreosConfigDrive = flags.Bool("xenserver-coreos-configdrive")

	return nil
}

func (d *Driver) GetURL() (string, error) {
	ip, _ := d.GetIP()
	if ip == "" {
		return "", nil
	}
	return fmt.Sprintf("tcp://%s:2376", ip), nil
}

func (d *Driver) GetIP() (string, error) {
	status, err := d.GetState()
	if err != nil {
		return "", err
	}
	if status != state.Running {
		return "", fmt.Errorf("Docker VM(%v) is not running", d.MachineName)
	}

	// Need Login first if it is a fresh session
	c, err := d.GetXenAPIClient()
	if err != nil {
		return "", err
	}

	// Get doker machine by label name
	vm, err := c.GetUniqueVMByNameLabel(d.MachineName)
	if err != nil {
		return "", err
	}

	// Get docker machine VM metrics
	metrics, err := vm.GetGuestMetrics()
	if err != nil {
		return "", err
	}

	// Get networks metrics
	networks, ok := metrics["networks"]
	if !ok {
		return "", fmt.Errorf("Docker VM(%v) get network metrics error: \"networks\" not presented", d.MachineName)
	}

	net, ok := networks.(xmlrpc.Struct)
	if !ok {
		return "", fmt.Errorf("Docker VM(%v) get network metrics error: \"networks\" is not a xmlrpc.Struct instance", d.MachineName)
	}

	for i := 0; i < len(net); i++ {
		ip, ok := net[fmt.Sprintf("%d/ip", i)]
		if ok && ip != "" {
			return ip.(string), nil
		}
	}

	return "", fmt.Errorf("Docker VM(%v) get ipaddr error", d.MachineName)
}

func (d *Driver) GetState() (state.State, error) {
	var err error

	// Need Login first if it is a fresh session
	c, err := d.GetXenAPIClient()
	if err != nil {
		return state.None, err
	}

	// Get docker machine VM by label name
	vm, err := c.GetUniqueVMByNameLabel(d.MachineName)
	if err != nil {
		return state.None, err
	}

	// Get doker machine VM power state
	powerState, err := vm.GetPowerState()
	if err != nil {
		return state.None, err
	}

	// https://github.com/xapi-project/xen-api/blob/cacbb2d3c5996efbf4cf117ab862439271a8cecd/ocaml/client_records/record_util.ml#L20
	switch strings.ToLower(powerState) {
	case "halted":
		return state.Stopped, nil
	case "paused":
		return state.Paused, nil
	case "running":
		return state.Running, nil
	case "suspended":
		return state.Paused, nil
	case "shutting down":
		return state.Stopping, nil
	case "migrating":
		return state.Running, nil
	}

	return state.None, nil
}

func (d *Driver) PreCreateCheck() error {
	if d.osTemplateLabelName == "Other install media" {
		// Downloading boot2docker to cache should be done here to make sure
		// that a download failure will not leave a machine half created.
		b2dutils := mcnutils.NewB2dUtils(d.StorePath)
		if err := b2dutils.UpdateISOCache(d.Boot2DockerURL); err != nil {
			return err
		}
	}
	return nil
}

func (d *Driver) Create() error {
	var err error

	d.setMachineNameIfNotSet()

	if d.osTemplateLabelName == "Other install media" {
		b2dutils := mcnutils.NewB2dUtils(d.StorePath)
		if err := b2dutils.CopyIsoToMachineDir(d.Boot2DockerURL, d.MachineName); err != nil {
			return err
		}
	}

	log.Infof("Logging into XenServer %s...", d.Server)
	c, err := d.GetXenAPIClient()
	if err != nil {
		return err
	}

	// Generate SSH Keys
	log.Infof("Creating SSH key...")

	if err := ssh.GenerateSSHKey(d.sshKeyPath()); err != nil {
		return err
	}

	// Only upload ISO image if using Other install media, otherwise use existing VM template
	var sr *xsclient.SR
	var isoVdiUuid, diskVdiUuid string

	// Get the SR
	if d.SR == "" {
		sr, err = c.GetDefaultSR()
		if sr.Ref == "OpaqueRef:NULL" {
			err := errors.New("No default SR found. Please configure a " +
				"default or specify the SR explicitly using " +
				"--xenserver-sr-label.")
			log.Errorf("%v", err)
			return err
		}
	} else {
		sr, err = c.GetUniqueSRByNameLabel(d.SR)
	}
	if err != nil {
		return err
	}

	if d.osTemplateLabelName == "Other install media" {

		log.Infof("Creating ISO VDI...")

		isoFileInfo, err := os.Stat(d.ISO)
		if err != nil {
			return err
		}

		// Create the VDI
		isoVdi, err := sr.CreateVdi(isoFilename, isoFileInfo.Size())
		if err != nil {
			log.Errorf("Unable to create ISO VDI '%s': %v", isoFilename, err)
			return err
		}

		// Import the VDI
		if err = d.importVdi(isoVdi, d.ISO, time.Duration(d.UploadTimeout)*time.Second); err != nil {
			return err
		}

		isoVdiUuid, err = isoVdi.GetUuid()
		if err != nil {
			return err
		}

		log.Infof("Creating Disk VDI...")
		err = d.generateDiskImage()
		if err != nil {
			return err
		}

		// Create the VDI
		diskVdi, err := sr.CreateVdi("bootdocker disk", int64(d.DiskSize)*1024*1024)
		if err != nil {
			log.Errorf("Unable to create ISO VDI '%s': %v", "bootdocker disk", err)
			return err
		}
		if err = d.importVdi(diskVdi, d.TAR, time.Duration(d.UploadTimeout)*time.Second); err != nil {
			return err
		}

		diskVdiUuid, err = diskVdi.GetUuid()
		if err != nil {
			return err
		}

	}

	log.Infof("Creating VM...")

	vm0, err := c.GetUniqueVMByNameLabel(d.osTemplateLabelName)
	if err != nil {
		return err
	}

	// Clone VM from VM template
	vm, err := vm0.Clone(fmt.Sprintf("__gui__%s", d.MachineName))
	if err != nil {
		return err
	}

	vmMacSeed, err := pseudoUuid()
	if err != nil {
		return err
	}

	hostname, err := os.Hostname()
	if err != nil {
		log.Errorf("Unable get local hostname")
	}

	otherConfig := map[string]string{
		"base_template_name":     d.osTemplateLabelName,
		"install-methods":        "cdrom,nfs,http,ftp",
		"linux_template":         "true",
		"mac_seed":               vmMacSeed,
		"docker-machine-creator": hostname,
	}
	err = vm.SetOtherConfig(otherConfig)
	if err != nil {
		return err
	}

	log.Infof("Provision VM...")
	err = vm.Provision()
	if err != nil {
		return err
	}

	// Set machine name
	err = vm.SetNameLabel(d.MachineName)
	if err != nil {
		return err
	}

	// Set vCPU number
	err = vm.SetVCPUsMax(d.CPU)
	if err != nil {
		return err
	}

	err = vm.SetVCPUsAtStartup(d.CPU)
	if err != nil {
		return err
	}

	platform_params := map[string]string{
		"acpi":             "1",
		"apic":             "true",
		"cores-per-socket": "1",
		"device_id":        "0001",
		"nx":               "true",
		"pae":              "true",
		"vga":              "std",
		"videoram":         "8",
		"viridian":         "false",
	}
	err = vm.SetPlatform(platform_params)
	if err != nil {
		return err
	}

	// Set machine memory size
	err = vm.SetStaticMemoryRange(uint64(d.Memory)*1024*1024, uint64(d.Memory)*1024*1024)
	if err != nil {
		return err
	}

	if d.osTemplateLabelName == "Other install media" {
		log.Infof("Add ISO VDI to VM...")
		diskVdi, err := c.GetVdiByUuid(isoVdiUuid)
		if err != nil {
			return err
		}

		err = vm.ConnectVdi(diskVdi, xsclient.Disk, "0")
		if err != nil {
			return err
		}

		log.Infof("Add Disk VDI to VM...")
		diskVdi, err = c.GetVdiByUuid(diskVdiUuid)
		if err != nil {
			return err
		}

		err = vm.ConnectVdi(diskVdi, xsclient.Disk, "1")
		if err != nil {
			return err
		}
	} else {
		pubKey, err := ioutil.ReadFile(d.publicSSHKeyPath())
		if err != nil {
			return err
		}
		vmUuid, err := vm.GetUuid()
		if err != nil {
			return err
		}
		srUuid, err := sr.GetUuid()
		if err != nil {
			return err
		}

		if d.CoreosConfigDrive {
			err := d.createCoreOSConfigDrive(pubKey, vmUuid, srUuid)
			if err != nil {
				return err
			}
		} else {
			log.Infof("Creating Config Drive...")
			isoVdiUuid, err := d.createGenericConfigDrive(pubKey, vmUuid, sr)
			if err != nil {
				return err
			}

			log.Infof("Add ConfigDrive ISO VDI to VM...")
			diskVdi, err := c.GetVdiByUuid(isoVdiUuid)
			if err != nil {
				return err
			}
			err = vm.ConnectVdi(diskVdi, xsclient.Disk, "")
			if err != nil {
				return err
			}
		}
	}

	log.Infof("Add Network to VM...")
	var networks []*xsclient.Network
	if d.Network == "" {
		networks1, err := c.GetNetworks()
		if err != nil {
			return err
		}
		for _, network := range networks1 {
			otherConfig, err := network.GetOtherConfig()
			if err != nil {
				return err
			}
			isInternal, ok := otherConfig["is_host_internal_management_network"]
			if ok && isInternal == "true" {
				continue
			}
			automaitc, ok := otherConfig["automatic"]
			if ok && automaitc == "false" {
				continue
			}
			networks = append(networks, network)
		}
	} else {
		network, err := c.GetUniqueNetworkByNameLabel(d.Network)
		if err != nil {
			return err
		}
		networks = append(networks, network)
	}
	if len(networks) == 0 {
		return fmt.Errorf("Unable get available networks for %v", d.MachineName)
	}

	vifDevices, err := vm.GetAllowedVIFDevices()
	if err != nil {
		return err
	}
	if len(vifDevices) < len(networks) {
		log.Warnf("VM(%s) networks number is limited to %d.", d.MachineName, len(vifDevices))
		networks = networks[:len(vifDevices)]
	}

	for i, network := range networks {
		_, err = vm.ConnectNetwork(network, vifDevices[i])
		if err != nil {
			return err
		}
	}

	log.Infof("Starting VM...")
	if d.Host == "" {
		if err = vm.Start(false, false); err != nil {
			return err
		}
	} else {
		host, err := c.GetUniqueHostByNameLabel(d.Host)
		if err != nil {
			return err
		}
		if err = vm.StartOn(host, false, false); err != nil {
			return err
		}
	}

	if err := d.wait(time.Duration(d.WaitTimeout) * time.Second); err != nil {
		return err
	}

	log.Infof("VM Created.")

	return nil
}

func (d *Driver) wait(timeout time.Duration) (err error) {
	log.Infof("Waiting for VM to start...")

	ctx, cancel := context.WithTimeout(context.Background(), timeout)
	defer cancel()

	out := make(chan error, 1)
	go func(ctx context.Context, out chan<- error) {
		var ip string
		for {
			ip, _ = d.GetIP()
			if ip != "" {
				break
			}
			if t, ok := ctx.Deadline(); ok && time.Now().After(t) {
				out <- fmt.Errorf("Wait GetIP timed out")
				return
			}
			time.Sleep(1 * time.Second)
		}

		port, err := d.GetSSHPort()
		if err != nil {
			out <- err
			return
		}

		addr := fmt.Sprintf("%s:%d", ip, port)
		d.IPAddress = ip
		log.Infof("Got VM address(%v), Now waiting for SSH", addr)
		out <- drivers.WaitForSSH(d)
	}(ctx, out)

	select {
	case err := <-out:
		return err
	case <-ctx.Done():
		return fmt.Errorf("Wait for VM to start timed out: %v", ctx.Err())
	}

	return nil
}

func (d *Driver) Start() error {
	var err error

	c, err := d.GetXenAPIClient()
	if err != nil {
		return err
	}

	vm, err := c.GetUniqueVMByNameLabel(d.MachineName)
	if err != nil {
		return err
	}

	if err = vm.Start(false, true); err != nil {
		return err
	}
	if err = d.wait(time.Duration(d.WaitTimeout) * time.Second); err != nil {
		return err
	}

	return nil
}

func (d *Driver) Stop() error {
	var err error

	c, err := d.GetXenAPIClient()
	if err != nil {
		return err
	}

	vm, err := c.GetUniqueVMByNameLabel(d.MachineName)
	if err != nil {
		return err
	}

	if err = vm.CleanShutdown(); err != nil {
		return err
	}

	return nil
}

func (d *Driver) Remove() error {
	var err error

	c, err := d.GetXenAPIClient()
	if err != nil {
		return err
	}

	vm, err := c.GetUniqueVMByNameLabel(d.MachineName)
	if err != nil {
		return err
	}

	vmState, err := d.GetState()
	if err != nil {
		return err
	}

	switch vmState {
	case state.None:
		return fmt.Errorf("Unable get VM(%v) state.", d.MachineName)
	case state.Stopping:
		return fmt.Errorf("VM(%v) state is stopping, please wait.", d.MachineName)
	case state.Stopped:
		break
	case state.Paused:
		if err = vm.HardShutdown(); err != nil {
			return err
		}
	default:
		if err = vm.CleanShutdown(); err != nil {
			if err = vm.HardShutdown(); err != nil {
				return err
			}
		}
	}

	disks, err := vm.GetDisks()
	if err != nil {
		return err
	}

	for _, disk := range disks {
		if err = disk.Destroy(); err != nil {
			return err
		}
	}

	if err = vm.Destroy(); err != nil {
		return err
	}

	return nil
}

func (d *Driver) Restart() error {
	if err := d.Stop(); err != nil {
		return err
	}

	return d.Start()
}

func (d *Driver) Kill() error {
	var err error

	c, err := d.GetXenAPIClient()
	if err != nil {
		return err
	}

	vm, err := c.GetUniqueVMByNameLabel(d.MachineName)
	if err != nil {
		return err
	}

	if err = vm.HardShutdown(); err != nil {
		return err
	}
	return nil
}

func (d *Driver) setMachineNameIfNotSet() {
	if d.MachineName == "" {
		d.MachineName = fmt.Sprintf("docker-machine-unknown")
	}
}

func (d *Driver) sshKeyPath() string {
	return d.GetSSHKeyPath()
}

func (d *Driver) publicSSHKeyPath() string {
	return d.sshKeyPath() + ".pub"
}

// Make a boot2docker VM disk image.
func (d *Driver) generateDiskImage() error {
	magicString := "boot2docker, please format-me"

	buf := new(bytes.Buffer)
	tw := tar.NewWriter(buf)

	log.Infof("Generate Disk Image...")
	// magicString first so the automount script knows to format the disk
	file := &tar.Header{Name: magicString, Size: int64(len(magicString))}
	if err := tw.WriteHeader(file); err != nil {
		return err
	}
	if _, err := tw.Write([]byte(magicString)); err != nil {
		return err
	}
	// .ssh/key.pub => authorized_keys
	file = &tar.Header{Name: ".ssh", Typeflag: tar.TypeDir, Mode: 0700}
	if err := tw.WriteHeader(file); err != nil {
		return err
	}
	pubKey, err := ioutil.ReadFile(d.publicSSHKeyPath())
	if err != nil {
		return err
	}
	file = &tar.Header{Name: ".ssh/authorized_keys", Size: int64(len(pubKey)), Mode: 0644}
	if err := tw.WriteHeader(file); err != nil {
		return err
	}
	if _, err := tw.Write([]byte(pubKey)); err != nil {
		return err
	}
	file = &tar.Header{Name: ".ssh/authorized_keys2", Size: int64(len(pubKey)), Mode: 0644}
	if err := tw.WriteHeader(file); err != nil {
		return err
	}
	if _, err := tw.Write([]byte(pubKey)); err != nil {
		return err
	}
	if err := tw.Close(); err != nil {
		return err
	}
	if err := ioutil.WriteFile(d.TAR, buf.Bytes(), 0644); err != nil {
		return err
	}
	return nil
}

func (d *Driver) GetXenAPIClient() (*XenAPIClient, error) {
	if d.xenAPIClient == nil {
		c := NewXenAPIClient(d.Server, d.Username, d.Password)
		if err := c.Login(); err != nil {
			return nil, err
		}
		d.xenAPIClient = &c
	}
	return d.xenAPIClient, nil
}

func (d *Driver) importVdi(vdi *xsclient.VDI, filename string, timeout time.Duration) error {
	f, err := os.Open(filename)
	if err != nil {
		log.Errorf("Unable to open disk image '%s': %v", filename, err)
		return err
	}

	// Get file length
	fi, err := f.Stat()
	if err != nil {
		log.Errorf("Unable to stat disk image '%s': %v", filename, err)
		return err
	}

	task, err := vdi.Client.CreateTask()
	if err != nil {
		return fmt.Errorf("Unable to create task: %v", err)
	}
	urlStr := fmt.Sprintf("https://%s/import_raw_vdi?vdi=%s&session_id=%s&task_id=%s",
		vdi.Client.Host, vdi.Ref, vdi.Client.Session.(string), task.Ref)

	// Define a new http Transport which allows self-signed certs
	tr := &http.Transport{
		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
	}

	req, err := http.NewRequest("PUT", urlStr, f)
	if err != nil {
		return err
	}
	req.ContentLength = fi.Size()

	resp, err := tr.RoundTrip(req)
	if err != nil {
		log.Errorf("Unable to upload VDI: %v", err)
		return err
	}
	defer resp.Body.Close()

	if resp.StatusCode != 200 {
		msg, _ := ioutil.ReadAll(resp.Body)
		err = fmt.Errorf("xenserver reply %s: %v", resp.Status, string(msg))
		log.Errorf("Unable to upload VDI: %v", err)
		return err
	}

	log.Infof("Waiting Upload VDI task(%v) to complete...", task.Ref)
	if err = d.waitTask(task, timeout); err != nil {
		return err
	}
	return nil
}

func (d *Driver) waitTask(task *xsclient.Task, timeout time.Duration) error {
	timeout_at := time.Now().Add(timeout)

	for {
		status, err := task.GetStatus()
		if err != nil {
			return fmt.Errorf("Failed to get task status: %s", err.Error())
		}

		if status == xsclient.Success {
			log.Infof("Upload VDI task(%s) completed", task.Ref)
			break
		}

		switch status {
		case xsclient.Pending:
			progress, err := task.GetProgress()
			if err != nil {
				return fmt.Errorf("Failed to get progress: %s", err.Error())
			}
			log.Debugf("Upload %.0f%% complete", progress*100)
			log.Infof("Uploading...")
		case xsclient.Failure:
			errorInfo, err := task.GetErrorInfo()
			if err != nil {
				errorInfo = []string{fmt.Sprintf("furthermore, failed to get error info: %s", err.Error())}
			}
			return fmt.Errorf("Task failed: %s", errorInfo)
		case xsclient.Cancelling, xsclient.Cancelled:
			return fmt.Errorf("Task Cancelled")
		default:
			return fmt.Errorf("Unknown task status %v", status)
		}

		if time.Now().After(timeout_at) {
			return fmt.Errorf("Upload VDI task(%s) timed out", task.Ref)
		}

		time.Sleep(5 * time.Second)
	}

	return nil
}

func pseudoUuid() (string, error) {
	b := make([]byte, 16)
	_, err := io.ReadFull(rand.Reader, b)
	if err != nil {
		return "", err
	}
	uuid := fmt.Sprintf("%x-%x-%x-%x-%x", b[0:4], b[4:6], b[6:8], b[8:10], b[10:])
	return uuid, nil
}

// CoreOS only Config Drive 
func (d *Driver) createCoreOSConfigDrive(pubKey []byte, vmuuid string, sruuid string) error {
	userdatatext := `#cloud-config
hostname: %XSVMNAMETOHOSTNAME%
coreos:
  units:
    # XenServer Linux Guest Agent
    - name: xe-linux-distribution.service
      command: start
      content: |
        [Unit]
        Description=XenServer Linux Guest Agent
        After=docker.service

        [Service]
        ExecStartPre=/media/configdrive/agent/xe-linux-distribution /var/cache/xe-linux-distribution
        Environment="XE_UPDATE_GUEST_ATTRS=/media/configdrive/agent/xe-update-guest-attrs"
        ExecStart=/media/configdrive/agent/xe-daemon
ssh_authorized_keys:
  # The following entry will automatically be replaced with a public key
  # generated by XenServer's container management. The key-entry must exist,
  # in order to enable container management for this VM.
  - ssh-rsa %XSCONTAINERRSAPUB%
  - ` + string(pubKey)
	hosts, err := d.xenAPIClient.GetHosts()
	if err != nil {
		log.Errorf("Could not retrieve hosts in the pool: %s", err)
		return err
	}
	ahost := hosts[0]
	args := make(map[string]string)
	args["vmuuid"] = vmuuid
	args["sruuid"] = sruuid
	args["configuration"] = userdatatext
	ahost.CallPlugin("xscontainer", "create_config_drive", args)

	return nil
}

// Generic Config Drive for cloud-init enabled OS templates
func (d *Driver) createGenericConfigDrive(pubKey []byte, vmUuid string, sr *xsclient.SR) (string, error) {
	userdatatext := `#cloud-config
ssh_authorized_keys:
  - ` + string(pubKey)

	metadatatext := `{ "uuid": "` + vmUuid + `"}`

        //create ISO file
        var diskSize int64
        diskSize = 10 * 1024 * 1024 // 10 MB
        var configIsoFilename = d.ResolveStorePath("configdrive.iso")
        cdDisk, err := diskfs.Create(configIsoFilename, diskSize, diskfs.Raw)
        if err != nil {
                log.Errorf("Unable to create configdrive.iso: %v", err)
        }

        // the following line is required for an ISO, which may have logical block sizes
        // only of 2048, 4096, 8192
        cdDisk.LogicalBlocksize = 2048
        fspec := disk.FilesystemSpec{Partition: 0, FSType: filesystem.TypeISO9660, VolumeLabel: "config-2"}
        cdFS, err := cdDisk.CreateFilesystem(fspec)
        if err != nil {
                log.Errorf("Unable to create ConfigDrive filesystem: %v", err)
        }

        cloudInitPrefix := path.Join("/", "openstack", "latest")

	// place down cloud-init info
	err = cdFS.Mkdir(cloudInitPrefix)
	if err != nil {
		log.Errorf("Error creating cloud init directory structure: %v", err)
	}

	metadataPath := path.Join(cloudInitPrefix, "meta_data.json")
	log.Infof("Opening %s", metadataPath)
	metadataFile, err := cdFS.OpenFile(metadataPath, os.O_CREATE|os.O_RDWR)
	if err != nil {
		log.Errorf("Error opening meta data: %v", err)
	}

	log.Infof("Writing metadata contents")
	_, err = metadataFile.Write([]byte(metadatatext))
	if err != nil {
		log.Errorf("Error writting meta data: %v", err)
	}

        userdataPath := path.Join(cloudInitPrefix, "user_data")
	log.Infof("Opening %s", userdataPath)
	userdataFile, err := cdFS.OpenFile(userdataPath, os.O_CREATE|os.O_RDWR)
	if err != nil {
		log.Errorf("Error opening user data: %v", err)
	}
	_, err = userdataFile.Write([]byte(userdatatext))
	if err != nil {
		log.Errorf("Error writting user data: %v", err)
	}

	//finalize ISO
        iso, ok := cdFS.(*iso9660.FileSystem)
        if !ok {
		log.Errorf("not an iso9660 filesystem")
        }
        err = iso.Finalize(iso9660.FinalizeOptions{})
        if err != nil {
                log.Errorf("Error finalizing configdrive.iso: %v", err)
        }

	// Create the VDI
	isoVdi, err := sr.CreateVdi(configIsoFilename, diskSize)
	if err != nil {
		log.Errorf("Unable to create ConfigDrive ISO VDI '%s': %v", configIsoFilename, err)
		return "", err
	}

	// Import the VDI
	log.Infof("Starting import of ConfigDrive VDI '%s'...", configIsoFilename)
	if err = d.importVdi(isoVdi, configIsoFilename, time.Duration(d.UploadTimeout)*time.Second); err != nil {
		return "", err
	}

	isoVdiUuid, err := isoVdi.GetUuid()
	if err != nil {
		return "", err
	}
	return isoVdiUuid, nil
}