infrakit: Use template based instance configuratio

This change now allows setting the Disk size, memory, and number of CPUs
for an instance via the JSON config file.

We now also write the hyperkit command line to the VM directory.

Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com>

tools/infrakit.hyperkit/cmd/instance.go

@@ -10,18 +10,25 @@ import (
 	"os/exec"
 	"path"
 	"strconv"
+	"strings"
 
 	log "github.com/Sirupsen/logrus"
+
 	"github.com/docker/infrakit/pkg/spi/instance"
+	"github.com/docker/infrakit/pkg/template"
 	"github.com/docker/infrakit/pkg/types"
 )
 
 // NewHyperKitPlugin creates an instance plugin for hyperkit.
-func NewHyperKitPlugin(vmLib, vmDir, hyperkit, vpnkitSock string) instance.Plugin {
+func NewHyperKitPlugin(vmLib, vmDir, hyperkit, vpnkitSock string, thyper, tkern *template.Template) instance.Plugin {
 	return &hyperkitPlugin{VMLib: vmLib,
 		VMDir:      vmDir,
 		HyperKit:   hyperkit,
-		VPNKitSock: vpnkitSock}
+		VPNKitSock: vpnkitSock,
+
+		HyperKitTmpl: thyper,
+		KernelTmpl:   tkern,
+	}
 }
 
 type hyperkitPlugin struct {
@@ -37,6 +44,9 @@ type hyperkitPlugin struct {
 
 	// VPNKitSock is the path to the VPNKit Unix domain socket.
 	VPNKitSock string
+
+	HyperKitTmpl *template.Template
+	KernelTmpl   *template.Template
 }
 
 const (
@@ -62,41 +72,31 @@ func (v hyperkitPlugin) Provision(spec instance.Spec) (*instance.ID, error) {
 	if properties["Moby"] == nil {
 		return nil, errors.New("Property 'Moby' must be set")
 	}
-	mobyStr, ok := properties["Moby"].(string)
-	if !ok {
-		return nil, errors.New("Property 'Moby' must be a string")
-	}
 	if properties["CPUs"] == nil {
 		properties["CPUs"] = 1
 	}
-	numCPUs, ok := properties["CPUs"].(int)
-	if !ok {
-		return nil, errors.New("Property 'CPUs' must be a integer")
-	}
 	if properties["Memory"] == nil {
 		properties["Memory"] = 512
 	}
-	memSz, ok := properties["Memory"].(int)
-	if !ok {
-		return nil, errors.New("Property 'Memory' must be a integer")
-	}
-
 	if properties["Disk"] == nil {
-		properties["Disk"] = 256
-	}
-	diskSz, ok := properties["Disk"].(int)
-	if !ok {
-		return nil, errors.New("Property 'Disk' must be a integer")
+		properties["Disk"] = float64(256)
 	}
 
 	instanceDir, err := ioutil.TempDir(v.VMDir, "infrakit-")
 	if err != nil {
 		return nil, err
 	}
-
 	id := instance.ID(path.Base(instanceDir))
 
-	err = v.execHyperKit(instanceDir, mobyStr, numCPUs, memSz, diskSz)
+	// Apply parameters
+	params := map[string]interface{}{
+		"VMLocation": instanceDir,
+		"VMLib":      v.VMLib,
+		"VPNKitSock": v.VPNKitSock,
+		"Properties": properties,
+	}
+
+	err = v.execHyperKit(params)
 	if err != nil {
 		v.Destroy(id)
 		return nil, err
@@ -243,42 +243,49 @@ func (v hyperkitPlugin) DescribeInstances(tags map[string]string) ([]instance.De
 	return descriptions, nil
 }
 
-func (v hyperkitPlugin) execHyperKit(instanceDir, moby string, cpus, memSz, diskSz int) error {
-	err := createDisk(instanceDir, diskSz)
+const hyperkitArgs = "-A -u -F {{.VMLocation}}/hyperkit.pid " +
+	"-c {{.Properties.CPUs}} -m {{.Properties.Memory}}M " +
+	"-s 0:0,hostbridge -s 31,lpc -s 5,virtio-rnd " +
+	"-s 4,virtio-blk,{{.VMLocation}}/disk.img " +
+	"-s 2:0,virtio-vpnkit,path={{.VPNKitSock}} " +
+	"-l com1,autopty={{.VMLocation}}/tty,log={{.VMLocation}}/console-ring"
+const hyperkitKernArgs = "kexec," +
+	"{{.VMLib}}/{{.Properties.Moby}}/vmlinuz64," +
+	"{{.VMLib}}/{{.Properties.Moby}}/initrd.img," +
+	"earlyprintk=serial console=ttyS0 panic=1 vsyscall=emulate page_poison=1 ntp=gateway"
+
+func (v hyperkitPlugin) execHyperKit(params map[string]interface{}) error {
+
+	instanceDir := params["VMLocation"].(string)
+
+	args, err := v.HyperKitTmpl.Render(params)
+	if err != nil {
+		return err
+	}
+	kernArgs, err := v.KernelTmpl.Render(params)
 	if err != nil {
 		return err
 	}
 
-	id := path.Base(instanceDir)
+	// Build arguments
+	c := []string{v.HyperKit}
+	c = append(c, strings.Split(args, " ")...)
+	c = append(c, "-f", kernArgs)
 
-	c := []string{v.HyperKit, "-A", "-u"}
+	// Write command line to state
+	if err := ioutil.WriteFile(path.Join(instanceDir, "cmdline"), []byte(strings.Join(c, " ")), 0666); err != nil {
+		return err
+	}
 
-	// Pid file
-	c = append(c, "-F", path.Join(instanceDir, hyperkitPid))
-
-	// CPU and Memory
-	c = append(c, "-c", fmt.Sprintf("%d", cpus))
-	c = append(c, "-m", fmt.Sprintf("%dM", memSz))
-
-	// Devices
-	c = append(c, "-s", "0:0,hostbridge")
-	c = append(c, "-s", "31,lpc")
-	c = append(c, "-s", "5,virtio-rnd")
-	c = append(c, "-s", fmt.Sprintf("4,virtio-blk,%s", path.Join(instanceDir, "disk.img")))
-	c = append(c, "-s", fmt.Sprintf("2:0,virtio-vpnkit,path=%s", v.VPNKitSock))
-	c = append(c, "-l", fmt.Sprintf("com1,autopty=%s,log=%s",
-		path.Join(instanceDir, "tty"),
-		path.Join(instanceDir, "console-ring")))
-
-	// Kernel command line
-	// Note, it is important that the kernel is one argv, not multiple
-	kernStr := fmt.Sprintf("kexec,%s,%s,",
-		path.Join(v.VMLib, moby, "vmlinuz64"),
-		path.Join(v.VMLib, moby, "initrd.img"))
-	kernStr += "earlyprintk=serial console=ttyS0"
-	kernStr += " panic=1 vsyscall=emulate page_poison=1"
-	kernStr += " ntp=gateway "
-	c = append(c, "-f", kernStr)
+	prop := params["Properties"].(map[string]interface{})
+	sz, ok := prop["Disk"].(float64)
+	if !ok {
+		return fmt.Errorf("Unable to extract Disk Size: %s", prop["Disk"])
+	}
+	err = createDisk(instanceDir, int(sz))
+	if err != nil {
+		return err
+	}
 
 	cmd := exec.Command(c[0], c[1:]...)
 	cmd.Env = os.Environ()
@@ -304,18 +311,19 @@ func (v hyperkitPlugin) execHyperKit(instanceDir, moby string, cpus, memSz, disk
 		for {
 			select {
 			case stderrl := <-stderrChan:
-				log.Warningln("HyperKit ", id, " STDERR: ", stderrl)
+				log.Warningln("HyperKit STDERR: ", stderrl)
 			case stdoutl := <-stdoutChan:
-				log.Infoln("HyperKit ", id, " STDOUT: ", stdoutl)
+				log.Infoln("HyperKit STDOUT: ", stdoutl)
 			case <-done:
 				return
 			}
 		}
 	}()
 
-	log.Infoln("Starting ", id, ": ", c)
+	log.Infoln("Starting: ", c)
 
 	err = cmd.Start()
+
 	return err
 }