Add support for vagrant with qemu

Once we have produced a qemu VM, we now have the option of using
the vagrant post-processor to create a .box file that can be used with
the vagrant-libvirt plugin.

This uses the new State method of the Artifact API to get necessary
information from the builder.

builder/qemu/artifact.go

@@ -8,8 +8,9 @@ import (
 // Artifact is the result of running the Qemu builder, namely a set
 // of files associated with the resulting machine.
 type Artifact struct {
-	dir string
-	f   []string
+	dir  string
+	f    []string
+	state map[string]interface{}
 }
 
 func (*Artifact) BuilderId() string {
@@ -29,7 +30,7 @@ func (a *Artifact) String() string {
 }
 
 func (a *Artifact) State(name string) interface{} {
-	return nil
+	return a.state[name]
 }
 
 func (a *Artifact) Destroy() error {

builder/qemu/builder.go

@@ -481,8 +481,14 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	artifact := &Artifact{
 		dir: b.config.OutputDir,
 		f:   files,
+		state: make(map[string]interface{}),
 	}
 
+	artifact.state["diskName"] = state.Get("disk_filename").(string)
+	artifact.state["diskType"] = b.config.Format
+	artifact.state["diskSize"] = uint64(b.config.DiskSize)
+	artifact.state["domainType"] = b.config.Accelerator
+
 	return artifact, nil
 }
 

builder/qemu/step_create_disk.go

@@ -16,8 +16,8 @@ func (s *stepCreateDisk) Run(state multistep.StateBag) multistep.StepAction {
 	config := state.Get("config").(*config)
 	driver := state.Get("driver").(Driver)
 	ui := state.Get("ui").(packer.Ui)
-	path := filepath.Join(config.OutputDir, fmt.Sprintf("%s.%s", config.VMName,
-		strings.ToLower(config.Format)))
+	name := config.VMName + "." + strings.ToLower(config.Format)
+	path := filepath.Join(config.OutputDir, name)
 
 	command := []string{
 		"create",
@@ -34,6 +34,8 @@ func (s *stepCreateDisk) Run(state multistep.StateBag) multistep.StepAction {
 		return multistep.ActionHalt
 	}
 
+	state.Put("disk_filename", name)
+
 	return multistep.ActionContinue
 }
 

post-processor/vagrant/libvirt.go

@@ -0,0 +1,64 @@
+package vagrant
+
+import (
+	"fmt"
+	"github.com/mitchellh/packer/packer"
+	"path/filepath"
+	"strings"
+)
+
+type LibVirtProvider struct{}
+
+func (p *LibVirtProvider) KeepInputArtifact() bool {
+	return false
+}
+func (p *LibVirtProvider) Process(ui packer.Ui, artifact packer.Artifact, dir string) (vagrantfile string, metadata map[string]interface{}, err error) {
+	diskName := artifact.State("diskName").(string)
+
+	// Copy the disk image into the temporary directory (as box.img)
+	for _, path := range artifact.Files() {
+		if strings.HasSuffix(path, "/"+diskName) {
+			ui.Message(fmt.Sprintf("Copying from artifact: %s", path))
+			dstPath := filepath.Join(dir, "box.img")
+			if err = CopyContents(dstPath, path); err != nil {
+				return
+			}
+		}
+	}
+
+	format := artifact.State("diskType").(string)
+	origSize := artifact.State("diskSize").(uint64)
+	size := origSize / 1024 // In MB, want GB
+	if origSize % 1024 > 0 {
+		// Make sure we don't make the size smaller
+		size++
+	}
+	domainType := artifact.State("domainType").(string)
+
+	// Convert domain type to libvirt driver
+	var driver string
+	switch domainType {
+	case "kvm", "qemu":
+		driver = domainType
+	default:
+		return "", nil, fmt.Errorf("Unknown libvirt domain type: %s", domainType)
+	}
+
+	// Create the metadata
+	metadata = map[string]interface{}{
+		"provider":     "libvirt",
+		"format":       format,
+		"virtual_size": size,
+	}
+
+	vagrantfile = fmt.Sprintf(libvirtVagrantfile, driver)
+	return
+}
+
+var libvirtVagrantfile = `
+Vagrant.configure("2") do |config|
+  config.vm.provider :libvirt do |libvirt|
+    libvirt.driver = "%s"
+  end
+end
+`

post-processor/vagrant/post-processor.go

@@ -23,6 +23,7 @@ var builtins = map[string]string{
 	"pearkes.digitalocean":      "digitalocean",
 	"packer.parallels":          "parallels",
 	"MSOpenTech.hyperv":         "hyperv",
+	"transcend.qemu":            "libvirt",
 }
 
 type Config struct {
@@ -223,6 +224,8 @@ func providerForName(name string) Provider {
 		return new(ParallelsProvider)
 	case "hyperv":
 		return new(HypervProvider)
+	case "libvirt":
+		return new(LibVirtProvider)
 	default:
 		return nil
 	}