QEMU: Initial QMP support

builder/qemu/builder.go

@@ -117,6 +117,8 @@ type Config struct {
 	OutputDir          string     `mapstructure:"output_directory"`
 	QemuArgs           [][]string `mapstructure:"qemuargs"`
 	QemuBinary         string     `mapstructure:"qemu_binary"`
+	QMPEnable          bool       `mapstructure:"qmp_enable"`
+	QMPSocketPath      string     `mapstructure:"qmp_socket_path"`
 	ShutdownCommand    string     `mapstructure:"shutdown_command"`
 	SSHHostPortMin     int        `mapstructure:"ssh_host_port_min"`
 	SSHHostPortMax     int        `mapstructure:"ssh_host_port_max"`
@@ -344,6 +346,7 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 		errs = packer.MultiErrorAppend(
 			errs, errors.New("ssh_host_port_min must be less than ssh_host_port_max"))
 	}
+
 	if b.config.SSHHostPortMin < 0 {
 		errs = packer.MultiErrorAppend(
 			errs, errors.New("ssh_host_port_min must be positive"))
@@ -354,6 +357,11 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 			errs, fmt.Errorf("vnc_port_min must be less than vnc_port_max"))
 	}
 
+	if b.config.QMPEnable && b.config.QMPSocketPath == "" {
+		socketName := fmt.Sprintf("%s.monitor", b.config.VMName)
+		b.config.QMPSocketPath = filepath.Join(b.config.OutputDir, socketName)
+	}
+
 	if b.config.QemuArgs == nil {
 		b.config.QemuArgs = make([][]string, 0)
 	}
@@ -425,6 +433,7 @@ func (b *Builder) Run(ctx context.Context, ui packer.Ui, hook packer.Hook) (pack
 	steps = append(steps,
 		new(stepConfigureVNC),
 		steprun,
+		new(stepConfigureQMP),
 		&stepTypeBootCommand{},
 	)
 

builder/qemu/builder_test.go

@@ -598,3 +598,25 @@ func TestBuilderPrepare_QemuArgs(t *testing.T) {
 		t.Fatalf("bad: %#v", b.config.QemuArgs)
 	}
 }
+
+func TestBuilderPrepare_QMP(t *testing.T) {
+	var b Builder
+	config := testConfig()
+
+	// QMP Defaults
+	config["qmp_enable"] = true
+	config["output_directory"] = "not-a-real-directory"
+	b = Builder{}
+	warns, err := b.Prepare(config)
+	if len(warns) > 0 {
+		t.Fatalf("bad: %#v", warns)
+	}
+	if err != nil {
+		t.Fatalf("should not have error: %s", err)
+	}
+
+	expected := "not-a-real-directory/packer-foo.monitor"
+	if !reflect.DeepEqual(b.config.QMPSocketPath, expected) {
+		t.Fatalf("Bad QMP socket Path: %s", b.config.QMPSocketPath)
+	}
+}

builder/qemu/step_configure_qmp.go

@@ -0,0 +1,56 @@
+package qemu
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/digitalocean/go-qemu/qmp"
+	"github.com/hashicorp/packer/helper/multistep"
+	"github.com/hashicorp/packer/packer"
+)
+
+// This step configures the VM to enable the QMP listener.
+//
+// Uses:
+//   config *config
+//   ui     packer.Ui
+//
+// Produces:
+type stepConfigureQMP struct {
+	monitor *qmp.SocketMonitor
+}
+
+func (s *stepConfigureQMP) Run(ctx context.Context, state multistep.StateBag) multistep.StepAction {
+	config := state.Get("config").(*Config)
+	ui := state.Get("ui").(packer.Ui)
+
+	if !config.QMPEnable {
+		return multistep.ActionContinue
+	}
+
+	msg := fmt.Sprintf("Opening QMP socket at: %s", config.QMPSocketPath)
+	ui.Say(msg)
+	log.Print(msg)
+
+	// Open QMP socket
+	var err error
+	s.monitor, err = qmp.NewSocketMonitor("unix", config.QMPSocketPath, 2*time.Second)
+	if err != nil {
+		err := fmt.Errorf("Error opening QMP socket: %s", err)
+		state.Put("error", err)
+		ui.Error(err.Error())
+		return multistep.ActionHalt
+	}
+	QMPMonitor := s.monitor
+
+	log.Printf("QMP socket open SUCCESS")
+
+	state.Put("qmp_monitor", QMPMonitor)
+
+	return multistep.ActionContinue
+}
+
+func (s *stepConfigureQMP) Cleanup(multistep.StateBag) {
+}

builder/qemu/step_run.go

@@ -85,6 +85,10 @@ func getCommandArgs(bootDrive string, state multistep.StateBag) ([]string, error
 		defaultArgs["-netdev"] = fmt.Sprintf("user,id=user.0")
 	}
 
+	if config.QMPEnable {
+		defaultArgs["-qmp"] = fmt.Sprintf("unix:%s,server,nowait", config.QMPSocketPath)
+	}
+
 	rawVersion, err := driver.Version()
 	if err != nil {
 		return nil, err

website/source/docs/builders/qemu.html.md.erb

@@ -282,6 +282,13 @@ Linux server and have not enabled X11 forwarding (`ssh -X`).
     switch/value pairs. Any value specified as an empty string is ignored. All
     values after the switch are concatenated with no separator.
 
+-   `qmp_enable` (bool) - Enable QMP socket. Location is specified by
+    `qmp_socket_path`.
+    Defaults to false.    
+
+-   `qmp_socket_path` (string) - QMP Socket Path when `qmp_enable` is true.
+    Defaults to `output_directory`/`vm_name`.monitor.
+
 ~> **Warning:** The qemu command line allows extreme flexibility, so beware
 of conflicting arguments causing failures of your run. For instance, using
 --no-acpi could break the ability to send power signal type commands (e.g.,