Rewrite in go, use libvirt

appvm.go

@@ -0,0 +1,212 @@
+/**
+ * @author Mikhail Klementev jollheef<AT>riseup.net
+ * @license GNU GPLv3
+ * @date July 2018
+ * @brief appvm launcher
+ */
+
+package main
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"syscall"
+	"time"
+
+	"github.com/digitalocean/go-libvirt"
+	"github.com/jollheef/go-system"
+	kingpin "gopkg.in/alecthomas/kingpin.v2"
+)
+
+var xmlTmpl = `
+<domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
+  <name>%s</name>
+  <memory unit='KiB'>1048576</memory>
+  <currentMemory unit='KiB'>1048576</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc-i440fx-2.12'>hvm</type>
+    <kernel>%s/kernel</kernel>
+    <initrd>%s/initrd</initrd>
+    <cmdline>loglevel=4 init=%s/init %s</cmdline>
+  </os>
+  <features>
+    <acpi/>
+  </features>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <!-- Graphical console -->
+    <graphics type='spice' autoport='yes'>
+      <listen type='address'/>
+      <image compression='off'/>
+    </graphics>
+    <!-- Fake (because -snapshot) writeback image -->
+    <disk type='file' device='disk'>
+      <driver name='qemu' type='qcow2' cache='writeback' error_policy='report'/>
+      <source file='%s'/>
+      <target dev='vda' bus='virtio'/>
+    </disk>
+    <video>
+      <model type='qxl' ram='524288' vram='524288' vgamem='262144' heads='1' primary='yes'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
+    </video>
+    <!-- filesystems -->
+    <filesystem type='mount' accessmode='passthrough'>
+      <source dir='/nix/store'/>
+      <target dir='store'/>
+      <readonly/>
+    </filesystem>
+    <filesystem type='mount' accessmode='mapped'>
+      <source dir='%s'/>
+      <target dir='xchg'/> <!-- workaround for nixpkgs/nixos/modules/virtualisation/qemu-vm.nix -->
+    </filesystem>
+    <filesystem type='mount' accessmode='mapped'>
+      <source dir='%s'/>
+      <target dir='shared'/> <!-- workaround for nixpkgs/nixos/modules/virtualisation/qemu-vm.nix -->
+    </filesystem>
+    <filesystem type='mount' accessmode='mapped'>
+      <source dir='%s'/>
+      <target dir='home'/>
+    </filesystem>
+  </devices>
+  <qemu:commandline>
+    <qemu:arg value='-device'/>
+    <qemu:arg value='e1000,netdev=net0'/>
+    <qemu:arg value='-netdev'/>
+    <qemu:arg value='user,id=net0'/>
+    <qemu:arg value='-snapshot'/>
+  </qemu:commandline>
+</domain>
+`
+
+func generateXML(name, vmNixPath, reginfo, img, sharedDir string) string {
+	// TODO: Define XML in go
+	return fmt.Sprintf(xmlTmpl, "appvm_"+name, vmNixPath, vmNixPath, vmNixPath,
+		reginfo, img, sharedDir, sharedDir, sharedDir)
+}
+
+func list(l *libvirt.Libvirt) {
+	domains, err := l.Domains()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// TODO list available to create VM's too
+	for _, d := range domains {
+		if d.Name[0:5] == "appvm" {
+			fmt.Println(d.Name[6:])
+		}
+	}
+}
+
+func start(l *libvirt.Libvirt, name string) {
+	// Currently binary-only installation is not supported, because we need *.nix configurations
+	gopath := os.Getenv("GOPATH")
+	err := os.Chdir(gopath + "/src/github.com/jollheef/appvm")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	_, _, _, err = system.System("nix-build", "<nixpkgs/nixos>", "-A", "config.system.build.vm",
+		"-I", "nixos-config=nix/"+name+".nix", "-I", ".")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	realpath, err := filepath.EvalSymlinks("result/system")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// TODO: Use go regex
+	reginfo, _, _, err := system.System("sh", "-c", "cat result/bin/run-nixos-vm | grep -o 'regInfo=.*/registration'")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	syscall.Unlink("result")
+
+	qcow2 := "/tmp/.appvm.fake.qcow2"
+	if _, err := os.Stat(qcow2); os.IsNotExist(err) {
+		system.System("qemu-img", "create", "-f", "qcow2", qcow2, "512M")
+		err := os.Chmod(qcow2, 0400) // qemu run with -snapshot, we only need it for create /dev/vda
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+
+	sharedDir := fmt.Sprintf(os.Getenv("HOME") + "/appvm/" + name)
+	os.MkdirAll(sharedDir, 0700)
+
+	// TODO: Search go libraries for manipulate ACL
+	_, _, _, err = system.System("setfacl", "-R", "-m", "u:qemu:rwx", os.Getenv("HOME")+"/appvm/")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	xml := generateXML(name, realpath, reginfo, qcow2, sharedDir)
+	_, err = l.DomainCreateXML(xml, libvirt.DomainStartValidate)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	cmd := exec.Command("virt-viewer", "-f", "appvm_"+name)
+	cmd.Start()
+}
+
+func stop(l *libvirt.Libvirt, name string) {
+	dom, err := l.DomainLookupByName("appvm_" + name)
+	if err != nil {
+		if libvirt.IsNotFound(err) {
+			log.Println("Appvm not found or already stopped")
+			return
+		} else {
+			log.Fatal(err)
+		}
+	}
+	err = l.DomainDestroy(dom)
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+func drop(name string) {
+	appDataPath := fmt.Sprintf(os.Getenv("HOME") + "/appvm/" + name)
+	os.RemoveAll(appDataPath)
+}
+
+func main() {
+	c, err := net.DialTimeout("unix", "/var/run/libvirt/libvirt-sock", time.Second)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	l := libvirt.New(c)
+	if err := l.Connect(); err != nil {
+		log.Fatal(err)
+	}
+	defer l.Disconnect()
+
+	kingpin.Command("list", "List applications")
+	startName := kingpin.Command("start", "Start application").Arg("name", "Application name").Required().String()
+	stopName := kingpin.Command("stop", "Stop application").Arg("name", "Application name").Required().String()
+	dropName := kingpin.Command("drop", "Remove application data").Arg("name", "Application name").Required().String()
+
+	switch kingpin.Parse() {
+	case "list":
+		list(l)
+	case "start":
+		start(l, *startName)
+	case "stop":
+		stop(l, *stopName)
+	case "drop":
+		drop(*dropName)
+	}
+}