From ba80fba648410399c6aabb4aa8ba002c68dcb3cf Mon Sep 17 00:00:00 2001
From: msm-code <msm@tailcall.net>
Date: Mon, 6 Apr 2020 09:12:46 +0000
Subject: [PATCH] Add --network switch to select a networking model (#22)

---
 appvm.go | 39 +++++++++++++++++++++++++++++++++------
 xml.go   | 44 ++++++++++++++++++++++++++++----------------
 2 files changed, 61 insertions(+), 22 deletions(-)

diff --git a/appvm.go b/appvm.go
index 48b716a..f7586de 100644
--- a/appvm.go
+++ b/appvm.go
@@ -31,6 +31,15 @@ import (
 	kingpin "gopkg.in/alecthomas/kingpin.v2"
 )
 
+
+type networkModel int
+
+const (
+    networkOffline networkModel = iota
+    networkQemu networkModel = iota
+    networkLibvirt networkModel = iota
+)
+
 func list(l *libvirt.Libvirt) {
 	domains, err := l.Domains()
 	if err != nil {
@@ -173,14 +182,14 @@ func isRunning(l *libvirt.Libvirt, name string) bool {
 
 func generateAppVM(l *libvirt.Libvirt,
 	nixName, vmName, appvmPath, sharedDir string,
-	verbose, online, gui bool) (err error) {
+	verbose bool, network networkModel, gui bool) (err error) {
 
 	realpath, reginfo, qcow2, err := generateVM(appvmPath, nixName, verbose)
 	if err != nil {
 		return
 	}
 
-	xml := generateXML(vmName, online, gui, realpath, reginfo, qcow2, sharedDir)
+	xml := generateXML(vmName, network, gui, realpath, reginfo, qcow2, sharedDir)
 	_, err = l.DomainCreateXML(xml, libvirt.DomainStartValidate)
 	return
 }
@@ -209,8 +218,8 @@ func isAppvmConfigurationExists(appvmPath, name string) bool {
 	return fileExists(appvmPath + "/nix/" + name + ".nix")
 }
 
-func start(l *libvirt.Libvirt, name string, verbose, online, gui, stateless bool,
-	args, open string) {
+func start(l *libvirt.Libvirt, name string, verbose bool, network networkModel,
+	gui, stateless bool, args, open string) {
 
 	appvmPath := configDir
 
@@ -267,7 +276,7 @@ func start(l *libvirt.Libvirt, name string, verbose, online, gui, stateless bool
 		}
 
 		err := generateAppVM(l, name, vmName, appvmPath, sharedDir,
-			verbose, online, gui)
+			verbose, network, gui)
 		if err != nil {
 			log.Fatal(err)
 		}
@@ -415,6 +424,22 @@ func cleanupStatelessVMs(l *libvirt.Libvirt) {
 	}
 }
 
+func parseNetworkModel(flagOffline bool, flagNetworking string) networkModel {
+	if flagNetworking != "" && flagOffline {
+		log.Fatal("Can't use both --network and --offline switches")
+	}
+	if flagOffline || flagNetworking == "offline" {
+		return networkOffline
+	}
+	if flagNetworking == "libvirt" {
+		return networkLibvirt
+	}
+	if flagNetworking == "qemu" {
+		return networkQemu
+	}
+	return networkQemu  // qemu is the default network model
+}
+
 var configDir = os.Getenv("HOME") + "/.config/appvm/"
 var appvmHomesDir = os.Getenv("HOME") + "/appvm/"
 
@@ -454,6 +479,7 @@ func main() {
 	startOffline := startCommand.Flag("offline", "Disconnect").Bool()
 	startCli := startCommand.Flag("cli", "Disable graphics mode, enable serial").Bool()
 	startStateless := startCommand.Flag("stateless", "Do not use default state directory").Bool()
+	startNetwork := startCommand.Flag("network", "Used networking model").Enum("offline", "qemu", "libvirt")
 
 	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()
@@ -498,8 +524,9 @@ func main() {
 		generate(*generateName, *generateBin, *generateVMName,
 			*generateBuildVM)
 	case "start":
+		networkModel := parseNetworkModel(*startOffline, *startNetwork)
 		start(l, *startName,
-			!*startQuiet, !*startOffline, !*startCli, *startStateless,
+			!*startQuiet, networkModel, !*startCli, *startStateless,
 			*startArgs, *startOpen)
 	case "stop":
 		stop(l, *stopName)
diff --git a/xml.go b/xml.go
index f559773..929c0e8 100644
--- a/xml.go
+++ b/xml.go
@@ -5,7 +5,7 @@ import "fmt"
 // You may think that you want to rewrite to proper golang structures.
 // Believe me, you shouldn't.
 
-func generateXML(vmName string, online, gui bool,
+func generateXML(vmName string, network networkModel, gui bool,
 	vmNixPath, reginfo, img, sharedDir string) string {
 
 	devices := ""
@@ -14,28 +14,40 @@ func generateXML(vmName string, online, gui bool,
 		devices = guiDevices
 	}
 
-	qemuParams := `
-          <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>
-        `
+	qemuParams := qemuParamsDefault
 
-	if !online {
-		qemuParams = `
-                  <qemu:commandline>
-                    <qemu:arg value='-snapshot'/>
-                  </qemu:commandline>
-                `
+	if network == networkQemu {
+		qemuParams = qemuParamsWithNetwork
+	} else if network == networkLibvirt {
+		devices += netDevices
 	}
 
 	return fmt.Sprintf(xmlTmpl, vmName, vmNixPath, vmNixPath, vmNixPath,
 		reginfo, img, sharedDir, sharedDir, sharedDir, devices, qemuParams)
 }
 
+var qemuParamsDefault = `
+  <qemu:commandline>
+    <qemu:arg value='-snapshot'/>
+  </qemu:commandline>
+`
+
+var qemuParamsWithNetwork = `
+  <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>
+`
+
+var netDevices = `
+    <interface type='network'>
+      <source network='default'/>
+    </interface>
+`
+
 var guiDevices = `
     <!-- Graphical console -->
     <graphics type='spice' autoport='yes'>