cmd: add vm list command

Get a list of virter VMs based on available metadata. If virter metadata
is found, also show the ID and access network based on the defined VM XML.

When getting a list of VMs for shell completion, only include VMs that
were created by virter.

cmd/vm.go

@@ -1,6 +1,8 @@
 package cmd
 
 import (
+	"slices"
+
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 	"golang.org/x/crypto/ssh"
@@ -19,6 +21,7 @@ func vmCommand() *cobra.Command {
 
 	vmCmd.AddCommand(vmCommitCommand())
 	vmCmd.AddCommand(vmExecCommand())
+	vmCmd.AddCommand(vmListCommand())
 	vmCmd.AddCommand(vmExistsCommand())
 	vmCmd.AddCommand(vmHostKeyCommand())
 	vmCmd.AddCommand(vmRmCommand())
@@ -59,18 +62,24 @@ func suggestVmNames(cmd *cobra.Command, args []string, toComplete string) ([]str
 	}
 	defer v.ForceDisconnect()
 
-	vms, err := v.ListVM()
+	vms, err := v.VMList()
 	if err != nil {
 		return nil, cobra.ShellCompDirectiveError
 	}
 
 	filtered := make([]string, 0, len(vms))
-outer:
 	for _, vm := range vms {
-		for _, arg := range args {
-			if arg == vm {
-				continue outer
-			}
+		if slices.Contains(args, vm) {
+			// already mentioned in previous argument
+			continue
+		}
+		info, err := v.VMInfo(vm)
+		if err != nil {
+			return nil, cobra.ShellCompDirectiveError
+		}
+		if info.ID == 0 {
+			// not a VM created by virter
+			continue
 		}
 
 		filtered = append(filtered, vm)

cmd/vm_list.go

@@ -0,0 +1,56 @@
+package cmd
+
+import (
+	"strconv"
+
+	"github.com/rodaine/table"
+	log "github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+
+	"github.com/LINBIT/virter/internal/virter"
+)
+
+func vmListCommand() *cobra.Command {
+	existsCmd := &cobra.Command{
+		Use:     "list",
+		Aliases: []string{"ls"},
+		Short:   "List all VMs",
+		Long:    `List all VMs along with their ID and access network if they were created by Virter`,
+		Args:    cobra.NoArgs,
+		Run: func(cmd *cobra.Command, args []string) {
+			v, err := InitVirter()
+			if err != nil {
+				log.Fatal(err)
+			}
+			defer v.ForceDisconnect()
+
+			vms, err := v.VMList()
+			if err != nil {
+				log.Fatal(err)
+			}
+
+			vmInfos := make([]*virter.VMInfo, 0, len(vms))
+
+			for _, vm := range vms {
+				vmInfo, err := v.VMInfo(vm)
+				if err != nil {
+					log.Fatal(err)
+				}
+
+				vmInfos = append(vmInfos, vmInfo)
+			}
+
+			t := table.New("Name", "ID", "Access Network")
+			for _, val := range vmInfos {
+				id := ""
+				if val.ID != 0 {
+					id = strconv.Itoa(int(val.ID))
+				}
+				t.AddRow(val.Name, id, val.AccessNetwork)
+			}
+			t.Print()
+		},
+		ValidArgsFunction: suggestVmNames,
+	}
+	return existsCmd
+}

internal/virter/dhcp.go

@@ -107,6 +107,16 @@ func AddToMAC(mac net.HardwareAddr, addend uint) (net.HardwareAddr, error) {
 	return out, nil
 }
 
+func IDFromMAC(mac, base net.HardwareAddr) uint {
+	var macValue, baseValue big.Int
+	macValue.SetBytes(mac)
+	baseValue.SetBytes(base)
+
+	macValue.Sub(&macValue, &baseValue)
+
+	return uint(macValue.Int64())
+}
+
 func (v *Virter) getIPNet(network libvirt.Network) (*net.IPNet, error) {
 	networkDescription, err := getNetworkDescription(v.libvirt, network)
 	if err != nil {

internal/virter/vm.go

@@ -3,6 +3,7 @@ package virter
 import (
 	"bytes"
 	"context"
+	"encoding/xml"
 	"fmt"
 	"net"
 	"path/filepath"
@@ -12,6 +13,7 @@ import (
 	"github.com/LINBIT/containerapi"
 	sshclient "github.com/LINBIT/gosshclient"
 	libvirt "github.com/digitalocean/go-libvirt"
+	lx "github.com/libvirt/libvirt-go-xml"
 	log "github.com/sirupsen/logrus"
 	"golang.org/x/crypto/ssh"
 	"golang.org/x/sync/errgroup"
@@ -66,7 +68,7 @@ func (v *Virter) anyImageExists(vmConfig VMConfig) (bool, error) {
 	return false, nil
 }
 
-func (v *Virter) ListVM() ([]string, error) {
+func (v *Virter) VMList() ([]string, error) {
 	domains, _, err := v.libvirt.ConnectListAllDomains(-1, 0)
 	if err != nil {
 		return nil, fmt.Errorf("failed to list domains")
@@ -80,6 +82,62 @@ func (v *Virter) ListVM() ([]string, error) {
 	return result, nil
 }
 
+type VMInfo struct {
+	Name          string
+	ID            uint
+	AccessNetwork string
+}
+
+// VMInfo returns the ID and access network of the named VM
+func (v *Virter) VMInfo(vmName string) (*VMInfo, error) {
+	dom, err := v.libvirt.DomainLookupByName(vmName)
+	if err != nil {
+		return nil, fmt.Errorf("failed to lookup domain: %w", err)
+	}
+
+	xmldesc, err := v.libvirt.DomainGetXMLDesc(dom, 0)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get XML description: %w", err)
+	}
+
+	desc := lx.Domain{}
+	err = xml.Unmarshal([]byte(xmldesc), &desc)
+	if err != nil {
+		return nil, fmt.Errorf("could not decode domain xml '%s': %w", vmName, err)
+	}
+
+	meta := metaWrapper{}
+	err = xml.Unmarshal([]byte(desc.Metadata.XML), &meta)
+	if err != nil {
+		// not a virter VM
+		return &VMInfo{Name: vmName}, nil
+	}
+
+	if len(desc.Devices.Interfaces) < 1 {
+		return nil, fmt.Errorf("no interfaces found for VM '%s'", vmName)
+	}
+
+	if desc.Devices.Interfaces[0].Source == nil || desc.Devices.Interfaces[0].Source.Network == nil || desc.Devices.Interfaces[0].Source.Network.Network == "" {
+		return nil, fmt.Errorf("no network found for VM '%s'", vmName)
+	}
+
+	network, err := v.NetworkGet(desc.Devices.Interfaces[0].Source.Network.Network)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get network '%s' for VM '%s': %w", desc.Devices.Interfaces[0].Source.Network.Network, vmName, err)
+	}
+
+	if desc.Devices.Interfaces[0].MAC == nil {
+		return nil, fmt.Errorf("no MAC address found for VM '%s'", vmName)
+	}
+
+	vmMac, err := net.ParseMAC(desc.Devices.Interfaces[0].MAC.Address)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse VM MAC address '%s' for VM '%s': %w", desc.Devices.Interfaces[0].MAC.Address, vmName, err)
+	}
+
+	return &VMInfo{Name: vmName, AccessNetwork: network.Name, ID: IDFromMAC(vmMac, QemuBaseMAC())}, nil
+}
+
 // VMRun starts a VM.
 func (v *Virter) VMRun(vmConfig VMConfig) error {
 	// checks