d2vm: add version command, lookup mbr.bin in well-known paths

Signed-off-by: Adphi <philippe.adrien.nousse@gmail.com>

Dockerfile

@@ -9,7 +9,7 @@ RUN go mod download
 
 COPY . .
 
-RUN go build -o d2vm ./cmd/d2vm
+RUN make build
 
 FROM ubuntu
 

Makefile

@@ -38,3 +38,6 @@ docker-run:
 		-v $(PWD):/build \
 		-w /build \
 		$(DOCKER_IMAGE) bash
+
+build:
+	@go build -o d2vm -ldflags "-s -w -X '$(MODULE).Version=$(VERSION)' -X '$(MODULE).BuildDate=$(shell date)'" ./cmd/d2vm

builder.go

@@ -66,13 +66,23 @@ ff02::3 ip6-allhosts
   KERNEL /boot/vmlinuz
   APPEND ro root=UUID=%s initrd=/boot/initrd.img net.ifnames=0 console=tty0 console=ttyS0,115200n8 
 `
-	mbrBin = "/usr/lib/EXTLINUX/mbr.bin"
 )
 
 var (
 	fdiskCmds = []string{"n", "p", "1", "", "", "a", "w"}
 
 	formats = []string{"qcow2", "qed", "raw", "vdi", "vhd", "vmdk"}
+
+	mbrPaths = []string{
+		// debian path
+		"/usr/lib/syslinux/mbr/mbr.bin",
+		// ubuntu path
+		"/usr/lib/EXTLINUX/mbr.bin",
+		// alpine path
+		"/usr/share/syslinux/mbr.bin",
+		// centos path
+		"/usr/share/syslinux/mbr.bin",
+	}
 )
 
 type builder struct {
@@ -86,6 +96,8 @@ type builder struct {
 	size     int64
 	mntPoint string
 
+	mbrPath string
+
 	loDevice string
 	loPart   string
 	diskUUD  string
@@ -105,6 +117,17 @@ func NewBuilder(workdir, src, disk string, size int64, osRelease OSRelease, form
 	if !valid {
 		return nil, fmt.Errorf("invalid format: %s valid formats are: %s", f, strings.Join(formats, " "))
 	}
+
+	mbrBin := ""
+	for _, v := range mbrPaths {
+		if _, err := os.Stat(v); err == nil {
+			mbrBin = v
+			break
+		}
+	}
+	if mbrBin == "" {
+		return nil, fmt.Errorf("unable to find syslinux's mbr.bin path")
+	}
 	if size == 0 {
 		size = 10 * int64(datasize.GB)
 	}
@@ -127,6 +150,7 @@ func NewBuilder(workdir, src, disk string, size int64, osRelease OSRelease, form
 		diskOut:   filepath.Join(workdir, disk+".qcow2"),
 		format:    f,
 		size:      size,
+		mbrPath:   mbrBin,
 		mntPoint:  filepath.Join(workdir, "/mnt"),
 	}
 	if err := os.MkdirAll(b.mntPoint, os.ModePerm); err != nil {
@@ -322,7 +346,7 @@ func (b *builder) installKernel(ctx context.Context) error {
 
 func (b *builder) setupMBR(ctx context.Context) error {
 	logrus.Infof("writing MBR")
-	if err := exec.Run(ctx, "dd", fmt.Sprintf("if=%s", mbrBin), fmt.Sprintf("of=%s", b.diskRaw), "bs=440", "count=1", "conv=notrunc"); err != nil {
+	if err := exec.Run(ctx, "dd", fmt.Sprintf("if=%s", b.mbrPath), fmt.Sprintf("of=%s", b.diskRaw), "bs=440", "count=1", "conv=notrunc"); err != nil {
 		return err
 	}
 	return nil
@@ -357,9 +381,6 @@ func checkDependencies() error {
 			merr = multierr.Append(merr, err)
 		}
 	}
-	if _, err := os.Stat(mbrBin); err != nil {
-		merr = multierr.Append(merr, err)
-	}
 	return merr
 }
 

cmd/d2vm/main.go

@@ -18,6 +18,8 @@ import (
 	"context"
 
 	"github.com/spf13/cobra"
+
+	"go.linka.cloud/d2vm"
 )
 
 var (
@@ -31,6 +33,7 @@ var (
 	rootCmd = &cobra.Command{
 		Use:          "d2vm",
 		SilenceUsage: true,
+		Version:      d2vm.Version,
 	}
 )
 

cmd/d2vm/version.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+
+	"go.linka.cloud/d2vm"
+)
+
+var (
+	cmdVersion = &cobra.Command{
+		Use: "version",
+		Run: func(cmd *cobra.Command, args []string) {
+			fmt.Println(d2vm.Version)
+			fmt.Println(d2vm.BuildDate)
+		},
+	}
+)
+
+func init() {
+	rootCmd.AddCommand(cmdVersion)
+}

examples/full/Dockerfile

@@ -20,6 +20,7 @@ ARG SSH_KEY=https://github.com/${USER}.keys
 
 # Setup user environment
 RUN DEBIAN_FRONTEND=noninteractive apt install -y \
+      bash-completion \
       curl \
       zsh \
       git \

version.go

@@ -0,0 +1,6 @@
+package d2vm
+
+var (
+	Version   = ""
+	BuildDate = ""
+)