From e2aa15e642df5991fe12d8984e36c0e7c394a74f Mon Sep 17 00:00:00 2001
From: Jacob Weinstock <jakobweinstock@gmail.com>
Date: Wed, 4 Sep 2024 20:42:34 -0600
Subject: [PATCH] Update grub2disk:

Use alpine for final container in the Dockerfile
as there are quite a few shell commands used.

Signed-off-by: Jacob Weinstock <jakobweinstock@gmail.com>
---
 grub2disk/Dockerfile   | 20 +++++++++-----------
 grub2disk/grub/grub.go |  7 +++----
 grub2disk/main.go      |  4 ----
 3 files changed, 12 insertions(+), 19 deletions(-)

diff --git a/grub2disk/Dockerfile b/grub2disk/Dockerfile
index 5eb8b8d..82663bb 100644
--- a/grub2disk/Dockerfile
+++ b/grub2disk/Dockerfile
@@ -1,6 +1,4 @@
-# syntax=docker/dockerfile:1
-
-FROM golang:1.21-alpine AS base
+FROM golang:1.23-alpine AS base
 
 FROM base AS build-amd64
 RUN apk add --no-cache grub grub-bios git ca-certificates gcc musl-dev
@@ -9,12 +7,12 @@ FROM base AS build-arm64
 RUN apk add --no-cache grub git ca-certificates gcc musl-dev
 
 FROM build-${TARGETARCH} AS grub2disk
-COPY . /src
-WORKDIR /src/grub2disk
-RUN --mount=type=cache,sharing=locked,id=gomod,target=/go/pkg/mod/cache \
-    --mount=type=cache,sharing=locked,id=goroot,target=/root/.cache/go-build \
-    CGO_ENABLED=1 GOOS=linux go build -a -ldflags "-linkmode external -extldflags '-static' -s -w" -o grub2disk
+WORKDIR /src
+COPY go.mod go.sum /src/
+RUN go mod download
+COPY . /src/
+RUN CGO_ENABLED=1 GOOS=linux go build -a -ldflags "-linkmode external -extldflags '-static' -s -w" -o /src/grub2disk/grub2disk /src/grub2disk/
 
-FROM scratch
-COPY --from=grub2disk /src/grub2disk/grub2disk /usr/bin/grub2disk
-ENTRYPOINT ["/usr/bin/grub2disk"]
+FROM alpine:3.20.2
+COPY --from=grub2disk /src/grub2disk/grub2disk /usr/sbin/grub2disk
+ENTRYPOINT ["/usr/sbin/grub2disk"]
diff --git a/grub2disk/grub/grub.go b/grub2disk/grub/grub.go
index 7bf6615..99206a1 100644
--- a/grub2disk/grub/grub.go
+++ b/grub2disk/grub/grub.go
@@ -2,6 +2,7 @@ package grub
 
 import (
 	"fmt"
+	"os"
 	"os/exec"
 	"syscall"
 
@@ -9,10 +10,8 @@ import (
 )
 
 func makeDirAndMount(devicePath string, mountPoint string, filesystemType string) (err error) {
-	// if err = os.Mkdir(mountPoint, os.ModeDir); err != nil {
-	if _, err = exec.Command("/bin/sh", "-c", "/bin/mkdir -p "+mountPoint).Output(); err != nil {
-		log.Error(fmt.Errorf("failed to create the directory %s", mountPoint))
-		return err
+	if err := os.MkdirAll(mountPoint, os.ModeDir); err != nil {
+		return fmt.Errorf("failed to create the directory %s: %w", mountPoint, err)
 	}
 
 	// if err = syscall.Mount(devicePath, mountPoint, filesystemType, flag, ""); err != nil {
diff --git a/grub2disk/main.go b/grub2disk/main.go
index 31b74e3..421f61d 100644
--- a/grub2disk/main.go
+++ b/grub2disk/main.go
@@ -3,7 +3,6 @@ package main
 import (
 	"fmt"
 	"os"
-	"os/exec"
 
 	log "github.com/sirupsen/logrus"
 	"github.com/tinkerbell/actions/grub2disk/grub"
@@ -15,9 +14,6 @@ func main() {
 	grubBlockDevice := os.Getenv("GRUB_DISK")
 	filesystemType := os.Getenv("FS_TYPE")
 
-	if _, err := exec.Command("/bin/sh", "-c", "apk add grub grub-bios").Output(); err != nil {
-		log.Fatal(fmt.Errorf("failed to install grub-install with error %w", err))
-	}
 	if err := grub.MountGrub(grubInstallPath, grubBlockDevice, filesystemType); err != nil {
 		log.Fatal(err)
 	}