From 582872921756f83910a67e55febefb4edfc9a92f Mon Sep 17 00:00:00 2001
From: Christian Kellner <christian@kellner.me>
Date: Wed, 13 May 2020 17:04:36 +0200
Subject: [PATCH] stages/grub2: turn write_grub_cfg into an object

The reason behind this is to combine all the necessary state in the
object instead of passing it all to the write_grub_cfg function.
The idea is that as more things will get configurable, say the
timeout or ignition support, more things need to be passed to it
and thus it is better to an object where these config options can
be set and then combined when writing the config.
---
 stages/org.osbuild.grub2 | 62 ++++++++++++++++++++++++++++------------
 1 file changed, 43 insertions(+), 19 deletions(-)

diff --git a/stages/org.osbuild.grub2 b/stages/org.osbuild.grub2
index a4543e28..ffafb4b7 100755
--- a/stages/org.osbuild.grub2
+++ b/stages/org.osbuild.grub2
@@ -176,23 +176,43 @@ def copy_efi_data(tree, vendor):
                         symlinks=False)
 
 
-def write_grub_cfg(tree, path, grub_fs):
-    """Write the grub config to `tree` at `path`"""
-    fs_type, fs_id = fs_spec_decode(grub_fs)
-    type2opt = {
-        "UUID": "--fs-uuid",
-        "LABEL": "--label"
-    }
-    search = type2opt[fs_type] + " " + fs_id
-    with open(os.path.join(tree, path), "w") as cfg:
-        cfg.write("set timeout=0\n"
-                  "load_env\n"
-                  f"search --no-floppy --set=root {search}\n"
-                  "set boot=${root}\n"
-                  "function load_video {\n"
-                  "  insmod all_video\n"
-                  "}\n"
-                  "blscfg\n")
+class GrubConfig:
+    def __init__(self, rootfs, bootfs):
+        self.rootfs = rootfs
+        self.bootfs = bootfs
+        self.path = "boot/grub2/grub.cfg"
+
+    @property
+    def grubfs(self):
+        """The filesystem containing the grub files,
+
+        This is  either a separate partition (self.bootfs if set) or
+        the root file system (self.rootfs)
+        """
+        return self.bootfs or self.rootfs
+
+    def write(self, tree):
+        """Write the grub config to `tree` at `self.path`"""
+        path = os.path.join(tree, self.path)
+
+        fs_type, fs_id = fs_spec_decode(self.grubfs)
+        type2opt = {
+            "UUID": "--fs-uuid",
+            "LABEL": "--label"
+        }
+
+        # options for the configuration strings
+        search = type2opt[fs_type] + " " + fs_id
+
+        with open(path) as cfg:
+            cfg.write("set timeout=0\n"
+                      "load_env\n"
+                      f"search --no-floppy --set=root {search}\n"
+                      "set boot=${root}\n"
+                      "function load_video {\n"
+                      "  insmod all_video\n"
+                      "}\n"
+                      "blscfg\n")
 
 
 def write_grub_cfg_redirect(tree, path, separate_boot):
@@ -231,6 +251,9 @@ def main(tree, options):
     # /boot/grub2 and will not have a grubenv itself.
     hybrid = uefi and legacy
 
+    # Prepare the actual grub configuration file, will be written further down
+    config = GrubConfig(root_fs, boot_fs)
+
     # grub_fs points to the filesystem containing the grub files, which is
     # either a separate partition (boot_fs) or the root file system (root_fs)
     grub_fs = boot_fs or root_fs
@@ -292,10 +315,11 @@ def main(tree, options):
         if hybrid:
             write_grub_cfg_redirect(tree, grubcfg, separate_boot)
         else:
-            write_grub_cfg(tree, grubcfg, grub_fs)
+            config.path = grubcfg
+            config.write(tree)
 
     if legacy:
-        write_grub_cfg(tree, "boot/grub2/grub.cfg", grub_fs)
+        config.write(tree)
         copy_modules(tree, legacy)
         copy_font(tree)