nixos/systemd-boot: move all template variables in one place

This makes it easier to reason about what variables are inserted during packaging.
We also make sure that template file is also valid python syntax, which makes editor errors go away during development.

1 files changed, 51 insertions, 38 deletions

diff --git a/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py b/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py
index 6cd46f30373b..055afe95df60 100644
--- a/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py
+++ b/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py
@@ -15,6 +15,19 @@ import json
 from typing import NamedTuple, Dict, List
 from dataclasses import dataclass
 
+# These values will be replaced with actual values during the package build
+EFI_SYS_MOUNT_POINT = "@efiSysMountPoint@"
+TIMEOUT = "@timeout@"
+EDITOR = bool("@editor@")
+CONSOLE_MODE = "@consoleMode@"
+BOOTSPEC_TOOLS = "@bootspecTools@"
+DISTRO_NAME = "@distroName@"
+NIX = "@nix@"
+SYSTEMD = "@systemd@"
+CONFIGURATION_LIMIT = int("@configurationLimit@")
+CAN_TOUCH_EFI_VARIABLES = "@canTouchEfiVariables@"
+GRACEFUL = "@graceful@"
+COPY_EXTRA_FILES = "@copyExtraFiles@"
 
 @dataclass
 class BootSpec:
@@ -29,7 +42,6 @@ class BootSpec:
     initrdSecrets: str | None = None
 
 
-
 libc = ctypes.CDLL("libc.so.6")
 
 class SystemIdentifier(NamedTuple):
@@ -75,16 +87,16 @@ def generation_conf_filename(profile: str | None, generation: int, specialisatio
 
 
 def write_loader_conf(profile: str | None, generation: int, specialisation: str | None) -> None:
-    with open("@efiSysMountPoint@/loader/loader.conf.tmp", 'w') as f:
-        if "@timeout@" != "":
-            f.write("timeout @timeout@\n")
+    with open(f"{EFI_SYS_MOUNT_POINT}/loader/loader.conf.tmp", 'w') as f:
+        if TIMEOUT != "":
+            f.write(f"timeout {TIMEOUT}\n")
         f.write("default %s\n" % generation_conf_filename(profile, generation, specialisation))
-        if not @editor@:
+        if not EDITOR:
             f.write("editor 0\n")
-        f.write("console-mode @consoleMode@\n")
+        f.write(f"console-mode {CONSOLE_MODE}\n")
         f.flush()
         os.fsync(f.fileno())
-    os.rename("@efiSysMountPoint@/loader/loader.conf.tmp", "@efiSysMountPoint@/loader/loader.conf")
+    os.rename(f"{EFI_SYS_MOUNT_POINT}/loader/loader.conf.tmp", f"{EFI_SYS_MOUNT_POINT}/loader/loader.conf")
 
 
 def get_bootspec(profile: str | None, generation: int) -> BootSpec:
@@ -95,7 +107,7 @@ def get_bootspec(profile: str | None, generation: int) -> BootSpec:
         bootspec_json = json.load(boot_json_f)
     else:
         boot_json_str = subprocess.check_output([
-        "@bootspecTools@/bin/synthesize",
+        f"{BOOTSPEC_TOOLS}/bin/synthesize",
         "--version",
         "1",
         system_directory,
@@ -116,7 +128,7 @@ def copy_from_file(file: str, dry_run: bool = False) -> str:
     store_dir = os.path.basename(os.path.dirname(store_file_path))
     efi_file_path = "/efi/nixos/%s-%s.efi" % (store_dir, suffix)
     if not dry_run:
-        copy_if_not_exists(store_file_path, "@efiSysMountPoint@%s" % (efi_file_path))
+        copy_if_not_exists(store_file_path, f"{EFI_SYS_MOUNT_POINT}%s" % (efi_file_path))
     return efi_file_path
 
 def write_entry(profile: str | None, generation: int, specialisation: str | None,
@@ -126,13 +138,14 @@ def write_entry(profile: str | None, generation: int, specialisation: str | None
     kernel = copy_from_file(bootspec.kernel)
     initrd = copy_from_file(bootspec.initrd)
 
-    title = "@distroName@{profile}{specialisation}".format(
+    title = "{name}{profile}{specialisation}".format(
+        name=DISTRO_NAME,
         profile=" [" + profile + "]" if profile else "",
         specialisation=" (%s)" % specialisation if specialisation else "")
 
     try:
         if bootspec.initrdSecrets is not None:
-            subprocess.check_call([bootspec.initrdSecrets, "@efiSysMountPoint@%s" % (initrd)])
+            subprocess.check_call([bootspec.initrdSecrets, f"{EFI_SYS_MOUNT_POINT}%s" % (initrd)])
     except subprocess.CalledProcessError:
         if current:
             print("failed to create initrd secrets!", file=sys.stderr)
@@ -142,7 +155,7 @@ def write_entry(profile: str | None, generation: int, specialisation: str | None
                   f'for "{title} - Configuration {generation}", an older generation', file=sys.stderr)
             print("note: this is normal after having removed "
                   "or renamed a file in `boot.initrd.secrets`", file=sys.stderr)
-    entry_file = "@efiSysMountPoint@/loader/entries/%s" % (
+    entry_file = f"{EFI_SYS_MOUNT_POINT}/loader/entries/%s" % (
         generation_conf_filename(profile, generation, specialisation))
     tmp_path = "%s.tmp" % (entry_file)
     kernel_params = "init=%s " % bootspec.init
@@ -167,7 +180,7 @@ def write_entry(profile: str | None, generation: int, specialisation: str | None
 
 def get_generations(profile: str | None = None) -> list[SystemIdentifier]:
     gen_list = subprocess.check_output([
-        "@nix@/bin/nix-env",
+        f"{NIX}/bin/nix-env",
         "--list-generations",
         "-p",
         "/nix/var/nix/profiles/%s" % ("system-profiles/" + profile if profile else "system"),
@@ -176,7 +189,7 @@ def get_generations(profile: str | None = None) -> list[SystemIdentifier]:
     gen_lines = gen_list.split('\n')
     gen_lines.pop()
 
-    configurationLimit = @configurationLimit@
+    configurationLimit = CONFIGURATION_LIMIT
     configurations = [
         SystemIdentifier(
             profile=profile,
@@ -189,14 +202,14 @@ def get_generations(profile: str | None = None) -> list[SystemIdentifier]:
 
 
 def remove_old_entries(gens: list[SystemIdentifier]) -> None:
-    rex_profile = re.compile(r"^@efiSysMountPoint@/loader/entries/nixos-(.*)-generation-.*\.conf$")
-    rex_generation = re.compile(r"^@efiSysMountPoint@/loader/entries/nixos.*-generation-([0-9]+)(-specialisation-.*)?\.conf$")
+    rex_profile = re.compile(r"^" + re.escape(EFI_SYS_MOUNT_POINT) + "/loader/entries/nixos-(.*)-generation-.*\.conf$")
+    rex_generation = re.compile(r"^" + re.escape(EFI_SYS_MOUNT_POINT) + "/loader/entries/nixos.*-generation-([0-9]+)(-specialisation-.*)?\.conf$")
     known_paths = []
     for gen in gens:
         bootspec = get_bootspec(gen.profile, gen.generation)
         known_paths.append(copy_from_file(bootspec.kernel, True))
         known_paths.append(copy_from_file(bootspec.initrd, True))
-    for path in glob.iglob("@efiSysMountPoint@/loader/entries/nixos*-generation-[1-9]*.conf"):
+    for path in glob.iglob(f"{EFI_SYS_MOUNT_POINT}/loader/entries/nixos*-generation-[1-9]*.conf"):
         if rex_profile.match(path):
             prof = rex_profile.sub(r"\1", path)
         else:
@@ -207,7 +220,7 @@ def remove_old_entries(gens: list[SystemIdentifier]) -> None:
             continue
         if not (prof, gen_number, None) in gens:
             os.unlink(path)
-    for path in glob.iglob("@efiSysMountPoint@/efi/nixos/*"):
+    for path in glob.iglob(f"{EFI_SYS_MOUNT_POINT}/efi/nixos/*"):
         if not path in known_paths and not os.path.isdir(path):
             os.unlink(path)
 
@@ -230,7 +243,7 @@ def install_bootloader(args: argparse.Namespace) -> None:
         # Since systemd version 232 a machine ID is required and it might not
         # be there on newly installed systems, so let's generate one so that
         # bootctl can find it and we can also pass it to write_entry() later.
-        cmd = ["@systemd@/bin/systemd-machine-id-setup", "--print"]
+        cmd = [f"{SYSTEMD}/bin/systemd-machine-id-setup", "--print"]
         machine_id = subprocess.run(
           cmd, text=True, check=True, stdout=subprocess.PIPE
         ).stdout.rstrip()
@@ -242,22 +255,22 @@ def install_bootloader(args: argparse.Namespace) -> None:
     # flags to pass to bootctl install/update
     bootctl_flags = []
 
-    if "@canTouchEfiVariables@" != "1":
+    if CAN_TOUCH_EFI_VARIABLES != "1":
         bootctl_flags.append("--no-variables")
 
-    if "@graceful@" == "1":
+    if GRACEFUL == "1":
         bootctl_flags.append("--graceful")
 
     if os.getenv("NIXOS_INSTALL_BOOTLOADER") == "1":
         # bootctl uses fopen() with modes "wxe" and fails if the file exists.
-        if os.path.exists("@efiSysMountPoint@/loader/loader.conf"):
-            os.unlink("@efiSysMountPoint@/loader/loader.conf")
+        if os.path.exists(f"{EFI_SYS_MOUNT_POINT}/loader/loader.conf"):
+            os.unlink(f"{EFI_SYS_MOUNT_POINT}/loader/loader.conf")
 
-        subprocess.check_call(["@systemd@/bin/bootctl", "--esp-path=@efiSysMountPoint@"] + bootctl_flags + ["install"])
+        subprocess.check_call([f"{SYSTEMD}/bin/bootctl", f"--esp-path={EFI_SYS_MOUNT_POINT}"] + bootctl_flags + ["install"])
     else:
         # Update bootloader to latest if needed
-        available_out = subprocess.check_output(["@systemd@/bin/bootctl", "--version"], universal_newlines=True).split()[2]
-        installed_out = subprocess.check_output(["@systemd@/bin/bootctl", "--esp-path=@efiSysMountPoint@", "status"], universal_newlines=True)
+        available_out = subprocess.check_output([f"{SYSTEMD}/bin/bootctl", "--version"], universal_newlines=True).split()[2]
+        installed_out = subprocess.check_output([f"{SYSTEMD}/bin/bootctl", f"--esp-path={EFI_SYS_MOUNT_POINT}", "status"], universal_newlines=True)
 
         # See status_binaries() in systemd bootctl.c for code which generates this
         installed_match = re.search(r"^\W+File:.*/EFI/(?:BOOT|systemd)/.*\.efi \(systemd-boot ([\d.]+[^)]*)\)$",
@@ -276,10 +289,10 @@ def install_bootloader(args: argparse.Namespace) -> None:
 
         if installed_version < available_version:
             print("updating systemd-boot from %s to %s" % (installed_version, available_version))
-            subprocess.check_call(["@systemd@/bin/bootctl", "--esp-path=@efiSysMountPoint@"] + bootctl_flags + ["update"])
+            subprocess.check_call([f"{SYSTEMD}/bin/bootctl", f"--esp-path={EFI_SYS_MOUNT_POINT}"] + bootctl_flags + ["update"])
 
-    os.makedirs("@efiSysMountPoint@/efi/nixos", exist_ok=True)
-    os.makedirs("@efiSysMountPoint@/loader/entries", exist_ok=True)
+    os.makedirs(f"{EFI_SYS_MOUNT_POINT}/efi/nixos", exist_ok=True)
+    os.makedirs(f"{EFI_SYS_MOUNT_POINT}/loader/entries", exist_ok=True)
 
     gens = get_generations()
     for profile in get_profiles():
@@ -302,9 +315,9 @@ def install_bootloader(args: argparse.Namespace) -> None:
             else:
                 raise e
 
-    for root, _, files in os.walk('@efiSysMountPoint@/efi/nixos/.extra-files', topdown=False):
-        relative_root = root.removeprefix("@efiSysMountPoint@/efi/nixos/.extra-files").removeprefix("/")
-        actual_root = os.path.join("@efiSysMountPoint@", relative_root)
+    for root, _, files in os.walk(f"{EFI_SYS_MOUNT_POINT}/efi/nixos/.extra-files", topdown=False):
+        relative_root = root.removeprefix(f"{EFI_SYS_MOUNT_POINT}/efi/nixos/.extra-files").removeprefix("/")
+        actual_root = os.path.join(f"{EFI_SYS_MOUNT_POINT}", relative_root)
 
         for file in files:
             actual_file = os.path.join(actual_root, file)
@@ -317,14 +330,14 @@ def install_bootloader(args: argparse.Namespace) -> None:
             os.rmdir(actual_root)
         os.rmdir(root)
 
-    os.makedirs("@efiSysMountPoint@/efi/nixos/.extra-files", exist_ok=True)
+    os.makedirs(f"{EFI_SYS_MOUNT_POINT}/efi/nixos/.extra-files", exist_ok=True)
 
-    subprocess.check_call("@copyExtraFiles@")
+    subprocess.check_call(COPY_EXTRA_FILES)
 
 
 def main() -> None:
-    parser = argparse.ArgumentParser(description='Update @distroName@-related systemd-boot files')
-    parser.add_argument('default_config', metavar='DEFAULT-CONFIG', help='The default @distroName@ config to boot')
+    parser = argparse.ArgumentParser(description=f"Update {DISTRO_NAME}-related systemd-boot files")
+    parser.add_argument('default_config', metavar='DEFAULT-CONFIG', help=f"The default {DISTRO_NAME} config to boot")
     args = parser.parse_args()
 
     try:
@@ -334,9 +347,9 @@ def main() -> None:
         # it can leave the system in an unbootable state, when a crash/outage
         # happens shortly after an update. To decrease the likelihood of this
         # event sync the efi filesystem after each update.
-        rc = libc.syncfs(os.open("@efiSysMountPoint@", os.O_RDONLY))
+        rc = libc.syncfs(os.open(f"{EFI_SYS_MOUNT_POINT}", os.O_RDONLY))
         if rc != 0:
-            print("could not sync @efiSysMountPoint@: {}".format(os.strerror(rc)), file=sys.stderr)
+            print(f"could not sync {EFI_SYS_MOUNT_POINT}: {os.strerror(rc)}", file=sys.stderr)
 
 
 if __name__ == '__main__':