mkosi-initrd: add --show-summary/-S

This is quite useful to figure out what configuration is used.

(I considered adding an option to allow arbitrary mkosi verbs.
But most verbs either don't make sense or don't work. E.g. 'shell'
could be potentially useful but it doesn't support cpio atm. So
limiting this to 'summary' for now seems OK. Having an easy way
to show the config will be useful even if we add a more generic
hookup into mkosi later.)

Author: keszybz

mkosi/addon.py

@@ -74,9 +74,13 @@ def main() -> None:
         if Path("/etc/kernel/cmdline").exists():
             cmdline += ["--kernel-command-line", Path("/etc/kernel/cmdline").read_text()]
 
+        if args.show_summary:
+            cmdline += ["summary"]
+
         run(cmdline, stdin=sys.stdin, stdout=sys.stdout)
 
-        initrd_finalize(Path(staging_dir), args.output, args.output_dir)
+        if not args.show_summary:
+            initrd_finalize(Path(staging_dir), args.output, args.output_dir)
 
 
 if __name__ == "__main__":

mkosi/initrd.py

@@ -293,6 +293,13 @@ def initrd_common_args(parser: argparse.ArgumentParser) -> None:
         action="store_true",
         default=False,
     )
+    parser.add_argument(
+        "-S",
+        "--show-summary",
+        help="Show the summary of configuration",
+        action="store_true",
+        default=False,
+    )
     parser.add_argument(
         "--version",
         action="version",
@@ -428,6 +435,9 @@ def main() -> None:
 
         cmdline += vconsole_config()
 
+        if args.show_summary:
+            cmdline += ["summary"]
+
         # Resolve dnf binary to determine which version the host uses by default
         # (to avoid preferring dnf5 if the host uses dnf4)
         # as there's a much bigger chance that it has a populated dnf cache directory.
@@ -438,7 +448,8 @@ def main() -> None:
             env=os.environ | ({"MKOSI_DNF": dnf.resolve().name} if (dnf := find_binary("dnf")) else {}),
         )
 
-        initrd_finalize(Path(staging_dir), args.output, args.output_dir)
+        if not args.show_summary:
+            initrd_finalize(Path(staging_dir), args.output, args.output_dir)
 
 
 if __name__ == "__main__":

mkosi/resources/man/mkosi-initrd.1.md

@@ -65,6 +65,9 @@ initrds and Unified Kernel Images for the current running system.
 `--show-documentation`, `-D`
 :   Show the man page for mkosi-initrd.
 
+`--show-summary`, `-S`
+:   Show the summary of configuration.
+
 `--version`
 :   Show package version.