stages(kickstart): implement "reboot" option

This commit implements the `reboot` option for kickstart files.

Note that there are two ways this can be enabled via the json.
Either via a boolean or by passing a dict with options.
```
{"reboot": true}
{"reboot": {"eject": true, "kexec": true}
```

Note that passing the empty dict as in:
```
{"reboot": {}}
```
will *not* write out a reboot line and the code also changes
"clearpart" have have the same behavior to be consistent.

I can see arguments that passing the empty dict should still
enable `reboot` without options. Happy to change it if someone
has strong(er) opinions.

stages/org.osbuild.kickstart

@@ -170,6 +170,26 @@ SCHEMA = r"""
         "type": "boolean"
       }
     }
+  },
+  "reboot": {
+    "description": "Reboot after the installation is successfully completed",
+    "oneOf": [
+    {
+      "type": "boolean"
+    }, {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "eject": {
+          "description": "Attempt to eject the installation media before rebooting",
+          "type": "boolean"
+        },
+        "kexec": {
+          "description": "Use this option to reboot into the new system using the kexec",
+          "type": "boolean"
+        }
+      }
+    }]
   }
 }
 """
@@ -238,7 +258,7 @@ def make_users(users: Dict) -> List[str]:
 
 def make_clearpart(options: Dict) -> str:
     clearpart = options.get("clearpart")
-    if clearpart is None:
+    if not clearpart:
         return ""
     cmd = "clearpart"
     al = clearpart.get("all", False)
@@ -259,6 +279,19 @@ def make_clearpart(options: Dict) -> str:
     return cmd
 
 
+def make_reboot(options):
+    reboot = options.get("reboot", None)
+    if not reboot:
+        return ""
+    cmd = "reboot"
+    if isinstance(reboot, dict):
+        if reboot.get("eject"):
+            cmd += " --eject"
+        if reboot.get("kexec"):
+            cmd += " --kexec"
+    return cmd
+
+
 def main(tree, options):
     path = options["path"].lstrip("/")
     ostree = options.get("ostree")
@@ -302,6 +335,10 @@ def main(tree, options):
     if clearpart:
         config += [clearpart]
 
+    reboot = make_reboot(options)
+    if reboot:
+        config += [reboot]
+
     target = os.path.join(tree, path)
     base = os.path.dirname(target)
     os.makedirs(base, exist_ok=True)

stages/test/test_kickstart.py

@@ -55,7 +55,8 @@
      'sshkey --username someusr "ssh-rsa not-really-a-real-key"'
      ),
     ({"zerombr": "true"}, "zerombr"),
-    ({"clearpart": {}}, "clearpart"),
+    # no clearpart for an empty dict (will not do anything with options anyway)
+    ({"clearpart": {}}, ""),
     ({"clearpart": {"all": True}}, "clearpart --all"),
     ({"clearpart": {"drives": ["hda", "hdb"]}}, "clearpart --drives=hda,hdb",),
     ({"clearpart": {"drives": ["hda"]}}, "clearpart --drives=hda"),
@@ -88,6 +89,14 @@
       },
         "lang en_US.UTF-8\nkeyboard us\ntimezone UTC\nzerombr\nclearpart --all --drives=sd*|hd*|vda,/dev/vdc",
      ),
+    # no reboot for an empty dict
+    ({"reboot": {}}, ""),
+    ({"reboot": True}, "reboot"),
+    ({"reboot": {"eject": False}}, "reboot"),
+    ({"reboot": {"eject": True}}, "reboot --eject"),
+    ({"reboot": {"kexec": False}}, "reboot"),
+    ({"reboot": {"kexec": True}}, "reboot --kexec"),
+    ({"reboot": {"eject": True, "kexec": True}}, "reboot --eject --kexec"),
 ])
 def test_kickstart(tmp_path, test_input, expected):
     ks_stage_path = os.path.join(os.path.dirname(__file__), "../org.osbuild.kickstart")
@@ -105,7 +114,8 @@ def test_kickstart(tmp_path, test_input, expected):
     assert ks_content == expected + "\n"
 
     # double check with pykickstart if the file looks valid
-    subprocess.check_call(["ksvalidator", ks_path])
+    if expected:
+        subprocess.check_call(["ksvalidator", ks_path])
 
 
 @pytest.mark.parametrize("test_data,expected_err", [
@@ -118,10 +128,14 @@ def test_kickstart(tmp_path, test_input, expected):
     ({"clearpart": {"list": ["\n%pre not allowed"]}}, "not allowed' does not match"),
     ({"clearpart": {"list": ["no,comma"]}}, "no,comma' does not match"),
     ({"clearpart": {"disklabel": "\n%pre not allowed"}}, "not allowed' does not match"),
+    ({"reboot": "random-string"}, "'random-string' is not valid "),
+    ({"reboot": {"random": "option"}}, "{'random': 'option'} is not valid "),
     # GOOD pattern we want to keep working
     ({"clearpart": {"drives": ["sd*|hd*|vda", "/dev/vdc"]}}, ""),
     ({"clearpart": {"drives": ["disk/by-id/scsi-58095BEC5510947BE8C0360F604351918"]}}, ""),
     ({"clearpart": {"list": ["sda2", "sda3", "sdb1"]}}, ""),
+    ({"reboot": True}, ""),
+    ({"reboot": {"kexec": False}}, ""),
 ])
 def test_schema_validation_smoke(test_data, expected_err):
     name = "org.osbuild.kickstart"