Run apply/rollback in background via systemd-run and add CLI modes

pikit-api.py

@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-import json, os, subprocess, socket, shutil, pathlib, datetime, tarfile
+import json, os, subprocess, socket, shutil, pathlib, datetime, tarfile, sys, argparse
 from http.server import BaseHTTPRequestHandler, HTTPServer
 import re
 import urllib.request
@@ -741,6 +741,28 @@ def rollback_update_stub():
     return state
 
 
+def start_background_task(mode: str):
+    """
+    Kick off a background update/rollback via systemd-run so nginx/API restarts
+    do not break the caller connection.
+    mode: "apply" or "rollback"
+    """
+    assert mode in ("apply", "rollback"), "invalid mode"
+    unit = f"pikit-update-{mode}"
+    flag = f"--{mode}-update"
+    cmd = [
+        "systemd-run",
+        "--unit",
+        unit,
+        "--quiet",
+        "/usr/bin/env",
+        "python3",
+        str(API_PATH),
+        flag,
+    ]
+    subprocess.run(cmd, check=False)
+
+
 def acquire_lock():
     try:
         ensure_dir(UPDATE_LOCK.parent)
@@ -899,11 +921,20 @@ class Handler(BaseHTTPRequestHandler):
             state = check_for_update()
             return self._send(200, state)
         if self.path.startswith("/api/update/apply"):
-            state = apply_update_stub()
-            return self._send(200, state)
+            # Start background apply to avoid breaking caller during service restart
+            start_background_task("apply")
+            state = load_update_state()
+            state["status"] = "in_progress"
+            state["message"] = "Starting background apply"
+            save_update_state(state)
+            return self._send(202, state)
         if self.path.startswith("/api/update/rollback"):
-            state = rollback_update_stub()
-            return self._send(200, state)
+            start_background_task("rollback")
+            state = load_update_state()
+            state["status"] = "in_progress"
+            state["message"] = "Starting rollback"
+            save_update_state(state)
+            return self._send(202, state)
         if self.path.startswith("/api/update/auto"):
             state = load_update_state()
             state["auto_check"] = bool(payload.get("enable"))
@@ -1043,4 +1074,20 @@ def main():
 
 
 if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description="Pi-Kit API / updater")
+    parser.add_argument("--apply-update", action="store_true", help="Apply latest release (non-HTTP mode)")
+    parser.add_argument("--check-update", action="store_true", help="Check for latest release (non-HTTP mode)")
+    parser.add_argument("--rollback-update", action="store_true", help="Rollback to last backup (non-HTTP mode)")
+    args = parser.parse_args()
+
+    if args.apply_update:
+        apply_update_stub()
+        sys.exit(0)
+    if args.check_update:
+        check_for_update()
+        sys.exit(0)
+    if args.rollback_update:
+        rollback_update_stub()
+        sys.exit(0)
+
     main()