perf: speed up Hub service status loading

app/sovran_systemsos_web/systemctl.py

@@ -18,6 +18,45 @@ def is_active(unit: str, scope: Literal["system", "user"] = "system") -> str:
     return _run(["systemctl", f"--{scope}", "is-active", unit]) or "unknown"
 
 
+def active_states(units_by_scope: dict[str, list[str]], timeout: float = 5) -> dict[tuple[str, str], str]:
+    """Return active states for many units with one systemctl call per scope.
+
+    The dashboard polls service state frequently. Spawning one ``systemctl``
+    process per tile makes a slow or unavailable system bus multiply the delay
+    (and can make the first dashboard render wait through many timeouts).  The
+    ``is-active`` command accepts multiple units, so batch them and cap the
+    whole batch at a single timeout.
+    """
+    states: dict[tuple[str, str], str] = {}
+    valid_scopes = {"system", "user"}
+
+    for scope, units in units_by_scope.items():
+        unique_units = list(dict.fromkeys(unit for unit in units if unit))
+        if not unique_units:
+            continue
+        if scope not in valid_scopes:
+            for unit in unique_units:
+                states[(scope, unit)] = "unknown"
+            continue
+
+        try:
+            result = subprocess.run(
+                ["systemctl", f"--{scope}", "is-active", "--", *unique_units],
+                capture_output=True,
+                text=True,
+                timeout=timeout,
+            )
+            lines = result.stdout.splitlines()
+            for index, unit in enumerate(unique_units):
+                state = lines[index].strip() if index < len(lines) else ""
+                states[(scope, unit)] = state or "unknown"
+        except Exception:
+            for unit in unique_units:
+                states[(scope, unit)] = "unknown"
+
+    return states
+
+
 def is_enabled(unit: str, scope: Literal["system", "user"] = "system") -> str:
     return _run(["systemctl", f"--{scope}", "is-enabled", unit]) or "unknown"