systemd: container/remote restart, permanent-error backoff, recursive section via loader (step 6)

plugin/src/systemd_service.rs

@@ -60,7 +60,13 @@ pub mod qobject {
 
         #[qinvokable]
         #[cxx_name = "restartUnit"]
-        fn restart_unit(self: Pin<&mut Self>, name: QString, scope: QString, machine: QString);
+        fn restart_unit(
+            self: Pin<&mut Self>,
+            name: QString,
+            scope: QString,
+            host: QString,
+            machine: QString,
+        );
     }
 
     impl cxx_qt::Initialize for SystemdService {}
@@ -527,13 +533,14 @@ impl qobject::SystemdService {
         let applet_open = self.as_ref().rust().applet_open;
         if applet_open {
             for target in &want_targets {
-                let prev_last_seen = self
+                let prev = self.as_ref().rust().remote_cache.get(target).cloned();
-                    .as_ref()
+                let prev_last_seen = prev.as_ref().map(|m| m.last_seen).unwrap_or(0);
-                    .rust()
+                // Backoff: don't retry hosts with a permanent error until
-                    .remote_cache
+                // either the config changes (cache cleared) or the user
-                    .get(target)
+                // restarts the shell. Reuse the cached entry verbatim.
-                    .map(|m| m.last_seen)
+                if prev.as_ref().is_some_and(|m| m.error_kind == "permanent") {
-                    .unwrap_or(0);
+                    continue;
+                }
                 let entry = match fetch_via_busctl(target, &["--host", target], false, "") {
                     Ok(mut m) => {
                         // Enumerate + fetch remote nspawn containers via the
@@ -599,28 +606,70 @@ impl qobject::SystemdService {
         }
     }
 
-    fn restart_unit(self: Pin<&mut Self>, name: QString, scope: QString, machine: QString) {
+    fn restart_unit(
+        self: Pin<&mut Self>,
+        name: QString,
+        scope: QString,
+        host: QString,
+        machine: QString,
+    ) {
         let name = name.to_string();
         let scope = scope.to_string();
+        let host = host.to_string();
         let machine = machine.to_string();
         let _ = self;
-        rt().block_on(async move {
+
-            // Local-only restart for now. Container/remote restart is TODO.
+        // Local + system or user scope: native zbus, supports user manager too.
-            if !machine.is_empty() {
+        if host.is_empty() && machine.is_empty() {
-                tracing::warn!(target: "nova_plugin", machine = %machine, "container/remote restart not yet implemented");
+            rt().block_on(async move {
-                return;
+                let conn = match scope.as_str() {
+                    "user" => Connection::session().await,
+                    _ => Connection::system().await,
+                };
+                let Ok(conn) = conn else { return };
+                let Ok(mgr) = SystemdManagerProxy::new(&conn).await else {
+                    return;
+                };
+                if let Err(e) = mgr.restart_unit(&name, "replace").await {
+                    tracing::warn!(target: "nova_plugin", unit = %name, error = %e, "restart_unit failed");
+                }
+            });
+            return;
+        }
+
+        // Container or remote: spawn busctl with the matching prefix flags.
+        // (busctl doesn't have a concept of `--user` over remote; we restart
+        // system units only for non-local hosts.)
+        let mut prefix: Vec<String> = Vec::new();
+        if !host.is_empty() {
+            prefix.push("--host".into());
+            prefix.push(host.clone());
+        }
+        if !machine.is_empty() {
+            prefix.push("--machine".into());
+            prefix.push(machine.clone());
+        }
+        let mut args: Vec<&str> = prefix.iter().map(String::as_str).collect();
+        args.extend([
+            "call",
+            "org.freedesktop.systemd1",
+            "/org/freedesktop/systemd1",
+            "org.freedesktop.systemd1.Manager",
+            "RestartUnit",
+            "ss",
+            name.as_str(),
+            "replace",
+        ]);
+        let out = std::process::Command::new("busctl").args(&args).output();
+        match out {
+            Ok(o) if o.status.success() => {}
+            Ok(o) => {
+                let stderr = String::from_utf8_lossy(&o.stderr);
+                tracing::warn!(target: "nova_plugin", unit = %name, host = %host, machine = %machine, error = %stderr, "restart_unit busctl failed");
             }
-            let conn = match scope.as_str() {
+            Err(e) => {
-                "user" => Connection::session().await,
+                tracing::warn!(target: "nova_plugin", unit = %name, error = %e, "restart_unit busctl spawn failed");
-                _ => Connection::system().await,
-            };
-            let Ok(conn) = conn else { return };
-            let Ok(mgr) = SystemdManagerProxy::new(&conn).await else {
-                return;
-            };
-            if let Err(e) = mgr.restart_unit(&name, "replace").await {
-                tracing::warn!(target: "nova_plugin", unit = %name, error = %e, "restart_unit failed");
             }
-        });
+        }
     }
 }

shell/applets/SystemdApplet.qml

@@ -32,7 +32,8 @@ Column {
             SystemdMachineSection {
                 width: _row.width
                 accentColor: root.accentColor
-                machineName: _row.modelData.isLocal ? "" : _row.modelData.name
+                hostTarget: _row.modelData.isLocal ? "" : _row.modelData.name
+                machineName: ""
                 title: _row.modelData.name
                 marker: _row.modelData.marker ?? ""
                 systemState: _row.modelData.systemState ?? "unknown"

shell/applets/SystemdMachineSection.qml

@@ -10,15 +10,17 @@ import NovaStats as NS
 Column {
     id: root
 
-    required property color accentColor
+    property color accentColor
-    required property string machineName
+    // SSH target string (for remote hosts/their containers); "" for local-side entries.
-    required property string title
+    property string hostTarget: ""
-    required property string marker
+    property string machineName: ""
-    required property string systemState
+    property string title: ""
-    required property int runningCount
+    property string marker: ""
-    required property int totalCount
+    property string systemState: "unknown"
-    required property var failedUnits
+    property int runningCount: 0
-    required property var runningUnits
+    property int totalCount: 0
+    property var failedUnits: []
+    property var runningUnits: []
     property string errorKind: ""
     property string errorReason: ""
     property int lastSeen: 0
@@ -169,6 +171,7 @@ Column {
             description: modelData.description ?? ""
             subState: modelData.subState ?? ""
             scope: modelData.scope ?? "system"
+            hostTarget: root.hostTarget
             machineName: root.machineName
             accentColor: root.accentColor
         }
@@ -229,40 +232,47 @@ Column {
             description: modelData.description ?? ""
             subState: modelData.subState ?? ""
             scope: modelData.scope ?? "system"
+            hostTarget: root.hostTarget
             machineName: root.machineName
             accentColor: root.accentColor
         }
     }
 
     // Nested containers running on this machine. Indented to convey hierarchy.
+    // QML disallows direct recursive component use, so we load the same .qml
+    // by source path through a Loader to break the static graph.
     Repeater {
         model: root.containers ?? []
         delegate: Item {
             id: _childWrap
             required property var modelData
             width: root.width
-            height: _child.height + 4
+            height: _childLoader.height + 4
 
-            SystemdMachineSection {
+            Loader {
-                id: _child
+                id: _childLoader
                 anchors.left: parent.left
                 anchors.leftMargin: 16
                 width: parent.width - 16
-                accentColor: root.accentColor
+                source: "SystemdMachineSection.qml"
-                machineName: _childWrap.modelData.name
+                onLoaded: {
-                title: _childWrap.modelData.name
+                    item.accentColor = root.accentColor;
-                marker: _childWrap.modelData.marker ?? ""
+                    item.hostTarget = root.hostTarget;
-                systemState: _childWrap.modelData.systemState ?? "unknown"
+                    item.machineName = _childWrap.modelData.name;
-                runningCount: _childWrap.modelData.runningCount ?? 0
+                    item.title = _childWrap.modelData.name;
-                totalCount: _childWrap.modelData.totalCount ?? 0
+                    item.marker = _childWrap.modelData.marker ?? "";
-                failedUnits: _childWrap.modelData.failedUnits ?? []
+                    item.systemState = _childWrap.modelData.systemState ?? "unknown";
-                runningUnits: _childWrap.modelData.runningUnits ?? []
+                    item.runningCount = _childWrap.modelData.runningCount ?? 0;
-                errorKind: _childWrap.modelData.errorKind ?? ""
+                    item.totalCount = _childWrap.modelData.totalCount ?? 0;
-                errorReason: _childWrap.modelData.errorReason ?? ""
+                    item.failedUnits = _childWrap.modelData.failedUnits ?? [];
-                lastSeen: _childWrap.modelData.lastSeen ?? 0
+                    item.runningUnits = _childWrap.modelData.runningUnits ?? [];
-                containers: _childWrap.modelData.containers ?? []
+                    item.errorKind = _childWrap.modelData.errorKind ?? "";
-                depth: root.depth + 1
+                    item.errorReason = _childWrap.modelData.errorReason ?? "";
-                onContentResized: root.contentResized()
+                    item.lastSeen = _childWrap.modelData.lastSeen ?? 0;
+                    item.containers = _childWrap.modelData.containers ?? [];
+                    item.depth = root.depth + 1;
+                    item.contentResized.connect(root.contentResized);
+                }
             }
         }
     }

shell/applets/SystemdUnitRow.qml

@@ -9,6 +9,7 @@ Item {
     required property string description
     required property string subState
     required property string scope
+    required property string hostTarget
     required property string machineName
     required property color accentColor
 
@@ -96,7 +97,7 @@ Item {
         }
         TapHandler {
             enabled: _rowHover.hovered
-            onTapped: S.SystemdService.restartUnit(root.unitName, root.scope, root.machineName)
+            onTapped: S.SystemdService.restartUnit(root.unitName, root.scope, root.hostTarget, root.machineName)
         }
     }
 }

shell/services/SystemdService.qml

@@ -21,8 +21,8 @@ QtObject {
         }
     }
 
-    function restartUnit(name, scope, machine) {
+    function restartUnit(name, scope, host, machine) {
-        NS.SystemdService.restartUnit(name, scope ?? "system", machine ?? "");
+        NS.SystemdService.restartUnit(name, scope ?? "system", host ?? "", machine ?? "");
     }
 
     function refresh() {

test/qmllint-baseline.txt

@@ -70,6 +70,7 @@ shell/applets/PowerApplet.qml: Type "QColor" of property "base0D" not found. Thi
 shell/applets/PowerApplet.qml: Type "QColor" of property "base0E" not found. This is likely due to a missing dependency entry or a type not being exposed declaratively. [unresolved-type]
 shell/applets/PowerApplet.qml: Unqualified access [unqualified]
 shell/applets/Separator.qml: Type "QColor" of property "base03" not found. This is likely due to a missing dependency entry or a type not being exposed declaratively. [unresolved-type]
+shell/applets/SystemdMachineSection.qml: Member "contentResized" not found on type "QObject" [missing-property]
 shell/applets/SystemdMachineSection.qml: Type "QColor" of property "base00" not found. This is likely due to a missing dependency entry or a type not being exposed declaratively. [unresolved-type]
 shell/applets/SystemdMachineSection.qml: Type "QColor" of property "base02" not found. This is likely due to a missing dependency entry or a type not being exposed declaratively. [unresolved-type]
 shell/applets/SystemdMachineSection.qml: Type "QColor" of property "base03" not found. This is likely due to a missing dependency entry or a type not being exposed declaratively. [unresolved-type]