fixes and improvements

backend/src/media_library_viewer_api/routers/dashboard.py

@@ -44,7 +44,32 @@ def get_monitoring_overview(
 ) -> dict[str, Any]:
     """Return one lightweight monitoring row per configured machine."""
     machines = store.list_machines()
-    rows = [collect_machine_overview(machine, store) for machine in machines]
+    rows: list[dict[str, Any]] = []
+    for machine in machines:
+        try:
+            rows.append(collect_machine_overview(machine, store))
+        except Exception as exc:
+            logger.exception(
+                "Dashboard monitoring overview failed for machine_id=%s",
+                machine.get("id"),
+            )
+            rows.append({
+                "machine": {k: machine.get(k) for k in ("id", "name", "mode", "enabled", "host", "port", "username", "media_root", "path_prefix", "notes")},
+                "status": "",
+                "status_error": str(exc),
+                "metrics_error": str(exc),
+                "disk_error": str(exc),
+                "sample_count": 0,
+                "latest_sample": None,
+                "cpu_summary": None,
+                "iowait_summary": None,
+                "mem_summary": None,
+                "net_rx_summary": None,
+                "net_tx_summary": None,
+                "disk_read_summary": None,
+                "disk_write_summary": None,
+                "disk": None,
+            })
     poller = get_monitoring_poller().snapshot()
     enabled_count = sum(1 for machine in machines if machine.get("enabled"))
     logger.info("Dashboard monitoring machines=%s enabled=%s", len(machines), enabled_count)

frontend/src/components/MonitoringOverviewTable.tsx

@@ -11,6 +11,7 @@ import {
 	TableHead,
 	TableRow,
 	TableSortLabel,
+	Tooltip,
 	Typography,
 } from "@mui/material";
 import type {
@@ -102,6 +103,19 @@ function sortableText(value: string) {
 	return value.toLowerCase();
 }
 
+function getStatusChipProps(row: MonitoringMachineOverview) {
+	if (row.status_error) {
+		return { color: "error" as const, label: row.status_error };
+	}
+	if (row.status === "running") {
+		return { color: "success" as const, label: "running" };
+	}
+	if (row.status === "not running") {
+		return { color: "warning" as const, label: "not running" };
+	}
+	return { color: "default" as const, label: row.status || "-" };
+}
+
 function metricSortValue(
 	row: MonitoringMachineOverview,
 	key: SortKey,
@@ -136,6 +150,34 @@ function metricSortValue(
 	}
 }
 
+function NoDataCell() {
+	return (
+		<Stack
+			sx={{
+				width: "100%",
+				minWidth: 0,
+				height: "100%",
+				minHeight: 118,
+				textAlign: "center",
+				justifyContent: "center",
+				py: 0.5,
+			}}
+		>
+			<Typography
+				variant="caption"
+				color="text.secondary"
+				sx={{
+					fontSize: "0.7rem",
+					fontStyle: "italic",
+					lineHeight: 1.2,
+				}}
+			>
+				No data
+			</Typography>
+		</Stack>
+	);
+}
+
 function MetricCell({
 	value,
 	min,
@@ -441,7 +483,7 @@ export function MonitoringOverviewTable({
 						) : (
 							sortedRows.map((row) => {
 								const machine = row.machine;
-								const status = row.status || row.status_error || "-";
+								const hasMetrics = row.sample_count > 0;
 								const cpu = formatSummary(
 									row.cpu_summary,
 									(value) => `${value.toFixed(1)}%`,
@@ -524,62 +566,106 @@ export function MonitoringOverviewTable({
 											</Stack>
 										</TableCell>
 										<TableCell sx={{ width: 90 }}>{machine.mode}</TableCell>
-										<TableCell sx={{ width: 120 }}>
+							<TableCell sx={{ width: 120 }}>
+								{(() => {
+									const chip = getStatusChipProps(row);
+									return (
+										<Tooltip
+											title={
+												row.metrics_error
+													? `Metrics: ${row.metrics_error}`
+													: row.sample_count === 0
+														? "No metrics collected yet. Start the collector to begin monitoring."
+														: ""
+											}
+											arrow
+										>
 											<Chip
 												size="small"
 												variant="outlined"
-												color={row.status_error ? "error" : "success"}
+												color={chip.color}
-												label={status}
+												label={chip.label}
 											/>
+										</Tooltip>
+									);
+								})()}
+							</TableCell>
+										<TableCell align="center">
+											{hasMetrics ? (
+												<MetricCell
+													value={cpu.value}
+													min={cpu.min}
+													max={cpu.max}
+												/>
+											) : (
+												<NoDataCell />
+											)}
 										</TableCell>
 										<TableCell align="center">
-											<MetricCell
+											{hasMetrics ? (
-												value={cpu.value}
+												<MetricCell
-												min={cpu.min}
+													value={iowait.value}
-												max={cpu.max}
+													min={iowait.min}
-											/>
+													max={iowait.max}
+												/>
+											) : (
+												<NoDataCell />
+											)}
 										</TableCell>
 										<TableCell align="center">
-											<MetricCell
+											{hasMetrics ? (
-												value={iowait.value}
+												<MetricCell
-												min={iowait.min}
+													value={mem.value}
-												max={iowait.max}
+													min={mem.min}
-											/>
+													max={mem.max}
+												/>
+											) : (
+												<NoDataCell />
+											)}
 										</TableCell>
 										<TableCell align="center">
-											<MetricCell
+											{hasMetrics ? (
-												value={mem.value}
+												<MetricCell
-												min={mem.min}
+													value={netDown.value}
-												max={mem.max}
+													min={netDown.min}
-											/>
+													max={netDown.max}
+												/>
+											) : (
+												<NoDataCell />
+											)}
 										</TableCell>
 										<TableCell align="center">
-											<MetricCell
+											{hasMetrics ? (
-												value={netDown.value}
+												<MetricCell
-												min={netDown.min}
+													value={netUp.value}
-												max={netDown.max}
+													min={netUp.min}
-											/>
+													max={netUp.max}
+												/>
+											) : (
+												<NoDataCell />
+											)}
 										</TableCell>
 										<TableCell align="center">
-											<MetricCell
+											{hasMetrics ? (
-												value={netUp.value}
+												<MetricCell
-												min={netUp.min}
+													value={diskRead.value}
-												max={netUp.max}
+													min={diskRead.min}
-											/>
+													max={diskRead.max}
+												/>
+											) : (
+												<NoDataCell />
+											)}
 										</TableCell>
 										<TableCell align="center">
-											<MetricCell
+											{hasMetrics ? (
-												value={diskRead.value}
+												<MetricCell
-												min={diskRead.min}
+													value={diskWrite.value}
-												max={diskRead.max}
+													min={diskWrite.min}
-											/>
+													max={diskWrite.max}
-										</TableCell>
+												/>
-										<TableCell align="center">
+											) : (
-											<MetricCell
+												<NoDataCell />
-												value={diskWrite.value}
+											)}
-												min={diskWrite.min}
-												max={diskWrite.max}
-											/>
 										</TableCell>
 										<TableCell align="center">
 											{disk ? (
@@ -588,22 +674,34 @@ export function MonitoringOverviewTable({
 													min={disk.min}
 													max={disk.max}
 												/>
-											) : (
+											) : hasMetrics ? (
 												"-"
+											) : (
+												<NoDataCell />
 											)}
 										</TableCell>
 										<TableCell sx={{ width: 180 }}>
 											<Stack spacing={0.1} sx={{ alignItems: "center" }}>
-												{updated.map((line) => (
+												{hasMetrics ? (
+													updated.map((line) => (
+														<Typography
+															key={line}
+															variant="caption"
+															color="text.secondary"
+															sx={{ lineHeight: 1.1 }}
+														>
+															{line}
+														</Typography>
+													))
+												) : (
 													<Typography
-														key={line}
 														variant="caption"
 														color="text.secondary"
-														sx={{ lineHeight: 1.1 }}
+														sx={{ lineHeight: 1.1, fontStyle: "italic" }}
 													>
-														{line}
+														No data yet
 													</Typography>
-												))}
+												)}
 											</Stack>
 										</TableCell>
 									</TableRow>