Cost-feature followups: libgssapi fix, daily CA, dashboard cost

Three small polish items on top of the cost-compute feature.

(A) Dockerfile: install libgssapi-krb5-2 in the runtime stage.
Silences the "Cannot load library libgssapi_krb5.so.2" warning that
Npgsql logs when probing for Kerberos auth on Linux. We don't actually
use Kerberos; the lib is ~3 MB and removes confusing log noise.

(B) FleetTimescaleBootstrapper: add hierarchical fleet.daily_per_customer
continuous aggregate on top of fleet.hourly_per_device. Per-customer
daily totals (samples, kwh imported/exported, avg/max/min kW).
Realtime, materialized_only=false, 365-day start_offset, hourly refresh.
Available for long-range dashboards / billing summaries that don't need
device-level or hourly detail. Not yet consumed by any query — exists
as a primitive for the next dashboard / report that wants it.

(C) Fleet dashboard: include per-customer cost today.
- FleetQueryService.GetDashboardAsync invokes FleetCostService.ComputeAsync
  per customer for today's UTC window. Failures for one customer don't
  break the dashboard (leave their CostToday null and continue).
- FleetCustomerSummary gains nullable CostToday; FleetDashboardDto
  gains TotalCostToday (sum across customers).
- AdminFleetDashboardPage adds a 5th Statistic card "Cost today" in
  green, and a "Today (cost)" column in the customer summary table.
- Perf note added in service comment: per-load cost compute scales
  with N customers; revisit with a materialised daily_cost view when
  N grows beyond ~100.

Verified on the running stack
- Admin container logs no longer contain "libgssapi" anywhere.
- timescaledb_information.continuous_aggregates shows both
  hourly_per_device and daily_per_customer.
- /api/fleet/dashboard returns totalCostToday=161.00, the single
  customer (DEV0001) row shows costToday=161.00 matching the
  cost endpoint's total for the same UTC day.

Deliberately not in this commit: per-customer Postgres RLS for
multi-Admin-user setups. That needs design decisions (claim source,
fleet-admin bypass model, connection-pooling interaction with session
variables) — I'd rather pose those questions and ship it right than
sneak in a half-baked version. Wrap-up message has the design qs.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

portal/Dockerfile

@@ -15,6 +15,14 @@ RUN dotnet publish Tau.Acuvim.Portal/Tau.Acuvim.Portal.csproj \
 
 FROM mcr.microsoft.com/dotnet/aspnet:10.0 AS runtime
 WORKDIR /app
+
+# Npgsql probes for Kerberos auth on Linux and logs a noisy "Cannot load library
+# libgssapi_krb5.so.2" error if missing. Installing the lib silences the warning;
+# we don't actually use Kerberos auth.
+RUN apt-get update \
+ && apt-get install -y --no-install-recommends libgssapi-krb5-2 \
+ && rm -rf /var/lib/apt/lists/*
+
 COPY --from=build /app/publish .
 COPY --from=frontend /app/frontend/dist ./wwwroot/
 

portal/frontend/src/api/fleet.ts

@@ -10,6 +10,7 @@ export interface FleetCustomerSummary {
   devices: number;
   measurementsToday: number;
   kwhImportedToday: number | null;
+  costToday: number | null;
 }
 
 export interface FleetDashboard {
@@ -17,6 +18,7 @@ export interface FleetDashboard {
   activeCustomers: number;
   totalMeasurementsToday: number;
   totalKwhImportedToday: number;
+  totalCostToday: number;
   oldestActiveLastSeenAt: string | null;
   customers: FleetCustomerSummary[];
 }

portal/frontend/src/pages/AdminFleetDashboardPage.tsx

@@ -1,6 +1,8 @@
 import { Card, Col, Row, Statistic, Table, Tag, Typography, Empty } from 'antd';
 import type { ColumnsType } from 'antd/es/table';
-import { ApartmentOutlined, ThunderboltOutlined, TeamOutlined, CheckCircleOutlined } from '@ant-design/icons';
+import {
+  ApartmentOutlined, ThunderboltOutlined, TeamOutlined, CheckCircleOutlined, DollarOutlined,
+} from '@ant-design/icons';
 import { useQuery } from '@tanstack/react-query';
 import { useNavigate } from 'react-router-dom';
 import { fetchFleetDashboard, type FleetCustomerSummary } from '../api/fleet';
@@ -36,17 +38,21 @@ export function AdminFleetDashboardPage() {
       title: 'Today (kWh imp.)', dataIndex: 'kwhImportedToday', key: 'kwh',
       render: (v: number | null) => v == null ? '—' : v.toFixed(2)
     },
+    {
+      title: 'Today (cost)', dataIndex: 'costToday', key: 'cost',
+      render: (v: number | null) => v == null ? <Text type="secondary">—</Text> : <Text strong>{v.toFixed(2)}</Text>
+    },
   ];
 
   return (
     <div>
       <Row gutter={16} style={{ marginBottom: 16 }}>
-        <Col span={6}>
+        <Col span={5}>
           <Card>
             <Statistic title="Customers" value={data?.totalCustomers ?? 0} prefix={<TeamOutlined />} loading={isLoading} />
           </Card>
         </Col>
-        <Col span={6}>
+        <Col span={5}>
           <Card>
             <Statistic
               title="Active (last hr)"
@@ -57,7 +63,7 @@ export function AdminFleetDashboardPage() {
             />
           </Card>
         </Col>
-        <Col span={6}>
+        <Col span={5}>
           <Card>
             <Statistic
               title="Measurements today"
@@ -67,10 +73,10 @@ export function AdminFleetDashboardPage() {
             />
           </Card>
         </Col>
-        <Col span={6}>
+        <Col span={4}>
           <Card>
             <Statistic
-              title="kWh imported today"
+              title="kWh today"
               value={data?.totalKwhImportedToday ?? 0}
               precision={2}
               prefix={<ThunderboltOutlined />}
@@ -78,6 +84,18 @@ export function AdminFleetDashboardPage() {
             />
           </Card>
         </Col>
+        <Col span={5}>
+          <Card>
+            <Statistic
+              title="Cost today"
+              value={data?.totalCostToday ?? 0}
+              precision={2}
+              prefix={<DollarOutlined />}
+              valueStyle={{ color: '#3f8600' }}
+              loading={isLoading}
+            />
+          </Card>
+        </Col>
       </Row>
 
       <Card title="Customers">

portal/src/Tau.Acuvim.Portal/DTOs/FleetDashboardDtos.cs

@@ -9,13 +9,15 @@ public sealed record FleetCustomerSummary(
     int Sites,
     int Devices,
     long MeasurementsToday,
-    double? KwhImportedToday);
+    double? KwhImportedToday,
+    decimal? CostToday);
 
 public sealed record FleetDashboardDto(
     int TotalCustomers,
     int ActiveCustomers,
     long TotalMeasurementsToday,
     double TotalKwhImportedToday,
+    decimal TotalCostToday,
     DateTime? OldestActiveLastSeenAt,
     IReadOnlyList<FleetCustomerSummary> Customers);
 

portal/src/Tau.Acuvim.Portal/Services/FleetQueryService.cs

@@ -5,7 +5,7 @@ using Tau.Acuvim.Portal.DTOs;
 
 namespace Tau.Acuvim.Portal.Services;
 
-public sealed class FleetQueryService(AdminDbContext db)
+public sealed class FleetQueryService(AdminDbContext db, FleetCostService costs)
 {
     private static readonly TimeSpan ActiveWindow = TimeSpan.FromHours(1);
 
@@ -14,6 +14,7 @@ public sealed class FleetQueryService(AdminDbContext db)
         var nowUtc = DateTime.UtcNow;
         var activeThreshold = nowUtc - ActiveWindow;
         var dayStart = DateTime.SpecifyKind(nowUtc.Date, DateTimeKind.Utc);
+        var dayEnd = dayStart.AddDays(1);
 
         var customers = await db.Customers.AsNoTracking()
             .OrderBy(c => c.Code)
@@ -32,12 +33,31 @@ public sealed class FleetQueryService(AdminDbContext db)
 
         var todayStats = await GetTodayStatsAsync(dayStart, ct);
 
+        // Per-customer cost for today. Computed once per dashboard load. For larger
+        // fleets this becomes the bottleneck — consider a materialised daily-cost view
+        // or caching layer when N customers grows beyond ~100.
+        var costToday = new Dictionary<Guid, decimal>();
+        foreach (var c in customers)
+        {
+            try
+            {
+                var r = await costs.ComputeAsync(c.Id, dayStart, dayEnd, ct);
+                if (r.TotalCost > 0) costToday[c.Id] = r.TotalCost;
+            }
+            catch (Exception)
+            {
+                // Cost compute failure for one customer shouldn't break the whole
+                // dashboard — leave their CostToday null and continue.
+            }
+        }
+
         var summaries = customers.Select(c => new FleetCustomerSummary(
             c.Id, c.Code, c.Name, c.IsActive, c.LastSeenAt,
             siteCounts.GetValueOrDefault(c.Id, 0),
             deviceCounts.GetValueOrDefault(c.Id, 0),
             todayStats.TryGetValue(c.Id, out var s) ? s.Measurements : 0,
-            todayStats.TryGetValue(c.Id, out s) ? s.KwhImported : null
+            todayStats.TryGetValue(c.Id, out s) ? s.KwhImported : null,
+            costToday.TryGetValue(c.Id, out var cost) ? cost : null
         )).ToList();
 
         var activeCount = customers.Count(c => c.LastSeenAt >= activeThreshold);
@@ -50,6 +70,7 @@ public sealed class FleetQueryService(AdminDbContext db)
             ActiveCustomers: activeCount,
             TotalMeasurementsToday: summaries.Sum(x => x.MeasurementsToday),
             TotalKwhImportedToday: summaries.Sum(x => x.KwhImportedToday ?? 0),
+            TotalCostToday: summaries.Sum(x => x.CostToday ?? 0m),
             OldestActiveLastSeenAt: oldestActive,
             Customers: summaries);
     }

portal/src/Tau.Acuvim.Portal/Services/FleetTimescaleBootstrapper.cs

@@ -80,6 +80,39 @@ public sealed class FleetTimescaleBootstrapper(
             );
             """, ct);
 
-        log.LogInformation("Fleet hypertable + compression + hourly_per_device CA ready.");
+        // Hierarchical CA: roll up the hourly per-device aggregate into a per-customer
+        // daily total. Cheap for long-range dashboards / billing summaries that don't
+        // need device-level or hourly detail. Hierarchical CAs (CA on CA) are supported
+        // in TimescaleDB 2.x. Realtime so back-fills appear without manual refresh.
+        await db.Database.ExecuteSqlRawAsync(
+            """
+            CREATE MATERIALIZED VIEW IF NOT EXISTS fleet.daily_per_customer
+            WITH (timescaledb.continuous, timescaledb.materialized_only = false) AS
+            SELECT
+                "CustomerId",
+                time_bucket(INTERVAL '1 day', bucket) AS day,
+                SUM(samples)                          AS samples,
+                SUM(COALESCE(kwh_imported_delta, 0))  AS kwh_imported_delta,
+                SUM(COALESCE(kwh_exported_delta, 0))  AS kwh_exported_delta,
+                AVG(avg_kw)                           AS avg_kw,
+                MAX(max_kw)                           AS max_kw,
+                MIN(min_kw)                           AS min_kw
+            FROM fleet.hourly_per_device
+            GROUP BY "CustomerId", day
+            WITH NO DATA;
+            """, ct);
+
+        await db.Database.ExecuteSqlRawAsync(
+            """
+            SELECT add_continuous_aggregate_policy(
+                'fleet.daily_per_customer',
+                start_offset => INTERVAL '365 days',
+                end_offset   => INTERVAL '1 day',
+                schedule_interval => INTERVAL '1 hour',
+                if_not_exists => TRUE
+            );
+            """, ct);
+
+        log.LogInformation("Fleet hypertable + compression + hourly_per_device + daily_per_customer CAs ready.");
     }
 }