feature: Schema, Migrations, Core CRUD, and Redis Threshold Cache

2026-06-16 17:59:16 +08:00
commit 882d4af3e6
63 changed files with 3923 additions and 0 deletions
@@ -0,0 +1,48 @@
+using System.Text.Json;
+using Microsoft.EntityFrameworkCore;
+using StackExchange.Redis;
+
+public class ThresholdCacheLoader : IHostedService
+{
+    private readonly IServiceProvider _services;
+    private readonly IConnectionMultiplexer _redis;
+    private readonly ILogger<ThresholdCacheLoader> _logger;
+
+    public ThresholdCacheLoader(
+        IServiceProvider services,
+        IConnectionMultiplexer redis,
+        ILogger<ThresholdCacheLoader> logger)
+    {
+        _services = services;
+        _redis = redis;
+        _logger = logger;
+    }
+
+    public async Task StartAsync(CancellationToken cancellationToken)
+    {
+        using var scope = _services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<AppDbContext>();
+        var cache = _redis.GetDatabase();
+
+        var thresholds = await db.AlertThresholds.ToListAsync(cancellationToken);
+        var batch = cache.CreateBatch();
+
+        foreach (var t in thresholds)
+        {
+            var json = JsonSerializer.Serialize(new
+            {
+                t.ObservationCode,
+                t.CriticalLow,
+                t.WarningLow,
+                t.WarningHigh,
+                t.CriticalHigh
+            });
+            _ = batch.StringSetAsync($"threshold:{t.ObservationCode}", json);
+        }
+
+        batch.Execute();
+        _logger.LogInformation("Loaded {Count} alert thresholds into Redis cache", thresholds.Count);
+    }
+
+    public Task StopAsync(CancellationToken cancellationToken) => Task.CompletedTask;
+}