95 lines
3.1 KiB
C#
95 lines
3.1 KiB
C#
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<GatewayDbContext>();
|
|
await RefreshAsync(db, _redis, _logger, cancellationToken);
|
|
}
|
|
|
|
public Task StopAsync(CancellationToken cancellationToken) => Task.CompletedTask;
|
|
|
|
/// <summary>
|
|
/// Reloads all gateway alert thresholds into Redis. Called on startup and after
|
|
/// <see cref="EncounterReplicaSyncService"/> pulls thresholds from central.
|
|
/// </summary>
|
|
public static async Task RefreshAsync(
|
|
GatewayDbContext db,
|
|
IConnectionMultiplexer redis,
|
|
ILogger logger,
|
|
CancellationToken cancellationToken = default)
|
|
{
|
|
var thresholds = await db.AlertThresholds.ToListAsync(cancellationToken);
|
|
if (thresholds.Count == 0)
|
|
{
|
|
logger.LogWarning("No alert thresholds in gateway DB — Redis cache not updated");
|
|
return;
|
|
}
|
|
|
|
const int maxAttempts = 3;
|
|
int[] backoffMs = [2000, 4000, 8000];
|
|
|
|
for (var attempt = 0; attempt < maxAttempts; attempt++)
|
|
{
|
|
try
|
|
{
|
|
WriteThresholds(redis, thresholds);
|
|
logger.LogInformation(
|
|
"Loaded {Count} alert thresholds into gateway Redis cache", thresholds.Count);
|
|
return;
|
|
}
|
|
catch (RedisException ex)
|
|
{
|
|
logger.LogWarning(ex,
|
|
"Redis unavailable during gateway threshold cache load — attempt {Attempt}/{Max}",
|
|
attempt + 1, maxAttempts);
|
|
|
|
if (attempt < maxAttempts - 1)
|
|
await Task.Delay(backoffMs[attempt], cancellationToken);
|
|
}
|
|
}
|
|
|
|
logger.LogError(
|
|
"Failed to load thresholds into gateway Redis after {Max} attempts — " +
|
|
"observation ingest falls back to PostgreSQL for threshold lookups",
|
|
maxAttempts);
|
|
}
|
|
|
|
private static void WriteThresholds(IConnectionMultiplexer redis, List<ReplicaAlertThreshold> thresholds)
|
|
{
|
|
var cache = redis.GetDatabase();
|
|
var batch = cache.CreateBatch();
|
|
|
|
foreach (var t in thresholds)
|
|
{
|
|
var json = JsonSerializer.Serialize(new ThresholdCacheEntry(
|
|
t.ObservationCode,
|
|
t.CriticalLow,
|
|
t.WarningLow,
|
|
t.WarningHigh,
|
|
t.CriticalHigh));
|
|
_ = batch.StringSetAsync($"threshold:{t.ObservationCode}", json);
|
|
}
|
|
|
|
batch.Execute();
|
|
}
|
|
}
|