feature: RabbitMQ Notification Workers and DLQ Escalation

2026-06-17 02:37:30 +08:00
parent ec780144c6
commit 0246143815
17 changed files with 1410 additions and 2 deletions
@@ -0,0 +1,139 @@
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Options;
+using RabbitMQ.Client;
+using RabbitMQ.Client.Exceptions;
+
+public sealed class RabbitMqTopologyProvisioner : IHostedService
+{
+    public const string Exchange   = "clinical.notifications.exchange";
+    public const string PagingKey  = "alerts.paging";
+    public const string EscalKey   = "alerts.escalation";
+    public const string DischargeKey = "notifications.discharge";
+
+    private readonly RabbitMqOptions _opts;
+    private readonly IHostEnvironment _env;
+    private readonly ILogger<RabbitMqTopologyProvisioner> _logger;
+
+    public RabbitMqTopologyProvisioner(
+        IOptions<RabbitMqOptions> opts,
+        IHostEnvironment env,
+        ILogger<RabbitMqTopologyProvisioner> logger)
+    {
+        _opts   = opts.Value;
+        _env    = env;
+        _logger = logger;
+    }
+
+    public Task StartAsync(CancellationToken ct)
+    {
+        var factory = BuildFactory();
+        using var connection = factory.CreateConnection();
+        using var channel    = connection.CreateModel();
+
+        if (_env.IsEnvironment("Testing"))
+        {
+            // Use a throwaway channel — a failed purge on a missing queue closes the
+            // channel, which would break the declare calls below.
+            using var cleanup = connection.CreateModel();
+
+            try
+            {
+                // Dev runs provision the DLQ with a 5-minute TTL; delete it so the
+                // test timeout (5 s) is applied when the queue is re-declared below.
+                cleanup.QueueDelete("alerts.paging.dlq", ifUnused: false, ifEmpty: false);
+            }
+            catch (OperationInterruptedException ex)
+            {
+                _logger.LogDebug(ex, "DLQ delete skipped — queue may not exist yet");
+            }
+
+            foreach (var queue in new[] { "alerts.paging.queue", "alerts.escalation.queue" })
+            {
+                try { cleanup.QueuePurge(queue); }
+                catch (OperationInterruptedException ex)
+                {
+                    _logger.LogDebug(ex, "Queue purge skipped for {Queue}", queue);
+                }
+            }
+        }
+
+        // Direct exchange — routing key determines destination queue.
+        channel.ExchangeDeclare(Exchange, ExchangeType.Direct, durable: true);
+
+        // --- alerts.paging.queue ---
+        // Dead-letters to the default exchange with routing key = alerts.paging.dlq.
+        // Prefetch is set per-consumer, not here.
+        channel.QueueDeclare(
+            queue:      "alerts.paging.queue",
+            durable:    true,
+            exclusive:  false,
+            autoDelete: false,
+            arguments: new Dictionary<string, object>
+            {
+                ["x-dead-letter-exchange"]     = "",                  // default exchange
+                ["x-dead-letter-routing-key"]  = "alerts.paging.dlq",
+            });
+        channel.QueueBind("alerts.paging.queue", Exchange, PagingKey);
+
+        // --- alerts.paging.dlq ---
+        // Messages land here after NACK from the paging worker.
+        // After x-message-ttl expires, re-routes to clinical.notifications.exchange
+        // with routing key alerts.escalation → reaches alerts.escalation.queue.
+        channel.QueueDeclare(
+            queue:      "alerts.paging.dlq",
+            durable:    true,
+            exclusive:  false,
+            autoDelete: false,
+            arguments: new Dictionary<string, object>
+            {
+                ["x-message-ttl"]              = (int)_opts.PagingAckTimeoutMs,
+                ["x-dead-letter-exchange"]     = Exchange,
+                ["x-dead-letter-routing-key"]  = EscalKey,
+            });
+        // DLQ is reached via the default exchange — no binding to the direct exchange needed.
+
+        // --- alerts.escalation.queue ---
+        channel.QueueDeclare(
+            queue:      "alerts.escalation.queue",
+            durable:    true,
+            exclusive:  false,
+            autoDelete: false,
+            arguments: null);
+        channel.QueueBind("alerts.escalation.queue", Exchange, EscalKey);
+
+        // --- notifications.discharge.queue ---
+        channel.QueueDeclare(
+            queue:      "notifications.discharge.queue",
+            durable:    true,
+            exclusive:  false,
+            autoDelete: false,
+            arguments: null);
+        channel.QueueBind("notifications.discharge.queue", Exchange, DischargeKey);
+
+        // --- notifications.appointment.queue (placeholder) ---
+        channel.QueueDeclare(
+            queue:      "notifications.appointment.queue",
+            durable:    true,
+            exclusive:  false,
+            autoDelete: false,
+            arguments: null);
+        channel.QueueBind("notifications.appointment.queue", Exchange, "notifications.appointment");
+
+        _logger.LogInformation(
+            "RabbitMQ topology provisioned. Exchange={Exchange} PagingDlqTtlMs={Ttl}",
+            Exchange, _opts.PagingAckTimeoutMs);
+
+        return Task.CompletedTask;
+    }
+
+    public Task StopAsync(CancellationToken ct) => Task.CompletedTask;
+
+    public IConnectionFactory BuildFactory() => new ConnectionFactory
+    {
+        HostName            = _opts.Host,
+        Port                = _opts.Port,
+        UserName            = _opts.Username,
+        Password            = _opts.Password,
+        DispatchConsumersAsync = true,
+    };
+}