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 +1,151 @@
+using System.Text;
+using System.Text.Json;
+using Confluent.Kafka;
+using Microsoft.Extensions.Options;
+using RabbitMQ.Client;
+
+public sealed class NotificationPublisherService : BackgroundService
+{
+    private readonly IOptions<RabbitMqOptions> _rabbitOpts;
+    private readonly KafkaOptions _kafkaOptions;
+    private readonly ILogger<NotificationPublisherService> _logger;
+
+    public NotificationPublisherService(
+        IOptions<RabbitMqOptions> rabbitOpts,
+        IOptions<KafkaOptions> kafkaOptions,
+        ILogger<NotificationPublisherService> logger)
+    {
+        _rabbitOpts    = rabbitOpts;
+        _kafkaOptions  = kafkaOptions.Value;
+        _logger        = logger;
+    }
+
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        // Short delay so topology provisioner finishes before first publish.
+        await Task.Delay(TimeSpan.FromSeconds(3), stoppingToken);
+
+        var factory    = BuildRabbitFactory();
+        using var conn = factory.CreateConnection("notification-publisher");
+        using var chan  = conn.CreateModel();
+
+        var props = chan.CreateBasicProperties();
+        props.Persistent = true;  // messages survive broker restart
+
+        var consumerConfig = new ConsumerConfig
+        {
+            BootstrapServers       = _kafkaOptions.BootstrapServers,
+            GroupId                = "notification-publisher",
+            AutoOffsetReset        = AutoOffsetReset.Earliest,
+            EnableAutoCommit       = false,
+        };
+
+        using var consumer = new ConsumerBuilder<string, string>(consumerConfig).Build();
+        consumer.Subscribe(new[]
+        {
+            _kafkaOptions.Topics.AlertGenerated,
+            _kafkaOptions.Topics.EncounterStatusChanged,
+        });
+
+        _logger.LogInformation("NotificationPublisherService started — consuming {Topics}",
+            string.Join(", ", _kafkaOptions.Topics.AlertGenerated, _kafkaOptions.Topics.EncounterStatusChanged));
+
+        try
+        {
+            while (!stoppingToken.IsCancellationRequested)
+            {
+                ConsumeResult<string, string>? result;
+                try
+                {
+                    result = consumer.Consume(TimeSpan.FromMilliseconds(500));
+                }
+                catch (ConsumeException ex)
+                {
+                    _logger.LogError(ex, "NotificationPublisher consume error");
+                    continue;
+                }
+
+                if (result is null) continue;
+
+                try
+                {
+                    if (result.Topic == _kafkaOptions.Topics.AlertGenerated)
+                        await HandleAlertGeneratedAsync(chan, props, result.Message.Value, stoppingToken);
+                    else if (result.Topic == _kafkaOptions.Topics.EncounterStatusChanged)
+                        await HandleEncounterStatusChangedAsync(chan, props, result.Message.Value, stoppingToken);
+
+                    consumer.Commit(result);
+                }
+                catch (Exception ex)
+                {
+                    _logger.LogError(ex, "NotificationPublisher failed to process message from {Topic}", result.Topic);
+                    // Do not commit — message will be reprocessed after consumer restart.
+                }
+            }
+        }
+        finally
+        {
+            consumer.Close();
+        }
+    }
+
+    private Task HandleAlertGeneratedAsync(
+        IModel chan, IBasicProperties props, string payload, CancellationToken ct)
+    {
+        var doc = JsonDocument.Parse(payload);
+        var severity = doc.RootElement.GetProperty("severity").GetString();
+
+        if (!string.Equals(severity, "Critical", StringComparison.OrdinalIgnoreCase))
+        {
+            // Warning-level alerts are not paged — they appear in the clinician dashboard only.
+            return Task.CompletedTask;
+        }
+
+        var body = Encoding.UTF8.GetBytes(payload);
+        chan.BasicPublish(
+            exchange:   RabbitMqTopologyProvisioner.Exchange,
+            routingKey: RabbitMqTopologyProvisioner.PagingKey,
+            basicProperties: props,
+            body:       body);
+
+        var alertId = doc.RootElement.GetProperty("alertId").GetString();
+        _logger.LogInformation("Published paging job to alerts.paging.queue for alert {AlertId}", alertId);
+
+        return Task.CompletedTask;
+    }
+
+    private Task HandleEncounterStatusChangedAsync(
+        IModel chan, IBasicProperties props, string payload, CancellationToken ct)
+    {
+        var doc = JsonDocument.Parse(payload);
+        var newStatus = doc.RootElement.GetProperty("newStatus").GetString();
+
+        if (!string.Equals(newStatus, "Discharged", StringComparison.OrdinalIgnoreCase))
+            return Task.CompletedTask;
+
+        var body = Encoding.UTF8.GetBytes(payload);
+        chan.BasicPublish(
+            exchange:   RabbitMqTopologyProvisioner.Exchange,
+            routingKey: RabbitMqTopologyProvisioner.DischargeKey,
+            basicProperties: props,
+            body:       body);
+
+        var encounterId = doc.RootElement.GetProperty("encounterId").GetString();
+        _logger.LogInformation("Published discharge summary job for encounter {EncounterId}", encounterId);
+
+        return Task.CompletedTask;
+    }
+
+    private IConnectionFactory BuildRabbitFactory()
+    {
+        var o = _rabbitOpts.Value;
+        return new ConnectionFactory
+        {
+            HostName               = o.Host,
+            Port                   = o.Port,
+            UserName               = o.Username,
+            Password               = o.Password,
+            DispatchConsumersAsync = true,
+        };
+    }
+}