First runnable prototype.

code/MessengerBroker/Handlers/HousekeepingHandler.cs

@@ -0,0 +1,41 @@
+using MessengerBroker.Configuration.Model;
+using MessengerBroker.Factories;
+using Microsoft.EntityFrameworkCore;
+
+namespace MessengerBroker.Handlers
+{
+    public class HousekeepingHandler
+    {
+        private readonly BrokerConfiguration brokerConfiguration;
+        private readonly BrokerDbContextFactory brokerDbContextFactory;
+
+        public HousekeepingHandler(BrokerConfiguration brokerConfiguration)
+        {
+            this.brokerConfiguration = brokerConfiguration;
+        }
+
+        public Task BeginHousekeeping(CancellationToken ct = default)
+        {
+            if(this.brokerConfiguration.HousekeepingEnabled == false)
+            {
+                return Task.CompletedTask;
+            }
+
+            return Task.Run(async () =>
+            {
+                while (!ct.IsCancellationRequested)
+                {
+                    await Task.Delay(TimeSpan.FromMinutes(1));
+
+                    using var context = this.brokerDbContextFactory.CreateDbContext();
+
+                    var oldestAllowedTimestamp = DateTime.UtcNow.AddMinutes(-this.brokerConfiguration.HousekeepingMessageAgeInMinutes);
+
+                    await context.Messages
+                        .Where(x => x.TimestampUtc < oldestAllowedTimestamp)
+                        .ExecuteDeleteAsync();
+                }
+            });
+        }
+    }
+}