refactoring, WiP

MalwareMultiScan.Scanner/Services/ConsulHostedService.cs

@@ -0,0 +1,85 @@
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Threading;
+using System.Threading.Tasks;
+using Consul;
+using MalwareMultiScan.Backends.Backends.Interfaces;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Hosting;
+
+namespace MalwareMultiScan.Scanner.Services
+{
+    public class ConsulHostedService : BackgroundService
+    {
+        private static readonly string ServiceId = Dns.GetHostName();
+        private static readonly string CheckId = $"ttl-{ServiceId}";
+
+        private readonly IConsulClient _consulClient;
+        private readonly AgentServiceRegistration _registration;
+        
+        public ConsulHostedService(
+            IConsulClient consulClient,
+            IConfiguration configuration,
+            IScanBackend scanBackend)
+        {
+            _consulClient = consulClient;
+
+            _registration = new AgentServiceRegistration
+            {
+                ID = ServiceId,
+                Name = configuration.GetValue<string>("CONSUL_SERVICE_NAME"),
+
+                Meta = new Dictionary<string, string>
+                {
+                    {"BackendId", scanBackend.Id}
+                }
+            };
+        }
+
+        /// <inheritdoc />
+        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+        {
+            while (!stoppingToken.IsCancellationRequested)
+            {
+                await _consulClient.Agent.PassTTL(
+                    CheckId, string.Empty, stoppingToken);
+
+                await Task.Delay(TimeSpan.FromSeconds(5), stoppingToken);
+            }
+        }
+
+        /// <inheritdoc />
+        public override async Task StartAsync(CancellationToken cancellationToken)
+        {
+            await _consulClient.Agent.ServiceDeregister(
+                _registration.ID, cancellationToken);
+
+            await _consulClient.Agent.ServiceRegister(
+                _registration, cancellationToken);
+
+            await _consulClient.Agent.CheckRegister(new AgentCheckRegistration
+            {
+                ID = CheckId,
+                Name = "TTL",
+                ServiceID = ServiceId,
+                TTL = TimeSpan.FromSeconds(15),
+                DeregisterCriticalServiceAfter = TimeSpan.FromSeconds(60)
+            }, cancellationToken);
+
+            await base.StartAsync(cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override async Task StopAsync(CancellationToken cancellationToken)
+        {
+            await _consulClient.Agent.ServiceDeregister(
+                _registration.ID, cancellationToken);
+
+            await _consulClient.Agent.CheckDeregister(
+                CheckId, cancellationToken);
+
+            await base.StopAsync(cancellationToken);
+        }
+    }
+}