feat: add ServiceDiscoveryIPv4 to EnvironmentInfo

Vostok.Commons.Environment.Tests/EnvironmentInfo_Tests.cs

@@ -25,6 +25,14 @@ public void FQDN_should_not_be_null_or_empty()
             Console.Out.WriteLine(EnvironmentInfo.FQDN);
         }
 
+        [Test]
+        public void IpAddress_should_not_be_null_or_empty()
+        {
+            EnvironmentInfo.ServiceDiscoveryIPv4.Should().NotBeNullOrEmpty();
+
+            Console.Out.WriteLine(EnvironmentInfo.ServiceDiscoveryIPv4);
+        }
+
         [Test]
         public void HomeDirectory_should_not_be_null_or_empty()
         {

Vostok.Commons.Environment/EnvironmentInfo.cs

@@ -4,6 +4,7 @@
 using System.Linq;
 using System.Net;
 using System.Net.NetworkInformation;
+using System.Net.Sockets;
 using System.Reflection;
 using System.Runtime.InteropServices;
 using JetBrains.Annotations;
@@ -18,10 +19,12 @@ internal static class EnvironmentInfo
     {
         public const string LocalHostnameVariable = "VOSTOK_LOCAL_HOSTNAME";
         public const string LocalFQDNVariable = "VOSTOK_LOCAL_FQDN";
+        public const string LocalServiceDiscoveryIPv4 = "VOSTOK_LOCAL_SERVICE_DISCOVERY_IPV4";
 
         private static Lazy<string> application = new Lazy<string>(ObtainApplicationName);
         private static Lazy<string> host = new Lazy<string>(ObtainHostname);
         private static Lazy<string> fqdn = new Lazy<string>(ObtainFQDN);
+        private static Lazy<string> serviceDiscoveryIPv4 = new Lazy<string>(ObtainServiceDiscoveryIPv4);
         private static Lazy<string> processName = new Lazy<string>(GetProcessNameOrNull);
         private static Lazy<string> homeDirectory = new Lazy<string>(ObtainHomeDirectory);
         private static Lazy<int?> processId = new Lazy<int?>(GetProcessIdOrNull);
@@ -41,6 +44,11 @@ internal static class EnvironmentInfo
         /// </summary>
         public static string FQDN => fqdn.Value;
 
+        /// <summary>
+        /// Returns the IPv4 of the machine running the application.
+        /// </summary>
+        public static string ServiceDiscoveryIPv4 => serviceDiscoveryIPv4.Value;
+
         /// <summary>
         /// Returns the name of current process. 
         /// </summary>
@@ -193,6 +201,35 @@ private static string ObtainFQDN()
             }
         }
 
+        private static string ObtainServiceDiscoveryIPv4()
+        {
+            try
+            {
+                var dnsAddresses = Dns.GetHostAddresses(ObtainHostname());
+
+                var interfaceAddresses = NetworkInterface
+                    .GetAllNetworkInterfaces()
+                    .Where(iface => iface.OperationalStatus == OperationalStatus.Up)
+                    .Where(iface => iface.GetIPProperties().GatewayAddresses.Any(info => !info.Address.Equals(IPAddress.Any)))
+                    .SelectMany(iface => iface.GetIPProperties().UnicastAddresses)
+                    .Select(info => info.Address)
+                    .ToList();
+
+                var address = dnsAddresses
+                    .Where(address => address.AddressFamily == AddressFamily.InterNetwork)
+                    .Where(address => !IPAddress.IsLoopback(address))
+                    .Where(address => interfaceAddresses.Contains(address))
+                    .Select(address => address.ToString())
+                    .First();
+
+                return address;
+            }
+            catch
+            {
+                return null;
+            }
+        }
+
         private static string GetWindowsDomainName()
         {
             try