changes to support specific run service URL (#2158)

* changes to support run service url

* feedback

src/Runner.Common/ActionsRunServer.cs

@@ -0,0 +1,51 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using GitHub.DistributedTask.Pipelines;
+using GitHub.DistributedTask.WebApi;
+using GitHub.Services.Common;
+using GitHub.Services.WebApi;
+
+namespace GitHub.Runner.Common
+{
+    [ServiceLocator(Default = typeof(ActionsRunServer))]
+    public interface IActionsRunServer : IRunnerService
+    {
+        Task ConnectAsync(Uri serverUrl, VssCredentials credentials);
+
+        Task<AgentJobRequestMessage> GetJobMessageAsync(string id, CancellationToken token);
+    }
+
+    public sealed class ActionsRunServer : RunnerService, IActionsRunServer
+    {
+        private bool _hasConnection;
+        private VssConnection _connection;
+        private TaskAgentHttpClient _taskAgentClient;
+
+        public async Task ConnectAsync(Uri serverUrl, VssCredentials credentials)
+        {
+            _connection = await EstablishVssConnection(serverUrl, credentials, TimeSpan.FromSeconds(100));
+            _taskAgentClient = _connection.GetClient<TaskAgentHttpClient>();
+            _hasConnection = true;
+        }
+
+        private void CheckConnection()
+        {
+            if (!_hasConnection)
+            {
+                throw new InvalidOperationException($"SetConnection");
+            }
+        }
+
+        public Task<AgentJobRequestMessage> GetJobMessageAsync(string id, CancellationToken cancellationToken)
+        {
+            CheckConnection();
+            var jobMessage = RetryRequest<AgentJobRequestMessage>(async () =>
+                                                    {
+                                                        return await _taskAgentClient.GetJobMessageAsync(id, cancellationToken);
+                                                    }, cancellationToken);
+
+            return jobMessage;
+        }
+    }
+}