SQL Agent configuration for Operators, Alerts and Proxies (WIP) (#621)

* Initial non-refactored SQL Agent alert classes (WIP)

* Move agent classes into subdirectories

* Refactor the agent config code a bit more

* Add more implementation for handlers

* Add more code to the create alert handler

* Clean up agent alert class

* Clean up alert methods a bit

* Initial Operator contracts

* Additonal SQL Agent config changes

* More Proxy config cleanup

* Cleanup AgentProxy class

* Additional cleanups

* Run SRGen

* Add security service to create credential objects

src/Microsoft.SqlTools.ServiceLayer/Security/SecurityService.cs

@@ -0,0 +1,116 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using System.Threading.Tasks;
+using Microsoft.SqlTools.Hosting.Protocol;
+using Microsoft.SqlTools.ServiceLayer.Admin;
+using Microsoft.SqlTools.ServiceLayer.Connection;
+using Microsoft.SqlTools.ServiceLayer.Hosting;
+using Microsoft.SqlTools.ServiceLayer.Security.Contracts;
+
+namespace Microsoft.SqlTools.ServiceLayer.Security
+{
+    /// <summary>
+    /// Main class for Security Service functionality
+    /// </summary>
+    public sealed class SecurityService : IDisposable
+    {
+        private bool disposed;
+
+        private ConnectionService connectionService = null;
+
+        private static readonly Lazy<SecurityService> instance = new Lazy<SecurityService>(() => new SecurityService());
+
+        /// <summary>
+        /// Construct a new SecurityService instance with default parameters
+        /// </summary>
+        public SecurityService()
+        {
+        }
+
+        /// <summary>
+        /// Gets the singleton instance object
+        /// </summary>
+        public static SecurityService Instance
+        {
+            get { return instance.Value; }
+        }
+
+        /// <summary>
+        /// Internal for testing purposes only
+        /// </summary>
+        internal ConnectionService ConnectionServiceInstance
+        {
+            get
+            {
+                if (connectionService == null)
+                {
+                    connectionService = ConnectionService.Instance;
+                }
+                return connectionService;
+            }
+
+            set
+            {
+                connectionService = value;
+            }
+        }
+
+        /// <summary>
+        /// Service host object for sending/receiving requests/events.
+        /// Internal for testing purposes.
+        /// </summary>
+        internal IProtocolEndpoint ServiceHost
+        {
+            get;
+            set;
+        }
+
+        /// <summary>
+        /// Initializes the Security Service instance
+        /// </summary>
+        public void InitializeService(ServiceHost serviceHost)
+        {
+            this.ServiceHost = serviceHost;
+            this.ServiceHost.SetRequestHandler(CreateCredentialRequest.Type, HandleCreateCredentialRequest);
+        }
+
+        /// <summary>
+        /// Handle request to create a credential
+        /// </summary>
+        internal async Task HandleCreateCredentialRequest(CreateCredentialParams parameters, RequestContext<CreateCredentialResult> requestContext)
+        {
+            try
+            {
+                var result = new CreateCredentialResult();
+                ConnectionInfo connInfo;
+                ConnectionServiceInstance.TryFindConnection(
+                    parameters.OwnerUri,
+                    out connInfo);
+
+                CDataContainer dataContainer = AdminService.CreateDataContainer(connInfo, databaseExists: true);
+                Credential credential = new Credential(dataContainer);
+
+                await requestContext.SendResult(result);
+            }
+            catch (Exception e)
+            {
+                await requestContext.SendError(e);
+            }
+        }
+
+        /// <summary>
+        /// Disposes the service
+        /// </summary>
+        public void Dispose()
+        {
+            if (!disposed)
+            {                
+                disposed = true;
+            }
+        }
+    }
+}