xenadmin/XenAdmin/Commands/RemoveHostFromPoolCommand.cs

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Sockets;
using System.Threading;
using XenAdmin.Actions;
using XenAdmin.Core;
using XenAdmin.Dialogs;
using XenAdmin.Network;
using XenAPI;

namespace XenAdmin.Commands
{
    /// <summary>
    /// Removes the selected host from its pool.
    /// </summary>
    internal class RemoveHostFromPoolCommand : Command
    {
        /// <summary>
        /// Initializes a new instance of this Command. The parameter-less constructor is required if 
        /// this Command is to be attached to a ToolStrip menu item or button. It should not be used in any other scenario.
        /// </summary>
        public RemoveHostFromPoolCommand()
        {
        }

        public RemoveHostFromPoolCommand(IMainWindow mainWindow, IEnumerable<SelectedItem> selection)
            : base(mainWindow, selection)
        {
        }

        public RemoveHostFromPoolCommand(IMainWindow mainWindow, Host host)
            : base(mainWindow, host)
        {
        }

        public RemoveHostFromPoolCommand(IMainWindow mainWindow, IEnumerable<Host> hosts)
            : base(mainWindow, hosts.Select(h => new SelectedItem(h)).ToList())
        {
        }

        protected override void RunCore(SelectedItemCollection selection)
        {
            List<AsyncAction> actions = new List<AsyncAction>();
            foreach (Host host in selection.AsXenObjects<Host>())
            {
                string opaque_ref = host.opaque_ref;
                Pool pool = Helpers.GetPool(host.Connection);

                if (selection.Count == 1 && pool.master == host.opaque_ref)
                {
                    // Trying to remove the coordinator from a pool.
                    using (var dlg = new ErrorDialog(Messages.MESSAGEBOX_POOL_COORDINATOR_REMOVE))
                        dlg.ShowDialog(MainWindowCommandInterface.Form);
                    return;
                }

                // Optimistically, add the ejected host as a standalone host (but don't connect to it yet)
                IXenConnection connection = new XenConnection();
                connection.Hostname = host.address;
                connection.Username = host.Connection.Username;
                connection.Password = host.Connection.Password;
                connection.FriendlyName = host.Name();

                lock (ConnectionsManager.ConnectionsLock)
                {
                    ConnectionsManager.XenConnections.Add(connection);
                }

                XenAdminConfigManager.Provider.HideObject(opaque_ref);

                var action = new EjectHostFromPoolAction(pool, host);
                action.Completed += delegate
                {
                    if (action.Succeeded)
                    {
                        ThreadPool.QueueUserWorkItem(WaitForReboot, connection);
                    }
                    else
                    {
                        XenAdminConfigManager.Provider.ShowObject(opaque_ref);
                        MainWindowCommandInterface.RemoveConnection(connection);
                    }
                };

                actions.Add(action);
            }

            RunMultipleActions(actions, Messages.REMOVING_SERVERS_FROM_POOL, Messages.POOLCREATE_REMOVING, Messages.POOLCREATE_REMOVED, true);
        }

        protected override string GetCantRunReasonCore(IXenObject item)
        {
            if (item is Host host)
            {
                if (host.IsCoordinator())
                    return Messages.MESSAGEBOX_POOL_COORDINATOR_REMOVE;

                if (!host.IsLive())
                    return Messages.HOST_UNREACHABLE;

                if (host.resident_VMs != null && host.resident_VMs.Count > 1)
                    return Messages.NEWPOOL_HAS_RUNNING_VMS;
            }

            return base.GetCantRunReasonCore(item);
        }

        public static bool CanRun(Host host)
        {
            if (host != null && host.Connection != null)
            {
                Pool pool = Helpers.GetPool(host.Connection);
                return pool != null && host.opaque_ref != pool.master && host.IsLive() &&
                       host.resident_VMs != null && host.resident_VMs.Count <= 1;
            }
            return false;
        }

        protected override bool CanRunCore(SelectedItemCollection selection)
        {
            // all selected items must be hosts and in the same pool

            return selection.Select(s => s.Connection).Count() == 1 &&
                   selection.All(s => s.XenObject is Host h && CanRun(h));
        }

        private void WaitForReboot(object o)
        {
            while (true)
            {
                IXenConnection connection = (IXenConnection)o;
                Thread.Sleep(30 * 1000); // wait 30s for server to shutdown
                int i = 0;
                int max = 27; // give up after 5 mins
                while (true)
                {
                    if (i > max)
                    {
                        MainWindowCommandInterface.Invoke(delegate
                        {
                            using (var dlg = new ErrorDialog(string.Format(Messages.MESSAGEBOX_RECONNECT_FAIL, connection.Hostname))
                                {WindowTitle = Messages.MESSAGEBOX_RECONNECT_FAIL_TITLE})
                            {
                                dlg.ShowDialog(Parent);
                            }
                        });
                        return;
                    }

                    Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                    try
                    {
                        socket.Connect(connection.Hostname, connection.Port);
                    }
                    catch (Exception)
                    {
                        // ignored
                    }

                    if (socket.Connected)
                    {
                        MainWindowCommandInterface.Invoke(() => XenConnectionUI.BeginConnect(connection, false, Program.MainWindow, false));
                        return;
                    }
                    i++;
                    Thread.Sleep(15 * 1000);
                }
            }
        }

        public override string ContextMenuText => Messages.REMOVE_SERVER_FROM_POOL_CONTEXT_MENU_ITEM_TEXT;

        protected override bool ConfirmationRequired => true;

        protected override string ConfirmationDialogText
        {
            get
            {
                SelectedItemCollection selection = GetSelection();

                if (selection.Count > 0)
                {
                    Host host = (Host)selection[0].XenObject;
                    Pool pool = Helpers.GetPool(host.Connection);
                    
                    if (selection.Count == 1)
                    {
                        return string.Format(Messages.MAINWINDOW_CONFIRM_REMOVE_FROM_POOL, host.Name().Ellipsise(500),
                                             Helpers.GetName(pool).Ellipsise(500), host.Name().Ellipsise(500));
                    }

                    return string.Format(Messages.MAINWINDOW_CONFIRM_REMOVE_FROM_POOL_MULTIPLE,
                                         Helpers.GetName(pool).Ellipsise(500));
                }
                return null;
            }
        }

        protected override string ConfirmationDialogTitle => Messages.MAINWINDOW_CONFIRM_REMOVE_FROM_POOL_TITLE;

        protected override string ConfirmationDialogYesButtonLabel => Messages.MAINWINDOW_CONFIRM_REMOVE_FROM_POOL_YES_BUTTON_LABEL;

        protected override bool ConfirmationDialogNoButtonSelected => true;
    }
}