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108 lines
4.1 KiB
108 lines
4.1 KiB
// Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
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//
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License, version 2.0, as
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// published by the Free Software Foundation.
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//
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// This program is also distributed with certain software (including
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// but not limited to OpenSSL) that is licensed under separate terms,
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// as designated in a particular file or component or in included license
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// documentation. The authors of MySQL hereby grant you an
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// additional permission to link the program and your derivative works
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// with the separately licensed software that they have included with
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// MySQL.
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//
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// Without limiting anything contained in the foregoing, this file,
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// which is part of MySQL Connector/NET, is also subject to the
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// Universal FOSS Exception, version 1.0, a copy of which can be found at
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// http://oss.oracle.com/licenses/universal-foss-exception.
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//
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// This program is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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// See the GNU General Public License, version 2.0, for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software Foundation, Inc.,
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// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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using MySql.Data.MySqlClient;
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using System;
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using System.Collections.Generic;
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using Sog.Properties;
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namespace MySql.Data.Failover
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{
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/// <summary>
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/// Manages the hosts available for client side failover using the Random Failover method.
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/// The Random Failover method attempts to connect to the hosts specified in the list randomly until all the hosts have been attempted.
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/// </summary>
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internal class RandomFailoverGroup : FailoverGroup
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{
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/// <summary>
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/// The initial host taken from the list.
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/// </summary>
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private FailoverServer _initialHost;
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/// <summary>
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/// The host for the current connection attempt.
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/// </summary>
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private FailoverServer _currentHost;
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/// <summary>
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/// Random object to get the next host.
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/// </summary>
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private readonly Random rnd = new Random();
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public RandomFailoverGroup(List<FailoverServer> hosts) : base(hosts) { }
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/// <summary>
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/// Sets the initial active host.
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/// </summary>
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protected internal override void SetInitialActiveServer()
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{
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if (this.Hosts == null || this.Hosts.Count == 0)
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{
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throw new MySqlException(Resources.Replication_NoAvailableServer);
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}
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var initialIndex = this.rnd.Next(this.Hosts.Count);
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this._initialHost = this.Hosts[initialIndex];
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this._initialHost.IsActive = true;
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this._initialHost.Attempted = true;
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this._activeHost = this._initialHost;
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this._currentHost = this._activeHost;
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}
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/// <summary>
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/// Determines the next host.
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/// </summary>
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/// <returns>A <see cref="FailoverServer"/> object that represents the next available host.</returns>
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protected internal override FailoverServer GetNextHost()
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{
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if (this.Hosts == null || this.Hosts?.Count == 0)
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{
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throw new MySqlException(Resources.Replication_NoAvailableServer);
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}
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this.Hosts.Find(h => h.Host == this._currentHost.Host && h.Port == this._currentHost.Port).IsActive = false;
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var notAttemptedHosts = this.Hosts.FindAll(h => h.Attempted == false);
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if (notAttemptedHosts.Count > 0)
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{
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this._activeHost = notAttemptedHosts[this.rnd.Next(notAttemptedHosts.Count)];
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this._activeHost.IsActive = true;
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this._activeHost.Attempted = true;
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this._currentHost = this._activeHost;
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}
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else
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{
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this._activeHost = this._initialHost;
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}
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return this._activeHost;
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}
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}
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}
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