mirror of
https://github.com/OPCFoundation/UA-.NETStandard.git
synced 2026-10-19 07:02:16 +08:00
Marc Schier
bd4543e961
- Add new managed session, wrapping session and providing connection management and failover handling - Add new Subscription engine that can act as alternative to current engine, but is based on channels with worker tasks - Add a fluent builder for managed session clients - Replace NodeCache with LruNodeCache, rename ILruNodeCache and LruNodeCache to INodeCache and NodeCache - Update migration guide and document new functionality.
79 lines
3.2 KiB
C#
79 lines
3.2 KiB
C#
/* ========================================================================
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* Copyright (c) 2005-2025 The OPC Foundation, Inc. All rights reserved.
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*
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* OPC Foundation MIT License 1.00
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use,
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* copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following
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* conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*
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* The complete license agreement can be found here:
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* http://opcfoundation.org/License/MIT/1.00/
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* ======================================================================*/
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using System.Threading;
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using System.Threading.Tasks;
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namespace Opc.Ua.Client
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{
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/// <summary>
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/// Handles server redundancy detection and failover target
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/// selection for a managed session.
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/// </summary>
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/// <remarks>
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/// See OPC UA Part 4 §6.6.2 for the server redundancy model.
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/// </remarks>
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public interface IServerRedundancyHandler
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{
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/// <summary>
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/// Reads redundancy information from the connected session.
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/// </summary>
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/// <param name="session">The active session to read from.</param>
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/// <param name="ct">Cancellation token.</param>
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/// <returns>
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/// A <see cref="ServerRedundancyInfo"/> describing the server's
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/// redundancy configuration.
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/// </returns>
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ValueTask<ServerRedundancyInfo> FetchRedundancyInfoAsync(
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ISession session,
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CancellationToken ct = default);
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/// <summary>
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/// Selects the best server to fail over to from the redundant
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/// server set.
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/// </summary>
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/// <param name="redundancyInfo">
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/// The redundancy information previously obtained via
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/// <see cref="FetchRedundancyInfoAsync"/>.
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/// </param>
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/// <param name="currentEndpoint">
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/// The endpoint the session is currently connected to.
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/// </param>
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/// <returns>
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/// A <see cref="ConfiguredEndpoint"/> for the best failover
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/// target, or <see langword="null"/> if no failover target is
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/// available (e.g., transparent redundancy or no suitable
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/// backup server).
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/// </returns>
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ConfiguredEndpoint? SelectFailoverTarget(
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ServerRedundancyInfo redundancyInfo,
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ConfiguredEndpoint currentEndpoint);
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}
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}
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