ConsoleLoggingSink.cs

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using System;
using System.Collections.Generic;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using Opc.Ua.PubSub.DataSets;
using Opc.Ua.PubSub.Encoding;

namespace Quickstarts.ConsoleReferencePubSubClient
{
    /// <summary>
    /// <see cref="ISubscribedDataSetSink"/> that prints every received
    /// DataSetMessage to the console via an
    /// <see cref="ILogger"/>. Demonstrates the Part 14 §6.2.9 sink
    /// extension point.
    /// </summary>
    public sealed class ConsoleLoggingSink : ISubscribedDataSetSink
    {
        private readonly ILogger m_logger;
        private long m_received;

        public ConsoleLoggingSink(ILogger logger)
        {
            if (logger is null)
            {
                throw new ArgumentNullException(nameof(logger));
            }
            m_logger = logger;
        }

        public ValueTask WriteAsync(
            IReadOnlyList<DataSetField> fields,
            CancellationToken cancellationToken = default)
        {
            cancellationToken.ThrowIfCancellationRequested();
            long sequence = Interlocked.Increment(ref m_received);
            var builder = new StringBuilder();
            for (int i = 0; i < fields.Count; i++)
            {
                DataSetField field = fields[i];
                if (i > 0)
                {
                    builder.Append(", ");
                }
                builder.Append(string.IsNullOrEmpty(field.Name) ? $"f{i}" : field.Name);
                builder.Append('=');
                builder.Append(field.Value.IsNull ? "(null)" : field.Value.ToString());
            }
            m_logger.LogInformation(
                "DataSet #{Sequence} received ({FieldCount} fields): {Fields}",
                sequence, fields.Count, builder.ToString());
            return ValueTask.CompletedTask;
        }
    }
}