In-memory Queue Console Logger

// ----------------------------------------------------------------------------
// ConsoleLoggerProcessor.cs
// https://github.com/aspnet/Logging/blob/master/src/Microsoft.Extensions.Logging.Console/Internal/ConsoleLoggerProcessor.cs
// ----------------------------------------------------------------------------

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Collections.Concurrent;
using System.Threading;

namespace Microsoft.Extensions.Logging.Console.Internal
{
    public class ConsoleLoggerProcessor : IDisposable
    {
        private const int _maxQueuedMessages = 1024;

        private readonly BlockingCollection<LogMessageEntry> _messageQueue = new BlockingCollection<LogMessageEntry>(_maxQueuedMessages);
        private readonly Thread _outputThread;

        public IConsole Console;
        public IConsole ErrorConsole;

        public ConsoleLoggerProcessor()
        {
            // Start Console message queue processor
            _outputThread = new Thread(ProcessLogQueue)
            {
                IsBackground = true,
                Name = "Console logger queue processing thread"
            };
            _outputThread.Start();
        }

        public virtual void EnqueueMessage(LogMessageEntry message)
        {
            if (!_messageQueue.IsAddingCompleted)
            {
                try
                {
                    _messageQueue.Add(message);
                    return;
                }
                catch (InvalidOperationException) { }
            }

            // Adding is completed so just log the message
            WriteMessage(message);
        }

        // for testing
        internal virtual void WriteMessage(LogMessageEntry message)
        {
            var console = message.LogAsError ? ErrorConsole : Console;

            if (message.TimeStamp != null)
            {
                console.Write(message.TimeStamp, message.MessageColor, message.MessageColor);
            }

            if (message.LevelString != null)
            {
                console.Write(message.LevelString, message.LevelBackground, message.LevelForeground);
            }

            console.Write(message.Message, message.MessageColor, message.MessageColor);
            console.Flush();
        }

        private void ProcessLogQueue()
        {
            try
            {
                foreach (var message in _messageQueue.GetConsumingEnumerable())
                {
                    WriteMessage(message);
                }
            }
            catch
            {
                try
                {
                    _messageQueue.CompleteAdding();
                }
                catch { }
            }
        }

        public void Dispose()
        {
            _messageQueue.CompleteAdding();

            try
            {
                _outputThread.Join(1500); // with timeout in-case Console is locked by user input
            }
            catch (ThreadStateException) { }
        }
    }
}

// ----------------------------------------------------------------------------
// IConsole.cs
// https://github.com/aspnet/Logging/blob/master/src/Microsoft.Extensions.Logging.Console/Internal/IConsole.cs
// ----------------------------------------------------------------------------

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;

namespace Microsoft.Extensions.Logging.Console.Internal
{
    public interface IConsole
    {
        void Write(string message, ConsoleColor? background, ConsoleColor? foreground);
        void WriteLine(string message, ConsoleColor? background, ConsoleColor? foreground);
        void Flush();
    }
}

// ----------------------------------------------------------------------------
// LogMessageEntry.cs
// https://github.com/aspnet/Logging/blob/master/src/Microsoft.Extensions.Logging.Console/Internal/LogMessageEntry.cs
// ----------------------------------------------------------------------------

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;

namespace Microsoft.Extensions.Logging.Console.Internal
{
    public struct LogMessageEntry
    {
        public string TimeStamp;
        public string LevelString;
        public ConsoleColor? LevelBackground;
        public ConsoleColor? LevelForeground;
        public ConsoleColor? MessageColor;
        public string Message;
        public bool LogAsError;
    }
}