MQTTnet/Samples/Diagnostics/Logger_Samples.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

// ReSharper disable UnusedType.Global
// ReSharper disable UnusedMember.Global
// ReSharper disable InconsistentNaming

using System.Text;
using MQTTnet.Diagnostics.Logger;

namespace MQTTnet.Samples.Diagnostics;

public static class Logger_Samples
{
    public static async Task Create_Custom_Logger()
    {
        /*
         * This sample covers the creation of a custom logger which can be used to forward MQTTnet log messages
         * to other loggers like Microsoft logger or Serilog or log4net etc.
         */

        var mqttFactory = new MqttClientFactory(new MyLogger());

        var mqttClientOptions = mqttFactory.CreateClientOptionsBuilder()
            .WithTcpServer("broker.hivemq.com")
            .Build();

        using (var mqttClient = mqttFactory.CreateMqttClient())
        {
            await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);

            Console.WriteLine("MQTT client is connected.");

            var mqttClientDisconnectOptions = mqttFactory.CreateClientDisconnectOptionsBuilder()
                .Build();

            await mqttClient.DisconnectAsync(mqttClientDisconnectOptions, CancellationToken.None);
        }
    }

    public static async Task Use_Event_Logger()
    {
        /*
         * This sample shows how to get logs from the library.
         *
         * ATTENTION: Only use the logger for debugging etc. The performance is heavily decreased when a logger is used.
         */

        // The logger ID is optional but can be set do distinguish different logger instances.
        var mqttEventLogger = new MqttNetEventLogger("MyCustomLogger");

        mqttEventLogger.LogMessagePublished += (sender, args) =>
        {
            var output = new StringBuilder();
            output.AppendLine($">> [{args.LogMessage.Timestamp:O}] [{args.LogMessage.ThreadId}] [{args.LogMessage.Source}] [{args.LogMessage.Level}]: {args.LogMessage.Message}");
            if (args.LogMessage.Exception != null)
            {
                output.AppendLine(args.LogMessage.Exception.ToString());
            }

            Console.Write(output);
        };

        var mqttFactory = new MqttClientFactory(mqttEventLogger);

        var mqttClientOptions = mqttFactory.CreateClientOptionsBuilder()
            .WithTcpServer("broker.hivemq.com")
            .Build();

        using (var mqttClient = mqttFactory.CreateMqttClient())
        {
            await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);

            Console.WriteLine("MQTT client is connected.");

            var mqttClientDisconnectOptions = mqttFactory.CreateClientDisconnectOptionsBuilder()
                .Build();

            await mqttClient.DisconnectAsync(mqttClientDisconnectOptions, CancellationToken.None);
        }
    }

    sealed class MyLogger : IMqttNetLogger
    {
        public bool IsEnabled { get; set; } = true;

        public void Publish(MqttNetLogLevel logLevel, string source, string message, object[] parameters, Exception exception)
        {
            // Forward the log message to other loggers.
            // 1. Convert log level to matching log level in target logger.
            // 2. Call target logger and pass data accordingly.
        }
    }
}