I have create a simple Serilog sink project that looks like this :

namespace MyApp.Cloud.Serilog.MQSink
{
    public class MessageQueueSink: ILogEventSink
    {
        private readonly IMQProducer _MQProducerService;
        public MessageQueueSink(IMQProducer mQProducerService)
        {
            _MQProducerService = mQProducerService;
        }
        public void Emit(LogEvent logEvent)
        {
            _MQProducerService.Produce<SendLog>(new SendLog() { LogEventJson = JsonConvert.SerializeObject(logEvent)});
        }
    }
}

The consuming microservice are starting up like this :

        var configurationBuilder = new ConfigurationBuilder().AddJsonFile("appsettings.json").Build();
        var appSettings = configurationBuilder.Get<AppSettings>();

        configurationBuilder = new ConfigurationBuilder().AddJsonFile("ExtendedSettings.json").Build();

            Host.CreateDefaultBuilder(args)
                .UseMyAppCloudMQ(context => context.UseSettings(appSettings.MQSettings))
                .UseSerilog((hostingContext, loggerConfiguration) => loggerConfiguration.ReadFrom.Configuration(hostingContext.Configuration))
                .ConfigureServices((hostContext, services) =>
                {
                    services
                        .AddHostedService<ExtendedProgService>()
                        .Configure<MQSettings>(configurationBuilder.GetSection("MQSettings"))
                })
                .Build().Run();

The serilog part of appsettings.json looks like this :

  "serilog": {
    "Using": [ "Serilog.Sinks.File", "Serilog.Sinks.Console", "MyApp.Cloud.Serilog.MQSink" ],
    "MinimumLevel": {
      "Default": "Debug",
      "Override": {
        "Microsoft": "Warning",
        "System": "Warning"
      }
    },
    "Enrich": [ "FromLogContext", "WithMachineName", "WithProcessId" ],
    "WriteTo": [
      {
        "Name": "MessageQueueSink",
        "Args": {}
        }
    ]
  }

The MQSink project is added as reference to the microservice project and I can see that the MQSink dll ends up in the bin folder.

The problem is that when executing a _logger.LogInformation(...) in the microservice the Emit are never triggered, but if I add a console sink it will output data? I also suspect that the injected MQ will not work properly?

How could this be solved?

EDIT :

Turned on the Serilog internal log and could see that the method MessageQueueSink could not be found. I did not find any way to get this working with appsetings.json so I started to look on how to bind this in code.

To get it working a extension hade to be created :

public static class MySinkExtensions
    {
        public static LoggerConfiguration MessageQueueSink(
                  this Serilog.Configuration.LoggerSinkConfiguration loggerConfiguration,
                  MyApp.Cloud.MQ.Interface.IMQProducer mQProducer = null)
        {
            return loggerConfiguration.Sink(new MyApp.Cloud.Serilog.MQSink.MessageQueueSink(mQProducer));
        }
    }

This made it possible to add the custom sink like this :

Host.CreateDefaultBuilder(args)
                    .UseMyAppCloudMQ(context => context.UseSettings(appSettings.MQSettings))
                     .ConfigureServices((hostContext, services) =>
                    {
                        services
                            .Configure<MQSettings>(configurationBuilder.GetSection("MQSettings"))
                    })
                    .UseSerilog((hostingContext, loggerConfiguration) => loggerConfiguration.ReadFrom.Configuration(hostingContext.Configuration).WriteTo.MessageQueueSink())
                    .Build().Run();

The custom sink is loaded and the Emit is triggered but I still do not know how to inject the MQ in to the sink? It would also be much better if I could do all the configuration of the Serilog and sink in the appsettings.json file.