EmitLogDirect.cs

using System;
using System.Linq;
using RabbitMQ.Client;
using System.Text;

class EmitLogDirect
{
    public static void Main(string[] args)
    {
        var factory = new ConnectionFactory() { HostName = "localhost" };
        using(var connection = factory.CreateConnection())
        using(var channel = connection.CreateModel())
        {
            channel.ExchangeDeclare(exchange: "direct_logs", type: "direct");

            var severity = (args.Length > 0) ? args[0] : "info";
            var message = (args.Length > 1) ? string.Join(" ", args.Skip(1).ToArray()) : "Hello World!";
            var body = Encoding.UTF8.GetBytes(message);
            channel.BasicPublish(exchange: "direct_logs", routingKey: severity, basicProperties: null, body: body);
            Console.WriteLine(" [x] Sent '{0}':'{1}'", severity, message);
        }

        Console.WriteLine(" Press [enter] to exit.");
        Console.ReadLine();
    }
}