RabbitMQ随手笔记（十）利用RabbitMQ记录日志(.netCore2.0)

本例中，我们将添加一个功能 - 我们将只能订阅一部分消息。例如，我们只能将重要的错误消息引导到日志文件（以节省磁盘空间），同时仍然能够在控制台上打印所有日志消息。C1代表记录日志到日志文件的消费者，C2代表在控制台打印出来日志的消费者，通过不同的routingKey绑定到不同的队列。
一个Exchange可以通过同一个routingKey来bind多个队列
也可以只bind一个队列
接下来我们介绍一个记录日志的sample：



我们将使用这个模型我们的日志系统. 我们用direct类型的exchange.我们将提供日志severity作为路由的关键routing key. 这样接收脚本将能够选择严重性要收到.
日志记录发起方 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();
}
}

日志记录接收方 ReceiveLogsDirect.cs
using System;
using RabbitMQ.Client;
using RabbitMQ.Client.Events;
using System.Text;

class ReceiveLogsDirect
{
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 queueName = channel.QueueDeclare().QueueName;

if(args.Length < 1)
{
Console.Error.WriteLine("Usage: {0} [info] [warning] [error]",
Environment.GetCommandLineArgs()[0]);
Console.WriteLine(" Press [enter] to exit.");
Console.ReadLine();
Environment.ExitCode = 1;
return;
}

foreach(var severity in args)
{
channel.QueueBind(queue: queueName,
exchange: "direct_logs",
routingKey: severity);
}

Console.WriteLine(" [*] Waiting for messages.");

var consumer = new EventingBasicConsumer(channel);
consumer.Received += (model, ea) =>
{
var body = ea.Body;
var message = Encoding.UTF8.GetString(body);
var routingKey = ea.RoutingKey;
Console.WriteLine(" [x] Received '{0}':'{1}'",
routingKey, message);
};
channel.BasicConsume(queue: queueName,
autoAck: true,
consumer: consumer);

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