RabbitMQ消费者作为Windows服务

Question

我有一个rabbitmq消费者应用程序实现“.net中的发布/订阅模式，它完美地作为控制台应用程序运行，但是当我将它部署为Windows服务时，它似乎不会保存数据到MongoDB的。

protected override void OnStart(string[] args) 
    { 
     try 
     { 
      var connectionString = "mongodb://localhost"; 
      var client = new MongoClient(connectionString); 
      var factory = new ConnectionFactory() { HostName = "localhost" };    
      using (var connection = factory.CreateConnection()) 
      { 
       using (var channel = connection.CreateModel()) 
       { 
        channel.ExchangeDeclare(exchange: "test", type: "fanout"); 
        var queueName = channel.QueueDeclare().QueueName; 
        channel.QueueBind(queue: queueName,          exchange: "logs", routingKey: ""); 

        var consumer = new EventingBasicConsumer(channel); 
        consumer.Received += (model, ea) => 
        { 
         var body = ea.Body; 
         var message = Encoding.UTF8.GetString(body); 
         BsonDocument document = BsonDocument.Parse(message); 
         var database = client.GetDatabase("test"); 
         var collection = database.GetCollection<BsonDocument>("test_collection"); 
         collection.InsertOneAsync(document); 
        }; 
        channel.BasicConsume(queue: queueName,          noAck: true,consumer: consumer); 

       } 
      } 
     } 
     catch (Exception ex) 
     { 
      throw; 
     } 
    } 

有什么我失踪？

Answer 1

在OnStart（）中忙于等待是一个糟糕的主意，因为操作系统会期待从它返回。在这里阅读：https://msdn.microsoft.com/en-us/library/zt39148a%28v=vs.110%29.aspx

编辑：上面的代码的问题是，你有你的连接和频道在using语句。这样做的全部意义在于将它们解决一次，超出范围。因此，在这种情况下，即使您添加了事件处理程序，您在退出范围并处理通道等操作之后不久，要解决此问题，请将连接，通道和使用者从“OnStart”方法中拉出并让他们成为班级（可能是私人）成员。即使您退出该方法并且您的活动应该继续收听，也应该保持其打开状态。

Answer 2

做以下修改到我的OnStart方法奏效了

protected override void OnStart(string[] args) 
    { 

     ConnectionFactory factory = new ConnectionFactory { HostName = localhost" }; 
     var connectionString = "mongodb://localhost"; 
     var client = new MongoClient(connectionString); 


     using (IConnection connection = factory.CreateConnection()) 
     { 
      using (IModel channel = connection.CreateModel()) 
      { 
       channel.ExchangeDeclare(exchange: "test", type: "fanout"); 

       string queueName = channel.QueueDeclare(); 

       channel.QueueBind(queueName, "test", ""); 

       this.EventLog.WriteEntry("Waiting for messages"); 

       QueueingBasicConsumer consumer = new QueueingBasicConsumer(channel); 
       channel.BasicConsume(queueName, true, consumer); 

       while (true) 
       { 
        BasicDeliverEventArgs e = (BasicDeliverEventArgs)consumer.Queue.Dequeue(); 
        var message = Encoding.UTF8.GetString(e.Body); 
        BsonDocument document = BsonDocument.Parse(message); 
        var database = client.GetDatabase("test"); 
        var collection = database.GetCollection<BsonDocument>("test_collection"); 
        collection.InsertOneAsync(document); 

       } 
      } 
     } 
    }