RabbitMQ consumer as a windows service

问题

I have a rabbitmq consumer application implementing "publish/subscribe pattern in .net, which runs perfectly as a console application but when I deploy that as a windows service it does not seem to be saving the data into mongodb.

    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;
        }
    }

Is there something that I'm missing?

回答1:

It's a bad idea to have a busy wait in OnStart() because the operating system will be expecting a return from it. Read here: https://msdn.microsoft.com/en-us/library/zt39148a%28v=vs.110%29.aspx

Edit: The problem with the code above is that you have your connection and channel in the using statements. The whole point of doing that is to Dispose them once out of scope. So in this case even though you're adding a event handler, you're shortly after exiting out of scope and disposing of the channel, etc. To fix this, pull the connection, channel, and consumer out of the `OnStart' method and make them class (probably private) members. That should keep them open even when you exit the method and your event should keep listening.

回答2:

Today we need made RabbitMQ consumer as a windows service and solve with Timer in method OnStart.

private Timer _timer;

protected override void OnStart(string[] args)

{
     _timer = new Timer();
     _timer.Interval = 5000; 
     _timer.Elapsed += new ElapsedEventHandler(this.OnTimer);
     _timer.Start();
}

public void OnTimer(object sender, System.Timers.ElapsedEventArgs args)
{
     _timer.Enabled = false;

     ...
}

Many thanks for the help and hope to have helped with this solution too

回答3:

Making the following changes to my Onstart method did the trick

    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);

                }
            }
        }
    }

来源：https://stackoverflow.com/questions/33702564/rabbitmq-consumer-as-a-windows-service