Access to new RabbitMQ messages from windows service

问题

I am trying to read new messages from RabbitMQ using a Windows service but the event of receiving new messages doesn't fire. This service could be launched as a Console Application in Debug Mode. In this case the event fires and I can read new messages. The service is launched with the user I use to log into Windows. This is a part of code in the OnStart service event handler

var factory = new ConnectionFactory() { HostName = "localhost" };
                using (var conn = factory.CreateConnection())
                {
                    using (var channel = conn.CreateModel())
                    {
                        channel.ExchangeDeclare("sm_posts", "fanout");
                        var argu = new Dictionary<string, object>();
                        argu.Add("x-max-length", 10000);

                        var consumerQueue = channel.QueueDeclare().QueueName;
                        channel.QueueBind(queue: consumerQueue, exchange: "sm_posts", routingKey: "");
                        var consumer = new EventingBasicConsumer(channel);

                        log.Info("Waiting for new messages...");

                        consumer.Received += (model, ea) =>
                        {
                            count++;
                            var body = ea.Body;
                            var message = Encoding.UTF8.GetString(body);

                            log.Info(message + "\n\n\n\n\n");

Why doesn't the windows service receive messages whereas when it is launched as Console application in Debug Mode it does receive messages?

回答1:

When you're working with windows services you have to change your code a bit. your code will work fine within a console mode app but not a windows service, your Connection, Channel and Consumer objects must be declared globally as class private members something like this:

private static ConnectionFactory _factory;
private static IConnection _connection;
private static IModel _channel;
private static EventingBasicConsumer _consumer;

Then OnStart method you can create your Connection and Channel objects i.e

    protected override void OnStart(string[] args)
            {
                _factory = new ConnectionFactory()
                {
                    HostName = "Host",
                    UserName = "username",
                    Password = "password"
                };
                _connection = _factory.CreateConnection();
                _channel = _connection.CreateModel();

                _channel.QueueDeclare(queue: _queueName, durable: false, exclusive: false,autoDelete: false, arguments: null);

                _consumer = new EventingBasicConsumer(_channel);

                _consumer.Received += (s, ev) =>
                {
                    //Handle messages here.
                };

                _channel.BasicConsume(queue: _queueName, autoAck: true, consumer: _consumer);
            }

Finally don't forget to dispose and close the connection and the channel upon the windows service stopping.

 protected override void OnStop()
        {
            _channel.Close();
            _connection.Close();
            _channel.Dispose();
            _connection.Dispose();
        }

回答2:

Check the user running the service (Log on As) if it has the right permissions to run what you have in the service

来源：https://stackoverflow.com/questions/43879901/access-to-new-rabbitmq-messages-from-windows-service

标签

windows-services

RabbitMQ