General
General Characteristics of Messaging
- Asynchronous
- Can be reliable
- Can be durable
- Routing
- Many message formats
- Recipients pull messages from a queue
Key Concepts of AMQP
- Message Broker (Centralized system that other systems would hook in to for messages)
- Exchanges (Direct, Fan-Out, Topic, Headers)
- Queues (FIFO)
- Bindings (Binds an exchange to a queueu)
Queue Persistance
- Durable (Msg saved to disk, Msg is still alive after server restart)
- Non-Durable (Msg only held in memory, better performance)
Messaging Patterns
- Simple One Way Message Pattern
- Worker Queues Patter
- Publish Subscribe Pattern
- Remote Procedure Call Pattern
Installing RabitMq
RabbitMQ Web Portal
To Enable Web Portal
rabbitmq-plugins enable rabbitmq_management
Web Portal Default Url
http://server-name:15672/
Default web login credentials are :
username : guest
password : guest
Command Line Tools
- RabbitMqCtl (Stop, Reset, Stop_app, Start_app)
- RabbitMq-Service (Stop, Start, Install)
List all exchanges
rabbitmqctl list_exchanges
.Net Specific Stuff
Nuget Install
- RabbitMQ.Client
Install-Package RabbitMQ.Client
Api Types with .Net
- IConnection
- IModel
- ConnectionFactory
- QueueingBasicConsumer
- Protocols
Basic Example
var connectionFactory = new RabbitMQ.Client.ConnectionFactory() { ... };
var connection = connectionFactory.CreateConnection();
var model = connection.CreateModel();
Send a Basic Message
static void SendMessage()
{
var factory = new ConnectionFactory() {HostName = "localhost"};
using (var connection = factory.CreateConnection())
{
using (var channel = connection.CreateModel())
{
channel.QueueDeclare("hello", false, false, false, null);
var message = "Hello Worlds!";
var body = Encoding.UTF8.GetBytes(message);
channel.BasicPublish("", "hello", null, body);
Console.WriteLine(" [x] Sent {0}", message);
}
}
}
Receive a Basic Message
static void ReceivedMessages()
{
var factory = new ConnectionFactory() {HostName = "localhost"};
using (var connection = factory.CreateConnection())
{
using (var channel = connection.CreateModel())
{
channel.QueueDeclare("hello", false, false, false, null);
var consumer = new QueueingBasicConsumer(channel);
channel.BasicConsume("hello", true, consumer);
Console.WriteLine(" [*] Waiting for messages." + "To exit press Ctrl+C");
while (true)
{
var ea = (BasicDeliverEventArgs) consumer.Queue.Dequeue();
var body = ea.Body;
var message = Encoding.UTF8.GetString(body);
Console.WriteLine(" [x] Recieved {0}", message);
}
}
}
}
Serialization & Data
Encoding a String
Object -> byte array = Serialization
var message = "Hello Worlds!";
var body = Encoding.UTF8.GetBytes(message);
Byte array -> object = De-serialization
var message = Encoding.UTF8.GetString(body);
Encoding a Object
Assume you have an object of type MyMessage.
Object -> byte array = Serialization
var jsonString = Newtonsoft.Json.JsonConvert.SerializeObject(myMessage);
byte[] messageBuffer = Encoding.Default.GetBytes(jsonString);
Byte array -> object = De-serialization
var jsonString = Encoding.Default.GetString(deliveryArgs.Body);
var myMessage = Newtonsoft.Json.JsonConvert.DeserializeObject<MyMessage>(jsonString);
References
Explanation about AMQP on RabbitMQ
Getting started tutorials
PluralSight RabbitMQ for .Net Part 1
