public IConnection Create(ConnectionType type)
{
var endpoints = _hostNames
.Select(node =>
{
var parts = node.Split(":", StringSplitOptions.RemoveEmptyEntries);
var hostName = parts[0];
if (parts.Length == 1)
{
return(new AmqpTcpEndpoint(hostName));
}
var port = int.Parse(parts[1]);
return(new AmqpTcpEndpoint(hostName, port));
}).ToArray();
var endpointResolver = new DefaultEndpointResolver(endpoints);
var identity = type.ToString().ToLower();
var id = $"{_serviceId}/{identity}";
if (_connectionFactory == null)
{
lock (this)
{
_connectionFactory ??= CreateConnectionFactory(_userName, _password, _virtualHost, id, type);
}
}
return(_connectionFactory.CreateConnection(endpointResolver, id));
}
protected void Connect()
{
try
{
/*
* When you create a new vhost on a cluster - don't forget to enable a HA-policy for that vhost (even if you don’t have
* a HA setup, you will need it for plan changes). Messages will not be synced between nodes without an HA-policy.
*/
IEndpointResolver endpointResolver = new DefaultEndpointResolver(_connectionConfig.EndPoints);
// Builds up url in the format
// "amqp://*****:*****@192.168.1.1:5672/virtual-host"
var factory = new ConnectionFactory
{
UserName = _connectionConfig.UserName,
Password = _connectionConfig.Password,
VirtualHost = _connectionConfig.VirtualHost,
HandshakeContinuationTimeout = new TimeSpan(TimeSpan.TicksPerSecond * 5),
RequestedConnectionTimeout = 3000
};
_logger.LogInformation($"Connecting...");
_connection = factory.CreateConnection(endpointResolver, "this is my client name");
_logger.LogInformation(
$"Connected to {_connection.Endpoint.HostName}:{_connection.Endpoint.Port}"); // successful and unsuccessful client connection events can be observed in server node logs
_channel = _connection.CreateModel();
/*
* ExchangeType.Direct - A message goes to the queue(s) whose binding key exactly matches the routing key of the message.
*
* ExchangeType.Fanout - The fanout copies and routes a received message to all queues that are bound to it regardless of
* routing keys or pattern matching as with direct and topic exchanges. Keys provided will simply be ignored.
* Fanout exchanges can be useful when the same message needs to be sent to one or more queues with
* consumers who may process the same message in different ways.
*
* ExchangeType.Headers - Headers exchanges route based on arguments containing headers and optional values. Headers exchanges
* are very similar to topic exchanges, but it routes based on header values instead of routing keys.
* A message is considered matching if the value of the header equals the value specified upon binding.
*
* ExchangeType.Topic - Topic exchanges route messages to queues based on wildcard matches between the routing key and
* the routing pattern specified by the queue binding. Messages are routed to one or many queues based
* on a matching between a message routing key and this pattern.
* eg; crypro.gdax.btc.usd.hour-1 stock.lse.gsk.gbp.hour-24
*
* Dead Letter Exchange - If no matching queue can be found for the message, the message is silently dropped. RabbitMQ provides
* an AMQP extension known as the "Dead Letter Exchange" - the dead letter exchange provides functionality
* to capture messages that are not deliverable.
*/
_channel.ExchangeDeclare(_channelConfig.ExchangeName, ExchangeType.Direct);
_channel.ModelShutdown += Channel_ModelShutdown;
// Persistent messages and durable queues for a message to survive a server restart = resilient / lower performance
// for high throughput send transient messages to non-lazy queues
// Limit queue size with TTL or max-length (queue will discard messages from the head of queue to keep within mex-length)
_channel.QueueDeclare(_channelConfig.QueueName, true, false, false, null);
_channel.QueueBind(_channelConfig.QueueName, _channelConfig.ExchangeName,
_channelConfig.RoutingKey, null);
// https://rabbitmq.github.io/rabbitmq-dotnet-client/api/RabbitMQ.Client.IModel.html
_logger.LogInformation(
$"Using channel {_channel.ChannelNumber}, which has timeout of {_channel.ContinuationTimeout.TotalSeconds} seconds");
_isConnected = true;
}
catch (BrokerUnreachableException)
{
_logger.LogError("Coinbase.Application.RabbitMq.Client.Connect() None of the specified endpoints were reachable; endpoints: {EndPoints} vhost: {VirtualHost}",
string.Join(',', _connectionConfig.EndPoints.Select(i => $"{i.HostName}:{i.Port}")),
_connectionConfig.VirtualHost);
}
catch (Exception e)
{
_logger.LogError(e, "Unhandled exception during Coinbase.Application.RabbitMq.Client.Connect");
}
}
