I want to delete several queues on our RabbitMQ server and have some code that looks like this:
string[] queuesToDelete = new[] {
"QueueThatExists1",
"QueueThatDoesn'tExist", // this queue causes an error - which I expect
"QueueThatExists2" }; // this queue also errors - which I don't expect
IConnectionFactory factory = ...
using (IModel = factory.CreateModel()) {
foreach (string queue in queuesToDelete) {
try {
model.QueueDelete(queue);
Console.WriteLine("Queue {0} deleted");
} catch (Exception e) {
Console.WriteLine("Queue {0} could not be deleted because {1}", queue, e);
}
}
}
However I get this as output:
Queue QueueThatExists1 deleted
Queue QueueThatDoesn'tExist could not be deleted because Queue Not Found
Queue QueueThatExists2 could not be deleted because Already Closed
I have changed the code to look more like this (which works as I expect):
string[] queuesToDelete = new[] {
"QueueThatExists1",
"QueueThatDoesn'tExist", // this queue causes an error - which I expect
"QueueThatExists2" }; // this queue also errors - which I don't expect
IConnectionFactory factory = ...
IModel model;
try {
model = factory.CreateModel();
foreach (string queue in queuesToDelete) {
try {
model.QueueDelete(queue);
Console.WriteLine("Queue {0} deleted");
} catch (Exception e) {
Console.WriteLine("Queue {0} could not be deleted because {1}", queue, e);
// reset the connection
model.Dispose();
model = factory.CreateModel();
}
} finally {
if (model != null)
model.Dispose();
}
}
However this looks bad. I have removed a using
statement and hand rolled the same thing with a try - finally
block. It feels like I am fighting the API. Question: Is there a more elegant way of achieving the same result?
I notice that RabbitMQ for java has lyra and autorecovery , but cannot find anything similar for C#.
Check out project EasyNetQ .
EasyNetQ implement subscriber reconnection ( EasyNetQ doc ).
Instead of a try/catch I recommend checking if that you're interested in exists. You can do this with the API. Here is our method to do that:
private bool DoesSomethingExist(string something, string queueOrExchange)
{
var connectionInfo = GetRabbitConnectionInfo();
var url = string.Format("{0}/{1}/{2}/{3}", connectionInfo.APIUrl, queueOrExchange, connectionInfo.VirtualHostName, something);
using (var client = new HttpClient())
{
var byteArray = Encoding.ASCII.GetBytes(string.Format("{0}:{1}", connectionInfo.UserName, connectionInfo.Password));
client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray));
var response = client.GetAsync(url).Result;
if (response.StatusCode == HttpStatusCode.OK)
{
return true;
}
if (response.StatusCode == HttpStatusCode.NotFound)
{
return false;
}
var content = response.Content;
throw new Exception(string.Format("Unhandled API response code of {0}, content: {1}", response.StatusCode, content));
}
}
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