static async Task MainAsync(string[] args)
{
// This queue will be the source of message for InMemoryQueuePollingMessageSource.
Queue <SampleMessage> queue = new Queue <SampleMessage>();
// This message source will check the queue for any newly enqueued message every 1 second.
IMessageSource <SampleMessage> messageSource = new InMemoryQueuePollingMessageSource(queue, pollingInterval: TimeSpan.FromSeconds(1));
// This message processor will process messages received and published by the message source.
MessageProcessor <SampleMessage> messageProcessor = new SampleMessageProcessor(messageSource);
Console.WriteLine("Press any key to start message processing.");
Console.ReadLine();
Console.WriteLine("Starting...");
// Will not block.
await messageProcessor.StartAsync();
while (true)
{
Console.WriteLine("Enter number of messages to queue:");
string input = Console.ReadLine();
if (string.Equals(input, "stop", StringComparison.OrdinalIgnoreCase))
{
Console.WriteLine("Stopping...");
// Wait till last message is finished.
await messageProcessor.StopAsync();
break;
}
if (int.TryParse(input, out int num))
{
for (int i = 0; i < num; i++)
{
var message = new SampleMessage();
Console.WriteLine($"Message {message.Id}: Queued for processing.");
// Newly queued message will be detected by the InMemoryQueuePollingMessageSource
// and will publish the new message to be processed by SampleMessageProcessor.
queue.Enqueue(message);
}
}
}
}
public async Task ShouldStartAllMessageProcessorsAndForwardTheMessage()
{
// Message Flow:
// TestMessageProcessor1 --> TestMessageProcessor2 --> TestMessageProcessor3
// Message source for message processor 1
var inMemoryQueue1 = new Queue <TestMessage>();
var queueMessageSource1 = new InMemoryQueuePollingMessageSource(inMemoryQueue1, TimeSpan.FromSeconds(1));
// Message source for message processor 2
var inMemoryQueue2 = new Queue <TestMessage>();
var queueMessageSource2 = new InMemoryQueuePollingMessageSource(inMemoryQueue2, TimeSpan.FromSeconds(1));
// Message source for message processor 3
var inMemoryQueue3 = new Queue <TestMessage>();
var queueMessageSource3 = new InMemoryQueuePollingMessageSource(inMemoryQueue3, TimeSpan.FromSeconds(1));
var messageProcessor1 = new TestMessageProcessor1(queueMessageSource1);
var messageProcessor2 = new TestMessageProcessor2(queueMessageSource2);
var messageProcessor3 = new TestMessageProcessor3(queueMessageSource3);
MessageProcessorHost host = new MessageProcessorHostBuilder()
.AddMessageProcessor <TestMessage>(messageProcessor1)
.AddMessageProcessor <TestMessage>(messageProcessor2)
.AddMessageProcessor <TestMessage>(messageProcessor3)
.Build();
await host.StartAsync();
// Put message to message processor 1's queue.
var testMessage = new TestMessage();
inMemoryQueue1.Enqueue(testMessage);
// Wait for message to be passed to message processor 3
await Task.Delay(TimeSpan.FromSeconds(5));
Assert.True(messageProcessor3.IsHoldingMessage(testMessage.MessageId));
}
