public async Task ConsumerCanPickUpWhereItLeftOff()
{
var receivedStrings = new ConcurrentQueue <string>();
var topic = BrokerFactory.GetNewTopic();
var producer = BrokerFactory.ConfigureProducer()
.Topics(m => m.Map <string>(topic))
.Create();
Using(producer);
IDisposable CreateConsumer(InMemPositionsStorage storage)
{
return(BrokerFactory.ConfigureConsumer("default-group")
.Handle(async(messages, token) =>
{
var strings = messages.Select(m => m.Body).Cast <string>();
receivedStrings.Enqueue(strings);
})
.Topics(t => t.Subscribe(topic))
.Positions(p => p.StoreInMemory(storage))
.Start());
}
var positionsStorage = new InMemPositionsStorage();
const string partitionKey = "same-every-time";
using (CreateConsumer(positionsStorage))
{
await producer.Send("HEJ", partitionKey : partitionKey);
await producer.Send("MED", partitionKey : partitionKey);
await producer.Send("DIG", partitionKey : partitionKey);
string GetFailureDetailsFunction() => $@"Got these strings:
{receivedStrings.ToPrettyJson()}";
await receivedStrings.WaitOrDie(
completionExpression : q => q.Count == 3,
failExpression : q => q.Count > 3,
failureDetailsFunction : GetFailureDetailsFunction
);
}
Console.WriteLine($@"Got these positions after FIRST run:
{string.Join(Environment.NewLine, positionsStorage.GetAll(topic).Select(position => $" {position}"))}
");
using (CreateConsumer(positionsStorage))
{
await producer.Send("MIN", partitionKey : partitionKey);
await producer.Send("SØDE", partitionKey : partitionKey);
await producer.Send("VEN", partitionKey : partitionKey);
await receivedStrings.WaitOrDie(q => q.Count == 6, failExpression : q => q.Count > 6);
// additional delay to be absolutely sure that no additional messages arrive after this point
await Task.Delay(TimeSpan.FromSeconds(1));
}
Console.WriteLine($@"Got these positions after SECOND run:
{string.Join(Environment.NewLine, positionsStorage.GetAll(topic).Select(position => $" {position}"))}
");
Assert.That(receivedStrings.Count, Is.EqualTo(6), $@"Queue did not contain 6 strings as expected:
{receivedStrings.ToPrettyJson()}");
var expectedReceivedStrings = new[]
{
"HEJ",
"MED",
"DIG",
"MIN",
"SØDE",
"VEN",
};
Assert.That(receivedStrings, Is.EqualTo(expectedReceivedStrings), $@"
Expected
{string.Join(", ", expectedReceivedStrings)}
but got
{string.Join(", ", receivedStrings)}
");
}
