public static async Task Main(string[] args)
{
Config fallbackConfig = ConfigurationFactory.ParseString(@"
akka.suppress-json-serializer-warning=true
akka.loglevel = DEBUG
").WithFallback(ConfigurationFactory.FromResource <ConsumerSettings <object, object> >("Akka.Streams.Kafka.reference.conf"));
var system = ActorSystem.Create("TestKafka", fallbackConfig);
var materializer = system.Materializer();
var consumerSettings = ConsumerSettings <Null, string> .Create(system, null, null)
.WithBootstrapServers($"{EventHubNamespace}.servicebus.windows.net:9093")
.WithGroupId(EventHubConsumerGroup)
.WithProperties(new Dictionary <string, string>
{
{ "security.protocol", "SASL_SSL" },
{ "sasl.mechanism", "PLAIN" },
{ "sasl.username", "$ConnectionString" },
{ "sasl.password", EventHubConnectionString },
});
var subscription = Subscriptions.Topics(EventHubName);
var committerDefaults = CommitterSettings.Create(system);
// Comment for simple no-commit consumer
DrainingControl <NotUsed> control = KafkaConsumer.CommittableSource(consumerSettings, subscription)
.SelectAsync(1, msg =>
Business(msg.Record).ContinueWith(done => (ICommittable)msg.CommitableOffset))
.ToMaterialized(
Committer.Sink(committerDefaults.WithMaxBatch(1)),
DrainingControl <NotUsed> .Create)
.Run(materializer);
// Uncomment for simple no-commit consumer
/*
* await KafkaConsumer.PlainSource(consumerSettings, subscription)
* .RunForeach(result =>
* {
* Console.WriteLine($"Consumer: {result.Topic}/{result.Partition} {result.Offset}: {result.Value}");
* }, materializer);
*/
Console.WriteLine("Press any key to stop consumer.");
Console.ReadKey();
// Comment for simple no-commit consumer
await control.Stop();
await system.Terminate();
}
public async Task SupervisionStrategy_Decider_on_complex_stream_should_work()
{
var topic = CreateTopic(1);
var group = CreateGroup(1);
var topicPartition = new TopicPartition(topic, 0);
var committedTopicPartition = new TopicPartition($"{topic}-done", 0);
var callCount = 0;
Directive Decider(Exception cause)
{
callCount++;
return(Directive.Resume);
}
var committerSettings = CommitterSettings.Create(Sys);
var consumerSettings = CreateConsumerSettings <string>(group);
var counter = 0;
// arrange
await Source.From(Enumerable.Range(1, 10))
.Select(elem => new ProducerRecord <Null, string>(topicPartition, elem.ToString()))
.RunWith(KafkaProducer.PlainSink(ProducerSettings), Materializer);
// act
var drainingControl = KafkaConsumer.CommittableSource(consumerSettings, Subscriptions.Assignment(topicPartition))
.Via(Flow.Create <CommittableMessage <Null, string> >().Select(x =>
{
counter++;
// Exception happened here, fail once, when counter is 5
if (counter == 5)
{
throw new Exception("BOOM!");
}
return(x);
}))
.WithAttributes(Attributes.CreateName("CommitableSource").And(ActorAttributes.CreateSupervisionStrategy(Decider)))
.Select(c => (c.Record.Topic, c.Record.Message.Value, c.CommitableOffset))
.SelectAsync(1, async t =>
{
Log.Info($"[{t.Topic}]: {t.Value}");
// simulate a request-response call that takes 10ms to complete here
await Task.Delay(10);
return(t);
})
.Select(t => ProducerMessage.Single(new ProducerRecord <Null, string>(committedTopicPartition, t.Value),
t.CommitableOffset))
.Via(KafkaProducer.FlexiFlow <Null, string, ICommittableOffset>(ProducerSettings)).WithAttributes(Attributes.CreateName("FlexiFlow"))
.Select(m => (ICommittable)m.PassThrough)
.AlsoToMaterialized(Committer.Sink(committerSettings), DrainingControl <NotUsed> .Create)
.To(Flow.Create <ICommittable>()
.Async()
.GroupedWithin(1000, TimeSpan.FromSeconds(1))
.Select(c => c.Count())
.Log("MsgCount").AddAttributes(Attributes.CreateLogLevels(LogLevel.InfoLevel))
.To(Sink.Ignore <int>()))
.Run(Sys.Materializer());
await Task.Delay(TimeSpan.FromSeconds(5));
await GuardWithTimeoutAsync(drainingControl.DrainAndShutdown(), TimeSpan.FromSeconds(10));
// There should be only 1 decider call
callCount.Should().Be(1);
// Assert that all of the messages, except for those that failed in the stage, got committed
var settings = CreateConsumerSettings <Null, string>(group);
var probe = KafkaConsumer
.PlainSource(settings, Subscriptions.Assignment(committedTopicPartition))
.Select(c => c.Message.Value)
.RunWith(this.SinkProbe <string>(), Materializer);
probe.Request(9);
var messages = new List <string>();
for (var i = 0; i < 9; ++i)
{
var message = probe.RequestNext();
messages.Add(message);
}
// Message "5" is missing because the exception happened downstream of the source and we chose to
// ignore it in the decider
messages.Should().BeEquivalentTo(new[] { "1", "2", "3", "4", "6", "7", "8", "9", "10" });
probe.Cancel();
}