use standard port 9092 in KafkaContainer

[bsideup]

See #732

[iNikem]

@bsideup When can we expect a public release for this? :)

[kiview]

Looks like an elegant solution to me.

[kiview]

I think it would be more consistent to use KAFKA_PORT here (as well as in line 35).

[bsideup]

@kiview changed to constants, could you please re-check?

[bsideup]

@iNikem we prepare some exciting changes (e.g. #710 ) for a next release, but if it will take more than it should, we will cut another minor release soon-ish to release what's done already

[kiview]

LGTM 👍

[iNikem]

Now, coming back to this after 2 months, I discovered that I don't understand how I should use KafkaContainer now :)

1. How do I connect to it from my test?
2. How do I connect to it from another test container?

@bsideup Can you help me? Then I probably will can make a PR to your official documentation :)

[bsideup]

@iNikem that would be amazing!

1. use kafka.getBootstrapServers()
2. put them into the same network (or use Kafka's network) and use port 9092. Example: https://github.com/bsideup/liiklus/blob/5faecebde8728865dff2bd7968b306b4fbedad1b/examples/plugin/src/test/java/com/github/bsideup/liiklus/plugins/example/support/AbstractIntegrationTest.java#L31

[YNedderhoff]

@bsideup @iNikem has this been documented in the meantime? I am trying the exact use case right now. I have all containers including the application that uses Kafka in one Network. Then I have tests outside the network. The producer in the tests connects fine using getBootstrapServers(). If I use kafka:9093 in the application, it says that it can not connect to the broker localhost:<mappedPort>, which makes sense I think? But when I use kafka:9092, the app complains about this instead:

2019-09-05 15:40:08,903 WARN  [   o.a.k.clients.NetworkClient] [] - [Consumer clientId=consumer-1, groupId=myGroupId] Error while fetching metadata with correlation id 2 : {myTopic=LEADER_NOT_AVAILABLE}

A quick google indicates it might have something to do with advertised hosts?

[iNikem]

@YNedderhoff With recent versions of testcontainers the following setup works nicely for me:

1. Create a network for all your containers: private Network network = Network.newNetwork()
2. Put all containers on this network and give them aliases:
   private KafkaContainer kafka = new KafkaContainer().withNetwork(network).withNetworkAliases('kafka')

Then all containers can access Kafka on kafka:9092. Your test, which runs outside the container, can access kafka on kafka.getBootstrapServers()

[YNedderhoff]

That's precisely my setup. Maybe it is actually working, I just know that my Spring app complains with that LEADER_NOT_AVAILABLE error I quoted above. I haven't actually fully tried to use Kafka in the tests yet, I am still in the setup phase.

[YNedderhoff]

Ok - I think you are right. Despite that message the app seems to consume data alright. Confusing, but nice that it works :) Thank you!