I am using Spring Cloud Contract, now I am making an integration test for event driven microservices.
Can i combine both Spring Cloud Contract (messaging) with Kafka container running on TestContainer? I want to use the StubTrigger of course but it should fetch the message also from my Kafka topic. Any suggestion? Does it even make sense? I think i am mixing the concepts.
Yes you can. You can check out the examples with kafka and testcontainers here https://github.com/spring-cloud-samples/spring-cloud-contract-samples/tree/main/consumer_kafka_middleware and here https://github.com/spring-cloud-samples/spring-cloud-contract-samples/tree/main/producer_kafka_middleware
Related
I want to do some integration testing in a spring boot project, where kafka is used.
For these tests I don't want any messages to be sent or received from kafka. Is there a way to configure this?
Kafka test containers help me to do integration tests with kafka
. May be it'll help you.
Do we need to use anyone framework like eventuate, camunda, etc. for implementing Orchestration-based SAGA microservices in spring boot?
You can use eventuate framework to setup a Orchestration-based Saga.
You will need to add Orchestra-tor dependency to your orchestra-tor, and participant dependencies to all the participant micro-services.
You will also need to run Eventuate CDC tram service, which enables the Transctional messaging services along with the DB.
Try this link and join the slack channel, Mr Cris himself will answer to your issues. Mostly in few hours or a day.
https://github.com/eventuate-tram/eventuate-tram-sagas-examples-customers-and-orders
Using Kafka as a messaging system in a microservice architecture what are the benefits of using spring-kafka vs. spring-cloud-stream + spring-cloud-starter-stream-kafka ?
The spring cloud stream framework supports more messaging systems and has therefore a more modular design. But what about the functionality ? Is there a gap between the functionality of spring-kafka and spring-cloud-stream + spring-cloud-starter-stream-kafka ?
Which API is better designed?
Looking forward to read about your opinions
Spring Cloud Stream with kafka binder rely on Spring-kafka. So the former has all functionalities supported by later, but the former will be more heavyweight. Below are some points help you make the choice:
If you might change kafka into another message middleware in the future, then Spring Cloud stream should be your choice since it hides implementation details of kafka.
If you want to integrate other message middle with kafka, then you should go for Spring Cloud stream, since its selling point is to make such integration easy.
If you want to enjoy the simplicity and not accept performance overhead, then choose spring-kafka
If you plan to migrate to public cloud service such as AWS Kensis, Azure EventHub, then use spring cloud stream which is part of spring cloud family.
Use Spring Cloud Stream when you are creating a system where one channel is used for input does some processing and sends it to one output channel. In other words it is more of an RPC system to replace say RESTful API calls.
If you plan to do an event sourcing system, use Spring-Kafka where you can publish and subscribe to the same stream. This is something that Spring Cloud Stream does not allow you do do easily as it disallows the following
public interface EventStream {
String STREAM = "event_stream";
#Output(EventStream.STREAM)
MessageChannel publisher();
#Input(EventStream.STREAM)
SubscribableChannel stream();
}
A few things that Spring Cloud Stream helps you avoid doing are:
setting up the serializers and deserializers
We are using plain Spring AMQP in our spring boot projects.
We want to make sure that our message consumers can test against real messages and avoid to test against static test messages.
Thus our producers could generate message snippets in a test phase that can be picked up by the consumer test to make sure it tests against the latest message version and see if changes in the producer break the consumer.
It seems like Spring Cloud Contract does exactly that. So is there a way to integrate spring cloud contract with spring amqp? Any hints in which direction to go would be highly appreciated.
Actually we don't support it out of the box but you can set it up yourself. In the autogenerated tests we're using an interface to receive and send messages so
you could implement your own class that uses spring-amqp. The same goes for the consumer side (the stub runner). What you would need to do is to implement and register a bean of
org.springframework.cloud.contract.verifier.messaging.MessageVerifier type for both producer and consumer. This should work cause what we're doing in the autogenerated tests is that we #Inject MessageVerifier
so if you register your own bean it will work.
UPDATE:
As #Mathias has mentioned it, the AMQP support is already there in Spring Cloud Contract https://cloud.spring.io/spring-cloud-contract/spring-cloud-contract.html#_stub_runner_spring_amqp
I use spring cloud config bus (rabbitmq) in my micro-service. Only purpose for me to use rabbitmq in my microservice is spring cloud bus... I have 2 questions below.
When I was experimenting, I found that spring expects rabbitmq to be UP and running during application start. Which is contrary to what Spring cloud evangelises... (Circuit breakers...) To be fair, even service discovery is not expected to be up and running before starting an application. Is there any sensible reason behind this...?
Say, I start my application when rabbitmq is up and running. For some reason, rabbitmq goes down... What I should be losing is just my ability to work with rabbitmq... instead, /health endpoint responds back as DOWN for my micro-service. Any eureka instance listening to heart beats from my micro-service is also marking the instance as down. Any reasons for doing this...?
To my knowledge, this is against the circuit breaker pattern that spring cloud has evangelised.
I personally feel that spring cloud config bus is not an important feature to mark an application as down...
Is there any alternatives to tell my spring boot micro-service that connection to rabbitmq is not a critical service?
Thanks in advance!