When a @SagaEventHandler needs to fetch data from another Microservice that also uses Axon Framework, is it a good practice to use QueryGateway to query another Microservice? Or it is better to use something like RestTemplate to call another Microservice from a @SagaEventHandler method?
Thank you
In my opinion, you can go any way as both of them have pros and cons.
But, since you are already using Axon, I would go with that because of the benefits of location transparency and all the types of query you get by granted from AxonFramework (point-to-point, scatter gather and subscription query).
Bear in mind that, when using "components" on the Saga, make them transient to not have them serializable.