using @FeignClient in spring currently has one fatal issue, which is demonstrated with this repository.

You will need BASH, Java 8 SDK and docker, to run the test script. During the test, ports 8761 and 8080 have to be free to use.

To run the entire test, just

./test.sh

This script is:

• starting an eureka server
• starting producer service
• running WebIntegrationTests from the consumer service
• terminating the producer
• stopping an removing the eureka container

We assume some foreign service, serving "foo" entities. You have to be authenticated to access this the foo resource and have a role "USER". If you have "ADMIN", you will see different data, as when "USER".

This behavior is implemented using plain spring boot with spring security in the "producer" service. Additionally it registers to an eureka instance, so some "consumer" service is able to fetch this.

So the consumer service should fetch data from consumer, automatically passing basic auth of "users he know". While this may not clearly makes sense for real world, something very similar is happening consuming OAuth2 secured resource servers with client credentials grant! So to get the data correctly, we define 2 clients, with individually set up basic auth credentials using feign client configuration.

Since the main application does not use @SpringBootApplication, but @EnableAutoConfiguration, and an exclude filter on @ComponentScan, the two different configuration do not declare the internal beans.

So the expected result of these 2 clients is: the UserFooClient retrieving at least a foo entity with value "user1", while the AdminFooClients result should contain a "admin1" foo.

To verify, which result is intended, the same test is done using plain old RestTemplate.

This issue leads towards we can't really use multiple feign clients in spring boot using the @FeignClient annotation, because as soon one client is using some authorization flow (basic, oauth2), this is applied to all other clients.