Implementing Service To Service OAuth 2.0 Authentication For Spring Cloud OpenFeign Client In Spring Boot with Spring Security

Spring Cloud OpenFeign OAuth 2.0 Client Credentials Non-interactive S2S Authentication With Spring Security 5

In the world of micro-services, we often come across scenarios of service to service (S2S) communication that require service to establish their authenticity for successful dialogue exchange. Here I will walk you through the simple steps of establishing OAuth2 authenticity using client credentials flow for consumer service, using the Spring Security 5 framework, to be able to talk to supplier service.

For brevity, let’s get straight to the code:

Step 1) Include the dependencies:

#build.gradle

implementation 'org.springframework.boot:spring-boot-starter-web'
implementation 'org.springframework.boot:spring-boot-starter-oauth2-client'
implementation 'org.springframework.cloud:spring-cloud-starter-openfeign'

Step 2) Spring configuration:

#application.yml

spring.security.oauth2.client:
  registration:
    #Repeat block for any number of AuthZ servers
    bar-auth: #unique supplier service name
      client-id: DUMMY_CLIENT_ID_XXX
      client-secret: DUMMY_CLIENT_SECRET_YYYY
      authorization-grant-type: client_credentials
      client-authentication-method: post
  provider:
    #Repeat block for any number of AuthZ servers
    bar-auth:
      token-uri…