Configuration

Reference for application.yaml, Config Server, and ecosystem integration.

Config Server Integration

The gateway pulls its routing configuration from the Spring Cloud Config Server at startup. This is the primary mechanism for defining routes centrally.

> Yaml code-highlight

spring:
  config:
    import: 'configserver:'
  cloud:
    config:
      uri: http://localhost:8090
  application:
    name: arya-banking-api-gateway

The spring.application.name determines which config file is fetched — arya-banking-api-gateway.yml from the Config Server.

Dockerized Deployment

The API Gateway runs as a container in the platform stack alongside the Service Registry and Config Server. It is defined in compose/platform.yml:

> Yaml code-highlight

api-gateway:
  image: karthikulkarni/arya-banking-api-gateway:latest
  container_name: api-gateway
  ports:
    - "8085:8085"
  environment:
    EUREKA_CLIENT_SERVICEURL_DEFAULTZONE: http://service-registry:8761/eureka/
    SPRING_CLOUD_CONFIG_URI: http://config-server:8090
  depends_on:
    service-registry:
      condition: service_started
    config-server:
      condition: service_healthy
  networks:
    - arya-banking-net

See the Infrastructure → Docker Compose page for the full platform stack.

Service Discovery

The gateway registers with Eureka for both advertisement and downstream route resolution.

> Yaml code-highlight

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka

Keycloak Integration

The gateway acts as both an OAuth2 Client (browser login) and OAuth2 Resource Server (JWT validation).

> Yaml code-highlight

app:
  config:
    keycloak:
      url: http://localhost:5433/
      realm: event-based-banking-application

spring:
  security:
    oauth2:
      client:
        provider:
          keycloak:
            token-uri: ${app.config.keycloak.url}/realms/${app.config.keycloak.realm}/protocol/openid-connect/token
            authorization-uri: ${app.config.keycloak.url}/realms/${app.config.keycloak.realm}/protocol/openid-connect/auth
            jwk-set-uri: ${app.config.keycloak.url}/realms/${app.config.keycloak.realm}/protocol/openid-connect/certs
            user-info-uri: ${app.config.keycloak.url}/realms/${app.config.keycloak.realm}/protocol/openid-connect/userinfo
        registration:
          banking-service-client:
            provider: keycloak
            client-id: banking-service-client
            client-secret: ${KEYCLOAK_CLIENT_SECRET}
            authorization-grant-type: authorization_code
            scope: openid
      resourceserver:
        jwt:
          jwk-set-uri: ${app.config.keycloak.jwk-set-uri}

Port 5433 is the standard host mapping for Keycloak in the Arya Banking infrastructure stack.

Maven Coordinates

Setting	Value
Parent	`spring-boot-starter-parent : 3.5.4`
BOM	`spring-cloud-dependencies : 2025.0.0`
Group ID	`org.arya.banking`
Artifact ID	`arya-banking-api-gateway`
Java	17

Dependencies

Key library focus:

spring-cloud-starter-gateway: Reactive proxy core.
spring-cloud-starter-config: Config Server client.
spring-boot-starter-oauth2-client: Authorization Code flow support.
spring-boot-starter-oauth2-resource-server: JWT validation.
spring-cloud-starter-netflix-eureka-client: Service discovery registration.
spring-boot-starter-actuator: Health checks and route inspection.

Routing & Path Mapping

Security