Spring Boot Gateway Setup [ for 'prod' profile - config server in use ]

application.yml

server:
  port: 8082

spring:
  application:
    name: gateway-service
  main:
    banner-mode: off
  zipkin:
    kafka:
      topic: zipkin
    sender:
      type: KAFKA
  kafka:
    bootstrap-servers: http://localhost:9092, http://localhost:9093, http://localhost:9094
    listener:
      missing-topics-fatal: false
  thymeleaf:
    enabled: false
  cloud:
    config:
      enabled: false
    gateway:
      globalcors:
        cors-configurations:
          '[/**]':
            allowedOrigins:
              - "http://localhost"
            allowedMethods:
              - POST
              - PUT
              - OPTIONS
      routes:
        - id: notification-service
          uri: http://localhost:8083
          predicates:
            - Path=/api/notifications/**
            - Header=X-CSRF-TOKEN, [0-9a-fA-F]{8}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{12}
            - Host=**localhost**
          filters:
            - name: NotificationPreFilter
            - name: NotificationPostFilter

resilience4j.timelimiter:
  configs:
    default:
      timeoutDuration: 1s
      cancelRunningFuture: false
  instances:
    notification-service:
      timeoutDuration: 250ms

logging:
  level:
    org.springframework: info
    org.springframework.cloud: info
    com.api.gateway.demo: info

---
spring:
  main:
    banner-mode: off
  cloud:
    config:
      enabled: true
  config:
    activate:
      on-profile: prod
    import: configserver:http://config-server-prod:8088?fail-fast=true&max-attempts=3&max-interval=1500&multiplier=1.2&initial-interval=1100

build.gradle.kts

import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
import org.jetbrains.kotlin.util.parseSpaceSeparatedArgs

plugins {
    application
    id("org.springframework.boot") version "2.5.2"
    id("io.spring.dependency-management") version "1.0.11.RELEASE"
    kotlin("jvm") version "1.5.20"
    kotlin("plugin.spring") version "1.5.20"
    id("com.google.cloud.tools.jib") version "3.1.1"
}

springBoot {
    buildInfo()
}

group = "by.vk"
version = "0.0.1"
java.sourceCompatibility = JavaVersion.VERSION_11

application {
    mainClass.set("com.api.gateway.demo.DemoApplicationKt")
    applicationName = "kafka-producer"
}

repositories {
    mavenCentral()
}

extra["springCloudVersion"] = "2020.0.3"

configurations.all {
    exclude(group = "org.junit.vintage", module = "junit-vintage-engine")
}

dependencies {
    implementation("org.jetbrains.kotlin:kotlin-reflect")
    implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
    implementation("org.springframework.cloud:spring-cloud-starter-gateway")
    implementation("org.springframework.cloud:spring-cloud-config-client")
    implementation("org.springframework.cloud:spring-cloud-starter-sleuth")
    implementation("org.springframework.cloud:spring-cloud-sleuth-zipkin")
    implementation("org.springframework.cloud:spring-cloud-stream-binder-kafka")
    implementation("org.springframework.cloud:spring-cloud-starter-circuitbreaker-reactor-resilience4j")
    implementation("io.github.resilience4j:resilience4j-spring-boot2:1.7.0")
    testImplementation("org.springframework.boot:spring-boot-starter-test")
    implementation("ch.qos.logback.contrib:logback-json-classic:0.1.5")
    implementation("ch.qos.logback.contrib:logback-jackson:0.1.5")
}

dependencyManagement {
    imports {
        mavenBom("org.springframework.cloud:spring-cloud-dependencies:${property("springCloudVersion")}")
    }
}

tasks.withType<Test> {
    useJUnitPlatform()
}

tasks.withType<KotlinCompile> {
    kotlinOptions {
        freeCompilerArgs = listOf("-Xjsr305=strict")
        jvmTarget = "11"
    }
}

object DockerProps {
    const val BASE_IMAGE = "gcr.io/distroless/java:11"
    const val APP_PORT = "8082"
    const val DEBUG_PORT = "5082"
    const val JMX_PORT = "38082"
}

object JVMProps {
    const val XMX = "256m"
    const val XMS = "64m"
    const val MAX_METASPACE_SIZE = "64m"
    const val MAX_DIRECT_MEMORY_SIZE = "128m"
    const val HEAPDUMP_PATH = "/opt/tmp/heapdump.bin"
}

jib {
    from {
        image = DockerProps.BASE_IMAGE
    }
    container {
        jvmFlags = parseSpaceSeparatedArgs("-noverify -XX:+UseContainerSupport -XX:MaxRAMPercentage=75.0 -XX:InitialRAMPercentage=50.0 -XX:+OptimizeStringConcat -XX:+UseStringDeduplication -XX:+ExitOnOutOfMemoryError -XX:+AlwaysActAsServerClassMachine -Xmx${JVMProps.XMX} -Xms${JVMProps.XMS} -XX:MaxMetaspaceSize=${JVMProps.MAX_METASPACE_SIZE} -XX:MaxDirectMemorySize=${JVMProps.MAX_DIRECT_MEMORY_SIZE} -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=${JVMProps.HEAPDUMP_PATH} -Djava.rmi.server.hostname=localhost -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=${DockerProps.JMX_PORT} -Dcom.sun.management.jmxremote.rmi.port=${DockerProps.JMX_PORT} -Dspring.profiles.active=prod")
        ports = listOf(DockerProps.APP_PORT, DockerProps.DEBUG_PORT, DockerProps.JMX_PORT)
        labels.set(mapOf("maintainer" to "Vadzim Kavalkou <[email protected]>",
                "app-name" to application.applicationName,
                "service-version" to version.toString()))
        creationTime = "USE_CURRENT_TIMESTAMP"
    }
}

NotificationPostFilter.kt

@Component
class NotificationPostFilter : AbstractGatewayFilterFactory<NotificationPostFilter.Config>(Config::class.java) {

    private val logger = LoggerFactory.getLogger(javaClass)

    class Config

    override fun apply(config: Config?): GatewayFilter {
        return GatewayFilter { exchange: ServerWebExchange?, chain: GatewayFilterChain ->
            chain.filter(exchange)
                .then(Mono.fromRunnable {
                    logger.info("[GATEWAY] Post filter")
                    when (exchange?.response?.statusCode) {
                        HttpStatus.NO_CONTENT -> exchange.response.headers["post-filter"] =
                            mutableListOf(UUID.randomUUID().toString())
                        else -> logger.warn("[GATEWAY] Something went wrong. Response status is [${exchange?.response?.statusCode}]")
                    }
                })
        }
    }
}

NotificationPreFilter.kt

@Component
class NotificationPreFilter : AbstractGatewayFilterFactory<NotificationPreFilter.Config>(Config::class.java) {

    private val logger = LoggerFactory.getLogger(javaClass)

    class Config

    override fun apply(config: Config?) =
        GatewayFilter { exchange: ServerWebExchange?, chain: GatewayFilterChain ->
            chain.filter(exchange).then(Mono.fromRunnable { logger.info("[GATEWAY] Pre filter") })
        }
}