Add spring-boot-microservices-project: config server, Eureka, gateway and three services on Boot 4.1.1 + Spring Cloud 2025.1.3

Product, order and inventory services behind Spring Cloud Gateway (WebMVC), configuration from a Config Server,
discovery with Eureka, a Resilience4j circuit breaker on order -> inventory and Brave tracing. Run as six plain jars;
output/ holds real transcripts (config, registry, requests, trace propagation, circuit breaker, startup race and the
load-balanced RestClient.Builder trap). Dockerfile and docker-compose.yml are included but were not run.

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01HhW8LD8r3EigoBaCGrQZx5

discovery-server/pom.xml

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.ankurm.shop</groupId>
+    <artifactId>shop</artifactId>
+    <version>1.0.0</version>
+  </parent>
+  <artifactId>discovery-server</artifactId>
+
+  <dependencies>
+    <dependency>
+      <groupId>org.springframework.cloud</groupId>
+      <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-actuator</artifactId>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-maven-plugin</artifactId>
+      </plugin>
+    </plugins>
+  </build>
+</project>

discovery-server/src/main/java/com/ankurm/shop/discovery/DiscoveryServerApplication.java

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+package com.ankurm.shop.discovery;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
+
+/** The service registry: every other service registers here and looks the others up here. */
+@SpringBootApplication
+@EnableEurekaServer
+public class DiscoveryServerApplication {
+    public static void main(String[] args) {
+        SpringApplication.run(DiscoveryServerApplication.class, args);
+    }
+}

discovery-server/src/main/resources/application.yml

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+spring:
+  application:
+    name: discovery-server
+server:
+  port: 8761
+eureka:
+  instance:
+    hostname: ${EUREKA_HOSTNAME:localhost}
+  client:
+    # This server is the registry; it must not try to register with itself or fetch from itself.
+    register-with-eureka: false
+    fetch-registry: false
+  server:
+    # Dev setting: a registry with one client would otherwise enter "self-preservation" and never evict dead instances.
+    enable-self-preservation: false