feat: ✨ 분산 코디네이션 도입을 고려한 서비스 탐색 서비스 API (#162)

* chore: 분산 코디네이션 설정 - 채팅 서버 url 고정값 설정

* chore: 분산 코디네이터 의존성 api 모듈 제어권 설정

* feat: 유효한 채팅 서버 url을 반환하기 위한 dto 정의

* feat: infra 모듈 내, 분산 코디네이션 인터페이스 및 기본 구현체 정의

* docs: 서비스 탐색 api 문서 정의

* feat: 채팅 서버 url 반환 usecase 구현

* feat: 채팅 서버 탐색 컨트롤러 구현

* fix: swagger config group에 서비스 탐색 서비스 항목 추가

* fix: 소켓 usecase와 채팅 서버 탐색 서비스 분리

pennyway-app-external-api/src/main/java/kr/co/pennyway/api/apis/socket/api/SocketApi.java

@@ -0,0 +1,16 @@
+package kr.co.pennyway.api.apis.socket.api;
+
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.media.Schema;
+import io.swagger.v3.oas.annotations.media.SchemaProperty;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import org.springframework.http.ResponseEntity;
+
+@Tag(name = "[서비스 탐색 API]")
+public interface SocketApi {
+    @Operation(summary = "연결 가능한 채팅 서버 정보 조회", description = "요청 헤더, 바디를 기반으로 연결 가능한 채팅 서버 정보를 조회한 후, 채팅 서버 정보를 반환합니다.")
+    @ApiResponse(responseCode = "200", description = "연결 가능한 채팅 서버 정보 조회 성공", content = @Content(schemaProperties = @SchemaProperty(name = "url", schema = @Schema(type = "string", description = "채팅 서버 URL"))))
+    ResponseEntity<?> getChatServerInfo();
+}

pennyway-app-external-api/src/main/java/kr/co/pennyway/api/apis/socket/controller/SocketController.java

@@ -0,0 +1,26 @@
+package kr.co.pennyway.api.apis.socket.controller;
+
+import kr.co.pennyway.api.apis.socket.api.SocketApi;
+import kr.co.pennyway.api.apis.socket.usecase.SocketUseCase;
+import kr.co.pennyway.api.common.response.SuccessResponse;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequiredArgsConstructor
+@RequestMapping("/v2/socket")
+public class SocketController implements SocketApi {
+    private static final String CHAT_SERVER_URL = "chatServerUrl";
+    private final SocketUseCase socketUseCase;
+
+    @Override
+    @GetMapping("/chat")
+    @PreAuthorize("isAuthenticated()")
+    public ResponseEntity<?> getChatServerInfo() {
+        return ResponseEntity.ok(SuccessResponse.from(CHAT_SERVER_URL, socketUseCase.getChatServerUrl()));
+    }
+}

pennyway-app-external-api/src/main/java/kr/co/pennyway/api/apis/socket/service/ChatServerSearchService.java

@@ -0,0 +1,20 @@
+package kr.co.pennyway.api.apis.socket.service;
+
+import kr.co.pennyway.infra.client.coordinator.CoordinatorService;
+import kr.co.pennyway.infra.client.coordinator.WebSocket;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Service;
+
+@Slf4j
+@Service
+@RequiredArgsConstructor
+public class ChatServerSearchService {
+    private final CoordinatorService defaultCoordinatorService;
+
+    public String getChatServerUrl() {
+        WebSocket.ChatServerUrl response = defaultCoordinatorService.readChatServerUrl(null, null);
+
+        return response.url();
+    }
+}

pennyway-app-external-api/src/main/java/kr/co/pennyway/api/apis/socket/usecase/SocketUseCase.java

@@ -0,0 +1,17 @@
+package kr.co.pennyway.api.apis.socket.usecase;
+
+import kr.co.pennyway.api.apis.socket.service.ChatServerSearchService;
+import kr.co.pennyway.common.annotation.UseCase;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+
+@Slf4j
+@UseCase
+@RequiredArgsConstructor
+public class SocketUseCase {
+    private final ChatServerSearchService chatServerSearchService;
+
+    public String getChatServerUrl() {
+        return chatServerSearchService.getChatServerUrl();
+    }
+}

pennyway-app-external-api/src/main/java/kr/co/pennyway/api/config/InfraConfig.java

@@ -17,7 +17,8 @@
         KakaoOidcProperties.class
 })
 @EnablePennywayInfraConfig({
-        PennywayInfraConfigGroup.FCM
+        PennywayInfraConfigGroup.FCM,
+        PennywayInfraConfigGroup.DistributedCoordinationConfig
 })
 public class InfraConfig {
 }

pennyway-app-external-api/src/main/java/kr/co/pennyway/api/config/SwaggerConfig.java

@@ -101,6 +101,17 @@ public GroupedOpenApi ledgerApi() {
                 .build();
     }
 
+    @Bean
+    public GroupedOpenApi socketApi() {
+        String[] targets = {"kr.co.pennyway.api.apis.socket"};
+
+        return GroupedOpenApi.builder()
+                .packagesToScan(targets)
+                .group("서비스 탐색 서비스")
+                .addOperationCustomizer(customizer())
+                .build();
+    }
+
     @Bean
     public GroupedOpenApi backOfficeApi() {
         String[] targets = {"kr.co.pennyway.api.apis.question"};

pennyway-infra/src/main/java/kr/co/pennyway/infra/client/coordinator/CoordinatorService.java

@@ -0,0 +1,13 @@
+package kr.co.pennyway.infra.client.coordinator;
+
+import java.util.Map;
+
+public interface CoordinatorService {
+    /**
+     * 채팅 서버에 연결하려는 클라이언트에게 유효한 채팅 서버의 URL을 반환합니다.
+     * 이 메서드는 다양한 방식으로 구현될 수 있습니다.
+     * 예를 들어, 단일 채팅 서버 환경에서는 고정된 채팅 서버 URL을 반환할 수 있습니다.
+     * 분산 채팅 서버 환경이라면, 분산 코디네이션과 같은 서비스를 통해 사용자의 지리적 위치, 채팅 서버의 부하 상태 등을 고려하여 적절한 채팅 서버 URL을 반환할 수 있습니다.
+     */
+    WebSocket.ChatServerUrl readChatServerUrl(Map<String, String> headers, Object payload);
+}

pennyway-infra/src/main/java/kr/co/pennyway/infra/client/coordinator/DefaultCoordinatorService.java

@@ -0,0 +1,20 @@
+package kr.co.pennyway.infra.client.coordinator;
+
+import java.util.Map;
+
+/**
+ * 이 클래스는 단일 채팅 서버 환경에서 사용할 수 있는 기본적인 {@link CoordinatorService} 구현체입니다.
+ * 미리 정의된 채팅 서버 URL을 반환합니다.
+ */
+public class DefaultCoordinatorService implements CoordinatorService {
+    private final String chatServerUrl;
+
+    public DefaultCoordinatorService(String chatServerUrl) {
+        this.chatServerUrl = chatServerUrl;
+    }
+
+    @Override
+    public WebSocket.ChatServerUrl readChatServerUrl(Map<String, String> headers, Object payload) {
+        return WebSocket.ChatServerUrl.of(chatServerUrl);
+    }
+}

pennyway-infra/src/main/java/kr/co/pennyway/infra/client/coordinator/WebSocket.java

@@ -0,0 +1,15 @@
+package kr.co.pennyway.infra.client.coordinator;
+
+import java.util.Objects;
+
+public final class WebSocket {
+    public record ChatServerUrl(String url) {
+        public ChatServerUrl {
+            Objects.requireNonNull(url, "url must not be null");
+        }
+
+        public static ChatServerUrl of(String url) {
+            return new ChatServerUrl(url);
+        }
+    }
+}

pennyway-infra/src/main/java/kr/co/pennyway/infra/common/importer/PennywayInfraConfigGroup.java

@@ -1,13 +1,15 @@
 package kr.co.pennyway.infra.common.importer;
 
+import kr.co.pennyway.infra.config.DistributedCoordinationConfig;
 import kr.co.pennyway.infra.config.FcmConfig;
 import lombok.Getter;
 import lombok.RequiredArgsConstructor;
 
 @Getter
 @RequiredArgsConstructor
 public enum PennywayInfraConfigGroup {
-    FCM(FcmConfig.class);
+    FCM(FcmConfig.class),
+    DistributedCoordinationConfig(DistributedCoordinationConfig.class);
 
     private final Class<? extends PennywayInfraConfig> configClass;
 }

pennyway-infra/src/main/java/kr/co/pennyway/infra/config/DistributedCoordinationConfig.java

@@ -0,0 +1,20 @@
+package kr.co.pennyway.infra.config;
+
+import kr.co.pennyway.infra.client.coordinator.CoordinatorService;
+import kr.co.pennyway.infra.client.coordinator.DefaultCoordinatorService;
+import kr.co.pennyway.infra.common.importer.PennywayInfraConfig;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.Bean;
+
+public class DistributedCoordinationConfig implements PennywayInfraConfig {
+    private final String chatServerUrl;
+
+    public DistributedCoordinationConfig(@Value("${distributed-coordination.chat-server.url}") String chatServerUrl) {
+        this.chatServerUrl = chatServerUrl;
+    }
+
+    @Bean
+    public CoordinatorService defaultCoordinatorService() {
+        return new DefaultCoordinatorService(chatServerUrl);
+    }
+}

pennyway-infra/src/main/resources/application-infra.yml

@@ -61,6 +61,10 @@ oauth2:
         jwks-uri: ${APPLE_JWKS_URI:http://localhost}
         secret: ${APPLE_CLIENT_SECRET:pennyway-jayang-was}
 
+distributed-coordination:
+  chat-server:
+    url: ${CHAT_SERVER_URL:ws://localhost:8000/chat}
+
 ---
 spring:
   config: