refactor: 회원 API 로깅 추가

src/main/kotlin/roomescape/member/business/MemberService.kt

@@ -1,5 +1,6 @@
 package roomescape.member.business
 
+import io.github.oshai.kotlinlogging.KotlinLogging
 import org.springframework.data.repository.findByIdOrNull
 import org.springframework.stereotype.Service
 import org.springframework.transaction.annotation.Transactional
@@ -10,26 +11,37 @@ import roomescape.member.infrastructure.persistence.MemberRepository
 import roomescape.member.infrastructure.persistence.Role
 import roomescape.member.web.*
 
+private val log = KotlinLogging.logger {}
+
 @Service
 @Transactional(readOnly = true)
 class MemberService(
-    private val memberRepository: MemberRepository
+    private val memberRepository: MemberRepository,
 ) {
-    fun findMembers(): MemberRetrieveListResponse = MemberRetrieveListResponse(
-        members = memberRepository.findAll().map { it.toRetrieveResponse() }
-    )
+    fun findMembers(): MemberRetrieveListResponse {
+        log.debug { "[MemberService.findMembers] 회원 조회 시작" }
 
-    fun findById(memberId: Long): MemberEntity = fetchOrThrow {
-        memberRepository.findByIdOrNull(memberId)
+        return memberRepository.findAll()
+            .also { log.info { "[MemberService.findMembers] 회원 ${it.size}명 조회 완료" } }
+            .toRetrieveListResponse()
     }
 
-    fun findByEmailAndPassword(email: String, password: String): MemberEntity = fetchOrThrow {
+    fun findById(memberId: Long): MemberEntity {
+        return fetchOrThrow("findById", "memberId=$memberId") {
+            memberRepository.findByIdOrNull(memberId)
+        }
+    }
+
+    fun findByEmailAndPassword(email: String, password: String): MemberEntity {
+        return fetchOrThrow("findByEmailAndPassword", "email=$email, password=$password") {
             memberRepository.findByEmailAndPassword(email, password)
         }
+    }
 
     @Transactional
-    fun create(request: SignupRequest): SignupResponse {
+    fun createMember(request: SignupRequest): SignupResponse {
         memberRepository.findByEmail(request.email)?.let {
+            log.info { "[MemberService.createMember] 회원가입 실패(이메일 중복): email=${request.email}" }
             throw MemberException(MemberErrorCode.DUPLICATE_EMAIL)
         }
 
@@ -39,10 +51,18 @@ class MemberService(
             password = request.password,
             role = Role.MEMBER
         )
+
         return memberRepository.save(member).toSignupResponse()
+            .also { log.info { "[MemberService.create] 회원가입 완료: email=${request.email} memberId=${it.id}" } }
     }
 
-    private fun fetchOrThrow(block: () -> MemberEntity?): MemberEntity {
-        return block() ?: throw MemberException(MemberErrorCode.MEMBER_NOT_FOUND)
+    private fun fetchOrThrow(calledBy: String, params: String, block: () -> MemberEntity?): MemberEntity {
+        log.debug { "[MemberService.$calledBy] 회원 조회 시작: params=$params" }
+        return block()
+            ?.also { log.info { "[MemberService.$calledBy] 회원 조회 완료: memberId=${it.id}" } }
+            ?: run {
+                log.info { "[MemberService.$calledBy] 회원 조회 실패: $params" }
+                throw MemberException(MemberErrorCode.MEMBER_NOT_FOUND)
+            }
     }
 }

src/main/kotlin/roomescape/member/web/MemberDTO.kt

@@ -16,6 +16,10 @@ data class MemberRetrieveResponse(
     val name: String
 )
 
+fun List<MemberEntity>.toRetrieveListResponse(): MemberRetrieveListResponse = MemberRetrieveListResponse(
+    members = this.map { it.toRetrieveResponse() }
+)
+
 data class MemberRetrieveListResponse(
     val members: List<MemberRetrieveResponse>
 )