src/main/kotlin/roomescape/auth/web/support/interceptors/AdminInterceptor.kt

@@ -4,7 +4,6 @@ import io.github.oshai.kotlinlogging.KLogger
 import io.github.oshai.kotlinlogging.KotlinLogging
 import jakarta.servlet.http.HttpServletRequest
 import jakarta.servlet.http.HttpServletResponse
-import org.slf4j.MDC
 import org.springframework.stereotype.Component
 import org.springframework.web.method.HandlerMethod
 import org.springframework.web.servlet.HandlerInterceptor
@@ -18,7 +17,7 @@ import roomescape.auth.exception.AuthException
 import roomescape.auth.infrastructure.jwt.JwtUtils
 import roomescape.auth.web.support.AdminOnly
 import roomescape.auth.web.support.accessToken
-import roomescape.common.dto.MDC_PRINCIPAL_ID_KEY
+import roomescape.common.util.MdcPrincipalId
 
 private val log: KLogger = KotlinLogging.logger {}
 
@@ -39,7 +38,7 @@ class AdminInterceptor(
 
         try {
             run {
-                val id: String = jwtUtils.extractSubject(token).also { MDC.put(MDC_PRINCIPAL_ID_KEY, it) }
+                val id: String = jwtUtils.extractSubject(token).also { MdcPrincipalId.set(it) }
                 val type: AdminType = validateTypeAndGet(token, annotation.type)
                 val permission: AdminPermissionLevel = validatePermissionAndGet(token, annotation.privilege)
 

src/main/kotlin/roomescape/auth/web/support/interceptors/UserInterceptor.kt

@@ -4,7 +4,6 @@ import io.github.oshai.kotlinlogging.KLogger
 import io.github.oshai.kotlinlogging.KotlinLogging
 import jakarta.servlet.http.HttpServletRequest
 import jakarta.servlet.http.HttpServletResponse
-import org.slf4j.MDC
 import org.springframework.stereotype.Component
 import org.springframework.web.method.HandlerMethod
 import org.springframework.web.servlet.HandlerInterceptor
@@ -14,7 +13,7 @@ import roomescape.auth.exception.AuthException
 import roomescape.auth.infrastructure.jwt.JwtUtils
 import roomescape.auth.web.support.UserOnly
 import roomescape.auth.web.support.accessToken
-import roomescape.common.dto.MDC_PRINCIPAL_ID_KEY
+import roomescape.common.util.MdcPrincipalId
 
 private val log: KLogger = KotlinLogging.logger {}
 
@@ -34,7 +33,7 @@ class UserInterceptor(
         val token: String? = request.accessToken()
 
         try {
-            val id: String = jwtUtils.extractSubject(token).also { MDC.put(MDC_PRINCIPAL_ID_KEY, it) }
+            val id: String = jwtUtils.extractSubject(token).also { MdcPrincipalId.set(it) }
 
             /**
              * CLAIM_ADMIN_TYPE_KEY 가 존재하면 관리자 토큰임

src/main/kotlin/roomescape/common/config/JpaConfig.kt

@@ -1,11 +1,10 @@
 package roomescape.common.config
 
-import org.slf4j.MDC
 import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
 import org.springframework.data.domain.AuditorAware
 import org.springframework.data.jpa.repository.config.EnableJpaAuditing
-import roomescape.common.dto.MDC_PRINCIPAL_ID_KEY
+import roomescape.common.util.MdcPrincipalId
 import java.util.*
 
 @Configuration
@@ -17,13 +16,5 @@ class JpaConfig {
 }
 
 class MdcAuditorAware : AuditorAware<Long> {
-    override fun getCurrentAuditor(): Optional<Long> {
+    override fun getCurrentAuditor(): Optional<Long> = MdcPrincipalId.extractAsOptionalLongOrEmpty()
-        val memberIdStr: String? = MDC.get(MDC_PRINCIPAL_ID_KEY)
-
-        if (memberIdStr == null) {
-            return Optional.empty()
-        } else {
-            return Optional.of(memberIdStr.toLong())
-        }
-    }
 }

src/main/kotlin/roomescape/common/dto/CommonAuth.kt

@@ -8,7 +8,6 @@ import roomescape.auth.web.LoginSuccessResponse
 import roomescape.auth.web.UserLoginSuccessResponse
 import roomescape.user.infrastructure.persistence.UserEntity
 
-const val MDC_PRINCIPAL_ID_KEY: String = "principal_id"
 
 abstract class LoginCredentials {
     abstract val id: Long

src/main/kotlin/roomescape/common/log/ApiLogMessageConverter.kt

@@ -2,8 +2,7 @@ package roomescape.common.log
 
 import com.fasterxml.jackson.databind.ObjectMapper
 import jakarta.servlet.http.HttpServletRequest
-import org.slf4j.MDC
+import roomescape.common.util.MdcPrincipalId
-import roomescape.common.dto.MDC_PRINCIPAL_ID_KEY
 
 enum class LogType {
     INCOMING_HTTP_REQUEST,
@@ -34,7 +33,7 @@ class ApiLogMessageConverter(
         controllerPayload: Map<String, Any>,
     ): String {
         val payload: MutableMap<String, Any> = commonRequestPayload(LogType.CONTROLLER_INVOKED, request)
-        val memberId: Long? = MDC.get(MDC_PRINCIPAL_ID_KEY)?.toLong()
+        val memberId: Long? = MdcPrincipalId.extractAsLongOrNull()
         if (memberId != null) payload["principal_id"] = memberId else payload["principal_id"] = "NONE"
 
         payload.putAll(controllerPayload)
@@ -48,7 +47,7 @@ class ApiLogMessageConverter(
         payload["endpoint"] = request.endpoint
         payload["status_code"] = request.httpStatus
 
-        MDC.get(MDC_PRINCIPAL_ID_KEY)?.toLongOrNull()
+        MdcPrincipalId.extractAsLongOrNull()
             ?.let { payload["principal_id"] = it }
             ?: run { payload["principal_id"] = "NONE" }
 

src/main/kotlin/roomescape/common/util/MDCUtils.kt

@@ -0,0 +1,27 @@
+package roomescape.common.util
+
+import org.slf4j.MDC
+import java.util.Optional
+
+private const val MDC_PRINCIPAL_ID_KEY = "principal_id"
+
+object MdcPrincipalId {
+
+    fun extractAsLongOrNull(): Long? {
+        return MDC.get(MDC_PRINCIPAL_ID_KEY)?.toLong()
+    }
+
+    fun extractAsOptionalLongOrEmpty(): Optional<Long> {
+        return MDC.get(MDC_PRINCIPAL_ID_KEY)?.let {
+            Optional.of(it.toLong())
+        } ?: Optional.empty()
+    }
+
+    fun set(id: String) {
+        MDC.put(MDC_PRINCIPAL_ID_KEY, id)
+    }
+
+    fun clear() {
+        MDC.remove(MDC_PRINCIPAL_ID_KEY)
+    }
+}