feat: 좋아요 기능 구현

.editorconfig

@@ -9,3 +9,4 @@ indent_style = space
 trim_trailing_whitespace = true
 insert_final_newline = true
 max_line_length = 120
+ktlint.no-wildcard-imports = false

.gitignore

@@ -50,3 +50,4 @@ data_crawling/ProjectStack.java
 data_crawling/project.stack.graphqls
 
 .env
+generated

pofo-api/build.gradle.kts

@@ -32,4 +32,7 @@ dependencies {
     implementation("org.springdoc:springdoc-openapi-starter-webmvc-ui:2.2.0")
 
     implementation("com.google.cloud.sql:postgres-socket-factory:1.21.2")
+
+    implementation("org.springframework.retry:spring-retry")
+    implementation("org.springframework:spring-aspects")
 }

pofo-api/src/main/kotlin/org/pofo/api/ApiApplication.kt

@@ -4,7 +4,9 @@ import org.springframework.boot.autoconfigure.SpringBootApplication
 import org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchDataAutoConfiguration
 import org.springframework.boot.autoconfigure.elasticsearch.ElasticsearchRestClientAutoConfiguration
 import org.springframework.boot.runApplication
+import org.springframework.retry.annotation.EnableRetry
 
+@EnableRetry
 @SpringBootApplication(
     exclude = [ElasticsearchDataAutoConfiguration::class, ElasticsearchRestClientAutoConfiguration::class],
 )

pofo-api/src/main/kotlin/org/pofo/api/domain/like/LikeApiDocs.kt

@@ -0,0 +1,42 @@
+package org.pofo.api.domain.like
+
+import io.swagger.v3.oas.annotations.Operation
+import io.swagger.v3.oas.annotations.Parameter
+import io.swagger.v3.oas.annotations.responses.ApiResponses
+import io.swagger.v3.oas.annotations.tags.Tag
+import org.pofo.api.common.response.ApiResponse
+import org.pofo.api.domain.security.PrincipalDetails
+import org.springframework.security.core.annotation.AuthenticationPrincipal
+import org.springframework.web.bind.annotation.PathVariable
+import io.swagger.v3.oas.annotations.responses.ApiResponse as SwaggerResponse
+
+@Tag(name = "[Like API]", description = "좋아요 관련 API")
+interface LikeApiDocs {
+    @Operation(summary = "좋아요 등록", description = "특정 프로젝트에 좋아요를 등록합니다.")
+    @ApiResponses(
+        value = [
+            SwaggerResponse(
+                responseCode = "200",
+                description = "좋아요 등록 성공",
+            ),
+        ],
+    )
+    fun likeProject(
+        @Parameter(hidden = true) @AuthenticationPrincipal principalDetails: PrincipalDetails,
+        @PathVariable("projectId") projectId: Long,
+    ): ApiResponse<Map<String, Int>>
+
+    @Operation(summary = "좋아요 해제", description = "특정 프로젝트에 등록된 좋아요를 해제합니다.")
+    @ApiResponses(
+        value = [
+            SwaggerResponse(
+                responseCode = "200",
+                description = "좋아요 해제 성공",
+            ),
+        ],
+    )
+    fun unlikeProject(
+        @Parameter(hidden = true) @AuthenticationPrincipal principalDetails: PrincipalDetails,
+        @PathVariable("projectId") projectId: Long,
+    ): ApiResponse<Map<String, Int>>
+}

pofo-api/src/main/kotlin/org/pofo/api/domain/like/LikeController.kt

@@ -0,0 +1,35 @@
+package org.pofo.api.domain.like
+
+import org.pofo.api.common.response.ApiResponse
+import org.pofo.api.domain.security.PrincipalDetails
+import org.pofo.common.response.Version
+import org.springframework.security.core.annotation.AuthenticationPrincipal
+import org.springframework.web.bind.annotation.DeleteMapping
+import org.springframework.web.bind.annotation.PathVariable
+import org.springframework.web.bind.annotation.PostMapping
+import org.springframework.web.bind.annotation.RequestMapping
+import org.springframework.web.bind.annotation.RestController
+
+@RestController
+@RequestMapping(Version.V1 + "/likes")
+class LikeController(
+    private val likeService: LikeService,
+) : LikeApiDocs {
+    @PostMapping("/{projectId}")
+    override fun likeProject(
+        @AuthenticationPrincipal principalDetails: PrincipalDetails,
+        @PathVariable projectId: Long,
+    ): ApiResponse<Map<String, Int>> {
+        val currentLikes = likeService.likeProject(principalDetails.jwtTokenData.userId, projectId)
+        return ApiResponse.success(mapOf("likes" to currentLikes))
+    }
+
+    @DeleteMapping("/{projectId}")
+    override fun unlikeProject(
+        @AuthenticationPrincipal principalDetails: PrincipalDetails,
+        @PathVariable projectId: Long,
+    ): ApiResponse<Map<String, Int>> {
+        val currentLikes = likeService.unlikeProject(principalDetails.jwtTokenData.userId, projectId)
+        return ApiResponse.success(mapOf("likes" to currentLikes))
+    }
+}

pofo-api/src/main/kotlin/org/pofo/api/domain/like/LikeService.kt

@@ -0,0 +1,105 @@
+package org.pofo.api.domain.like
+
+import org.hibernate.StaleObjectStateException
+import org.pofo.common.exception.CustomException
+import org.pofo.common.exception.ErrorCode
+import org.pofo.domain.rds.domain.like.Like
+import org.pofo.domain.rds.domain.like.LikeRepository
+import org.pofo.domain.rds.domain.project.repository.ProjectRepository
+import org.pofo.domain.rds.domain.user.UserRepository
+import org.springframework.dao.OptimisticLockingFailureException
+import org.springframework.retry.annotation.Backoff
+import org.springframework.retry.annotation.Retryable
+import org.springframework.stereotype.Service
+import org.springframework.transaction.annotation.Transactional
+
+@Service
+@Transactional(readOnly = true)
+class LikeService(
+    private val likeRepository: LikeRepository,
+    private val projectRepository: ProjectRepository,
+    private val userRepository: UserRepository,
+) {
+    @Retryable(
+        value = [OptimisticLockingFailureException::class, StaleObjectStateException::class],
+        maxAttempts = 10,
+        backoff = Backoff(delay = 50, multiplier = 2.0),
+    )
+    @Transactional
+    fun likeProject(
+        userId: Long,
+        projectId: Long,
+    ): Int {
+        val user =
+            userRepository.findById(userId)
+                ?: throw CustomException(ErrorCode.USER_NOT_FOUND)
+
+        val project =
+            projectRepository.findById(projectId)
+                ?: throw CustomException(ErrorCode.PROJECT_NOT_FOUND)
+
+        if (likeRepository.existsByUserAndProject(user, project)) {
+            throw CustomException(ErrorCode.ALREADY_LIKED_PROJECT)
+        }
+
+        val like =
+            Like
+                .builder()
+                .project(project)
+                .user(user)
+                .build()
+        project.increaseLikes()
+        projectRepository.save(project)
+        likeRepository.save(like)
+        return project.likes
+    }
+
+    @Retryable(
+        value = [OptimisticLockingFailureException::class, StaleObjectStateException::class],
+        maxAttempts = 10,
+        backoff = Backoff(delay = 50, multiplier = 2.0),
+    )
+    @Transactional
+    fun unlikeProject(
+        userId: Long,
+        projectId: Long,
+    ): Int {
+        val user =
+            userRepository.findById(userId)
+                ?: throw CustomException(ErrorCode.USER_NOT_FOUND)
+
+        val project =
+            projectRepository.findById(projectId)
+                ?: throw CustomException(ErrorCode.PROJECT_NOT_FOUND)
+
+        val like =
+            likeRepository.findByUserAndProject(user, project)
+                ?: throw CustomException(ErrorCode.LIKE_NOT_FOUND)
+
+        project.decreaseLikes()
+        projectRepository.save(project)
+        likeRepository.delete(like)
+        return project.likes
+    }
+
+    @Deprecated(message = "이유를 모르겠으나 제대로 작동안하는 재시도 로직. 참고용으로 남김")
+    private fun <T> retryOptimisticLock(action: () -> T): T {
+        var attempts = 0
+        val maxRetries = 10
+        var waitTime = 50L
+        while (true) {
+            try {
+                return action()
+            } catch (ex: OptimisticLockingFailureException) {
+                if (++attempts > maxRetries) {
+                    throw CustomException(ErrorCode.LIKE_FAILED)
+                }
+            } catch (ex: StaleObjectStateException) {
+                if (++attempts > maxRetries) {
+                    throw CustomException(ErrorCode.LIKE_FAILED)
+                }
+            }
+            Thread.sleep(waitTime)
+        }
+    }
+}