[Spring Boot] Kotlin으로 REST API 만들기(9) - Transaction 적용

Kotlin으로 REST API 만들기(9) - Transaction 적용

1. Transaction 란?
모든 작업이 정상적으로 완료되면 Commit을 실행하고, 작업 처리 중 에러가 발생하면 Rollback하는 방식으로 처리하는 일련의 작업들을 하나의 단위로 묶어서 처리하는 것을 트랜잭션이라고 합니다.
 
2. Transaction의 기본 원칙
Atomicity (원자성)
트랜잭션의 연산은 데이터베이스에 모두 반영되든지 아니면 전혀 반영되지 않아야 합니다. (All or Nothing)
Consistency (일관성)
트랜잭션이 성공적으로 완료하면 모든 데이터는 일관성을 유지해야 합니다.
Isolation (독립성, 격리성)
트랜잭션은 독립적으로 처리되며, 처리되는 중간에 외부에서의 간섭은 없어야 합니다.
Durablility (영속성, 지속성)
성공적으로 완료된 트랜잭션의 결과는 영구적으로 지속되어야 한다.
 
3. Transaction 적용
3_1. DataSourceConfig.kt 수정
선언적 트랜잭션 처리를 활성화하기 위해서 @EnableTransactionManagement을 추가한 후 PlatformTransactionManager의 구현 클래스 중 JDBC 기반 트랜잭션 관리자인 DataSourceTransactionManager 클래스를 빈으로 등록하세요. 

DataSourceConfig.kt 수정

package com.example.springbootrestapi.config

import com.zaxxer.hikari.HikariDataSource
import org.apache.ibatis.session.SqlSessionFactory
import org.mybatis.spring.SqlSessionFactoryBean
import org.mybatis.spring.SqlSessionTemplate
import org.mybatis.spring.annotation.MapperScan
import org.springframework.boot.context.properties.ConfigurationProperties
import org.springframework.boot.jdbc.DataSourceBuilder
import org.springframework.context.ApplicationContext
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.ComponentScan
import org.springframework.context.annotation.Configuration
import org.springframework.core.io.support.PathMatchingResourcePatternResolver
import org.springframework.jdbc.datasource.DataSourceTransactionManager
import javax.sql.DataSource


@ComponentScan(basePackages = ["com.example.springbootrestapi.service"])
@MapperScan(
  basePackages = ["com.example.springbootrestapi.mapper"],
  sqlSessionFactoryRef = "sqlSessionFactory"
)
@Configuration
class DataSourceConfiguration {

  @Bean
  @ConfigurationProperties(prefix = "spring.datasource.hikari")
  fun dataSource(): DataSource {
    return DataSourceBuilder.create()
      .type(HikariDataSource::class.java)
      .build()
  }

  @Bean
  fun sqlSessionFactory(
    dataSource: DataSource,
    applicationContext: ApplicationContext
  ): SqlSessionFactory {
    val sessionFactory = SqlSessionFactoryBean()
    sessionFactory.setDataSource(dataSource)
    sessionFactory.setMapperLocations(
      *PathMatchingResourcePatternResolver()
        .getResources("classpath:mapper/*.xml")
    )
    return sessionFactory.`object`!!
  }

  @Bean
  fun sqlSession(
    sqlSessionFactory: SqlSessionFactory
  ): SqlSessionTemplate {
    return SqlSessionTemplate(sqlSessionFactory)
  }

  @Bean
  fun transactionManager(): DataSourceTransactionManager {
    return DataSourceTransactionManager(dataSource())
  }
}

3_2. @Transactional 추가
트랜잭션을 적용하려는 클래스 및 메소드에 @Transactional 추가하세요. 
TodoService.kt

package com.example.springbootrestapi.service

import com.example.springbootrestapi.domain.TodoRequest
import com.example.springbootrestapi.domain.TodoResponse
import com.example.springbootrestapi.mapper.TodoMapper
import org.springframework.stereotype.Service
import org.springframework.transaction.annotation.Transactional


@Service
class TodoService(
  val todoMapper: TodoMapper
) {

  /** To-Do 조회  */
  fun getTodos(todoRequest: TodoRequest): MutableList<TodoResponse> {
    return todoMapper.getTodos(todoRequest)
  }

  /**
   * To-Do 상세 조회
   */
  fun getTodoById(id: Long): TodoResponse {
    return todoMapper.getTodoById(id)
  }

  /**
   * To-Do 저장
   */
  fun insertTodo(todoRequest: TodoRequest): TodoResponse {
    var todoResponse = TodoResponse()
    var result = todoMapper.insertTodo(todoRequest)
    if(result > 0){
      todoRequest.id?.let {
        todoResponse = todoMapper.getTodoById(it)
      }
    }
    return todoResponse
  }

  /**
   * To-Do 수정
   */
  fun updateTodo(todoRequest: TodoRequest): TodoResponse {
    var todoResponse = TodoResponse()
    var result = todoMapper.updateTodo(todoRequest)
    if (result > 0) {
      todoRequest.id?.let {
        todoResponse = todoMapper.getTodoById(it)
      }
    }
    return todoResponse
  }

  /**
   * To-Do 삭제
   */
  fun deleteTodoById(id: Long): TodoResponse {
    var todoResponse = TodoResponse()
    var result = todoMapper.deleteTodoById(id)
    if (result > 0) {
      todoResponse = todoMapper.getTodoById(id)
    }
    return todoResponse
  }

  /**
   * To-Do 저장 시 title이 #으로 시작하는 경우 RuntimeException 발생
   */
  @Transactional
  fun insertTodosFailed(todoRequests: List<TodoRequest>): Int {
    var result = 0
    for (todoRequest in todoRequests) {
      if (todoRequest.title.startsWith("#")) {
        throw RuntimeException("title이 #으로 시작")
      }
      result += todoMapper.insertTodo(todoRequest)
    }
    return result
  }
}

TodoServiceTest.kt

package com.example.springbootrestapi.service

import com.example.springbootrestapi.domain.TodoRequest
import com.example.springbootrestapi.mapper.TodoMapper
import org.junit.jupiter.api.Assertions.*
import org.junit.jupiter.api.DisplayName
import org.junit.jupiter.api.Test
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.boot.test.context.SpringBootTest
import org.springframework.test.context.ActiveProfiles
import org.springframework.transaction.annotation.Transactional


@SpringBootTest
@ActiveProfiles("local")
class TodoServiceTest {

  @Autowired
  lateinit var todoService: TodoService

  @Autowired
  lateinit var todoMapper: TodoMapper

  @Transactional
  @DisplayName("getTodos_To-Do 목록 조회")
  @Test
  fun testGetTodos() {

    // Given
    insertTodo("Title Junit Test Insert 01", "Description Junit Test Insert 01", false)
    insertTodo("Title Junit Test Insert 02", "Description Junit Test Insert 02", true)
    insertTodo("Title Junit Test Insert 03", "Description Junit Test Insert 03", false)
    insertTodo("Title Junit Test Insert 04", "Description Junit Test Insert 04", true)
    insertTodo("Title Junit Test Insert 05", "Description Junit Test Insert 05", false)

    val todoRequest = TodoRequest().apply {
      this.title = "Title Junit Test Insert"
      this.description = "Description Junit Test Insert"
      this.completed = true
    }

    // When
    val todoResponses = todoService.getTodos(todoRequest)

    // Then
    assertTrue(todoResponses.isNotEmpty())
  }

  @Transactional
  @DisplayName("getTodoById_To-Do 상세 조회")
  @Test
  fun testGetTodoById() {

    // Given
    val title = "Title Junit Test Insert"
    val description = "Description Junit Test Insert"
    val completed = false
    val insertId = insertTodo(title, description, completed)

    // When
    val todoResponse = todoService.getTodoById(insertId)

    // Then
    assertEquals(title, todoResponse.title)
    assertEquals(description, todoResponse.description)
    assertEquals(completed, todoResponse.completed)
  }

  @Transactional
  @DisplayName("insertTodo_To-Do 저장")
  @Test
  fun testInsertTodo() {

    // Given
    val todoRequest = TodoRequest().apply {
      this.title = "Title Junit Test Insert"
      this.description = "Description Junit Test Insert"
      this.completed = true
    }

    // When
    val todoResponse = todoService.insertTodo(todoRequest)

    // Then
    assertEquals(todoRequest.title, todoResponse.title)
    assertEquals(todoRequest.description, todoResponse.description)
    assertEquals(todoRequest.completed, todoResponse.completed)
  }

  @Transactional
  @DisplayName("updateTodo_To-Do 수정")
  @Test
  fun testUpdateTodo() {

    // Given
    val insertId = insertTodo("Title Junit Test Insert", "Description Junit Test Insert", false)

    val todoRequest = TodoRequest().apply {
      this.id = insertId
      this.title = "Title Junit Test Update"
      this.description = "Description Junit Test Upate"
      this.completed = true
    }

    // When
    val todoResponse = todoService.updateTodo(todoRequest)

    // Then
    assertEquals(todoRequest.title, todoResponse.title)
    assertEquals(todoRequest.description, todoResponse.description)
    assertEquals(todoRequest.completed, todoResponse.completed)
  }

  @Transactional
  @DisplayName("deleteTodoById_To-Do 삭제")
  @Test
  fun testDeleteTodoById() {

    // Given
    val insertId = insertTodo("Title Junit Test Insert", "Description Junit Test Insert", false)

    // When
    val todoResponse = todoService.deleteTodoById(insertId)

    // Then
    assertNull(todoResponse)
  }

  fun insertTodo(
    title: String,
    description: String,
    completed: Boolean
  ): Long {

    val todoRequest = TodoRequest().apply {
      this.title = title
      this.description = description
      this.completed = completed
    }

    todoMapper.insertTodo(todoRequest)

    return todoRequest.id ?: 0
  }

  @DisplayName("insertTodosFailed_To-Do 저장 시 title이 #으로 시작하는 경우 RuntimeException 발생")
  @Test
  fun testInsertTodosFailed() {

    // Given
    val todoRequests = mutableListOf<TodoRequest>()
    todoRequests.add(
      TodoRequest().apply {
        this.title = "Title Junit Test Insert 01"
        this.description = "Description Junit Test Insert 01"
        this.completed = false
      }
    )
    todoRequests.add(
      TodoRequest().apply {
        this.title = "Title Junit Test Insert 02"
        this.description = "Description Junit Test Insert 02"
        this.completed = false
      }
    )

    todoRequests.add(
      TodoRequest().apply {
        this.title = "#Title Junit Test Insert 03"
        this.description = "Description Junit Test Insert 03"
        this.completed = false
      }
    )

    // When
    var result = 0
    try {
      result = todoService.insertTodosFailed(todoRequests)
    } catch (e: Exception) {
      e.printStackTrace()
    }

    // Then
    assertEquals(0, result)
  }
}

4. 결과 확인
TodoServiceTest.testInsertTodosFailed() 실행 시 RuntimeException(Unchecked Exception)이 발생하여 정상적으로 롤백되는지 확인하세요.
Error, Checked Exception : 예외 상황이 발생할 경우 트랜잭션 커밋
Unchecked Exception : 예외 상황이 발생할 경우 트랜잭션 롤백

 

소스 코드는 Github Repository - https://github.com/tychejin1218/kotlin-springboot-rest-api.git (branch : section08) 를 참조하세요.

GitHub에서 프로젝트 복사하기(Get from Version Control) - https://tychejin.tistory.com/325
단축키 기본 및 응용 - https://tychejin.tistory.com/364