Part4: refactoring to coroutines

antonarhipov · antonarhipov · commit 58fd4ecf2ccf · 2020-12-07T18:25:10.000+02:00
diff --git a/build.gradle.kts b/build.gradle.kts
@@ -20,19 +20,23 @@ repositories {
 dependencies {
 	implementation("org.springframework.boot:spring-boot-starter-actuator")
 	implementation("org.springframework.boot:spring-boot-starter-thymeleaf")
-	implementation("org.springframework.boot:spring-boot-starter-web")
+	implementation("org.springframework.boot:spring-boot-starter-webflux")
+	implementation("org.springframework.boot:spring-boot-starter-data-r2dbc")
+	implementation("io.r2dbc:r2dbc-h2")
 
 	implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
 	implementation("com.github.javafaker:javafaker:1.0.2")
 
 	implementation("org.jetbrains.kotlin:kotlin-reflect")
 	implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
+	implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core")
+	implementation("org.jetbrains.kotlinx:kotlinx-coroutines-reactive")
+	implementation("org.jetbrains.kotlinx:kotlinx-coroutines-reactor")
 
 	testImplementation("org.springframework.boot:spring-boot-starter-test") {
 		exclude(group = "org.junit.vintage", module = "junit-vintage-engine")
 	}
 
-	implementation("org.springframework.boot:spring-boot-starter-data-jdbc")
 	runtimeOnly("com.h2database:h2")
 
 	implementation("org.jetbrains:markdown:0.1.45")
diff --git a/src/main/kotlin/com/example/kotlin/chat/ChatKotlinApplication.kt b/src/main/kotlin/com/example/kotlin/chat/ChatKotlinApplication.kt
@@ -1,11 +1,27 @@
 package com.example.kotlin.chat
 
+import io.r2dbc.spi.ConnectionFactory
 import org.springframework.boot.autoconfigure.SpringBootApplication
 import org.springframework.boot.runApplication
+import org.springframework.context.annotation.Bean
+import org.springframework.core.io.ClassPathResource
+import org.springframework.r2dbc.connection.init.CompositeDatabasePopulator
+import org.springframework.r2dbc.connection.init.ConnectionFactoryInitializer
+import org.springframework.r2dbc.connection.init.ResourceDatabasePopulator
 
 @SpringBootApplication
 class ChatKotlinApplication
 
 fun main(args: Array<String>) {
 	runApplication<ChatKotlinApplication>(*args)
-}
+}
+
+@Bean
+fun initializer(connectionFactory: ConnectionFactory): ConnectionFactoryInitializer {
+	val initializer = ConnectionFactoryInitializer()
+	initializer.setConnectionFactory(connectionFactory)
+	val populator = CompositeDatabasePopulator()
+	populator.addPopulators(ResourceDatabasePopulator(ClassPathResource("./sql/schema.sql")))
+	initializer.setDatabasePopulator(populator)
+	return initializer
+}
diff --git a/src/main/kotlin/com/example/kotlin/chat/controller/HtmlController.kt b/src/main/kotlin/com/example/kotlin/chat/controller/HtmlController.kt
@@ -2,6 +2,7 @@ package com.example.kotlin.chat.controller
 
 import com.example.kotlin.chat.service.MessageService
 import com.example.kotlin.chat.service.MessageVM
+import kotlinx.coroutines.flow.toList
 import org.springframework.stereotype.Controller
 import org.springframework.ui.Model
 import org.springframework.ui.set
@@ -11,7 +12,7 @@ import org.springframework.web.bind.annotation.GetMapping
 class HtmlController(val messageService: MessageService) {
 
     @GetMapping("/")
-    fun index(model: Model): String {
+    suspend fun index(model: Model): String {
         val messages: List<MessageVM> = messageService.latest()
 
         model["messages"] = messages
diff --git a/src/main/kotlin/com/example/kotlin/chat/controller/MessageResource.kt b/src/main/kotlin/com/example/kotlin/chat/controller/MessageResource.kt
@@ -2,6 +2,10 @@ package com.example.kotlin.chat.controller
 
 import com.example.kotlin.chat.service.MessageService
 import com.example.kotlin.chat.service.MessageVM
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.emitAll
+import kotlinx.coroutines.flow.onStart
+import org.springframework.http.MediaType.TEXT_EVENT_STREAM_VALUE
 import org.springframework.http.ResponseEntity
 import org.springframework.web.bind.annotation.*
 
@@ -10,7 +14,7 @@ import org.springframework.web.bind.annotation.*
 class MessageResource(val messageService: MessageService) {
 
     @GetMapping
-    fun latest(@RequestParam(value = "lastMessageId", defaultValue = "") lastMessageId: String): ResponseEntity<List<MessageVM>> {
+    suspend fun latest(@RequestParam(value = "lastMessageId", defaultValue = "") lastMessageId: String): ResponseEntity<List<MessageVM>> {
         val messages = if (lastMessageId.isNotEmpty()) {
             messageService.after(lastMessageId)
         } else {
@@ -31,7 +35,7 @@ class MessageResource(val messageService: MessageService) {
     }
 
     @PostMapping
-    fun post(@RequestBody message: MessageVM) {
+    suspend fun post(@RequestBody message: MessageVM) {
         messageService.post(message)
     }
 }
diff --git a/src/main/kotlin/com/example/kotlin/chat/repository/MessageRepository.kt b/src/main/kotlin/com/example/kotlin/chat/repository/MessageRepository.kt
@@ -1,10 +1,11 @@
 package com.example.kotlin.chat.repository
 
-import org.springframework.data.jdbc.repository.query.Query
-import org.springframework.data.repository.CrudRepository
+import kotlinx.coroutines.flow.Flow
+import org.springframework.data.r2dbc.repository.Query
+import org.springframework.data.repository.kotlin.CoroutineCrudRepository
 import org.springframework.data.repository.query.Param
 
-interface MessageRepository : CrudRepository<Message, String> {
+interface MessageRepository : CoroutineCrudRepository<Message, String> {
 
     // language=SQL
     @Query("""
@@ -14,7 +15,7 @@ interface MessageRepository : CrudRepository<Message, String> {
             LIMIT 10
         ) ORDER BY "SENT"
     """)
-    fun findLatest(): List<Message>
+    suspend fun findLatest(): List<Message>
 
     // language=SQL
     @Query("""
@@ -24,5 +25,5 @@ interface MessageRepository : CrudRepository<Message, String> {
             ORDER BY "SENT" DESC 
         ) ORDER BY "SENT"
     """)
-    fun findLatest(@Param("id") id: String): List<Message>
+    suspend fun findLatest(@Param("id") id: String): List<Message>
 }
diff --git a/src/main/kotlin/com/example/kotlin/chat/service/FakeMessageService.kt b/src/main/kotlin/com/example/kotlin/chat/service/FakeMessageService.kt
diff --git a/src/main/kotlin/com/example/kotlin/chat/service/MessageService.kt b/src/main/kotlin/com/example/kotlin/chat/service/MessageService.kt
@@ -2,9 +2,9 @@ package com.example.kotlin.chat.service
 
 interface MessageService {
 
-    fun latest(): List<MessageVM>
+    suspend fun latest(): List<MessageVM>
 
-    fun after(messageId: String): List<MessageVM>
+    suspend fun after(messageId: String): List<MessageVM>
 
-    fun post(message: MessageVM)
+    suspend fun post(message: MessageVM)
 }
diff --git a/src/main/kotlin/com/example/kotlin/chat/service/PersistentMessageService.kt b/src/main/kotlin/com/example/kotlin/chat/service/PersistentMessageService.kt
@@ -3,22 +3,20 @@ package com.example.kotlin.chat.service
 import com.example.kotlin.chat.asDomainObject
 import com.example.kotlin.chat.mapToViewModel
 import com.example.kotlin.chat.repository.MessageRepository
-import org.springframework.context.annotation.Primary
 import org.springframework.stereotype.Service
 
 @Service
-@Primary
 class PersistentMessageService(val messageRepository: MessageRepository) : MessageService {
 
-    override fun latest(): List<MessageVM> =
+    override suspend fun latest(): List<MessageVM> =
         messageRepository.findLatest()
             .mapToViewModel()
 
-    override fun after(messageId: String): List<MessageVM> =
+    override suspend fun after(messageId: String): List<MessageVM> =
         messageRepository.findLatest(messageId)
             .mapToViewModel()
 
-    override fun post(message: MessageVM) {
+    override suspend fun post(message: MessageVM) {
         messageRepository.save(message.asDomainObject())
     }
 }
diff --git a/src/main/resources/application.properties b/src/main/resources/application.properties
@@ -1,6 +1 @@
-spring.datasource.schema=classpath:sql/schema.sql
-spring.datasource.url=jdbc:h2:file:./build/data/testdb
-spring.datasource.driverClassName=org.h2.Driver
-spring.datasource.username=sa
-spring.datasource.password=password
-spring.batch.initialize-schema=always
+spring.r2dbc.url=r2dbc:h2:file:///./build/data/testdb;USER=sa;PASSWORD=password
diff --git a/src/test/kotlin/com/example/kotlin/chat/ChatKotlinApplicationTests.kt b/src/test/kotlin/com/example/kotlin/chat/ChatKotlinApplicationTests.kt
@@ -5,6 +5,8 @@ import com.example.kotlin.chat.repository.Message
 import com.example.kotlin.chat.repository.MessageRepository
 import com.example.kotlin.chat.service.MessageVM
 import com.example.kotlin.chat.service.UserVM
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.runBlocking
 import org.assertj.core.api.Assertions.assertThat
 import org.junit.jupiter.api.AfterEach
 import org.junit.jupiter.api.BeforeEach
@@ -26,7 +28,7 @@ import java.time.temporal.ChronoUnit.MILLIS
 @SpringBootTest(
     webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT,
     properties = [
-        "spring.datasource.url=jdbc:h2:mem:testdb"
+        "spring.r2dbc.url=r2dbc:h2:mem:///testdb;USER=sa;PASSWORD=password"
     ]
 )
 class ChatKotlinApplicationTests {
@@ -42,7 +44,7 @@ class ChatKotlinApplicationTests {
     val now: Instant = Instant.now()
 
     @BeforeEach
-    fun setUp() {
+    fun setUp() = runBlocking {
         val secondBeforeNow = now.minusSeconds(1)
         val twoSecondBeforeNow = now.minusSeconds(2)
         val savedMessages = messageRepository.saveAll(
@@ -74,13 +76,13 @@ class ChatKotlinApplicationTests {
     }
 
     @AfterEach
-    fun tearDown() {
+    fun tearDown() = runBlocking {
         messageRepository.deleteAll()
     }
 
     @ParameterizedTest
     @ValueSource(booleans = [true, false])
-    fun `test that messages API returns latest messages`(withLastMessageId: Boolean) {
+    fun `test that messages API returns latest messages`(withLastMessageId: Boolean) = runBlocking{
         val messages: List<MessageVM>? = client.exchange(
             RequestEntity<Any>(
                 HttpMethod.GET,
@@ -117,7 +119,7 @@ class ChatKotlinApplicationTests {
 
 
 	@Test
-	fun `test that messages posted to the API is stored`() {
+	fun `test that messages posted to the API is stored`() = runBlocking {
 		client.postForEntity<Any>(
 			URI("/api/v1/messages"),
 			MessageVM(

Original file line number	Diff line number	Diff line change
`@@ -2,9 +2,9 @@ package com.example.kotlin.chat.service`
`2`	`2`
`3`	`3`	`interface MessageService {`
`4`	`4`
`5`		`- fun latest(): List<MessageVM>`
	`5`	`+ suspend fun latest(): List<MessageVM>`
`6`	`6`
`7`		`- fun after(messageId: String): List<MessageVM>`
	`7`	`+ suspend fun after(messageId: String): List<MessageVM>`
`8`	`8`
`9`		`- fun post(message: MessageVM)`
	`9`	`+ suspend fun post(message: MessageVM)`
`10`	`10`	`}`