Split code into different microservices based on features: webmvc, jp…

…a, kafka.

README.md

@@ -1,6 +1,12 @@
 # Spring example project
 
-This is a simple example project that demonstrates how to use Spring Boot with Kotlin.
+This repo contains several Spring Boot example projects to demonstrate various features available in
+the Spring ecosystem in a purposefully opinionated way to help showcase best practices. Each example
+microservice is a separate subproject in the `spring-apps` directory, which is the root project of
+the gradle build.
+
+These projects can also be used as components to test drive other things, such as CICD pipelines /
+Github workflows, monitoring, etc.
 
 ## Docs
 

spring-apps/settings.gradle.kts

@@ -1,3 +1,5 @@
 rootProject.name = "spring-apps"
 
+include("spring-webmvc")
+include("spring-jpa")
 include("spring-cloud-stream-kafka")

spring-apps/spring-cloud-stream-kafka/build.gradle.kts

@@ -22,21 +22,18 @@ dependencies {
     implementation(platform(libs.spring.cloud.dependencies))
 
     implementation("org.springframework.boot:spring-boot-starter-actuator")
-    implementation("org.springframework.boot:spring-boot-starter-data-jpa")
     implementation("org.springframework.boot:spring-boot-starter-web")
     implementation("org.springframework.cloud:spring-cloud-starter-stream-kafka")
     implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
     implementation("org.jetbrains.kotlin:kotlin-reflect")
     implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
     implementation(libs.logstash.logback.encoder)
     runtimeOnly("io.micrometer:micrometer-registry-prometheus")
-    runtimeOnly("org.postgresql:postgresql")
     developmentOnly("org.springframework.boot:spring-boot-devtools")
 
     testImplementation("org.springframework.boot:spring-boot-starter-test")
     testImplementation("org.springframework.boot:spring-boot-testcontainers")
     testImplementation("org.testcontainers:junit-jupiter")
-    testImplementation("org.testcontainers:postgresql")
     testImplementation("org.springframework.kafka:spring-kafka-test")
     testImplementation("org.awaitility:awaitility")
     testImplementation("org.testcontainers:kafka")

spring-apps/spring-cloud-stream-kafka/docker-compose.yaml

@@ -1,14 +1,4 @@
 services:
-  postgres:
-    image: postgres:14-alpine
-    ports:
-      - '5432:5432'
-    environment:
-      POSTGRES_DB: spring-example
-      POSTGRES_USER: postgres
-      POSTGRES_PASSWORD: postgres
-      POSTGRES_HOST_AUTH_METHOD: trust
-
   kafdrop:
     image: obsidiandynamics/kafdrop
     ports:

spring-apps/spring-cloud-stream-kafka/requests.http

@@ -0,0 +1,10 @@
+### new transaction
+POST http://127.0.0.1:8080/transactions HTTP/1.1
+Content-Type: application/json
+
+{
+    "priority": 3,
+    "accountNumber": "ACC-123456",
+    "amount": 100,
+    "description": "Test transaction"
+}

spring-apps/spring-cloud-stream-kafka/src/main/kotlin/com/vacuumlabs/example/SpringCloudStreamKafkaApplication.kt

@@ -0,0 +1,11 @@
+package com.vacuumlabs.example
+
+import org.springframework.boot.autoconfigure.SpringBootApplication
+import org.springframework.boot.runApplication
+
+@SpringBootApplication
+class SpringCloudStreamKafkaApplication
+
+fun main(args: Array<String>) {
+    runApplication<SpringCloudStreamKafkaApplication>(*args)
+}

spring-apps/spring-cloud-stream-kafka/src/main/kotlin/com/vacuumlabs/example/kafka/KafkaConfiguration.kt

@@ -1,19 +1,21 @@
 package com.vacuumlabs.example.kafka
 
-import com.vacuumlabs.example.db.MessageEntity
-import com.vacuumlabs.example.db.MessageRepository
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
 import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
 import java.util.function.Consumer
 
 @Configuration
 class KafkaConfiguration {
+    val logger: Logger = LoggerFactory.getLogger(javaClass)
+
     @Bean("message-saver")
-    fun messageSaver(messageRepository: MessageRepository) =
-        Consumer<TransactionDto> { message ->
-            if (message.accountNumber != "ACC-123456") {
-                throw java.lang.IllegalArgumentException("Account doesn't exist: ${message.accountNumber}")
+    fun messageSaver(transactionRepository: TransactionRepository) =
+        Consumer<TransactionDto> { transaction ->
+            if (transaction.accountNumber != "ACC-123456") {
+                throw java.lang.IllegalArgumentException("Account doesn't exist: ${transaction.accountNumber}")
             }
-            messageRepository.save(MessageEntity(id = null, message = message.description ?: ""))
+            transactionRepository.save(transaction)
         }
 }

spring-apps/spring-cloud-stream-kafka/src/main/kotlin/com/vacuumlabs/example/kafka/TransactionRepository.kt

@@ -0,0 +1,16 @@
+package com.vacuumlabs.example.kafka
+
+import org.springframework.stereotype.Service
+
+@Service
+class TransactionRepository() {
+    private val transactions = mutableListOf<TransactionDto>()
+
+    fun save(transaction: TransactionDto) {
+        transactions.add(transaction)
+    }
+
+    fun findAll(): List<TransactionDto> {
+        return transactions
+    }
+}

spring-apps/spring-cloud-stream-kafka/src/main/kotlin/com/vacuumlabs/example/kafka/TransactionsController.kt

@@ -1,6 +1,5 @@
 package com.vacuumlabs.example.kafka
 
-import com.vacuumlabs.example.db.MessageRepository
 import org.springframework.cloud.stream.function.StreamBridge
 import org.springframework.web.bind.annotation.PostMapping
 import org.springframework.web.bind.annotation.RequestBody
@@ -9,7 +8,6 @@ import org.springframework.web.bind.annotation.RestController
 @RestController
 class TransactionsController(
     private val streamBridge: StreamBridge,
-    private val messageRepository: MessageRepository,
 ) {
     @PostMapping("/transactions")
     fun transactionSender(

spring-apps/spring-cloud-stream-kafka/src/main/resources/application.yaml

@@ -31,9 +31,3 @@ spring:
         message-saver-in-0:
           destination: test-topic
           group: message-saver
-  datasource:
-    url: jdbc:postgresql://localhost:5432/spring-example
-    username: postgres
-    password: postgres
-
-spring.jpa.hibernate.ddl-auto: create

spring-apps/spring-cloud-stream-kafka/src/test/kotlin/com/vacuumlabs/example/ContainerConfiguration.kt

@@ -2,22 +2,14 @@ package com.vacuumlabs.example
 
 import org.springframework.boot.fromApplication
 import org.springframework.boot.test.context.TestConfiguration
-import org.springframework.boot.testcontainers.service.connection.ServiceConnection
 import org.springframework.boot.with
 import org.springframework.context.annotation.Bean
 import org.springframework.test.context.DynamicPropertyRegistry
 import org.testcontainers.containers.KafkaContainer
-import org.testcontainers.containers.PostgreSQLContainer
 import org.testcontainers.utility.DockerImageName
 
 @TestConfiguration(proxyBeanMethods = false)
 class ContainerConfiguration {
-    @Bean
-    @ServiceConnection
-    fun postgresContainer(): PostgreSQLContainer<*> {
-        return PostgreSQLContainer(DockerImageName.parse("postgres:14-alpine"))
-    }
-
     @Bean
     fun kafkaContainer(properties: DynamicPropertyRegistry): KafkaContainer {
         val kafka = KafkaContainer(DockerImageName.parse("confluentinc/cp-kafka:7.1.2"))
@@ -27,5 +19,5 @@ class ContainerConfiguration {
 }
 
 fun main(args: Array<String>) {
-    fromApplication<ExampleApplication>().with(ContainerConfiguration::class).run(*args)
+    fromApplication<SpringCloudStreamKafkaApplication>().with(ContainerConfiguration::class).run(*args)
 }

spring-apps/spring-cloud-stream-kafka/src/test/kotlin/com/vacuumlabs/example/KafkaIntegrationTests.kt

@@ -1,9 +1,8 @@
 package com.vacuumlabs.example
 
 import com.fasterxml.jackson.databind.ObjectMapper
-import com.vacuumlabs.example.db.MessageEntity
-import com.vacuumlabs.example.db.MessageRepository
 import com.vacuumlabs.example.kafka.TransactionDto
+import com.vacuumlabs.example.kafka.TransactionRepository
 import org.apache.kafka.clients.consumer.ConsumerRecord
 import org.apache.kafka.clients.consumer.KafkaConsumer
 import org.apache.kafka.common.TopicPartition
@@ -33,20 +32,21 @@ class KafkaIntegrationTests
     constructor(
         val mockMvc: MockMvc,
         val objectMapper: ObjectMapper,
-        val messageRepository: MessageRepository,
+        val transactionRepository: TransactionRepository,
         val kafkaContainer: KafkaContainer,
     ) {
         @Test
         @DirtiesContext
         fun `new transaction`() {
+            val transactionDto = TransactionDto(1, "ACC-123456", BigDecimal(1000), "Test transaction")
             postNewTransaction(
-                TransactionDto(1, "ACC-123456", BigDecimal(1000), "Test transaction"),
+                transactionDto,
             ).andExpect { status { isOk() } }
 
             Awaitility.await().pollDelay(Duration.ofMillis(100)).atMost(Duration.ofSeconds(5)).until {
-                messageRepository.findAll().toList().isNotEmpty()
+                transactionRepository.findAll().toList().isNotEmpty()
             }
-            assertThat(messageRepository.findAll()).isEqualTo(listOf(MessageEntity(1, "Test transaction")))
+            assertThat(transactionRepository.findAll()).isEqualTo(listOf(transactionDto))
         }
 
         @Test
@@ -59,7 +59,7 @@ class KafkaIntegrationTests
             val record = awaitRecord("error.test-topic.message-saver")
             val exceptionMessage = record?.headers()?.lastHeader("x-exception-message")?.value()?.decodeToString()
             assertThat(exceptionMessage).endsWith("Account doesn't exist: ACC-654321")
-            assertThat(messageRepository.findAll()).isEmpty()
+            assertThat(transactionRepository.findAll()).isEmpty()
         }
 
         private fun postNewTransaction(transactionDto: TransactionDto): ResultActionsDsl {

spring-apps/spring-jpa/build.gradle.kts

@@ -0,0 +1,50 @@
+import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+
+plugins {
+    alias(libs.plugins.kotlin.jvm)
+    alias(libs.plugins.kotlin.spring)
+    alias(libs.plugins.kotlin.jpa)
+    alias(libs.plugins.spring.boot)
+    alias(libs.plugins.spring.dependency.management)
+    alias(libs.plugins.ktlint)
+    alias(libs.plugins.benmanes.versions)
+}
+
+group = "com.vacuumlabs.example"
+version = "0.0.1-SNAPSHOT"
+java.sourceCompatibility = JavaVersion.VERSION_17
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation(platform(libs.spring.cloud.dependencies))
+
+    implementation("org.springframework.boot:spring-boot-starter-actuator")
+    implementation("org.springframework.boot:spring-boot-starter-data-jpa")
+    implementation("org.springframework.boot:spring-boot-starter-web")
+    implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
+    implementation("org.jetbrains.kotlin:kotlin-reflect")
+    implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
+    implementation(libs.logstash.logback.encoder)
+    runtimeOnly("io.micrometer:micrometer-registry-prometheus")
+    runtimeOnly("org.postgresql:postgresql")
+    developmentOnly("org.springframework.boot:spring-boot-devtools")
+
+    testImplementation("org.springframework.boot:spring-boot-starter-test")
+    testImplementation("org.springframework.boot:spring-boot-testcontainers")
+    testImplementation("org.testcontainers:junit-jupiter")
+    testImplementation("org.testcontainers:postgresql")
+}
+
+tasks.withType<KotlinCompile> {
+    kotlinOptions {
+        freeCompilerArgs = listOf("-Xjsr305=strict")
+        jvmTarget = "17"
+    }
+}
+
+tasks.withType<Test> {
+    useJUnitPlatform()
+}

spring-apps/spring-jpa/docker-compose.yaml

@@ -0,0 +1,10 @@
+services:
+  postgres:
+    image: postgres:14-alpine
+    ports:
+      - '5432:5432'
+    environment:
+      POSTGRES_DB: spring-example
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_HOST_AUTH_METHOD: trust

spring-apps/spring-jpa/requests.http

@@ -0,0 +1,2 @@
+### get messages
+GET http://127.0.0.1:8080/messages HTTP/1.1

spring-apps/spring-cloud-stream-kafka/src/main/kotlin/com/vacuumlabs/example/ExampleApplication.kt → spring-apps/spring-jpa/src/main/kotlin/com/vacuumlabs/example/SpringJpaApplication.kt

@@ -4,8 +4,8 @@ import org.springframework.boot.autoconfigure.SpringBootApplication
 import org.springframework.boot.runApplication
 
 @SpringBootApplication
-class ExampleApplication
+class SpringJpaApplication
 
 fun main(args: Array<String>) {
-    runApplication<ExampleApplication>(*args)
+    runApplication<SpringJpaApplication>(*args)
 }

spring-apps/spring-jpa/src/main/resources/application.yaml

@@ -0,0 +1,22 @@
+management:
+  endpoints:
+    web:
+      exposure:
+        include: "*"
+  endpoint:
+    health:
+      show-details: always
+      probes:
+        enabled: true
+
+spring:
+  profiles:
+    active: # json-logging
+  application:
+    name: spring-example
+  datasource:
+    url: jdbc:postgresql://localhost:5432/spring-example
+    username: postgres
+    password: postgres
+
+spring.jpa.hibernate.ddl-auto: create

spring-apps/spring-jpa/src/main/resources/logback-spring.xml

@@ -0,0 +1,14 @@
+<configuration>
+    <springProfile name="default">
+        <include resource="org/springframework/boot/logging/logback/base.xml"/>
+    </springProfile>
+
+    <springProfile name="json-logging">
+        <appender name="jsonConsoleAppender" class="ch.qos.logback.core.ConsoleAppender">
+            <encoder class="net.logstash.logback.encoder.LogstashEncoder"/>
+        </appender>
+        <root level="INFO">
+            <appender-ref ref="jsonConsoleAppender"/>
+        </root>
+    </springProfile>
+</configuration>

spring-apps/spring-jpa/src/test/kotlin/com/vacuumlabs/example/ContainerConfiguration.kt

@@ -0,0 +1,22 @@
+package com.vacuumlabs.example
+
+import org.springframework.boot.fromApplication
+import org.springframework.boot.test.context.TestConfiguration
+import org.springframework.boot.testcontainers.service.connection.ServiceConnection
+import org.springframework.boot.with
+import org.springframework.context.annotation.Bean
+import org.testcontainers.containers.PostgreSQLContainer
+import org.testcontainers.utility.DockerImageName
+
+@TestConfiguration(proxyBeanMethods = false)
+class ContainerConfiguration {
+    @Bean
+    @ServiceConnection
+    fun postgresContainer(): PostgreSQLContainer<*> {
+        return PostgreSQLContainer(DockerImageName.parse("postgres:14-alpine"))
+    }
+}
+
+fun main(args: Array<String>) {
+    fromApplication<SpringJpaApplication>().with(ContainerConfiguration::class).run(*args)
+}