Add embedded kafka system (#1)

README.md

@@ -22,6 +22,7 @@ class SomeEnvironment : Environment(
     mapOf(
         "RABBIT" to RabbitContainerSystem(),
         "IBMMQ" to IbmMQContainerSystem(),
+        "KAFKA" to KafkaContainerSystem(),
         "REDIS" to RedisContainerSystem(),
         "POSTGRES" to PostgreSqlContainerSystem(),
         "ORACLE" to OracleContainerSystem(),

build.gradle

@@ -3,7 +3,7 @@ buildscript {
     ext.testContainers_version = '1.15.2'
     ext.wiremock_version = '2.27.2'
     ext.klogging_version = '2.0.6'
-    ext.libVersion = "2.1.0"
+    ext.libVersion = "2.2.0"
     ext.libGroup = 'io.github.adven27'
     repositories {
         mavenCentral()

env-mq-kafka-embedded/build.gradle

@@ -0,0 +1,11 @@
+plugins {
+    id 'java-library'
+}
+
+apply from: "$rootDir/gradle/publish.gradle"
+
+dependencies {
+    api project(':env-core')
+    api("org.springframework.kafka:spring-kafka-test:2.7.1")
+    testImplementation("org.jetbrains.kotlin:kotlin-test-junit")
+}

env-mq-kafka-embedded/src/main/java/io/github/adven27/env/mq/kafka/embedded/EmbeddedKafkaSystem.kt

@@ -0,0 +1,57 @@
+package io.github.adven27.env.mq.kafka.embedded
+
+import io.github.adven27.env.core.Environment.Companion.setProperties
+import io.github.adven27.env.core.Environment.Prop
+import io.github.adven27.env.core.Environment.Prop.Companion.set
+import io.github.adven27.env.core.ExternalSystem
+import org.springframework.kafka.test.EmbeddedKafkaBroker
+
+open class EmbeddedKafkaSystem(
+    topics: Array<String>,
+    @Suppress("SpreadOperator")
+    private val embeddedKafka: EmbeddedKafkaBroker = EmbeddedKafkaBroker(
+        NUMBER_OF_BROKERS,
+        CONTROLLED_SHUTDOWN,
+        NUMBER_OF_PARTITIONS,
+        *topics
+    )
+) : ExternalSystem {
+    private var config: Config = Config()
+    private var isRunning = false
+
+    override fun running() = isRunning
+
+    @Suppress("unused")
+    fun config(): Config = config
+
+    override fun start() {
+        embeddedKafka.afterPropertiesSet()
+        config = Config(PROP_BOOTSTRAPSERVERS set embeddedKafka.brokersAsString)
+        isRunning = true
+    }
+
+    override fun stop() {
+        embeddedKafka.destroy()
+        isRunning = false
+    }
+
+    override fun describe() = super.describe() + "\n\t" + config.asMap().entries.joinToString("\n\t") { it.toString() }
+
+    data class Config(val bootstrapServers: Prop = PROP_BOOTSTRAPSERVERS set "PLAINTEXT://localhost:$DEFAULT_KAFKA_PORT") {
+        init {
+            asMap().setProperties()
+        }
+
+        fun asMap() = mapOf(bootstrapServers.pair())
+    }
+
+    companion object {
+        private const val DEFAULT_KAFKA_PORT = 9093
+
+        private const val NUMBER_OF_BROKERS = 1
+        private const val NUMBER_OF_PARTITIONS = 1
+        private const val CONTROLLED_SHUTDOWN = true
+
+        const val PROP_BOOTSTRAPSERVERS = "env.mq.kafka.bootstrapServers"
+    }
+}

env-mq-kafka-embedded/src/test/kotlin/io/github/adven27/env/mq/kafka/embedded/EmbeddedKafkaSystemTest.kt

@@ -0,0 +1,35 @@
+package io.github.adven27.env.mq.kafka.embedded
+
+import io.github.adven27.env.core.Environment
+import io.github.adven27.env.mq.kafka.embedded.EmbeddedKafkaSystem.Companion.PROP_BOOTSTRAPSERVERS
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class EmbeddedKafkaSystemTest {
+    private lateinit var sut: SomeEnvironment
+
+    @Test
+    fun embeddedKafkaSystemStartsInEnvironment() {
+        sut = SomeEnvironment().apply { up() }
+
+        assertTrue(sut.kafka().running())
+
+        val bootstrapServers = sut.kafka().config().bootstrapServers.value
+        assertNotNull(bootstrapServers)
+        assertEquals(bootstrapServers, System.getProperty(PROP_BOOTSTRAPSERVERS))
+    }
+
+    @After
+    fun tearDown() {
+        sut.down()
+    }
+}
+
+class SomeEnvironment : Environment(
+    "EMBEDDED_KAFKA" to EmbeddedKafkaSystem(topics = arrayOf("some-topic"))
+) {
+    fun kafka() = systems["EMBEDDED_KAFKA"] as EmbeddedKafkaSystem
+}

settings.gradle

@@ -8,6 +8,7 @@ include 'env-db-postgresql'
 include 'env-db-db2'
 include 'env-db-oracle'
 include 'env-mq-kafka'
+include 'env-mq-kafka-embedded'
 include 'env-mq-rabbit'
 include 'env-mq-redis'
 include 'env-mq-ibmmq'