Kotlin
Any language compiled into byte code which is run on JVM can be used to write microservices for JLupin. The example of such a language is Kotling. It also supports using Java libraries inside Kotlin's code, so it is easy to use JLupin Client library.
Native microservice
You can use libraries written in Java in your Kotlin code, so you won't see any plain Java class.
Project structure and dependencies
This is standard structure of Kotlin project with use of Maven. Create directories and empty files as shown below.
Remember to configure Maven by editing pm.xml file:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>kotlin-hello-world</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<spring.version>4.3.9.RELEASE</spring.version>
<jlupin.version>1.4.1.0-RC6</jlupin.version>
<kotlin.version>1.2.41</kotlin.version>
<jlupin.next.server.maven.plugin.version>1.2.1</jlupin.next.server.maven.plugin.version>
</properties>
<repositories>
<!-- Repository is also accessible using https connection: -->
<!-- https://support.jlupin.com/maven2/ -->
<repository>
<id>jlupin-central</id>
<name>jlupin</name>
<url>http://support.jlupin.com/maven2/</url>
</repository>
</repositories>
<pluginRepositories>
<!-- Repository is also accessible using https connection: -->
<!-- https://support.jlupin.com/maven2/ -->
<pluginRepository>
<id>jlupin-central</id>
<name>jlupin</name>
<url>http://support.jlupin.com/maven2/</url>
</pluginRepository>
</pluginRepositories>
<dependencies>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-stdlib</artifactId>
<version>${kotlin.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>com.jlupin</groupId>
<artifactId>jlupin-client-assembly</artifactId>
<version>${jlupin.version}</version>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<sourceDirectory>${project.basedir}/src/main/kotlin</sourceDirectory>
<testSourceDirectory>${project.basedir}/src/test/kotlin</testSourceDirectory>
<plugins>
<plugin>
<artifactId>kotlin-maven-plugin</artifactId>
<groupId>org.jetbrains.kotlin</groupId>
<version>${kotlin.version}</version>
<executions>
<execution>
<id>compile</id>
<goals>
<goal>compile</goal>
</goals>
</execution>
<execution>
<id>test-compile</id>
<goals>
<goal>test-compile</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>com.jlupin</groupId>
<artifactId>jlupin-next-server-maven-plugin</artifactId>
<version>${jlupin.next.server.maven.plugin.version}</version>
<executions>
<execution>
<id>jlupin-zip</id>
<goals>
<goal>zip</goal>
</goals>
<configuration>
<additionalFilesDirectories>
<param>additional-files</param>
</additionalFilesDirectories>
</configuration>
</execution>
<execution>
<id>jlupin-deploy</id>
<goals>
<goal>deploy</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
It is standard JLupin's Maven configuration. Only difference is with using different library for compiling code and Kotling standard library is added. All dependencies except Kotlin's standard library are set to scope provided because they are available on server by default. By default server does not contain Kotlin's standard library and it is certain that our microservice requires it to run - ended up it is written in kotlin. By adding it here it will be automatically added to our microservice zip.
Microservice code
Add two files with configuration: one for JLupin (KotlinHelloWorldJLupinConfiguration) and one for Spring container (KotlinHelloWorldSpringConfiguration). Create package com.example.configuration and put classed there.
package com.example.configuration
import com.jlupin.impl.container.application.spring.JLupinAbstractSpringApplicationContainer
import com.jlupin.interfaces.configuration.microservice.container.application.JLupinAbstractApplicationContainerProducer
import com.jlupin.interfaces.container.application.JLupinApplicationContainer
import org.springframework.context.annotation.AnnotationConfigApplicationContext
import org.springframework.context.support.AbstractApplicationContext
class KotlinHelloWorldJLupinConfiguration : JLupinAbstractApplicationContainerProducer() {
override fun produceJLupinApplicationContainer(): JLupinApplicationContainer {
return object : JLupinAbstractSpringApplicationContainer() {
override fun getAbstractApplicationContext(): AbstractApplicationContext {
return AnnotationConfigApplicationContext(KotlinHelloWorldSpringConfiguration::class.java)
}
}
}
}
package com.example.configuration
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.ComponentScan
import org.springframework.context.annotation.Configuration
import java.util.*
@Configuration
@ComponentScan("com.example")
open class KotlinHelloWorldSpringConfiguration() {
@Bean("jLupinRegularExpressionToRemotelyEnabled")
open fun getRemotelyBeanList(): List<String> {
val list = ArrayList<String>()
list.add("exampleService")
return list
}
}
Microservice is configured but does nothing. Create two packages com.example.service.interfaces and com.example.service.impl and put service definitions in them:
package com.example.service.interfaces
interface ExampleService {
fun hello(name: String): String
}
package com.example.service.impl
import com.example.service.interfaces.ExampleService
import org.springframework.stereotype.Service
@Service(value = "exampleService")
class ExampleServiceImpl : ExampleService {
override fun hello(name: String): String {
return "Hello, $name!"
}
}
Microservice is done. You only need to add configuration for it. Create special directory for it called additional-files. Put in there two files: configuration.yml and log4j2.xml.
SERVERS:
JLRMC: #JLupin Remote Method Calls Fast Protocol
readTimeout: 480000
isWaitForFinishExecuteAllRequests: true
waitToShutdownThreadsOnStop: 60000
backlog: 0
receiveBufferSize: 0
isReuseAddress: false
threadPoolSize: 128
isLogPeriodicOnDebug: true
isDestroyThreadOnTimeout: false
threadExecutingTimeOut: 240000
TRANSMISSION:
readTimeout: 480000
isWaitForFinishExecuteAllRequests: false
waitToShutdownThreadsOnStop: 60000
backlog: 0
receiveBufferSize: 0
isReuseAddress: false
threadPoolSize: 8
isLogPeriodicOnDebug: true
isDestroyThreadOnTimeout: false
threadExecutingTimeOut: 3600000
QUEUE:
readTimeout: 480000
isWaitForFinishExecuteAllRequests: true
waitToShutdownThreadsOnStop: 60000
backlog: 1024
receiveBufferSize: 1024
isReuseAddress: false
threadPoolSize: 128
isLogPeriodicOnDebug: true
isDestroyThreadOnTimeout: false
threadExecutingTimeOut: 240000
ENTRY_POINTS:
QUEUE:
threadAmount: 512
howOftenCheckingServerInMillis: 5000
repeatsAmount: 4
timeToWaitBetweenRepeatProbeInMillis: 1000
PROPERTIES:
#jvmOptions1: '-Xms128M -Xmx256M -agentlib:jdwp=transport=dt_socket,address=12998,server=y,suspend=n'
jvmOptions1: '-Xms64M -Xmx128M' #jvmOptions_2 - default the same as jvmOptions_1
#jvmOptions2: '-Xms128M -Xmx256M'
externalPort: '8000'
version: '1.0'
switchDelayTime: 0
connectionSocketTimeoutInMillis: 1000
readTimeoutInMillis: 30000
isKeepAlive: false
isOOBInline: false
isTcpNoDelay: false
isReuseAddress: false
sendBufferSize: 0
receiveBufferSize: 0
soLinger: 0
trafficClass: 0
#javaExecutablePath: 'c:\\jvm\\bin\\java.exe'
#additionalClassPath: 'c:\\temp\\*'
isStartOnMainServerInitialize: true
priorityStartOnMainServerInitialize: 4
waitForProcessInitResponseTimeInMillis: 90000
waitForProcessStartResponseTimeInMillis: 90000
waitForProcessDestroyResponseTimeInMillis: 30000
isAllFilesToJVMAppClassLoader: false
isArchiveOnStart: false
startLogMode: INFO
isInitErrorCauseWithNetworkInformation: true
checkAvailableScript: 'function isAvailable(checkResponseTimeInMillis, jrmcActiveThreads, jrmcMaxThreads,
queueActiveThreads, queueMaxThreads, servletActiveThreads, servletMaxThreads,
jvmMaxMemoryInBytes, jvmTotalMemoryInBytes, jvmFreeMemoryInBytes,
jvmProcessCpuLoadInPercentage, userAvailableFlag) {
var isAvailableByUser = Boolean(userAvailableFlag);
if(checkResponseTimeInMillis > 20000 || !isAvailableByUser) {
return false;
}
return true;
}'
APPLICATION:
applicationContainerProducerClassName: 'com.example.configuration.KotlinHelloWorldJLupinConfiguration'
INITIALIZING_LOGGER:
#directoryPath: '/logs/server'
#fileName: 'file_name'
fileExtension: 'log'
fileSizeInMB: 20
maxFiles: 10
MEMORY_ERRORS:
isRestartOnError: true
howManyTimes: 4
percentageGrowth: 15
isHeapDump: true
THREAD_POOLS:
THREAD_POOL_1:
size: 8
waitingTimeForTasksCompletionInMillis: 10000
#THREAD_POOL_2:
# size: 8
# waitingTimeForTasksCompletionInMillis: 10000
<?xml version="1.0" encoding="UTF-8"?>
<!-- ===================================================================== -->
<!-- -->
<!-- Log4j2 Configuration -->
<!-- -->
<!-- ===================================================================== -->
<!--
| For more configuration information and examples see the Apache Log4j2
| website: https://logging.apache.org/log4j/2.x/index.html
-->
<Configuration status="WARN">
<!-- Extract log directory and file name into variables -->
<Properties>
<Property name="logDirectory">../logs/microservice/kotlin-hello-world</Property>
<Property name="logFileName">microservice</Property>
</Properties>
<Appenders>
<!-- RollingFileAppender configured to role every day -->
<RollingFile name="FILE">
<FileName>${logDirectory}/${logFileName}.log</FileName>
<FilePattern>${logDirectory}/${logFileName}.%d{yyyy-MM-dd}.log</FilePattern>
<!-- Compress log files to gzip -->
<!-- More configuration https://logging.apache.org/log4j/2.x/manual/appenders.html#DefaultRolloverStrategy -->
<!-- <FilePattern>${logDirectory}/${logFileName}.%d{yyyy-MM-dd}.log.gz</FilePattern> -->
<!-- Do not truncate file -->
<Append>true</Append>
<!-- The default pattern: Date Priority [Category] (Thread) Message\n -->
<PatternLayout pattern="%d %-5p [%c] (%t) %m%n" />
<Policies>
<!-- Rollover every microservice start - very useful for debugging -->
<!-- <OnStartupTriggeringPolicy /> -->
<!-- Rollover at the top of each day -->
<TimeBasedTriggeringPolicy interval="1" modulate="true" />
<!-- Rollover if file size is greater than 200 MB -->
<!-- <SizeBasedTriggeringPolicy size="200 MB"/> -->
</Policies>
<!-- Keep last 10 log files -->
<!-- More configuration https://logging.apache.org/log4j/2.x/manual/appenders.html#DefaultRolloverStrategy -->
<!-- <DefaultRolloverStrategy max="10" /> -->
</RollingFile>
<!-- AsyncAppender for high performance -->
<Async name="ASYNC_FILE">
<BufferSize>1000</BufferSize>
<AppenderRef ref="FILE" />
</Async>
</Appenders>
<Loggers>
<!-- Setup for root logger with AsyncAppender -->
<Root level="info">
<AppenderRef ref="ASYNC_FILE" />
</Root>
</Loggers>
</Configuration>
Microservice deployment
To deploy micrservice make sure that you have started JLupin Platform and just run command mvn clean package jlupin-next-server:deploy. It will build our application, create deployable zip and deploy microservice to server.