AWS Lambda : Kotlin

alb.json

{
    "requestContext": {
        "elb": {
            "targetGroupArn": "arn:aws:elasticloadbalancing:us-east-1:123456789012:targetgroup/lambda-target/d6190d154bc908a5"
        }
    },
    "httpMethod": "GET",
    "path": "/health",
    "queryStringParameters": {
        "price": 1000,
        "weight": 500
    },
    "headers": {
        "accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
        "accept-encoding": "gzip",
        "accept-language": "en-US,en;q=0.5",
        "connection": "keep-alive",
        "cookie": "cookie",
        "host": "lambda-846800462.elb.amazonaws.com",
        "upgrade-insecure-requests": "1",
        "user-agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:60.0) Gecko/20100101 Firefox/60.0",
        "x-amzn-trace-id": "Root=1-5bdb40ca-556d8b0c50dc66f0511bf520",
        "x-forwarded-for": "72.21.198.66",
        "x-forwarded-port": "80",
        "x-forwarded-proto": "http"
    },
    "body": "",
    "isBase64Encoded": false
}

build.gradle

plugins {
    id 'org.jetbrains.kotlin.jvm' version '1.3.11'
}

repositories {
    mavenCentral()
}

dependencies {
    compile fileTree(dir: 'jars', include: '*.jar')
    compile 'com.amazonaws:aws-lambda-java-core:1.1.0'
    compile 'com.amazonaws:aws-lambda-java-events:1.1.0'
    compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
    compile "org.jetbrains.kotlin:kotlin-reflect"
    compile "com.fasterxml.jackson.module:jackson-module-kotlin:2.9.7"
}

compileKotlin {
    kotlinOptions.jvmTarget = "1.8"
}
compileTestKotlin {
    kotlinOptions.jvmTarget = "1.8"
}

task buildZip(type: Zip) {
    from compileKotlin
    from processResources
    into('lib') {
        from configurations.compileClasspath
    }
}

build.dependsOn buildZip

Main.kt

package example

import com.amazonaws.services.lambda.runtime.Context
import java.io.*
import com.fasterxml.jackson.annotation.JsonIgnoreProperties
import com.fasterxml.jackson.module.kotlin.*

@JsonIgnoreProperties(ignoreUnknown = true)
data class ALBRequest(
    val requestContext: Map<String, Map<String, String>>,
    val httpMethod: String,
    val path: String,
    val queryStringParameters: Map<String, String>,
    val headers: Map<String, String>,
    val body: String
)

data class Response(val message: String, val status: Int = 200)

class Main {
    private val mapper = jacksonObjectMapper()

    fun handler(input: InputStream, output: OutputStream, context: Context): Unit {
        val request = mapper.readValue<ALBRequest>(input)
        mapper.writeValue(output, Response(request.toString(), 400))
    }
}

Makefile

.PHONY: clear build test

build:
	gradle build

test: build
	rm -rf runtime/
	unzip -d runtime build/distributions/lambda.kt.zip
	cat $(payload) | docker run --rm -v $(PWD)/runtime:/var/task -i -e DOCKER_LAMBDA_USE_STDIN=1 lambci/lambda:java8 example.Main::handler