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AWS Hello Lambda

AWS Lambda is currently an option to implement Serverless architecture which is a name to refer to applications that run in ephemeral containers, such architectures remove the need for the traditional ‘always on’ server and with that we save a lot of money in up time server consuming.

In this post I will show you how to create a hello world concept using AWS arquitecture. First we need to create a Java basic project this time using lazybones.

lazybones create java-basic hello-aws-lambda

Previous command will create this structure

<proj>
      |
      +- src
          |
          +- main
          |     |
          |     +- java
          |
          +- test
          |   |
          |   +- java

Edit your build.gradle file to create a make a Jar task and add lambda AWS dependencies.

apply plugin: "java"
apply plugin: "application"

version = '0.0.1'

task buildJar(type: Jar) {
  manifest {
    attributes 'Implementation-Title': 'Hello AWS Lambda',
    'Implementation-Version': version,
    'Main-Class': 'example.Hello'
  }
  baseName = project.name + '-all'
  from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } }
  with jar
}

repositories {
  mavenCentral()
}

dependencies {
  compile 'com.amazonaws:aws-lambda-java-core:1.1.0'
  compile 'com.amazonaws:aws-lambda-java-events:1.1.0'
}

Then define Java classes under project-dir/src/main/java/example/

Hello.java

package example;

import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.RequestHandler;

public class Hello implements RequestHandler<HelloRequest, HelloResponse> {

  @Override
  public HelloResponse handleRequest(HelloRequest input, Context context) {
    return new HelloResponse(input.getInput());
  }

}

HelloRequest.java

package example;

public class HelloRequest {

  private String input;

  public HelloRequest(String input) {
    this.input = input;
  }

  public HelloRequest() {
  }

  public String getInput() {
    return input;
  }

  public void setInput(String input) {
    this.input = input;
  }

}

HelloResponse.java

package example;

public class HelloResponse {

  private String hello;

  public HelloResponse(String hello) {
    this.hello = hello;
  }

  public HelloResponse() {
  }

  public String getHello() {
    return hello;
  }

  public void setHello(String hello) {
    this.hello = hello;
  }

}

Use the following gradle command to generate your standalone .jar deployment file

gradle buildJar

This will generate the .jar file with all dependencies under build/libs.

That’s it, test your code uploading the jar file in to the AWS Lambda console

Click Test button and change the JSON content with the following:

{
  "input": "josdem"
}

To download the code:

git clone https://github.com/josdem/java-topics.git
cd hello-aws-lambda

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