AWS Lambda Function in java

Question

I need to create a sample lambda function in AWS that is capable on starting or stopping a EC2 instance on call. The first thing that I tried was to create a jar from the project using the following pom

<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>Ec2Ops</groupId>
<artifactId>Ec2Ops</artifactId>
<version>0.0.1</version>
<name>Ec2Ops</name>
<description>Application to perform EC2Operations</description>
<dependencies>
    <dependency>
        <groupId>com.amazonaws</groupId>
        <artifactId>aws-java-sdk</artifactId>
        <version>1.11.136</version>
    </dependency>
    <dependency>
        <groupId>com.amazonaws</groupId>
        <artifactId>aws-lambda-java-core</artifactId>
        <version>1.1.0</version>
    </dependency>
</dependencies>
<build>
    <sourceDirectory>src</sourceDirectory>
    <plugins>
        <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.1</version>
            <configuration>
                <source>1.7</source>
                <target>1.7</target>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-dependency-plugin</artifactId>
            <version>3.0.1</version>
            <executions>
                <execution>
                    <id>copy-dependencies</id>
                    <phase>package</phase>
                    <goals>
                        <goal>copy-dependencies</goal>
                    </goals>
                    <configuration>
                        <!-- configure the plugin here -->
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

I uploaded the jar file I got using this pom into my lambda function; there I'm getting the following error in return

{
  "errorMessage": "com/amazonaws/services/ec2/AmazonEC2",
  "errorType": "java.lang.NoClassDefFoundError",
  "stackTrace": [
    "com.ec2ops.handler.Ec2OpsHandler.handleRequest(Ec2OpsHandler.java:14)",
    "com.ec2ops.handler.Ec2OpsHandler.handleRequest(Ec2OpsHandler.java:9)"
  ],
  "cause": {
     "errorMessage": "com.amazonaws.services.ec2.AmazonEC2",
     "errorType": "java.lang.ClassNotFoundException",
       "stackTrace": [
       "java.net.URLClassLoader.findClass(URLClassLoader.java:381)",
       "java.lang.ClassLoader.loadClass(ClassLoader.java:424)",
       "java.lang.ClassLoader.loadClass(ClassLoader.java:357)",
        "com.ec2ops.handler.Ec2OpsHandler.handleRequest(Ec2OpsHandler.java:14)",
       "com.ec2ops.handler.Ec2OpsHandler.handleRequest(Ec2OpsHandler.java:9)"
     ]
  }
}

Please note I'm using AWS Java SDK to manipulate the instance. I understood from the error that the library is not available; so I tried to include the library also into the jar by using the shade plugin.

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <version>2.3</version>
    <configuration>
        <createDependencyReducedPom>false</createDependencyReducedPom>
    </configuration>
    <executions>
        <execution>
            <phase>package</phase>
            <goals>
                <goal>shade</goal>
            </goals>
        </execution>
    </executions>
</plugin>

When I'm doing this that size of the jar file is more than 50MB, hence I cannot upload this into the jar file. The code I'm using for the EC2 operation is given below.

public boolean startInstance(String instanceId) {
    AmazonEC2 ec2 = new AmazonEC2Client();
    StartInstancesRequest startInstanceRequest = new StartInstancesRequest()
            .withInstanceIds(instanceId);
    StartInstancesResult instancesResult = ec2
            .startInstances(startInstanceRequest);

    List<InstanceStateChange> stateChangeList = instancesResult
            .getStartingInstances();

    return checkStateOfInstance(stateChangeList, 16, instanceId) || checkStateOfInstance(stateChangeList, 80, instanceId);
}

Can someone tell what I'm doing wrong here.

Manesh · Accepted Answer · 2017-06-05 06:25:26Z

1

I have sucessfully found out how to get this lambda function to work. This is for anyone who is looking for an answer in regards to implementation of AWS services related operations in AWS lambda. There is very little documentation on this.

Since the AWS SDK is too large it is not possible for lambda to accommodate jar when this is included. So what we can do is just include that package that is needed; considering the question, the only SDK library I need reference to is EC2 hence I added the dependency to my pom only for EC2 as given below.

<!-- https://mvnrepository.com/artifact/com.amazonaws/aws-java-sdk-ec2 -->
<dependency>
    <groupId>com.amazonaws</groupId>
    <artifactId>aws-java-sdk-ec2</artifactId>
    <version>1.9.0</version>
</dependency>

answered Jun 5, 2017 at 6:25

Manesh

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