awslambdainvoke

AWS Lambda Function Invoke Java example

This folder contains a Java application example that handles Lambda functions on AWS (Amazon Web Services).

Invoke an AWS Lambda function.

Requirements

• You must have an Amazon Web Services (AWS) account.

• The code was written for:

  • Java 8
  • Apache Maven 3
  • AWS SDK for Java (SDK V2)

Using the code

• Configure your AWS access keys.

  Important: For security, it is strongly recommend that you use IAM users instead of the root account for AWS access.

  When you initialize a new service client without supplying any arguments, the AWS SDK for Java attempts to find AWS credentials by using the default credential provider chain.

  Setting your credentials for use by the AWS SDK for Java can be done in a number of ways, but here are the recommended approaches:

  • The default credential profiles file.

    Set credentials in the AWS credentials profile file on your local system, located at:

    • ~/.aws/credentials on Linux, macOS, or Unix.

    • C:\Users\USERNAME\.aws\credentials on Windows.

    This file should contain lines in the following format:

    [default]
    aws_access_key_id = <YOUR_ACCESS_KEY_ID>
    aws_secret_access_key = <YOUR_SECRET_ACCESS_KEY>

    Replace the values of <YOUR_ACCESS_KEY_ID> and <YOUR_SECRET_ACCESS_KEY> by your AWS credentials.

  • Environment variables AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY.

    Set the AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables.

    To set these variables on Linux, macOS, or Unix, use export:

    export AWS_ACCESS_KEY_ID=<YOUR_ACCESS_KEY_ID>
    export AWS_SECRET_ACCESS_KEY=<YOUR_SECRET_ACCESS_KEY>

    To set these variables on Windows, use set:

    set AWS_ACCESS_KEY_ID=<YOUR_ACCESS_KEY_ID>
    set AWS_SECRET_ACCESS_KEY=<YOUR_SECRET_ACCESS_KEY>

    Replace the values of <YOUR_ACCESS_KEY_ID> and <YOUR_SECRET_ACCESS_KEY> by your AWS credentials.

• You can create a Lambda function on AWS.

  You can use the AWS Lambda Function Hello World JSON Java example: awslambdahellojson.

• You can select the AWS region of the Lambda function changing the value of REGION variable in the code.

• You can change the values of the payload to the Lambda function in the code (withPayload):

  {
    "firstName": "Peter",
    "lastName": "Parker"
  }

• Run the code.

  You must provide 1 parameter, replace the value of:

  • <FUNCTION_NAME> by Lambda function name.

  Run application:

  java -jar awslambdainvoke.jar <FUNCTION_NAME>

  You can use as name of the Lambda function 2 name formats:

  • Function name

    Ex.: HelloJsonJava

  • Function ARN

    Ex.: arn:aws:lambda:eu-west-1:123456789012:function:HelloJsonJava

    You can retrieve the function ARN by looking at the function in the AWS Console.

• Test the application.

  You should see the response from the Lambda function:

  For example:

  • Lambda return value: {"greetings":"Hello Peter Parker."}
  • Lambda status code: 200