AWS Lambda on Localstack using Java-SdK-v1

Continuing with Localstack, next is a closer look into the code to deploy and execute AWS Lambda code on Localstack from AWS Java-Sdk-v1. The localstack-lambda-java-sdk-v1 code uses the same structure used in localstack-aws-sdk-examples & fills in for the missing AWS Lambda bit.

The LambdaService class has 3 primary methods - listFunctions(), createFunction() & invokeFunction().  The static AWSLambda client is setup with Mock credentials and pointing to the Localstack endpoint.
 
The main() method first creates the function (createFunction()), if it does not exist.

• It builds a CreateFunctionRequest object with the handler, runtime, role, etc specified
• It also reads the jar file of the Java executable from the resources folder into a FunctionCode object & adds it to the CreateFunctionRequest
• Next a call is made to the AWSLambda client createFunction() with the CreateFunctionRequest which hits the running Localstack instance (Localstack set-up explained earlier).

If all goes well, control returns to main() which invokes the listFunctions() to show details of the created Lambda function (& all others functions existing).

Finally, there is call from main() to invokeFunction() method.

• Which invokes the recently created function with a InvokeRequest object filled with some test values as the payload.
• The response from the invoked function is a InvokeResult object who's payload contains the results of the lambda function computation.

Comments welcome, localstack-lambda-java-sdk-v1 is available to play around!