Extension ID

com.castsoftware.awsjava

What's new?

See AWS Java 1.0 - Release Notes for more information.

Objects

In what situation should you install this extension?

The AWSJava extension is responsible of creating objects describing Amazon Web Service (AWS) lambda functions but only in the context of java technology. (Similarly the NodeJS extension is responsible of AWS lambda Functions created for the nodejs runtime). To run fully, this extension needs to add a Universal Analysis Unit and to switch on the HTML5 language. This allows analyzing serverless configuration (YAML) files used to define the lambda  functions. This is particularly necessary for the creation of operation-type objects like Java AWS Lambda GET Operation and the Java AWS Lambda Function object. The complementary analysis responsible of creating Java Call to AWS Lambda Function objects is based on the analysis of java files and it will be launched without any further requirement upon installation of the com.castsoftware.awsjava plugin.

Server side (serverless framework)

Below a typical serverless configuration file serverless.yml is presented (any name is supported, with both 'yml' and 'yaml' extensions, but the latter extension might require to be added explicitly in the Analysis Unit configuration in CAST-MS).

# serverless.yml, adapted from https://github.com/zanon-io/aws-serverless-demo

service: my-serverless-demo
provider:
  name: aws
  runtime: nodejs4.3
  region: us-east-1
  iamRoleStatements:
    - Effect: "Allow"
      Action:
        - 'sdb:Select'
      Resource: "arn:aws:sdb:${self:provider.region}:*:domain/Weather"
functions:
  weather:
    handler: handler.currentTemperature
    events:
      - http: GET weather/temperature
      - http: POST weather/temperature
    memorySize: 128
    timeout: 10
  meanweather:
    handler: handler.meanTemperature
    events:
      - http:
          path: weather/temperature/mean
          method: get
    memorySize: 128
    timeout: 10
    runtime: java8

The com.castsoftware.awsjava will analyze the .yml file and it will create a JAVA AWS Lambda Function object only for the meanweather lambda function, because of the runtime java8.

The links between the Java AWS Lambda Function object and the actual java method (if present and resolved) will be done at application-level and indicated with a line in the log similar to:

Running plugin com.castsoftware.awsjava...
Start application level analysis (AWSJava)
Created link from lambda function meanweather to Java handler method com.castsoftware.api.common.lambda.MeanWeather.handleRequest
...
Done running plugin com.castsoftware.awsjava.

As an example, we can analyze one of the samples provided by Amazon lambda-java8-dynamodb.

service: java-dynamo    # simplified version of the "serverless.yml" file

provider:
  name: aws
  runtime: java8
  ...
...

functions:
  getTags:
    handler: com.serverless.TagsHandler
    events:
      - http:
          path: java-dynamo/tags/{brand_id}/{language}
          method: get

The events field in the serverless file links a URL to a given Lambda function. This connection is represented by a Java AWS Lambda GET Operation object.

The call-back code to be executed after invocation of the Lambda function:

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

public class TagsHandler implements RequestHandler<Map<String, Object>, ApiGatewayResponse> {
    ...
    
    @Override
    public ApiGatewayResponse handleRequest(Map<String, Object> input, Context context) {
	   	// the content of the AWS Lambda Function
	}
    ...
}

The results of the analysis as shown in Enlighten:

Similar results are expected for the predefined interface com.amazonaws.services.lambda.runtime.RequestStreamHandler.

Client-side

@LambdaFunction annotation

The following two annotations (equally named) are supported (one for Android and the other one for Java applications):

• com.amazonaws.mobileconnectors.lambdainvoker.LambdaFunction
• com.amazonaws.services.lambda.invoke.LambdaFunction

The example below reproduced from the official documentation https://docs.aws.amazon.com/lambda/latest/dg/with-android-example.html, illustrates how one can define (but not implemented) the lambda function by annotating the AndroidBackendLambdaFunction method. 

// https://docs.aws.amazon.com/lambda/latest/dg/with-android-example.html
import com.amazonaws.mobileconnectors.lambdainvoker.LambdaFunction;
public interface MyInterface {

    /**
     * Invoke the Lambda function "AndroidBackendLambdaFunction". 
     * The function name is the method name.
     */
    @LambdaFunction
     ResponseClass AndroidBackendLambdaFunction(RequestClass request);

}

The @LambdaFunction annotation maps the specific client method to the same-name Lambda function. The expected behavior of the JEE analyzer is to resolve the actual Lambda Function invocation via method calls (elsewhere) to the annotated interface methods. The com.castsoftware.awsjava extension on the other hand will create a Java Call to AWS Lambda Function object and the respective incoming callLink from the annotated interface method AndroidBackendLambdaFunction.

Linking client/server

The extension com.castsoftware.wbslinker is responsible of matching Java Call to AWS Lambda Function objects to Lambda Function objects such as Java AWS Lambda Function. 

Limitations

• A single inheritance depth level is only supported for classes implementing predefined interfaces such as RequestHandler andRequestStreamHandler when searching for handler methods. However overriding/overloading of the handler methods is not fully supported.
• No custom lambda function resolver is supported, i.e. that passed to lambdaFunctionNameResolver (conntected to the building of LambdaInvokerFactory).