springboot-response-streaming-zip

Spring Boot 2 Zip example

A basic file streaming application written with the Spring Boot 2 framework. You can build and test it locally as a typical Spring Boot 2 application.

The application can be deployed in an AWS account using the Serverless Application Model. The template.yaml file in the root folder contains the application definition.

To run the application we are using the run.sh script located in the resources folder:

#!/bin/sh

exec java -cp "./:lib/*" "com.amazonaws.demo.stream.Application"

In the configuration we have to specify the AWS Lambda adapter as a layer and configure the script as handler:

 Properties:
      MemorySize: 512
      Handler: run.sh
      CodeUri: app/
      Runtime: java11
      AutoPublishAlias: live
      SnapStart:
        ApplyOn: PublishedVersions      
      Environment:
        Variables:
          RUST_LOG: info
          READINESS_CHECK_PATH: /healthz
          REMOVE_BASE_PATH: /v1
          AWS_LAMBDA_EXEC_WRAPPER: /opt/bootstrap
          AWS_LWA_INVOKE_MODE: response_stream
      Layers:
        - !Sub arn:aws:lambda:${AWS::Region}:753240598075:layer:LambdaAdapterLayerX86:23

In this template, we enable SnapStart for this function. SnapStart drastically reduces cold start time for Java functions using Firecracker MicroVM snapshotting technology. Read more about SnapStart here.

Remove the base path

The file stream application is deployed under /v1/{proxy+}. But the application does not know that. So in the SAM template file, we configured environment variable REMOVE_BASE_PATH=/v1. This configuration tells the Adapter to remove /v1 from http request path, so that the pet store application works without changing code.

Pre-requisites

The following tools should be installed and configured.

• AWS CLI
• SAM CLI
• Maven
• Docker

Deploy to Lambda

Navigate to the sample's folder and use the SAM CLI to build the application:

$ sam build

This command compiles the application and prepares a deployment package in the .aws-sam sub-directory.

To deploy the application in your AWS account, you can use the SAM CLI's guided deployment process and follow the instructions on the screen

$ sam deploy --guided

Once the deployment is completed, the SAM CLI will print out the stack's outputs, including the new application URL. You can use curl or a web browser to make a call to the URL

...
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Outputs                                                                                                                                                                       
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Key                 StreamFilesFunctionUrl                                                                                                                                    
Description         Function URL for StreamFiles function to stream a dummy 15mb file                                                                                         
Value               https://abcdxxxxxxxxxxxx.lambda-url.us-west-2.on.aws/stream-dummy?size=15                                                                 

Key                 StreamFilesFunction                                                                                                                                       
Description         StreamFilesFunction Lambda Function ARN                                                                                                                   
Value               arn:aws:lambda:us-west-2:111111111111:function:spring-wa-StreamFilesFunction-abcdxxxxxxxxxxxx     
...

$ curl  https://abcdxxxxxxxxxxxx.lambda-url.us-west-2.on.aws/stream-dummy?size=15

To stream a preexisting mp4 file  

$ curl  https://abcdxxxxxxxxxxxx.lambda-url.us-west-2.on.aws/stream   

Clean up

This example use provisioned concurrency to reduce cold start time. It incurs additional cost. You can remove the whole example with the following command.

sam delete