flask-zip

flask-zip

This example shows how to use Lambda Adapter to run an Flask application on managed python runtime.

How does it work?

We add Lambda Adapter layer to the function and configure wrapper script.

1. attach Lambda Adapter layer to your function. This layer containers Lambda Adapter binary and a wrapper script.
   1. x86_64: arn:aws:lambda:${AWS::Region}:753240598075:layer:LambdaAdapterLayerX86:23
   2. arm64: arn:aws:lambda:${AWS::Region}:753240598075:layer:LambdaAdapterLayerArm64:23
2. configure Lambda environment variable AWS_LAMBDA_EXEC_WRAPPER to /opt/bootstrap. This is a wrapper script included in the layer.
3. set function handler to a startup command: run.sh. The wrapper script will execute this command to boot up your application.

To get more information of Wrapper script, please read Lambda documentation here.

Build and Deploy

Run the following commands to build and deploy the application to lambda.

sam build --use-container
sam deploy --guided

When the deployment completes, take note of FlaskApi's Value. It is the API Gateway endpoint URL.

Verify it works

Open FlaskApi's URL in a browser, you should see "hello world" on the page.