sam-python-serverless-stack

In this project I set up the backend and AWS Services needed to build the serverless Notes application found here but instead of using a Node.js backend and the serverless.com framework I use a Python backend and the AWS SAM framework.

The combination of this project and the frontend put together here serve as a good example project for a Serverless Web Application built on AWS with the SAM Framework.

AWS Services Used

• Lambda
• DynamoDB
• API Gateway
• Cognito
• IAM
• S3
• Amplify

Prerequisites

1. AWS SAM CLI (and its prereqs Docker and AWS CLI)
2. Optional see notes PyCharm IDE or of the other IDEs that have an AWS Toolkit Plugin
3. AWS Toolkit Plugin for PyCharm you should also be able to find this on the Pycharm Plugins Marketplace. Settings -> Plugins -> Marketplace

Notes

• Python Version 3.6 used
• You can used SAM CLI for all the build and deployment I used the AWS Toolkit for PyCharm because the deployment is built into the IDE and you can use it to set breakpoints and debug lambda functions locally or deployed remotely.

Steps

Environment Setup

Clone the repo

$ git clone https://github.com/aaronosb/sam-python-serverless-stack

Open the project in PyCharm [Insert Photo]

Mark the lambda folder as sources root (right click folder -> Mark Directory As -> Sources Root) [Insert Photo]

Backend Deployment

To deploy the stack right click on the project and select Deploy Serverless Application [Insert Photo]

Select Create Stack and give the stack a name like sam-serverless-test

Create an S3 Bucket to be used to upload the code for your lambda functions [Inset Photo]

Then select Deploy

After it is completed you should be able to go into the AWS Console see the stack deployed as well as get the outputs from the Outputs that will be needed when configuring the React frontend application.

Frontend Deployment

Now you are ready to connect the react frontend to these services you've deployed via AWS Amplify.

The first step is to clone the repository with the frontend application (into a seperate directory) and install the NPM packages .

$ git clone clone https://github.com/AnomalyInnovations/serverless-stack-demo-client
$ npm install

Then replace serverless-stack-demo-client/src/config.js with the following fill in all the outputs from the stack that was deployed with the SAM. Ignore the STRIPE_KEY and BUCKET for now if you would like to see info on how to implement them check out https://serverless-stack.com:

export default {
  MAX_ATTACHMENT_SIZE: 5000000,
  STRIPE_KEY: "not_implemented",
  s3: {
    REGION: "us-east-1",
    BUCKET: "not_implemented"
  },
  apiGateway: {
    REGION: "us-east-1",
    URL: "SAM_TEMPLATE_OUTPUT_1"
  },
  cognito: {
    REGION: "us-east-1",
    USER_POOL_ID: "SAM_TEMPLATE_OUTPUT_4",
    APP_CLIENT_ID: "SAM_TEMPLATE_OUTPUT_5",
    IDENTITY_POOL_ID: "SAM_TEMPLATE_OUTPUT_3"
  }
};

Once that is done you can run it locally

$ npm run start

Using the Application

First thing you will need to do is sign up. You can do so by either using a real email address so that you can verify it when it goes to create the coginto user or use the AWS CLI to create a test user guide on this here.

Then when you log in you should be able to Create, Edit, and Delete notes in the notes application.

[Insert GIF here]

with S3 bucket not set up adding attachments will not work

After playing around a bit and creating some notes, go back into the AWS Console and check on the DynamoDB Table to see the records being stored there.

That's it, from here edit away or use this project as a template for your next AWS SAM Serverless Web Application.

Tips

• Debugging errors on deployment (deleting stack if in Rollback_Complete)
• Testing/Debugging Lambda with AWS Toolkit on PyCharm
• Cloud watch logs

Resources

• https://github.com/AnomalyInnovations/serverless-stack-demo-api
• https://github.com/AnomalyInnovations/serverless-stack-demo-client
• https://github.com/aws-samples/aws-cognito-apigw-angular-auth
• https://github.com/awslabs/serverless-application-model

TODOs

• Finish S3 bucket for attachments
• Write Unit Tests for Lambda Functions
• Attempt to get template.yaml to work by using implicit API Gateway provisioned with AWS::Serverless::Function rather than specifing explicitly NotesApi as a AWS::Serverless::Api resource
• Tailor Dynamo permissions per lambda function