In this post we will use AWS Serverless Application Model (SAM) to create and deploy a simple Lambda function written in Python. The Function get’s built and deployed with Github Actions.

Prerequisites

• AWS CLI
• Python 3
• Git client
• SAM CLI installed
• Docker installed

Create project

sam init -r python3.8 -n pyth38-demo

Build and test local

Change to the newly created directory pyth38-demo.

sam build
sam local invoke --event events/event.json

Import the project into Github

Create a new repository in Github. Import the project in the new repository.

Create Github Action

Go ot the repositories Settings and add your AWS access key (AWS_ACCESS_KEY_ID) and secret (AWS_SECRET_ACCESS_KEY) as Secrets. Create a blank Github Action in your new repository with this code.

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on: [push]

jobs:
  aws_sam:
    runs-on: ubuntu-latest
    steps:

      - name: Checkout
        uses: actions/checkout@master

      - name: sam build
        uses: youyo/aws-sam-action/python3.8@master
        with:
          sam_command: build
        env:
          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
          AWS_DEFAULT_REGION: eu-west-1

      - name: sam deploy
        uses: youyo/aws-sam-action/python3.8@master
        with:
          sam_command: 'deploy --stack-name pyth38-demo --s3-bucket bucket_name --capabilities CAPABILITY_IAM --no-fail-on-empty-changeset'
        env:
          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
          AWS_DEFAULT_REGION: eu-west-1

Change the S3 bucket name to an existing bucket in the same region as your Lambda. Commit your changes. The Lambda Function will be built and deployed to your AWS account.

Test remote

Get the API Gateway endpoint url

aws cloudformation describe-stacks --stack-name pyth38-demo

Invoke API

curl endpoint url

Delete

aws cloudformation delete-stack --stack-name pyth38-demo