AWS Lambda

An event-driven, serverless computing platform. It is a computing service that runs code in response to events and automatically manages the computing resources required by that code.

How to set up an AWS Lambda function and auto deployments with Github Actions (in Ruby)

  1. Create a Lambda function(say my-serverless-function) on AWS.
    1. Open the Lambda service from AWS home console.
    2. Open the Functions page of the Lambda console.
    3. Choose Create function
    4. Provide the basic information like function name and runtime environment.
    5. Click on Create function
  2. Create a GitHub repository, clone it on your system(optional).
  3. Navigate to your repository, create a file lambda_function.rb, and provide the sample code of a lambda function. 
      require 'json'

  def lambda_handler(event:, context:)
    msg = "Hello from Lambda!"
    { statusCode: 200, 
      body: JSON.generate(msg) 
    }
  end
  4. Push the code to your GitHub repository if working locally.
  5. Navigate to Actions → New Workflow → Set up a workflow yourself. 
       # This is a basic workflow to help you get started with Actions

   name: Ruby CI to AWS Lambda

   # Controls when the workflow will run
   on:
     # Triggers the workflow on push or pull request events but only for the main branch
     push:
       branches: [ main ]
     pull_request:
       branches: [ main ]

     # Allows you to run this workflow manually from the Actions tab
     workflow_dispatch:

   jobs:
     deploy_source:
       name: build and deploy lambda
       runs-on: ubuntu-latest
       steps:
         - uses: actions/checkout@v3
         - name: Set up Ruby
           uses: ruby/setup-ruby@359bebbc29cbe6c87da6bc9ea3bc930432750108
           with:
             ruby-version: '2.7'
         - name: Install dependencies
           run: bundle install
           env:
             CI: true
         - name: zip
           uses: montudor/action-zip@v0.1.0
           with:
             args: zip -qq -r ./bundle.zip ./
         - name: default deploy
           uses: appleboy/lambda-action@master
           with:
             aws_access_key_id: $
             aws_secret_access_key: $
             aws_region: us-east-2
             function_name: ss-auto-deploy-ruby-function
             zip_file: bundle.zip
  6. Make sure, the function_name, aws_region is the same as your lambda function name and the region.
  7. We need to add the value for AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY in the secrets. We could hardcode here, but that’s not recommended.
    1. Where to get the access key id and secret access key? Go to AWS Console → Services → IAM → Users → Select your user → Security Credentials → Access Keys.
  8. In your GitHub repository. Go to Settings → Secrets → Actions and add your access key id and secret access key with the name as given above.
  9. Now, whenever code is pushed into the main branch of your GitHub repository the changes will be reflected in your AWS Lambda function.

The source code of this activity is available here: https://github.com/ahasunos/aws-lambda-ruby-auto-deploy