AWS-Lambda-NodeJS-Boilerplate

Boilerplate code for AWS Lambda Function - using NodeJS runtime.

Features

• API Gateway → Exposes endpoints for CRUD operations.
• AWS Lambda - Hello World
• AWS Lambda → Handles business logic for order management.
• Amazon DocumentDB (MongoDB-compatible) → Stores order data.
• Amazon SQS → Handles message queue processing.
• Amazon ElastiCache (Redis) → Caches order details for fast retrieval.
• AWS SAM (Serverless Application Model) → Defines infrastructure as code.
• Deployment Pipeline using Github actions (manual trigger)
• Authentication
• Authorization
• GraphQL - for order details

---

Deploy the Lambda function using GitHub Actions?

read

• Step 1: Fork this repository
• Step 2: Configure valid AWS credentials in your cloned repository's "Settings" tab -> "Secrets and Variables" -> "Repository Secrets" Section

• Step 3: Go to Actions
• Step 4: Select "SAM Deploy"
• Step 5: Click "Run Workflow" dropdown on the right hand side

• Step 6: Verify all the inputs and click "Run Workflow" to trigger the deployment
• Step 7: Your deployment is triggered, monitor the workflow logs until completion.
• Step 8: Once the workflow steps are completed successfully, expand this step to gather the deployment endpoint of your lambda function.

---

Setup your dev environment

read

1️⃣ template.yaml (AWS SAM Template)

Defines the Lambda functions, API Gateway, SQS, and ElastiCache.

1. Create mongodb test instance (preferably local), Configure your mongodb url at DB_URI in template.yaml
2. Create redis test instance at REDIS_HOST

docker run --name local-redis -p 6379:6379 -d redis

This command will start a Redis server on localhost at port 6379.

Commands you can use next.

• Create pipeline: cd order-manager && sam pipeline init --bootstrap
• Validate SAM template: cd order-manager && sam validate
• Test Function in the Cloud: cd order-manager && sam sync --stack-name {stack-name} --watch

Build project

sam build

Deploy project

sam deploy --guided

The AWS SAM CLI deploys your application by doing the following:

• The AWS SAM CLI creates  ̑an Amazon S3 bucket and uploads your .aws-sam directory.
• The AWS SAM CLI transforms your AWS SAM template into AWS CloudFormation and uploads it to the AWS CloudFormation service.
• AWS CloudFormation provisions your resources.

Output

Once the stack is created/updated successfully, then you will find the api gateway endpoint url.

To get the endpoint url:

Use the sam list endpoints --output json command to get this information

To Invoke the function

1. Using curl

curl https://ets1gv8lxi.execute-api.us-west-2.amazonaws.com/Prod/hello/
{"message": "hello world"}

2. Using sam command

sam remote invoke HelloWorldFunction --stack-name sam-app

Modify and sync your application to the AWS Cloud

Use the AWS SAM CLI sam sync --watch command to sync local changes to the AWS Cloud.

In your command line, from the sam-app project directory, run the following:

sam sync --watch

The AWS SAM CLI prompts you to confirm that you are syncing a development stack. Since the sam sync --watch command automatically deploys local changes to the AWS Cloud in real time, we recommend it for development environments only.

Test your application locally

Use the AWS SAM CLI sam local command to test your application locally. To accomplish this, the AWS SAM CLI creates a local environment using Docker. This local environment emulates the cloud-based execution environment of your Lambda function.

1. Create a local environment for your Lambda function and invoke it.
2. Host your HTTP API endpoint locally and use it to invoke your Lambda function.

In your command line, from the sam-app project directory, run the following:

sam local invoke

// To call a specific function
sam local invoke CreateOrderFunction --event events/createOrder.json

// To pass local env variables - only for local testing
sam local invoke CreateOrderFunction --event events/createOrder.json --env-vars env.json

To host your API locally

In your command line, from the sam-app project directory, run the following:

sam local start-api

Delete

In your command line, from the sam-app project directory, run the following:

sam delete

🚨 Recovering from Accidental S3 Bucket Deletion in AWS SAM

If you've accidentally deleted the S3 bucket used by AWS SAM, you’ll need to create a new bucket and remap it to AWS SAM.

---

1️⃣ Create a New S3 Bucket

You can manually create an S3 bucket or use the AWS CLI:

aws s3 mb s3://my-new-sam-bucket --region us-east-1

🔹 Replace my-new-sam-bucket with a unique bucket name.
🔹 Replace us-east-1 with your AWS region.

---

2️⃣ Update AWS SAM to Use the New Bucket

Modify your SAM configuration file (samconfig.toml) to reference the new bucket.

🔹 Locate samconfig.toml in your project.
🔹 Update the s3_bucket value:

[default.deploy.parameters]
s3_bucket = "my-new-sam-bucket"
s3_prefix = "my-app"
region = "us-east-1"
capabilities = "CAPABILITY_IAM"
stack_name = "my-app-stack"

Alternatively, specify the new bucket during deployment:

sam deploy --s3-bucket my-new-sam-bucket

---

3️⃣ Rebuild and Deploy AWS SAM

Run the following to rebuild and redeploy:

sam build
sam deploy --guided

This ensures that SAM now uses the new S3 bucket.

---

4️⃣ Optional: Clean Up Old References

If AWS SAM was using a deleted bucket, you might encounter an error like:

🚨 "The specified bucket does not exist"

To fix this:

• Check .aws-sam directory:

  rm -rf .aws-sam

• Clear SAM cache (if needed):

  sam cache clear

• Then rebuild & deploy again.

---

✅ Summary

✔️ Created a new S3 bucket
✔️ Updated AWS SAM to use the new bucket
✔️ Rebuilt & deployed the application

Github Actions

• https://aws.amazon.com/blogs/compute/using-github-actions-to-deploy-serverless-applications/

References

• https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-getting-started-hello-world.html
• JavaScript environment for the SubmitData App tutorial