• Have built using the https://sst.dev framework and is built to deploy to AWS.
• Uses a serverless, event-driven architecture.
• AWS EventBridge is used for the event bus.
• For each event there is an AWS SQS instance subscribed to the event bus with a filter rule to define what events should be pushed to it.
• When an event is put onto the event bus, if it matches one of the defined filter rules, it will be pushed into the associated queue.
• The queue will pipe the events to Lambda instances, which will process them and execute any logic in response.
• IaC is located in /stack, the application code is located in /src.

• The src/handler/cron/happy-birthday.ts handler is scheduled to run at 9am every morning.
• When run, it loads the list of friends from a friends.csv file that's stored in an S3 bucket.
• The file is parsed and an event is published for each friend who's birthday is today.
• The event that's published depends on the message delivery medium for the friend.
  • The happy-birthday.send-message.email event is used to send message via email.
  • The happy-birthday.send-message.sms event is used to send message via SMS.
• The src/handler/event/send-message-email.ts && src/handler/event/send-message-sms.ts handlers are configured to respond to the corresponding events.
• When a matching event is detected, the send-message-{medium}.ts Lambda will be run, which will send the friend a birthday message using the corresponding medium.

This can be deployed to AWS in a development environment, where it should work, using SST's local-development capabilities. To do this:

• You'll need the AWS CLI configured with a set of IAM access key.
• I didn't have time to documented the minimum permissions required that should be associated with the IAM user, so you might just need to go with admin permissions 😬.
• In src/foundation/config/default configure the sending email domain and name by setting DEFAULT_EMAIL_SENDER_ADDRESS and DEFAULT_EMAIL_SENDER_NAME.
  • Ideally these would be configured externally as env vars, or something, but I ran out of time, so for now they're hard coded.
  • The sending domain you choose will have to be configured in SES before you can send emails from it.
  • If SES is in sandbox mode for your AWS account, you'll have to verify the friend's email addresses before you can send emails to them.
• Install the project dependencies: npm install.
• Start the development environment: npm run dev.
  • This will deploy a set of development stacks to AWS
• Once deployed, upload your friends.csv file to the S3 bucket that's created during the deployment.
  • The easiest way to do this is using the SST dev console.
  • A dummy file can be found in /resource.
• The trigger lambda is configured to run at 9am every day, but for testing purposes you can invoke the Lambda manually using the SST dev console.
• If the friends.csv file you uploaded contains any friends who's birthday is today, they should 🤞 get emails.

• Run tests by running npm run test.
• I have added one example of an integration test and one example of a unit test.
• I haven't added full code coverage at all, and if this was a real application, I'd add tests to cover all the different scenarios.

• I didn't have a huge amount of time to build this out to the extent I would have liked, so to give you an idea of what I would have liked to do and my thought process, I've left to-dos and comments throughout.
• An event-driven architecture is a little over engineered for a personal app like this, but it's meant to demonstrate skills and understanding of different approaches, which is why I took the approach I did.

• Action all 🎯 TODOs.
• Hook this up to https://www.moonpig.com and have it automatically purchase and deliver cards 😂.