Chapter 8: Real-World Example #3

🚀 Call Lambda Functions from Your Rails App

Call Lambda Functions Like Ruby Methods

In Chapter 7, we learned how to expose Lambda functions as HTTP endpoints using API Gateway. But sometimes you want something more direct - calling a Lambda function from your Rails application as if it were a regular Ruby method, without HTTP overhead.

This approach is perfect for:

• Server-to-server communication (no public endpoints needed)
• Background jobs that need to offload heavy processing
• Internal microservices within your AWS infrastructure
• Processing tasks that benefit from Lambda's auto-scaling

The AWS SDK approach gives you:

• ✅ Direct invocation - no HTTP layer
• ✅ Simple payloads - send plain JSON objects
• ✅ Built-in retry logic - AWS handles failures
• ✅ IAM security - leverages your existing AWS credentials

Think of it as calling a Ruby method that happens to run on AWS Lambda instead of your Rails server.