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Adding A Mock Integration AWS API Gateway with Serverless

A curious use-case came up to me this week. We have a REST API in AWS API Gateway that integrates with a Lambda. This is set up using Serverless. This is a multi-tenant system and because a former client didn’t do their cleanup, we’re still receiving a lot of calls that basically return errors (because […]

CloudWatch: Raising an Alarm Between Two Values

AWS CloudWatch allows you to raise alarms when certain values are above or below a given threshold. But what if you want the alarm only when it is between certain thresholds? That’s where metric math comes in. A Simple Alarm In CloudFormation, you can define an alarm quite easily: This will raise an alarm when […]

NestJS & AWS Lambda Without HTTP

At a current client, we’re looking to move (most of) our AWS Lambda functions to NestJS. The company has built up an extensive collection of Lambda functions and it’s time to bring some structure and similarity in them. But NestJS is geared towards incoming HTTP calls. This is fine if your Lambda function is behind […]

Finding AWS Lambda Cold Start Durations

I recently had to provide some numbers on AWS Lambda cold starts. These aren’t readily available in the AWS console. In fact, I couldn’t find a way anywhere online. There are lots of articles about AWS Lambda cold starts, how to avoid them, but none on how to measure them (without code changes). Here’s at […]