Solve it by Lambda attached to an SNS topic — You have a custom logger in place for a lambda function in your AWS account and this logger writes JSON records to CloudWatch through that lambda log group. Now out of all these log records being dumped in the log group, you want to send all logs that contain the…

Leetcode hard (it’s all about prime factors though) — Problem Description You are given a 0-indexed integer array nums of length n. A split at an index i where 0 ≤ i ≤ n-2 is called valid if the product of the first i + 1 elements and the product of the remaining elements are coprime. For example, if…

A tricky Binary Search problem — Problem Description There are several consecutive houses along a street, each of which has some money inside. There is also a robber, who wants to steal money from the homes, but he refuses to steal from adjacent homes. The capability of the robber is the maximum amount of money he…

extended fan-out architecture with DynamoDB being the data producer — In my current project as a lot of business needs were unfolding that would require listening to various types of changes/updates on DynamoDB table (single table), I couldn’t handle all of those using just a single DynamoDB stream that comes with the table. DynamoDB stream can connect to maximum two…

Case study: installing python libraries — In my work, we have multiple lambda functions where they all need to use Google’s translate python library. We used to install this same python library multiple times, one for each lambda function. This approach increased the time of lambda SAM deployment. We solved this problem by creating a common…

Use case: deploying AppSync stack — In my work, a throttling issue started to happen at the time of deploying a CloudFormation stack that creates/modifies AppSync resources such as mutations, functions and queries. We run that stack (a yaml file) locally from any developer’s computer to a specific AWS account using a python script. In our…

With the purpose of triggering a lambda to store metadata in DynamoDB — In my current work, I had to find a way to trigger a single lambda based on the file uploads on two separate buckets. The purpose of triggering the lambda is to update the DynamoDB table with file/object metadata. One obvious solution is to create two lambda functions where each…

A Dynamic Programming (DP) problem — You are given a 0-indexed m x n integer matrix grid and an integer k. You are currently at position (0, 0) and you want to reach position (m - 1, n - 1) moving only down or right. Return the number of paths where the sum of the elements…

How it helped to eliminate confusions in code — In my work, we use AWS SAM template to define the serverless architecture in DEV, QA and PROD AWS accounts/environments. The template file in this architecture contains the definition of all lambda functions, lambda permissions, apis, event source mappings etc. Now there were some common environment variables being used across…