Published in AWS in Plain English·PinnedMember-onlyHow to Clean Up DynamoDB Records Through Time-to-Live (TTL)Archive obsolete table records into the S3 bucket — One way you can remove any DynamoDB table record is via hard delete operations such as DeleteItem or BatchWriteItem with DeleteRequest. These delete operations have to be triggered by administrators or any user who has delete privilege. On top of that, these deletes are real-time. …AWS3 min readAWS3 min read
Published in AWS in Plain English·PinnedMember-onlyCloudWatch Log Records— Send Critical Ones to a Slack ChannelSolve 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…AWS3 min readAWS3 min read
Published in AWS in Plain English·Dec 11, 2022Member-onlyHow do I create lambda layer in AWS SAM templateCase 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…AWS2 min readAWS2 min read
Published in AWS in Plain English·Nov 21, 2022Member-onlyHow did I Fix CloudFormation throttling issueUse 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…Cloudformation3 min readCloudformation3 min read
Published in AWS in Plain English·Oct 13, 2022Member-onlyCreate Single Eventbridge Rule for Uploads on Multiple S3 BucketsWith 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…AWS2 min readAWS2 min read
Published in coding interview preparation·Oct 10, 2022Member-onlyLeetcode: Paths in Matrix Whose Sum Is Divisible by KA 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…Leetcode3 min readLeetcode3 min read
Published in AWS in Plain English·Oct 6, 2022Member-onlyAWS SAM template: Globals sectionHow 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…Aws Sam2 min readAws Sam2 min read
Published in coding interview preparation·Sep 23, 2022Member-onlyLeetcode: Reverse Odd Levels of Binary TreeA practice problem for a level-order traversal of a tree — Given the root of a perfect binary tree, reverse the node values at each odd level of the tree. For example, suppose the node values at level 3 are [2,1,3,4,7,11,29,18], then it should become [18,29,11,7,4,3,1,2]. Return the root of the reversed tree. A binary tree is perfect if all parent…Binary Tree2 min readBinary Tree2 min read
Published in coding interview preparation·Sep 9, 2022Member-onlyLeetcode: Longest Nice SubarrayA bitmask problem — You are given an array nums consisting of positive integers. We call a subarray of nums nice if the bitwise AND of every pair of elements that are in different positions in the subarray is equal to 0. Return the length of the longest nice subarray. A subarray is a…Bitmasking2 min readBitmasking2 min read
Published in coding interview preparation·Aug 21, 2022Member-onlyLeetcode: Amount of Time for Binary Tree to Be InfectedA binary tree/graph problem — You are given the root of a binary tree with unique values, and an integer start. At minute 0, an infection starts from the node with value start. Each minute, a node becomes infected if: The node is currently uninfected. The node is adjacent to an infected node. Return the…Python2 min readPython2 min read
