Amazon Web Services (AWS) offers a various messaging services, two of the most used messaging services are Amazon Simple Email Service (SES) and Amazon Simple Notification Service (SNS). Both services are designed to send messages to users or customers, but both differ in their functionality, target audience and use cases. 1. Functionality …

When it comes to event-driven execution or batch processing job execution, two of the most popular options are AWS Lambda and AWS Batch, both offered by Amazon Web Services. Both have different benefits, features and limitations. So, choosing between these two services can be a challenge. So to help you…

Sometimes you need to sort list of objects such that few elements are sorted in ascending order and few elements are sorted in descending order. Let’s say you have below Java POJO class: package com.custom.sorting.model; import lombok.AllArgsConstructor; import lombok.Builder; import lombok.Data; import lombok.NoArgsConstructor; …

Sometimes you need to access objects of S3 bucket present in other AWS account. So for that you need to do cross account setup. Let’s say you want to access objects of S3 bucket present in AWS account A from AWS account B. For that we need to follow below…

Trees are widely used data structure in Computer Science. A tree is a collection of nodes connected by edges, where each node has a parent node and zero or more child nodes. The top-most node in a tree is called the root node, and the nodes with no children are…

Sometimes we need to update DynamoDB record only when specific conditions met for existing record of DynamoDB. Let’s say you have below SampleTable DynamoDB entity/model class: @NoArgsConstructor @AllArgsConstructor @Builder @Data @DynamoDBTable(tableName = "sampletable") public class SampleTable { private String hashKeyAttribute; private String rangeKeyAttribute; private Integer otherAttribute…

Sometimes require that AWS resources should be created if specific condition fulfils. Let’s say you want to create Amazon S3 bucket only if var var_x = abc or var_x = xyz. We can do this with the help of count attribute in Terraform. Example: sample-bucket will be created only if var_a = abc or var_a = xyz, you can refer below Terraform source code: resource "aws_s3_bucket" "sample-bucket-resource" { bucket = "sample-bucket" acl = "private" tags = { # add tags if you want } count = (var.var_a == "abc" || var.var_a == "xyz") ? 1 : 0 }

Sometimes we have table name as {env}_{table-name}. For example: test_sampletable. Consider we have below DynamoDB table model/entity class SampleTable: @DynamoDBTable(tableName = "sampletable") public class SampleTable { private String hashKeyAttribute; private String rangeKeyAttribute; private Integer otherAttribute…

Many times you need to create and write CSV file at runtime. You can do this with the help of AWS SDK. Java example: public void writeFileToS3(String s3BucketName, String dataToWrite, String resFileKey) { try { ObjectMetadata objectMetadata…