As Terraform codebase grows, there are chances where you may need to refactor or rename resources in your codebase which can result into deletion and recreation of resources. This happens because terraform thinks that you want to delete and create new resource and it allocates new id to the resource. Instead, you should let terraform know that you want to simply move the resource instead of replacing it. To mimic this we will take simple example where we will have AWS instance with name a and we want to change it to b ...

In a previous blog post, we learned how to create and run commands in Go. Now, let’s explore how to recreate the following command: ls -l | grep hello Let’s create the first command: lsCmd := exec.Command("ls", "-l") Next, create the second command: grepCmd := exec.Command("grep", "hello") To connect them, we need to understand what’s happening in the Linux command. Essentially, we are taking the stdout of the first command ls -l and passing it to the stdin of the second command grep hello. To achieve this in Go, follow these steps: ...

Sometimes, there are certain use cases where you may have to run shell commands through a Golang app. This is where the os/exec package comes in handy. If you want to run a command like sleep 1, you can simply do the following: cmd := exec.Command("sleep", "1") err := cmd.Run() This will run the command and wait until the execution finishes, but it doesn’t capture the stdout. If you intend to capture both stdout and stderr, you can use the following code: ...

One of the best ways to learn a language is via building equivalent Linux commands using the language of your choice. which is my all-time favourite command to see if the binary is present on the server or not. You can see which usage as shown below, $ which kubectl-eks /Users/surajnarwade/.krew/bin/kubectl-eks We simply pass the binary name to which command and it will give us the absolute path to the binary. ...

Encrypting and decrypting strings using AWS Key Management Service (KMS) and the AWS Command Line Interface (CLI) is a crucial part of securing sensitive data in your AWS environment. In this blog post, we’ll walk through the process of encrypting and decrypting a string using KMS and the AWS CLI. This is a fundamental skill for protecting your data in AWS services like S3, RDS, and Lambda. Requirement You will need AWS CLI, You can follow this doc to install it, https://docs.aws.amazon.com/cli/latest/userguide/getting-started-install.html You can follow this guide to create the KMS key, https://docs.aws.amazon.com/kms/latest/developerguide/create-keys.html Encrypting String Let’s create a simple plaintext string for encryption purposes. echo "Hello World" > hello.txt Let’s run the following command to encrypt our string. If you notice we are outputting it to encrypted.base64 because AWS CLI will encrypt it and then encode it into base64. aws kms encrypt --key-id <KMS_ID> \ --plaintext fileb://hello.txt \ --output text --query CiphertextBlob > encrypted.bas64 Now this string is safe to store as only the KMS key can decrypt this. ...

AWS has more than 200 instance types under EC2. It’s very tricky to select appropriate ec2-instance types and surely AWS docs can be daunting. You can check the official doc here: https://aws.amazon.com/ec2/instance-types/ ec2-instance-selector is an open-source project by AWS. It is a CLI tool to helps you select compatible instance types. Check out the repo here, https://github.com/aws/amazon-ec2-instance-selector Features You can filter AWS Instance types using criteria like vcpu, memory, network performance, etc. You can use this project as a Go library to embed this functionality into your Golang projects, I will surely embed this in awsctl. Installing ec2-instance-selector On Mac brew tap aws/tap brew install ec2-instance-selector On Linux & Windows, you can download the binary from the release page. verify installation ec2-instance-selector --version v2.4.1 Usage Lookup all the instance type details interactively ec2-instance-selector -o interactive ...

Up until now, we’ve been using the DefaultServeMux, but it’s time to wield more control and precision by explicitly using the http.ServeMux. Plus, we’ll look at the powerful frameworks available, like Gorilla Mux and Echo, that take web server functionality to new heights. Check out previous posts: Part 1: https://surajincloud.com/understanding-http-server-in-go-basic Part 2: https://surajincloud.com/understanding-http-server-in-go-using-httpserver-struct Part 3: https://surajincloud.com/understanding-http-server-in-go-handlers Part 4: https://surajincloud.com/understanding-http-server-in-go-multiple-handlers Part 5: https://surajincloud.com/understanding-http-server-in-go-handlefunc Why do we need this? While the DefaultServeMux In Golang does a great job of handling basic routing, there will come a point where you’ll want more control over your application’s routes. This is where the http.ServeMux steps in. It empowers you to explicitly define how your application responds to different routes, giving you fine-grained control over your server’s behaviour. ...

Welcome back to the fifth instalment of our in-depth exploration of creating dynamic web servers using Golang! In this post, we’re diving into the fascinating world of HandlerFunc. As you’ve come to expect, GoLang provides us with an elegant and powerful way to handle requests through this mechanism. Let’s embark on this journey of discovery. Check out previous posts: Part 1: https://surajincloud.com/understanding-http-server-in-go-basic Part 2: https://surajincloud.com/understanding-http-server-in-go-using-httpserver-struct Part 3: https://surajincloud.com/understanding-http-server-in-go-handlers Part 4: https://surajincloud.com/understanding-http-server-in-go-multiple-handlers Let’s dive into the code to uncover the magic behind HandleFunc: ...

In the previous blog post, we made our webserver useful for the first time where we printed Hello World instead of 404. Check out previous blog posts: Part 1: https://surajincloud.com/understanding-http-server-in-go-basic Part 2: https://surajincloud.com/understanding-http-server-in-go-using-httpserver-struct Part 3: https://surajincloud.com/understanding-http-server-in-go-handlers It was still useless as it was printing the same response on all the paths. Now in real real-world scenario, we won’t have just one URL right, We will need multiple paths and handlers and we still don’t have mux so now in this case we can still have multiple handlers ...

Welcome to the exciting third instalment of our journey into creating web servers using Golang. In our previous articles, we covered the basics of creating a web server and explored the concept of custom servers using the http.Server struct. Check out the previous blog posts: \ Part 1:* https://surajincloud.com/understanding-http-server-in-go-basic \ part 2:* https://surajincloud.com/understanding-http-server-in-go-using-httpserver-struct However, as you might have noticed, our server was, until now, simply returning a 404 error. Fear not, because in this article, we’re about to breathe life into our server by diving into the realm of handlers. ...