Infrastructure to Code: Terraformer

What if I say, that you can just draw your cloud infrastructure in the web interface and get a terraform code? Don’t you believe me? Anton Babenko already did that in the modules.tf project, just build your infra diagram on cloudcraft and get your terraform code. Sounds pretty nice, huh?

But what, if you already have some infrastructure and want to migrate it to the code? Or another case: you always created Datadog monitors manually, and now, you want to manage them as a code. There is a tool that could help you with that. Terraformer — a CLI tool that generates tf/json and tfstate files based on existing infrastructure.

Let’s talk a bit about the terraformer below.

Are you surprised? Or not?

I’m not a terraformer developer, just used it in my job, and want to share some information about this great tool.

---

Intro

It’s quite rare that the entire infrastructure begins to be written from scratch. Usually, something is already added manually through the CLI or Web UI, some resources are added to terraform, etc.

IMHO, terraformer greatly facilitates process when you need to get any info about this infrastructure. Or, for example, you want to migrate from CloudFormation or something like that or do periodic checks for manual changes in the infrastructure.

About the terraformer project

The project is created and maintained by Sergey Lanzman, SRE from Google/Waze. The first public release was published on 2 May 2019. This release supported AWS and GCP.

At the time of this writing, terraformer supports 11 clouds and more than 10 providers like Kubernetes, Datadog, Keycloack, etc. The full list of supported providers is here.

More than 50 developers already contributed to this project, so we say that project is really alive and gets a lot of new features every day.

#devops #terraform #terraformer #iaac

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How to Use Hotwire Rails

Introduction

We are back with another exciting and much-talked-about Rails tutorial on how to use Hotwire with the Rails application. This Hotwire Rails tutorial is an alternate method for building modern web applications that consume a pinch of JavaScript.

Rails 7 Hotwire is the default front-end framework shipped with Rails 7 after it was launched. It is used to represent HTML over the wire in the Rails application. Previously, we used to add a hotwire-rails gem in our gem file and then run rails hotwire: install. However, with the introduction of Rails 7, the gem got deprecated. Now, we use turbo-rails and stimulus rails directly, which work as Hotwire’s SPA-like page accelerator and Hotwire’s modest JavaScript framework.

What is Hotwire?

Hotwire is a package of different frameworks that help to build applications. It simplifies the developer’s work for writing web pages without the need to write JavaScript, and instead sending HTML code over the wire.

Introduction to The Hotwire Framework:

1. Turbo:

It uses simplified techniques to build web applications while decreasing the usage of JavaScript in the application. Turbo offers numerous handling methods for the HTML data sent over the wire and displaying the application’s data without actually loading the entire page. It helps to maintain the simplicity of web applications without destroying the single-page application experience by using the below techniques:

Turbo Frames: Turbo Frames help to load the different sections of our markup without any dependency as it divides the page into different contexts separately called frames and updates these frames individually.
Turbo Drive: Every link doesn’t have to make the entire page reload when clicked. Only the HTML contained within the tag will be displayed.
Turbo Streams: To add real-time features to the application, this technique is used. It helps to bring real-time data to the application using CRUD actions.

2. Stimulus

It represents the JavaScript framework, which is required when JS is a requirement in the application. The interaction with the HTML is possible with the help of a stimulus, as the controllers that help those interactions are written by a stimulus.

3. Strada

Not much information is available about Strada as it has not been officially released yet. However, it works with native applications, and by using HTML bridge attributes, interaction is made possible between web applications and native apps.

Simple diagrammatic representation of Hotwire Stack:

Prerequisites For Hotwire Rails Tutorial

As we are implementing the Ruby on Rails Hotwire tutorial, make sure about the following installations before you can get started.

• Ruby on Rails
• Hotwire gem
• PostgreSQL/SQLite (choose any one database)
• Turbo Rails
• Stimulus.js

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Create a new Rails Project

Find the following commands to create a rails application.

mkdir ~/projects/railshotwire
cd ~/projects/railshotwire
echo "source 'https://rubygems.org'" > Gemfile
echo "gem 'rails', '~> 7.0.0'" >> Gemfile
bundle install  
bundle exec rails new . --force -d=postgresql

Now create some files for the project, up till now no usage of Rails Hotwire can be seen.
Fire the following command in your terminal.

• For creating a default controller for the application

echo "class HomeController < ApplicationController" > app/controllers/home_controller.rb
echo "end" >> app/controllers/home_controller.rb

• For creating another controller for the application

echo "class OtherController < ApplicationController" > app/controllers/other_controller.rb
echo "end" >> app/controllers/home_controller.rb

• For creating routes for the application

echo "Rails.application.routes.draw do" > config/routes.rb
echo '  get "home/index"' >> config/routes.rb
echo '  get "other/index"' >> config/routes.rb
echo '  root to: "home#index"' >> config/routes.rb
echo 'end' >> config/routes.rb

• For creating a default view for the application

mkdir app/views/home
echo '<h1>This is Rails Hotwire homepage</h1>' > app/views/home/index.html.erb
echo '<div><%= link_to "Enter to other page", other_index_path %></div>' >> app/views/home/index.html.erb

• For creating another view for the application

mkdir app/views/other
echo '<h1>This is Another page</h1>' > app/views/other/index.html.erb
echo '<div><%= link_to "Enter to home page", root_path %></div>' >> app/views/other/index.html.erb

• For creating a database and schema.rb file for the application

bin/rails db:create
bin/rails db:migrate

• For checking the application run bin/rails s and open your browser, your running application will have the below view.

Additionally, you can clone the code and browse through the project. Here’s the source code of the repository: Rails 7 Hotwire application

Now, let’s see how Hotwire Rails can work its magic with various Turbo techniques.

Hotwire Rails: Turbo Drive

Go to your localhost:3000 on your web browser and right-click on the Inspect and open a Network tab of the DevTools of the browser.

Now click on go to another page link that appears on the home page to redirect from the home page to another page. In our Network tab, we can see that this action of navigation is achieved via XHR. It appears only the part inside HTML is reloaded, here neither the CSS is reloaded nor the JS is reloaded when the navigation action is performed.

By performing this action we can see that Turbo Drive helps to represent the HTML response without loading the full page and only follows redirect and reindeer HTML responses which helps to make the application faster to access.

Hotwire Rails: Turbo Frame

This technique helps to divide the current page into different sections called frames that can be updated separately independently when new data is added from the server.
Below we discuss the different use cases of Turbo frame like inline edition, sorting, searching, and filtering of data.

Let’s perform some practical actions to see the example of these use cases.

Make changes in the app/controllers/home_controller.rb file

#CODE

class HomeController < ApplicationController
   def turbo_frame_form
   end
   
   def turbo_frame submit
      extracted_anynumber = params[:any][:anynumber]
      render :turbo_frame_form, status: :ok, locals: {anynumber: extracted_anynumber,      comment: 'turbo_frame_submit ok' }
   end
end

Add app/views/home/turbo_frame_form.html.erb file to the application and add this content inside the file.

#CODE

<section>

    <%= turbo_frame_tag 'anyframe' do %>
            
      <div>
          <h2>Frame view</h2>
          <%= form_with scope: :any, url: turbo_frame_submit_path, local: true do |form| %>
              <%= form.label :anynumber, 'Type an integer (odd or even)', 'class' => 'my-0  d-inline'  %>
              <%= form.text_field :anynumber, type: 'number', 'required' => 'true', 'value' => "#{local_assigns[:anynumber] || 0}",  'aria-describedby' => 'anynumber' %>
              <%= form.submit 'Submit this number', 'id' => 'submit-number' %>
          <% end %>
      </div>
      <div>
        <h2>Data of the view</h2>
        <pre style="font-size: .7rem;"><%= JSON.pretty_generate(local_assigns) %></pre> 
      </div>
      
    <% end %>

</section>

Make some adjustments in routes.rb

#CODE

Rails.application.routes.draw do
  get 'home/index'
  get 'other/index'

  get '/home/turbo_frame_form' => 'home#turbo_frame_form', as: 'turbo_frame_form'
  post '/home/turbo_frame_submit' => 'home#turbo_frame_submit', as: 'turbo_frame_submit'


  root to: "home#index"
end

• Next step is to change homepage view in app/views/home/index.html.erb

#CODE

<h1>This is Rails Hotwire home page</h1>
<div><%= link_to "Enter to other page", other_index_path %></div>

<%= turbo_frame_tag 'anyframe' do %>        
  <div>
      <h2>Home view</h2>
      <%= form_with scope: :any, url: turbo_frame_submit_path, local: true do |form| %>
          <%= form.label :anynumber, 'Type an integer (odd or even)', 'class' => 'my-0  d-inline'  %>
          <%= form.text_field :anynumber, type: 'number', 'required' => 'true', 'value' => "#{local_assigns[:anynumber] || 0}",  'aria-describedby' => 'anynumber' %>
          <%= form.submit 'Submit this number', 'id' => 'submit-number' %>
      <% end %>
  <div>
<% end %>

After making all the changes, restart the rails server and refresh the browser, the default view will appear on the browser.

Now in the field enter any digit, after entering the digit click on submit button, and as the submit button is clicked we can see the Turbo Frame in action in the below screen, we can observe that the frame part changed, the first title and first link didn’t move.

Hotwire Rails: Turbo Streams

Turbo Streams deliver page updates over WebSocket, SSE or in response to form submissions by only using HTML and a series of CRUD-like operations, you are free to say that either

• Update the piece of HTML while responding to all the other actions like the post, put, patch, and delete except the GET action.
• Transmit a change to all users, without reloading the browser page.

This transmit can be represented by a simple example.

• Make changes in app/controllers/other_controller.rb file of rails application

#CODE

class OtherController < ApplicationController

  def post_something
    respond_to do |format|
      format.turbo_stream {  }
    end
  end

   end

Add the below line in routes.rb file of the application

#CODE

post '/other/post_something' => 'other#post_something', as: 'post_something'

Superb! Rails will now attempt to locate the app/views/other/post_something.turbo_stream.erb template at any moment the ‘/other/post_something’ endpoint is reached.

For this, we need to add app/views/other/post_something.turbo_stream.erb template in the rails application.

#CODE

<turbo-stream action="append" target="messages">
  <template>
    <div id="message_1">This changes the existing message!</div>
  </template>
</turbo-stream>

This states that the response will try to append the template of the turbo frame with ID “messages”.

Now change the index.html.erb file in app/views/other paths with the below content.

#CODE

<h1>This is Another page</h1>
<div><%= link_to "Enter to home page", root_path %></div>

<div style="margin-top: 3rem;">
  <%= form_with scope: :any, url: post_something_path do |form| %>
      <%= form.submit 'Post any message %>
  <% end %>
  <turbo-frame id="messages">
    <div>An empty message</div>
  </turbo-frame>
</div>

• After making all the changes, restart the rails server and refresh the browser, and go to the other page.

• Once the above screen appears, click on the Post any message button

This action shows that after submitting the response, the Turbo Streams help the developer to append the message, without reloading the page.

Another use case we can test is that rather than appending the message, the developer replaces the message. For that, we need to change the content of app/views/other/post_something.turbo_stream.erb template file and change the value of the action attribute from append to replace and check the changes in the browser.

#CODE

<turbo-stream action="replace" target="messages">
  <template>
    <div id="message_1">This changes the existing message!</div>
  </template>
</turbo-stream>

When we click on Post any message button, the message that appear below that button will get replaced with the message that is mentioned in the app/views/other/post_something.turbo_stream.erb template

Stimulus

There are some cases in an application where JS is needed, therefore to cover those scenarios we require Hotwire JS tool. Hotwire has a JS tool because in some scenarios Turbo-* tools are not sufficient. But as we know that Hotwire is used to reduce the usage of JS in an application, Stimulus considers HTML as the single source of truth. Consider the case where we have to give elements on a page some JavaScript attributes, such as data controller, data-action, and data target. For that, a stimulus controller that can access elements and receive events based on those characteristics will be created.

Make a change in app/views/other/index.html.erb template file in rails application

#CODE

<h1>This is Another page</h1>
<div><%= link_to "Enter to home page", root_path %></div>

<div style="margin-top: 2rem;">
  <%= form_with scope: :any, url: post_something_path do |form| %>
      <%= form.submit 'Post something' %>
  <% end %>
  <turbo-frame id="messages">
    <div>An empty message</div>
  </turbo-frame>
</div>

<div style="margin-top: 2rem;">
  <h2>Stimulus</h2>  
  <div data-controller="hello">
    <input data-hello-target="name" type="text">
    <button data-action="click->hello#greet">
      Greet
    </button>
    <span data-hello-target="output">
    </span>
  </div>
</div>

Make changes in the hello_controller.js in path app/JavaScript/controllers and add a stimulus controller in the file, which helps to bring the HTML into life.

#CODE

import { Controller } from "@hotwired/stimulus"

export default class extends Controller {
  static targets = [ "name", "output" ]

  greet() {
    this.outputTarget.textContent =
      `Hello, ${this.nameTarget.value}!`
  }
}

Go to your browser after making the changes in the code and click on Enter to other page link which will navigate to the localhost:3000/other/index page there you can see the changes implemented by the stimulus controller that is designed to augment your HTML with just enough behavior to make it more responsive.

With just a little bit of work, Turbo and Stimulus together offer a complete answer for applications that are quick and compelling.

Using Rails 7 Hotwire helps to load the pages at a faster speed and allows you to render templates on the server, where you have access to your whole domain model. It is a productive development experience in ROR, without compromising any of the speed or responsiveness associated with SPA.

Conclusion

We hope you were satisfied with our Rails Hotwire tutorial. Write to us at service@bacancy.com for any query that you want to resolve, or if you want us to share a tutorial on your query.

For more such solutions on RoR, check out our Ruby on Rails Tutorials. We will always strive to amaze you and cater to your needs.

Original article source at: https://www.bacancytechnology.com/

#rails #ruby 

Infrastructure as Code vs. Infrastructure as Software

Infrastructure as Code has been the hottest trend in cloud-native application development in recent years. By transforming infrastructure management into simple coded runtimes and routines, Infrastructure as Code or IaC allows developers to be more involved in the deployment part of their CI/CD pipelines. Even the most complex cloud infrastructure can be created with several lines of code.

IaC also means that server management, resource provisioning, and even long-term maintenance of complex cloud infrastructures are entirely simplified. Tools like Terraform certainly make maintaining a production environment that is both capable and efficient easy, even when there is no dedicated infrastructure team to handle the associated tasks.

A new trend that we’re seeing right now is further simplification of IaC, mainly known as Infrastructure as Software or IaS. Now that cloud services and the providers behind them are easier to access and control using tools and software, it is not impossible for the entire cloud infrastructure to be provisioned and managed as software libraries.

How does Infrastructure as Code differ from Infrastructure as Software? Which approach is better? We are going to answer these questions, and several others about these two trends, in this article.

IaC and IaS

The two approaches have some stark differences, but we are going to take a closer look at each of them first before we start differentiating the two. Infrastructure as Code is obviously the older approach of the two, and it has been very popular among developers. Using tools designed for managing infrastructure through lines of code, you can either manage the configurations of your cloud infrastructure or manage the provisioning of cloud resources; or both.

Terraform, a popular tool used by millions of developers, applies the second approach. The tool is not just handy for managing multiple configurations and making sure that key infrastructure variables are coded properly; it is also capable of provisioning resources and automating server deployment as needed. Terraform is very extensive in this respect.

Upon close inspection, Infrastructure as Software performs similar⁠—if not the same⁠—tasks using similar tools. You can deploy new server instances or configure the entire architecture using a few lines of codes. You can also automate provisioning and management, and you can still integrate IaS with your existing CI/CD pipelines.

Services that are available today support both approaches in most cases. The tools that fall into these two categories basically use the same API calls and available cloud resources to perform their runtimes, but they take different approaches when it comes to management. That actually brings us to our next point.

IaC vs. IaS

Now that we know how the two approaches are relatively similar, it is time to get the obvious out of the way. Infrastructure as Code and Infrastructure as Software has one huge difference, and that difference lies in the programming languages used by the tools. The easiest way to understand this difference is by comparing Terraform with Pulumi, which is a popular IaS tool.

Terraform requires you to use its native programming language. The HCL language is used for low-level programming. While the language is also used by other tools, the way it is used by Terraform is not always as straightforward as it seems. Terraform also supports JSON syntax but parsing and generating can quickly become bottlenecks as you try to organize massive cloud infrastructure environments.

Pulumi, on the other hand, uses programming languages you are already familiar with. It actually supports many of them, including Python, Go, and JavaScript. Don’t forget that loops and the programming structure of these familiar languages are carried over, so you define your cloud infrastructure the way you code functions in your cloud-native apps.

Since the programming language being used carries its own best practices and things like package management, you can implement the same set of elements into your IaS routine. No need to worry about having difficulties pushing infrastructure modules or doing plenty of adjustments in order for the configuration to be deployed at all.

#blog #code #continuous delivery #continuous integration #ci/cd pipeline #infrastructure as code #infrastructure as software #pulumi #terraform

Static Code Analysis: What It Is? How to Use It?

Static code analysis refers to the technique of approximating the runtime behavior of a program. In other words, it is the process of predicting the output of a program without actually executing it.

Lately, however, the term “Static Code Analysis” is more commonly used to refer to one of the applications of this technique rather than the technique itself — program comprehension — understanding the program and detecting issues in it (anything from syntax errors to type mismatches, performance hogs likely bugs, security loopholes, etc.). This is the usage we’d be referring to throughout this post.

“The refinement of techniques for the prompt discovery of error serves as well as any other as a hallmark of what we mean by science.”

• J. Robert Oppenheimer

Outline

We cover a lot of ground in this post. The aim is to build an understanding of static code analysis and to equip you with the basic theory, and the right tools so that you can write analyzers on your own.

We start our journey with laying down the essential parts of the pipeline which a compiler follows to understand what a piece of code does. We learn where to tap points in this pipeline to plug in our analyzers and extract meaningful information. In the latter half, we get our feet wet, and write four such static analyzers, completely from scratch, in Python.

Note that although the ideas here are discussed in light of Python, static code analyzers across all programming languages are carved out along similar lines. We chose Python because of the availability of an easy to use ast module, and wide adoption of the language itself.

How does it all work?

Before a computer can finally “understand” and execute a piece of code, it goes through a series of complicated transformations:

As you can see in the diagram (go ahead, zoom it!), the static analyzers feed on the output of these stages. To be able to better understand the static analysis techniques, let’s look at each of these steps in some more detail:

Scanning

The first thing that a compiler does when trying to understand a piece of code is to break it down into smaller chunks, also known as tokens. Tokens are akin to what words are in a language.

A token might consist of either a single character, like (, or literals (like integers, strings, e.g., 7, Bob, etc.), or reserved keywords of that language (e.g, def in Python). Characters which do not contribute towards the semantics of a program, like trailing whitespace, comments, etc. are often discarded by the scanner.

Python provides the tokenize module in its standard library to let you play around with tokens:

Python

1

import io

2

import tokenize

3

4

code = b"color = input('Enter your favourite color: ')"

5

6

for token in tokenize.tokenize(io.BytesIO(code).readline):

7

    print(token)

Python

1

TokenInfo(type=62 (ENCODING),  string='utf-8')

2

TokenInfo(type=1  (NAME),      string='color')

3

TokenInfo(type=54 (OP),        string='=')

4

TokenInfo(type=1  (NAME),      string='input')

5

TokenInfo(type=54 (OP),        string='(')

6

TokenInfo(type=3  (STRING),    string="'Enter your favourite color: '")

7

TokenInfo(type=54 (OP),        string=')')

8

TokenInfo(type=4  (NEWLINE),   string='')

9

TokenInfo(type=0  (ENDMARKER), string='')

(Note that for the sake of readability, I’ve omitted a few columns from the result above — metadata like starting index, ending index, a copy of the line on which a token occurs, etc.)

#code quality #code review #static analysis #static code analysis #code analysis #static analysis tools #code review tips #static code analyzer #static code analysis tool #static analyzer

Terraform Tips: My Favorite Tools

TFSwitch

This is an amazing tool from Warrensbox which you can find on Warren’s website here or on the github repo here.

Tfswitch allows you to switch between different versions of Terraform on the fly. In addition to switching between Terraform versions tfswitch will download any version of Terraform you do not have installed if the version is selected.

Here are a couple of gifs from Warren’s github README that demonstrate how it is used.

To check out the tool and find more information on usage go check out the repo! Or just install it using this command:

brew install warrensbox/tap/tfswitch

Terraform-docs

Terraform-docs is an excellent tool for quickly creating a README.md for your terraform modules. You can find the github repository here.

All you have to do is change directory to your Terraform configuration files and run this command:

terraform-docs markdown ./

Then copy the output that will look something like this:

### Requirements

No requirements.
### Providers
| Name | Version |
|------|---------|
| aws | n/a |
### Inputs
| Name | Description | Type | Default | Required |
|------|-------------|------|---------|:--------:|
| availability\_zone | Variable for AZ | `string` | `"us-east-1a"` | no |
### Outputs
No output.

Paste this output into a README.md file for your module. Then you will have a beautiful markdown file in github that looks like this:

On to the next tool!

Visual Studio Code Extensions

For a multitude of reasons I switched from using Sublime Text to using Visual Studio Code. That is a topic for another article, but just know I found VS Code to be FAR superior.

Here are some of the extensions I found to be helpful for writing Terraform code.

Bracket Pair Colorizer 2

Bracket pair colorizer highlights your brackets and helps you to make sure your syntax is correct. Missing a bracket? It will help point that out as well! Here is what it looks like:

HashiCorp Terraform

This probably goes without saying, but I use HashiCorp Terraform to highlight the terraform syntax and verify that my code looks correct. Here is some code that looks good:

Here is some that looks bad:

It won’t solve your syntax problems for you, of course. Definitely helps find them though!

#hashicorp-terraform #coding #devops #terraform #infrastructure-as-code

How To Manage Infrastructure With Terraform

It is a tool that is used for building, changing and versioning infrastructure safely and effectively. Using the configuration file you describe to Terraform what components are needed. Terraform then goes and generates an execution plan describing what the desired state should be. And then it goes and executes and builds it. Terraform manages all this through a state file. Now there are two flavors of Terraform:

• An open-source version
• An enterprise version

Terraform supports a wide variety of cloud and infrastructure platforms. This includes AWS, OpenStack, Azure, GCP, Kubernetes and much more.

Deploying Infrastructure with Terraform

The syntax of Terraform configurations is called HashiCorp Configuration Language (HCL). It is meant to strike a balance between being human-readable and editable, and being machine-friendly. For machine-friendliness, Terraform can also read JSON configurations.

The Terraform language uses configuration files that are named with .tf file extension. There is also a JSON-based variant of the language that is named with the .tf.json file extension.

We will start by creating a very simple Terraform file that will pull down the image from Docker Hub and start the container. In addition, we will use input variables. They serve as parameters for a Terraform file. A variable block configures a single input variable for a Terraform module. Each block declares a single variable. And we will create a map to specify different environment variables based on conditions.

This allows us to dynamically deploy infrastructure configurations based on information we pass to the deployment.

To start with we need to set up the environment:

mkdir terraform/
cd terraform/

#terraform #infrastructure #serverless #cloud-computing #docker #devops #infrastructure-as-code #aws