What is Terraform Configuration Language (HCL)

HashiCorp has open sourced a tool called Terraform that enables defining and managing of infrastructure with code. At the core, HashiCorp Configuration Language (HCL) is a domain specific language aimed at producing human readable and concise descriptions of infrastructure infrastructure. HCL speeds the process for infrastructure creation, modification, and versioning to enable developers and operations teams to work and deploy resources across multiple cloud providers and on premises.

Key Features of HashiCorp Configuration Language (HCL)

HCL offers several features that make it a popular choice for infrastructure as code (IaC):

• Human-Readable Syntax: It is easy for developer to understand and for the non developer to understand. That means you can have clear communication and collaborate with teams.Terraform handles that underlying complexity (without needing people to define what infrastructure to setup, only what infrastructure they want).
• Declarative Approach: Users tell Terraform, not how to build, but what infrastructure they want, which Terraform manages the underlying complexity of building.
• Modularity: HCL supports Modules by which users can create Reusable and Sharable configurations for promoting the best practice and avoiding duplication.
• Built-in Functions: HCL is a versatile and a powerful tool owing to the built in functionalities in HCL data manipulation, string interpolation and conditionals.
• Extensive Provider Support: We work with a myriad of providers: from basic to advanced Tableau, Qlik, SAS, even big cloud platforms like AWS and Azure, and many more other clients.

Structure and Syntax of Terraform Configuration Language

The structure of HCL is straightforward, consisting of blocks, arguments, and expressions:

• Blocks: Each block defines a specific resource or component. For example, a resource block specifies a cloud resource, while a provider block configures the cloud provider being used.

provider "aws" {
region = "us-west-2"
}

resource "aws_instance" "example" {
ami = "ami-12345678"
instance_type = "t2.micro"
}

• Arguments: These are key-value pairs within blocks that define the properties of the resource. In the example above, ami and instance_type are arguments of the aws_instance resource.
• Expressions: HCL supports expressions that can be used to reference variables or perform operations. For example, you can use interpolation to construct values dynamically.

Writing and Managing Infrastructure as Code with HCL

Using HCL to manage infrastructure as code involves several key steps:

• Define Infrastructure: Write HCL configuration files to specify the desired state of your infrastructure.
• Initialize Terraform: Run terraform init to initialize your working directory and download the necessary provider plugins.
• Plan Changes: Use terraform plan to see a preview of the changes that will be made to your infrastructure.
• Apply Changes: Execute terraform apply to create or modify resources according to your configuration.
• Version Control: Store HCL files in a version control system (like Git) to track changes and collaborate with others.

Best Practices for Using Terraform Configuration Language (HCL) Effectively

To maximize the benefits of HCL and Terraform, consider the following best practices:

• Use Modules: Make your configurations manageable, buildable and reusuable by organizing them in modules. It helps to encapsulate related resources and make the config easier.
• Keep Configurations DRY: Use variables and modules as a way to not repeat yourself.
• Version Control: Alway put your HCL files under version control. It enables this concept of collaboration, auditing changes and rolling back.
• Document Your Code: Comments give you an opportunity to explain some difficult configurations or decisions translated in your code. It makes it easier for others (and you later on) to understand why some choices were made.
• Use Terraform Workspaces: If you have multiple environments (e.g., development, staging, production), having the ability to deploy and manage these environments is useful; for that you can use terraform workspaces to encapsulate the configurations and states.

Finally, Terraform Configuration Language (HCL) is such a beautiful tool to define and manage infrastructure in an efficient and effective manner. HCL’s key features empower organizations to manage their infrastructure in a streamlined manner, by following best practices, and improve the collaboration between the teams.

Conclusion