The inputs.tf File¶

Why?¶

We need to be able to provide flexibility to our code via external data sources. In this case we need to take in a few AWS credentials from the environment, allowing us to dynamically change the AWS account we run our Terraform code against.

This is why we need variable {} blocks.

Breakdown¶

We need three pieces of information for working with AWS:

1. The region we're operating inside of
2. The API access key
3. The API secret key

First we define a variable for the region:

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variable "aws_region" {
  description = "The AWS region to deploy the solution into"
  type        = string
}

Then we ask for the access key:

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variable "aws_access_key" {
  description = "The access key to authenticate with"
  type        = string
}

And finally we ask for the secret key:

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variable "aws_secret_key" {
  description = "The secret key to authenticate with"
  type        = string
}

Once we've got our variable defined we can define their values using a lot of different methods. We're interested in using environment variables.

If we wanted to configure each variable via the environment, we'd do this:

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export TF_VAR_aws_region=ap-southeast-2
export TF_VAR_aws_access_key=some-value
export TF_VAR_aws_secret_key=secret-value

You'll notice the formatting here: TF_VAR_ follow by the variable name exactly (including case.) When Terraform parses a variable {} block it'll look for a value in multiple places. For environment variables it'll look for TF_VAR_the_variable_name and read it for a value.

The Solution¶

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variable "aws_region" {
  description = "The AWS region to deploy the solution into"
  type        = string
}

variable "aws_access_key" {
  description = "The access key to authenticate with"
  type        = string
}

variable "aws_secret_key" {
  description = "The secret key to authenticate with"
  type        = string
}

Terraform Documentation¶

Committing the Code¶

1. Set your working directory to the infrastructure/terraform repository
2. Save the file as inputs.tf and use git add inputs.tf to add it to the Git staging area
3. Use git commit -am 'defining our aws inputs' to commit the file to our repository
4. Push the code to GitLab.com: git push