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In this hands-on lesson, you’ll explore HashiCorp Configuration Language (HCL) fundamentals using OpenTofu. You’ll identify resource types and names, initialize your working directory, and apply changes to a local file resource.

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Q1: Identify the HCL File Extension

Navigate to your HCL project directory and list its contents: 
cd ~/opentofu-projects/HCL/
ls
# → main.tf
Alternatively, open the folder in VS Code and observe that the filename is main.tf.
Answer: .tf

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Q2: Determine the Resource Type

Inspect the resource block in main.tf: 
resource "local_file" "games" {
  file    = "/root/favorite-games"
  content = "FIFA 21"
}
Answer: local_file

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Q3: Find the Resource Name

Within the same block, the second quoted identifier denotes the resource name: 
resource "local_file" "games" { … }
Answer: games

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Q4: Identify the Provider Name

The provider is indicated by the prefix of the resource type: 
resource "local_file" "games" { … }
Here, local is the provider.
Answer: local

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Q5: Valid vs. Invalid Arguments

The local_file resource supports only filename and content. It does not accept resource_type.
ArgumentValidDescription
filenameYesPath to create the file
contentYesData to write into the file
resource_typeNoNot a supported resource argument
Answer: resource_type = "local_file"

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Q6: Why tofu plan Fails Initially

Running: 
tofu plan
Produces: 
Error: Inconsistent dependency lock file
… no version is selected
The directory must be initialized first.
Always run tofu init before planning or applying any changes.

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Initialize the Working Directory

tofu init
You should see: 
OpenTofu has been successfully initialized!
…

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Q7: Locate the Provider Plugin Version

After initialization, OpenTofu downloads provider plugins. You can confirm the version (2.5.1) from the output or by inspecting .terraform:
The image shows a split screen with a multiple-choice question on the left asking about the version of a local provider plugin, and a code editor on the right displaying a Terraform configuration file.
Answer: 2.5.1

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Q8: Re-run tofu plan with Incorrect Arguments

tofu plan
Results in: 
Error: Missing required argument
  on main.tf line 1, in resource "local_file" "games":
   1: resource "local_file" "games" {
The argument "filename" is required, but no definition was found.

Error: Unsupported argument
  on main.tf line 2, in resource "local_file" "games":
   2:   file = "/root/favorite-games"
An argument named "file" is not expected here.
You used file instead of filename and omitted filename.

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Q9: Identify the Unsupported Argument

Referring to the Local Provider Documentation, file is not supported.
Answer: file

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Q10: Correct the Configuration and Apply

Update main.tf: 
resource "local_file" "games" {
  filename = "/root/favorite-games"
  content  = "FIFA 21"
}
Run: 
tofu plan
tofu apply
# → Apply complete! Resources: 1 added, 0 changed, 0 destroyed.

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Q11: Switch to a Sensitive File Resource

To mask content in plans, use local_sensitive_file: 
resource "local_sensitive_file" "games" {
  filename = "/root/favorite-games"
  content  = "FIFA 21"
}
Attempting to add an unsupported sensitive_content argument will fail: 
tofu plan

Error: Unsupported argument
  on main.tf line 4, in resource "local_sensitive_file" "games":
   4:   sensitive_content = "FIFA 21"
Remove sensitive_content; it’s not supported.

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Q12: Apply the Sensitive File Resource

With main.tf updated: 
resource "local_sensitive_file" "games" {
  filename = "/root/favorite-games"
  content  = "FIFA 21"
}
Run: 
tofu plan
tofu apply
# → Apply complete! Resources: 1 added, 0 changed, 1 destroyed.
Plans will now hide the file’s content.

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Q13: Destroy the Resource

tofu destroy

Plan: 0 to add, 0 to change, 1 to destroy.
Enter a value: yes

Destroy complete! Resources: 1 destroyed.
Congratulations—you’ve completed the lab! 🎉

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