Demo Output Variables

In this hands-on lab, you’ll learn how to configure, apply, and manage output variables in OpenTofu using the random provider. By the end, you’ll be able to expose resource attributes and query them on demand.

1. Setup and Resource Configuration

1. Change into the sample project directory:

   cd /root/OpenTofu-projects/data
   

2. Examine the HCL files defining nine resources with the random provider:

   # random_integer resources
   resource "random_integer" "order1" {
     min = 1
     max = 99999
   }
   
   resource "random_integer" "order2" {
     min = 1
     max = 222222
   }
   
   # random_uuid resources
   resource "random_uuid" "id1" {}
   resource "random_uuid" "id2" {}
   resource "random_uuid" "id3" {}
   resource "random_uuid" "id4" {}
   resource "random_uuid" "id5" {}
   resource "random_uuid" "id6" {}
   resource "random_uuid" "id7" {}
   

3. Open the accompanying output.tf to see how each resource is exposed as an output variable.

2. Initialize, Plan, and Apply

Initialize the working directory, preview the plan, and apply the configuration.

tofu init
tofu plan
tofu apply
# Type "yes" to confirm

After a successful apply, you should see:

Apply complete! Resources: 9 added, 0 changed, 0 destroyed.

Outputs:
id1     = "82b3b221-136c-88c6-88c2-e9f878d86a"
id2     = "9687669a-73d4-9717-52a2-6497826815a1"
id3     = "23982b58-763d-49ae-af62-45a7856ac42c"
id4     = "890c9540-59e1-4b28-8fba-9a4f418c0c86"
id5     = "e2171b2e-1ff0-40a6-8fdb-c472f017c5b5"
id6     = "2212bac2-d5c1-ecac-2490-012bcab1f19a"
id7     = "b4e83b80-46c8-4efb-bd73-3a7865d647d6"
order1  = 16106
order2  = 16106

3. Querying Individual Outputs

Test your understanding:

1. What is the value of id2?
   From the example above, id2 = "9687669a-73d4-9717-52a2-6497826815a1".

2. What is the value of order1?
   It is 16106.

You can also fetch specific outputs:

tofu output id2
tofu output order1
# => 16106

4. Inspecting a New Configuration

Switch to the second lab directory and review main.tf:

cd /root/OpenTofu-projects/data/output

In main.tf, you’ll find:

resource "random_pet" "my_pet" {
  length = var.length
}

output "pet-name" {
  value       = random_pet.my_pet.id
  description = "Record the value of pet ID generated by the random pet"
}

Confirm the output:

tofu output pet-name
# => "marlin"

5. Adding a New Output Variable

The same main.tf defines a local_file resource:

resource "local_file" "welcome" {
  filename = "/root/message.txt"
  content  = "Welcome to Kodekloud."
}

Add an output block below it to capture the file’s content:

output "welcome_message" {
  value = local_file.welcome.content
}

Save your changes, then re-run the workflow:

tofu init
tofu plan
tofu apply
# Type "yes" to confirm

Finally, verify the new output:

tofu output welcome_message
# => "Welcome to Kodekloud."

Congratulations! You’ve successfully configured and managed OpenTofu output variables.