CODEWITHSUNDEEP
azure-devopsterraformazure-pipelinesinfrastructure
Rajeev
Rajeev

Reputation: 1371

How to print terraform variable values?

I am learning terraform. I want to print values of variables in "plan" stage. So I found how to do it. seems I am doing something wrong here....

in variables.tf:....

variable "VMCount" {
    description = "How many VMs do you want to start with (number)? default=1 max=5"
    type = number
}

in main.tf

output "VMCount" {
  value = "${var.VMCount > 2 && var.VMCount < 6 ? var.VMCount : 2}"
}

after that i run terraform plan and the condition seem to be working fine (it creates right num of VMs)

but the variable output is not coming. why?

$ terraform output
VMC = 56

that VMC is might be from some previous attempts ( I tried several things).

How to print the value of user entry (variable)?

Upvotes: 27

Views: 118753

Answers (4)

adamency
adamency

Reputation: 1510

My answer is disregarding the context of the original question (which has already been answered in the past), but only focusing on the question in the title:

How to print terraform variable values?

And I want to correct something that is implied by all these other answers, i.e. that a terraform variable can only be retrieved programmatically via the outputs, and thus needing to terraform apply first. This is not true. You only need terraform init beforehand.

There is a way to print an actual variable (i.e. from variables.tf and/or terraform.tfvars) It is a bit hidden, there is no direct subcommand designed for this (as opposed to terraform output) but you can do it with this short "one-liner":

terraform console <<EOF
var.<your_variable>
EOF

Upvotes: 1

Dommondke
Dommondke

Reputation: 502

I tested with Terraform v1.3.4. When outputs are defined, terraform plan appears to print them as a final section after the resource changeset. It starts with Changes to Outputs:.

I don't know if it will still work when the outputs haven't changed. The easy solution is to simply add some dummy string to them to artificially create a change.

In your question, the value expression is quite complex. There may be bugs in that which are causing the value to not be printed. I think that's something for a separate question, because many people who come to this question looking for a way to print outputs will not have the same complex expression. You should see the outputs printed when you use:

output "example" {
  value = "this should show up in plan, at least until you apply it"
}

Upvotes: 3

Ben
Ben

Reputation: 482

As stated here in the terraform documentation:

Outputs are only rendered when Terraform applies your plan. Running terraform plan will not render outputs.

Upvotes: 8

Krzysztof Madej
Krzysztof Madej

Reputation: 40603

I tested with this:

variable "VMCount" {
    description = "How many VMs do you want to start with (number)? default=1 max=5"
    type = number
}

output "VMCount" {
  value = "${var.VMCount > 2 && var.VMCount < 6 ? var.VMCount : 2}"
}

and it works well.

Terraform will perform the following actions:

Plan: 0 to add, 0 to change, 0 to destroy.

Changes to Outputs:
  + VMCount = 4

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes


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

Outputs:

VMCount = 4
PS C:\d\m\terraform\output-and-variable> terraform output
VMCount = 4
PS C:\d\m\terraform\output-and-variable> terraform apply
var.VMCount
  How many VMs do you want to start with (number)? default=1 max=5

  Enter a value: 8


Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:

Terraform will perform the following actions:

Plan: 0 to add, 0 to change, 0 to destroy.

Changes to Outputs:
  ~ VMCount = 4 -> 2

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes


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

Outputs:

VMCount = 2
PS C:\d\m\terraform\output-and-variable> terraform output
VMCount = 2
PS C:\d\m\terraform\output-and-variable>

Could you check what outouts doyou have in state? VMC or VMCount?

Upvotes: 22

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