Resolving steps.plan.outputs.* returns Empty Issue with hashicorp/setup-terraform@v3

A quick blog post to include the fix/what is needed to resolve steps.plan.outputs.* is empty when using GitHub Action hashicorp/setup-terraform@v3

I recently came across a situation while working with the hashicorp/setup-terraform@v3 GitHub Action. I wanted to make use of steps.plan.outputs.stdout to display the Terraform Plan, but I noticed that the output was consistently empty.

Even though successful Terraform plans should have output as shown below, mine was not showing anything.

When attempting to reference the output ${{ steps.plan.outputs.stdout }} it was returning as empty, Example below:

This was my current example snippet from the GitHub Action workflow:

    - name: Setup Terraform
      uses: hashicorp/setup-terraform@v3

    - name: Terraform Init
      id: init
      run: terraform init -backend-config="resource_group_name=$tf_resource_group_name" -backend-config="storage_account_name=$tf_storage_account_name" -backend-config="container_name=$tf_state_container" -backend-config="key=$tf_state_key"
      env:
        ARM_CLIENT_ID: ${{ secrets.CLIENT_ID }}
        ARM_CLIENT_SECRET: ${{ secrets.CLIENT_SECRET }}
        ARM_SUBSCRIPTION_ID: ${{ secrets.SUBSCRIPTION_ID }}
        ARM_TENANT_ID: ${{ secrets.TENANT_ID }}
      working-directory: ./terraform
      shell: bash
      
    - name: Terraform Plan  
      id: plan
      run: terraform plan -no-color -var deployment_subscription_id=$DEPLOYMENT_SUBSCRIPTION_ID
      env:
        ARM_CLIENT_ID: ${{ secrets.CLIENT_ID }}
        ARM_CLIENT_SECRET: ${{ secrets.CLIENT_SECRET }}
        ARM_SUBSCRIPTION_ID: ${{ secrets.SUBSCRIPTION_ID }}
        ARM_TENANT_ID: ${{ secrets.TENANT_ID }}
        DEPLOYMENT_SUBSCRIPTION_ID: ${{ secrets.SUBSCRIPTION_ID }}
      working-directory: ./terraform
      shell: bash
      continue-on-error: false

    - name: View Plan Output
      run: echo "${{ steps.plan.outputs.stdout }}"
      working-directory: ./terraform
      shell: bash

The fix

The fix was very simple, after reviewing some documentation :

This action does not configure any outputs directly. However, when you set the terraform_wrapper input to true, the following outputs are available for subsequent steps that call the terraform binary:

• stdout – The STDOUT stream of the call to the terraform binary.
• stderr – The STDERR stream of the call to the terraform binary.
• exitcode – The exit code of the call to the terraform binary.

https://github.com/marketplace/actions/hashicorp-setup-terraform#outputs

The hashicorp/setup-terraform@v3 action doesn’t directly configure any outputs. However, setting the terraform_wrapper input to true makes the following outputs available for subsequent steps calling the terraform binary.

Updating the GitHub Action with terraform_wrapper = true resolved my issue:

    - name: Setup Terraform
      uses: hashicorp/setup-terraform@v3
      with:
        terraform_wrapper: true

Now reviewing the output ${{ steps.plan.outputs.stdout }} it was returning as expected:

This fix proves useful when combining with various other actions and usages!