So, I am working with simple NestJS application, docker, and terraform. My CI/CD scripts consists of 3 jobs, Docker, Terraform, and Deploy (with GCP). So I need to store the external IP of my created vm instance (by terraform) during the Terraform job. When I use the stored external IP, it is worked when I print it using echo. But, it seems doesn’t work when I use it in SSH with appleboy/ssh-action. Here is the detail.

Screenshot of my GitHub Actions Jobs

And here is my CI/CD scripts.

name: 'Automatic Deployment with Terraform and Docker to GCP'

on:
  push:
    branches: [ "master" ]
  pull_request:

permissions:
  contents: read

jobs:
  docker:
    name: 'Docker'
    runs-on: ubuntu-latest
    steps:
      - name: Checkout Repository
        uses: actions/checkout@v2

      - name: Docker Hub Authentication
        uses: docker/login-action@v1
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v2

      - name: Build Docker Image
        run: docker build -t ${{ secrets.DOCKERHUB_USERNAME }}/${{ vars.DOCKER_IMAGE_NAME }}:latest .

      - name: Tag Docker Image
        run: docker tag ${{ secrets.DOCKERHUB_USERNAME }}/${{ vars.DOCKER_IMAGE_NAME }}:latest ${{ secrets.DOCKERHUB_USERNAME }}/${{ vars.DOCKER_IMAGE_NAME }}:latest

      - name: Push Docker Image to Docker Hub
        run: docker push ${{ secrets.DOCKERHUB_USERNAME }}/${{ vars.DOCKER_IMAGE_NAME }}:latest


  terraform:
    name: 'Terraform'
    runs-on: ubuntu-latest
    outputs:
      external_ip: ${{ steps.store.outputs.vm_external_ip }}
    # Use the Bash shell regardless whether the GitHub Actions runner is ubuntu-latest, macos-latest, or windows-latest
    defaults:
      run:
        shell: bash

    steps:
    # Checkout the repository to the GitHub Actions runner
    - name: Checkout
      uses: actions/checkout@v4

    # Authenticate via gcloud CLI
    - name: Setup gcloud CLI
      uses: google-github-actions/[email protected]
      with:
        project_id: ${{ secrets.GCP_PROJECT_ID }}
        service_account_key: ${{ secrets.GOOGLE_CREDENTIALS }}  
        export_default_credentials: true

    # Install the latest version of Terraform CLI and configure the Terraform CLI configuration file with a Terraform Cloud user API token
    - name: Setup Terraform
      uses: hashicorp/setup-terraform@v1
      with:
        cli_config_credentials_token: ${{ secrets.TF_API_TOKEN }}

    - name: Create Terraform Variables
      id: vars
      run: |
        cat > terraform.tfvars <<EOF
        project="${{ secrets.GCP_PROJECT_ID }}"
        region="${{ vars.GCP_REGION }}"
        zone="${{ vars.GCP_ZONE }}"
        ssh_pub_key="${{ secrets.SSH_PUBLIC_KEY }}"
        ssh_username="${{ secrets.GCP_USER }}"
        vm_instance_name="${{ vars.VM_INSTANCE_NAME }}"
        EOF

    # Initialize a new or existing Terraform working directory by creating initial files, loading any remote state, downloading modules, etc.
    - name: Terraform Init
      run: terraform init

    # Checks that all Terraform configuration files adhere to a canonical format
    - name: Terraform Format
      run: terraform fmt

    # Generates an execution plan for Terraform
    - name: Terraform Plan
      run: terraform plan -out=plan

      # On push to "master", build or change infrastructure according to Terraform configuration files
      # Note: It is recommended to set up a required "strict" status check in your repository for "Terraform Cloud". See the documentation on "strict" required status checks for more information: https://help.github.com/en/github/administering-a-repository/types-of-required-status-checks
    - name: Terraform Apply
      run: terraform apply "plan"

    - name: Store Terraform Output
      run: |
        EXTERNAL_IP=$(terraform-bin output -raw vm_external_ip)
        echo "VM_EXTERNAL_IP=$EXTERNAL_IP" >> $GITHUB_ENV
        echo "not env: $EXTERNAL_IP"
        echo "env: ${{ env.VM_EXTERNAL_IP }}"
    
    - name: Echo Terraform Output 
      id: store
      env:
        EXTERNAL_IP: ${{ env.VM_EXTERNAL_IP }}
      run: |
        echo "env directly: ${{ env.VM_EXTERNAL_IP }}"
        echo "env variable: $EXTERNAL_IP"
        echo "vm_external_ip=$EXTERNAL_IP" >> "$GITHUB_OUTPUT"

    # - name: Terraform Destroy
    #   run: terraform destroy -auto-approve


  deploy:
    runs-on: ubuntu-latest
    needs: [docker, terraform]
    steps:
      - name: Echo VM External IP
        env:
          VM_EXTERNAL_IP: ${{ needs.terraform.outputs.external_ip }}
        run: echo "$VM_EXTERNAL_IP"

      - name: Set up Cloud CLI
        uses: google-github-actions/[email protected]
        with:
          project_id: ${{ secrets.GCP_PROJECT_ID }}
          service_account_key: ${{ secrets.GOOGLE_CREDENTIALS }}
          export_default_credentials: true

      - name: Access gcloud CLI
        run: |
          gcloud auth configure-docker

      - name: Checkout repository
        uses: actions/checkout@v3

      - name: SSH into GCP and Run Docker Container
        env:
            VM_EXTERNAL_IP: ${{ needs.terraform.outputs.external_ip }}
        uses: appleboy/ssh-action@master
        with:
          host: $VM_EXTERNAL_IP
          username: ${{ secrets.GCP_USER }}
          key: ${{ secrets.SSH_PRIVATE_KEY }}
          script: |
            docker pull ${{ secrets.DOCKERHUB_USERNAME }}/${{ vars.DOCKER_IMAGE_NAME }}:latest
            docker run -d -p 3000:3000 ${{ secrets.DOCKERHUB_USERNAME }}/${{ vars.DOCKER_IMAGE_NAME }}:latest

Thank you very much.