Azure CLI Tasks to Authenticate with an SPN

Terraform-Plan-Steps.yml

- task: AzureCLI@1
  displayName: 'Setup Authentication'
  inputs:
    azureSubscription: '$(SUBSCRIPTION_NAME)'
    addSpnToEnvironment: true
    scriptLocation: inlineScript
    failOnStandardError: 'true'
    inlineScript: |   
      echo "##vso[task.setvariable variable=ARM_SUBSCRIPTION_ID]$(az account show --query="id" -o tsv)"
      echo "##vso[task.setvariable variable=ARM_CLIENT_ID]${servicePrincipalId}"
      echo "##vso[task.setvariable variable=ARM_CLIENT_SECRET]${servicePrincipalKey}"
      echo "##vso[task.setvariable variable=ARM_TENANT_ID]$(az account show --query="tenantId" -o tsv)"
      echo "##vso[task.setvariable variable=ARM_ACCESS_KEY]$(az storage account keys list -n ${STORAGE_ACCOUNT} --query="[0].value" -o tsv
- script: |
    export TF_IN_AUTOMATION=true
    export TF_VAR_subscription_id="$(ARM_SUBSCRIPTION_ID)"
    export TF_VAR_client_id="$(ARM_CLIENT_ID)"
    export TF_VAR_client_secret="$(ARM_CLIENT_SECRET)"
    export TF_VAR_tenant_id="$(ARM_TENANT_ID)"
    export TF_VAR_vm_username="$(vm_username)"
    export TF_VAR_vm_password="$(vm_password)"
    terraform init -no-color -input=false
    terraform plan -out=tfplan -no-color -input=false
  displayName: 'Terraform Plan'
  workingDirectory: '$(TFPATH)'
  enabled: true