title: Azure pipeline variable default values
body: <p>I am writing azure pipelines and using variables from variable groups. As part of adding flexibility, we are trying to make most of  the parts of pipeline configurable ( more variables). So, i was looking for a way to add default value to variable if it is not present in variable group.</p>
  
  <p>The way we use is like below:</p>
  
  <pre><code>variables:
    dockerId: $(docker_id)
    imageName: $(DOCKER_IMAGE_NAME)
  </code></pre>
  
  <p>Is there option to specify default for the variable, if it doesn't find it from variable group. Something like below:</p>
  
  <pre><code>variables:
    dockerId: $(docker_id:"defaultDockerId")
    imageName: $(DOCKER_IMAGE_NAME:"defaultDockerImageName")
  </code></pre>