title: Google Cloud Platform - How to filter instances.list by tag?
body: <p>I'm trying to filter list of instances by tag name</p>
  
  <p>What works perfectly with gcloud, e.g. </p>
  
  <pre><code>gcloud compute instances list --filter 'tags.items=firewall-client-mongodb'
  </code></pre>
  
  <p>Does not work with API, which always returns 400:</p>
  
  <pre><code>{
   "error": {
    "errors": [
     {
      "domain": "global",
      "reason": "invalid",
      "message": "Invalid value for field 'filter': 'tags.items = test'. Invalid list filter expression."
     }
    ],
    "code": 400,
    "message": "Invalid value for field 'filter': 'tags.items = test'. Invalid list filter expression."
   }
  }
  </code></pre>
  
  <p>Is there any way to filter instances by tag, or any user defined variable? I'm testing with
  <a href="https://cloud.google.com/compute/docs/reference/rest/v1/instances/list" rel="noreferrer">https://cloud.google.com/compute/docs/reference/rest/v1/instances/list</a></p>