an><span class="pi">:</span>
  <span class="na">service</span><span class="pi">:</span> <span class="s">my-service.com</span>
</code></pre></div></div><p>When the <em>service</em> field is specified, all other implicit or explicit values of the other fields are ignored.</p><h3 id="qualify-rules-by-sourceheaders">Qualify rules by source/headers</h3><p>Rules can optionally be qualified to only apply to requests that match some specific criteria such as the following:</p><p><em>1. Restrict to a specific caller