ria-labelledby=tabset-docs-reference-config-proxy-extensions-attributegen-3-0-tab><pre><code class=language-yaml>   {
     &quot;value&quot;: &quot;GetBook&quot;,
     &quot;condition&quot;:
     &quot;request.url_path.matches('^/shelves/[[:alnum:]]*/books/[[:alnum:]]*$')
     &amp;&amp; request.method == 'GET'&quot;
   },
</code></pre><p>Note: CEL uses <a href=https://github.com/google/re2/wiki/Syntax>re2</a> regex
library. Use anchors <code>{^, $}</code> to ensure that the regex evaluates
efficiently.</p>