title: Replacing plain strings in YAML config file with variables
body: <p>I'm working on a Java app with configuration stored in the application.yaml file, with endpoints defined as plain strings as follows:</p>
  <pre><code>security:
    oauth2:
      client:
        provider:
          keycloak:
            token-uri: path/to/somewhere
            authorization-uri: path/to/somewhere
            userinfo-uri: path/to/somewhere
  </code></pre>
  <p>And so on. The thing is, I don't like the idea of keeping the endpoints defined as plain strings here, I would strongly prefer to import them from somewhere else in the app, e.g. from a Java enum. But as far as I can see there is no real way to use variables in YAML, so what are my options?</p>