How to use @google/genai with Vertex BYOK?

[hsab]

I've been trying to understand how to get @google/genai working with BYOK/Unified Billing gateways.

The following works for unauthenticated gateways, but defeats the purpose of centralizing secrets since they need to be passed at client creation.

  client = new GoogleGenAI({
    vertexai: true,
    project: googleCredentials.project_id,
    location: 'global',
    googleAuthOptions: {
      credentials: {
        client_email: googleCredentials.client_email,
        private_key: googleCredentials.private_key,
      },
    },
    httpOptions: {
      baseUrl: `${CF_GATEWAY_BASE_URL({
        accountId: c.env.CF_ACCOUNT_ID,
        gatewayId: c.env.CF_AI_GATEWAY_UNAUTHED_ID,
      })}/google-vertex-ai`,
    },
  });