title: How to deploy pubsub-triggered cloud function with message ordering?
body: <p>I want to deploy a Pubsub-triggered Cloud Function with message ordering:
  <a href="https://cloud.google.com/pubsub/docs/ordering" rel="noreferrer">https://cloud.google.com/pubsub/docs/ordering</a></p>
  <p><code>gcloud functions deploy</code> doesn't have an option to set an <code>--enable-message-ordering</code> option:
  <a href="https://cloud.google.com/sdk/gcloud/reference/functions/deploy" rel="noreferrer">https://cloud.google.com/sdk/gcloud/reference/functions/deploy</a></p>
  <p>Should I pre-create the subscription before deploying the function? If so, does Cloud Functions have a well-known format for how it matches to a subscription name? It seems maybe the format is: <code>gcf-{function-name}-{region}-{topic-name}</code>, but it also looks like the name format has changed over time, e.g. older deployed functions don't have the region name in the subscription. Is there a stable way to do this?</p>