Cloud SQL with Firebase Functions V2

I'm receiving connect ENOENT /cloudsql/<proj>:us-west1:<instance>/.s.PGSQL.5432 When connecting to a Cloud SQL instance of PostgreSQL 15 from a Firebase V2 Callable function. I've looked everywhere and even reluctantly used ChatGPT but I cannot seem to fix the issue.

1. I have checked my connection config (with the values substituted out)

export const createUnixSocketPool = (config: DatabaseConfig) => {
  return knex({
    client: "pg",
    connection: {
      user: config.user,
      password: config.password,
      database: "default",
      host: "/cloudsql/<proj-id>:us-west1:<instance-name>",
    },
    pool: { min: 0, max: 1 },
  });
};

2. project@appspot.gserviceaccount.com has the appropriate Client role for Cloud SQL.
3. Cloud SQL Admin API is enabled.

Your code configuration looks good, but the service configuration is not. You must tell to the service to open a connection with your Cloud SQL database, and then to open a unix socket for your code

I didn't find anywhere how to set up a Cloud SQL connection for Firebase Functions V2. The most appropriate documentation page is on Cloud Functions.