Does runtime persistence options thread safed?

[midnight-wonderer]

I just read about this neat feature about Runtime Persistence Options.

To recap, Mongoid allows

MyModel.with({ client: :query }) do |collection|
  collection.last
  # something else
end

to explicitly specify client usage for some operations.

During the operation, if some other thread accesses MyModel, does it use :default client or :query client?
It isn't obvious from the code; as the library seems to mutate the state to me.
I wonder if this is thread-safe.

Also, is there any other way I can utilize non-default clients?

[jamis]

Hello @midnight-wonderer! The persistence options are thread safe; they ultimately call PersistenceContext#get_context (here), which fetches the information from thread-local storage.

By "non-default" clients, do you mean clients created ad-hoc, instead of declared in the mongoid config? The client option requires a client name, but you can declare a new client and assign it a name programmatically, like so:

Mongoid::Clients.set(:client_name, client_instance)

In general, we encourage developers to use previously-declared clients for this, rather than ad-hoc clients. Use of ad-hoc clients can make it difficult to understand what the behavior of a particular query or update really is.