Process.whereis/1 can be called from any function but it does need to be run on the node which it is checking. You could do something like:
:rpc.call(node_name, Process, :whereis, [:slack_bot])
which would tell you if there is a process with the registered name :slack_bot running on it and return its pid. I don’t know of an Elixir equivalent module to :rpc.
