@benwilson512 I think that handle_event is from another process; how is it blocked by start from another GenServer in this case?
thiagomajesk
0
benwilson512
Author of Craft GraphQL APIs in Elixir with Absinthe
You call start in handle_event. Start is not in another process, it’s in the liveview process. init is in another process, but start waits on init to return before it returns, that’s part of the standard genserver contract see:
iex(4)> defmodule Foo do
...(4)> use GenServer
...(4)>
...(4)> def start() do
...(4)> GenServer.start(__MODULE__, nil)
...(4)> end
...(4)>
...(4)>
...(4)> def init(_) do
...(4)> Process.sleep(1000)
...(4)> {:ok, nil}
...(4)> end
...(4)> end
iex(7)> :timer.tc(fn -> Foo.start() end)
{1000836, {:ok, #PID<0.145.0>}}
EDIT: Further reading
https://github.com/erlang/otp/blob/master/lib/stdlib/src/gen_server.erl#L74-L91
3
cevado
the liveview lives inside a single process for a particular session, so the handle_event of the liveview and the handle_info are blocking each other.
1
thiagomajesk
Oh, I see, that makes total sense! Thanks for the well-rounded explanation @benwilson512. I completely forgot that the GenServer process everything linearly like you mentioned (because it’s basically just a loop waiting for its time to process something). This definitely is what’s going on here.
2
rafaeliga
Thank you @benwilson512 !
The code below worked:
def init(_params) do
send(self(), :broadcast)
{:ok, nil}
end
def handle_info(:broadcast, state) do
Then looking at the Genserver documentation, handle_continue did the job too:
@impl true
def init(_params) do
{:ok, nil, {:continue, "continue"}}
end
@impl true
def handle_continue("continue", state) do
5