Maxximiliann
defmodule Sandbox do
use GenServer
def start_link() do
GenServer.start_link(__MODULE__, [], name: __MODULE__)
end
@impl true
def init(_) do
:observer.start
main()
{:ok, :running}
end
def main do
IO.puts("Hello World!")
end
This is part of the application Foo. Sandbox is a supervised GenServer which executes the main function when Foo is started and whenever Sandbox crashes and is restarted by the Supervisor. :observer displays it as Elixir.Sandbox under its Applications tab.
However, if main is changed as follows-
def main do
IO.puts("Hello World!")
main()
end
:observer no longer shows the app nor the Elixir.Sandbox GenServer process which seems to indicate that either the Supervisor or the GenServer didn’t start. (Please correct me if this is not actually the case.)
The goal: To keep mainrunning perpetually even after its restarted by the Supervisor. What’s the best way to accomplish this?
Edit: use GenServer added
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kokolegorille
Learning about processes is the heart of the BEAM. It is also why the BEAM is attractive.
But it is hard and I advise You to watch those free lessons here before writing your own gen_server.
In particular, classes 2 and 3. Because class 1 is more about FP.
Your code needs corrections…
You should learn about processes, and You will understand their power.
If I mention those classes, it’s because they had great impact on my understanding.
Maxximiliann
Thanks for pointing out that oversight. OP has been corrected
Thank you for sharing that
Thanks for the resource, I really appreciate it
al2o3cr
A GenServer isn’t considered “started” until the
initfunction returns - seeGenServer.init/1for more detail. Makingmaincall itself means thatinitnever returns.