I am creating multiple Genservers and have set an exit condition on them. I create each Genserver with a process id and then
def handle_cast({:receive_message, message}, zero_counter_gossip_true) do
// counter increased for the number of times this message has been called for this particular process
if new_message_counter < 9 do
GenServer.cast(self(), {:send_periodic_message})
else
Process.exit(self(), :normal)
end
def handle_cast({:send_periodic_message}, zero_counter_gossip_true) do
// The node to send is chosen from a list of nodes
GenServer.cast(node_to_send,{:receive_message, "ChitChat"}
GenServer.cast(self(), {:send_periodic_message})
// some code below
I expect the Genserver to exit only when the counter reaches 9 but I can see a lot of Genservers exiting with the message.
The node transmitting message is: [#PID<0.77.0>, 1]
where the first part is the PID and second the counter on number of times the receive_message has been called. Am I missing something here. Is the process timing out ? Any help would be appreciated TIA.
How complete is the code? Your first clause of handle_cast/2 should return {:noreply, zero_counter_gossip_true}. Btw wouldn’t it be better to wrap that state in a struct even if it only has one field? It would make it clearer what you are passing around in all the callbacks.
Hey, thanks for looking into it. I have attached a pastebin of the code below if you wanna see that. Do you mean to say that I should do in the if part of the receive message. I am returning something but that is common for both if and else and after the loop.
I am thanktul to everyone who has tried to help. I would like to clarify one of my statement though.
When I say the process exits, I am not sure if it has exited in the backend. I just know that the command prompt returned back to me without the process reaching the 9 counter value. I know the counter value since I put an inspect statement over there.
Do you see any output from the system that a process has died or is it quiet?
How do you mean “return to the command prompt”? How have you started the system and how are you running it? I mean do you have a function you call to send a cast message to the server?
If your system is running asynchronously then you may very well return to the command prompt while the system is still running. Doing a GenServer.cast is asynchronous and returns immediately, that is why I am asking.
Another way of terminating the genserver is for handle_cast to return {:stop, reason, state} where reason could be :normal in your case.
There is a way to see which processes are running in the system and that is to call the erlang function :c.i() which lists all the processes currently running. I don’t know if there is an equivalent helper function in the elixir shell.
