ZMQ lazy pirate pattern - server - erlzmq2

lps.es

#!/usr/bin/env escript
-module(lps).

-mode(compile).

-define(request_timeout,2500). %% msecs, (> 1000!)
-define(request_retries,3). %% before we abandon
-define(halt_strategy,die).

main(_Args) ->
    %% Append project ebin to path
    true = code:add_pathz(filename:dirname(escript:script_name()) ++ "/../ebin"),

    %% Create ZMQ client with REQ client socket pattern and connect
    {ok, Ctx} = erlzmq:context(),
    {ok, Sock} = erlzmq:socket(Ctx, rep),
    ok = erlzmq:bind(Sock, "tcp://*:4321"),

    Cycles = 0,
    loop(Cycles,{Ctx,Sock}).

loop(Cycles,{Ctx,Sock}) ->
    {ok,Msg} = erlzmq:recv(Sock),
    io:format("RECV: ~p~n", [Msg]),

    case trunc(random:uniform() * 9) == 0 of
        true -> 
            io:format("Simulate down [exiting]~n",[]), maybehalt();
            %% dont send response as 'down' (ie: simulates loss)
        false -> 
            case trunc(random:uniform() * 5) == 0 of
                true ->
                    io:format("Simulate saturation [delay]~n", []), 
                    %% sleep an inordinate amount of time (simulate delay)
                    timer:sleep(1000),
                    erlzmq:send(Sock,Msg);
                false ->
                    erlzmq:send(Sock,Msg)
            end
    end,
    loop(Cycles+1,{Ctx,Sock}).

maybehalt() ->
    case ?halt_strategy of
        die -> halt(1);
        _ -> ok
       %% side-effect: 0MQ send blocks forever, but msg is effectively "lost by N/W"
    end.