<div dir="ltr">Yes, because I am not on the chapter which teaches about it yet. My understanding is that the same semantics could be reaching without using it as well.<div><br></div><div>Having said that, I do believe supervisor would be the best solution, but this problem has to be used without Supervisor. I guess the exercise is given to understand the semantics of Supervisor works</div><div><br></div><div>Thank you</div><div>+ Harit Himanshu</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Jan 14, 2015 at 1:02 AM, Roberto Ostinelli <span dir="ltr"><<a href="mailto:roberto@widetag.com" target="_blank">roberto@widetag.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Is there any reason why you're not considering a supervisor [1]?<div><br></div><div>Best,</div><div>r.</div><div><br></div><div>[1] <a href="http://erlang.org/doc/man/supervisor.html" target="_blank">http://erlang.org/doc/man/supervisor.html</a></div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="h5">On Wed, Jan 14, 2015 at 4:52 AM, Harit Himanshu <span dir="ltr"><<a href="mailto:harit.subscriptions@gmail.com" target="_blank">harit.subscriptions@gmail.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5"><div dir="ltr">I was working on the following problem and wrote the code that works, but I have conceptual questions which are still bothering me. So I thought to put them in community and seek recommendations and guidance<div><br></div><div><b>Question</b></div><div>Write a function that starts and monitors several worker processes. If any of the worker processes dies abnormally, restart it.<b><br></b></div><div><br></div><div>My attempt looks like </div><div><div>monitor_workers(F, NumberOfWorkers) -></div><div> spawn(error_handling, monitor_workers_loop, [F, NumberOfWorkers]).</div><div><br></div><div><br></div><div>monitor_workers_loop(F, NumberOfWorkers) -></div><div> Workers = [spawn_monitor(F) || _Worker <- lists:seq(1, NumberOfWorkers)],</div><div> io:format("started workers: ~p.~n", [Workers]),</div><div> receive</div><div> {'DOWN', _, process, _, _} -></div><div> io:format("one of workers killed, starting one.~n"),</div><div> monitor_workers_loop(F, 1)</div><div> end.</div></div><div><br></div><div>and when I run, I see </div><div><br></div><div><div>1> c(error_handling).</div><div>{ok,error_handling}</div><div>2> </div><div>2> error_handling:monitor_workers(fun()-> area_server0:loop() end, 2).</div><div>started workers: [{<0.40.0>,#Ref<0.0.0.81>},{<0.41.0>,#Ref<0.0.0.82>}].</div><div><0.39.0></div><div>3> </div><div>3> Worker1 = list_to_pid("<0.40.0>").</div><div><0.40.0></div><div>4> </div><div>4> Worker2 = list_to_pid("<0.41.0>").</div><div><0.41.0></div><div>5> </div><div>5> exit(Worker1, kill).</div><div>one of workers killed, starting one.</div><div>started workers: [{<0.45.0>,#Ref<0.0.0.98>}].</div><div>true</div><div>6> exit(Worker2, kill).</div><div>one of workers killed, starting one.</div><div>started workers: [{<0.47.0>,#Ref<0.0.0.105>}].</div><div>true</div><div>7> </div></div><div><br></div><div><b>Problem(s)?</b></div><div><ol><li>A better way to solve this would be pass in different functions(than same, what I did) and let workers work on different problems. In such a scenario all we know if Pid and Ref to the workers.</li><li>When any process fails, it matches {'DOWN', Ref, process, Pid, Why}, and given this context how could I identify what function this process was running?</li></ol><div>I am very new to Erlang so have not much knowledge to solve such problems.</div></div><div><br></div><div>Thank you</div><span><font color="#888888"><div>+ Harit Himanshu</div></font></span></div>
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