supervisor, behaviour(application), rebar3

[Papa Tana]

Thank you!

Regards,

2020-07-19 23:07 UTC+03:00, Leonard B <leonard.boyce@REDACTED>:
> Suggestion:
> https://learnyousomeerlang.com/content
>
>
> On Sun, Jul 19, 2020 at 2:42 PM Papa Tana <papa.tana101@REDACTED> wrote:
>>
>> Hi All,
>>
>> I have the following straightforward UDP Server:
>>
>>  - ONLY accept Data <<0:32>>,
>>  - otherwise it crash
>>
>> -module(server).
>> -export([listen/1]).
>>
>> listen(Port) ->
>>                 spawn(fun()->run_it(Port) end).
>>
>> run_it(Port) ->
>>         {ok, Skt} = gen_udp:open(Port, [binary]),
>>         loop(Skt).
>>
>> loop(Skt) ->
>>         receive
>>                 {udp, Skt, _, _, Bin} ->
>>                         case Bin of
>>                                 <<0:32>> ->
>>                                         io:fwrite("~p~n", [{"Good Format:
>> ", Bin}]),
>>                         loop(Skt)
>>                         end
>>         end.
>>
>> Now, Client is going to send a malformed data.
>>
>> I can write a case clause to match any message and simply ignore any
>> malformed message.
>>
>> However, that would be a catch-all-clause, which will not help me if
>> there is eventual bugs.
>>
>> I have read somewhere: "Don't program defensively, let it crash, then fix
>> it".
>>
>> =ERROR REPORT==== 19-Jul-2020::21:15:29.872000 ===
>> Error in process <0.93.0> with exit value:
>> {{case_clause,<<0>>},[{ggsn,loop,1,[{file,"ggsn.erl"},{line,16}]}]}
>>
>> Cool, it crash, But I want my server to restart automatically anyway :-)
>>
>> I have read also that a process called "supervisor" can monitor my
>> server and restarts it when it detects that it died.
>>
>> So, I have used "rebar3" because it helped me a lot when I compile
>> several files with just 1 single line 'rebar3 compile'.
>>
>> It creates automatically a /src/ with 3 files, but only 2 are
>> interesting me for now:
>>  - server_app.erl
>>  - server_sup.erl
>>
>> Ok, I have read the documentations but I'm still far from understanding.
>>
>> Can anyone advise please, or transform my 19 lines of code server.erl
>> to server_app.erl and supervised by a server_sup.erl?
>>
>> N.B: I'm not looking for a gen_server, I see it a lot but am I
>> obligated to transform this to a gen_server also, or only
>> application+supervisor is ok for my requirement?
>>
>> Thanks in advance,
>> Best Regards,
>