starbelly

rebar3 vs hex_core vs rebar3_hex vs hexpm... let them fight.

• Laziness is a virtue : Janky automated integration testing script thingy.
  • Huh?
  • The script
• Doing things the silly manual way
  • Setup a local instance of hexpm
  • Test steps

Laziness is a virtue : Janky automated integration testing script thingy.

rsampaio

Table of Contents

• 1. Week 1
  • 1.1. Introduction
    • 1.1.1. Logistics
    1.1.2. Material overview

guillermo

#!/bin/bash

# This is a unix wrapper around the erlang vm. It provides the following functionality:
#
# * Spawns in foreground
# * Handle SIGHUP and call RELOADFUNC
# * Handle SIGTERM SIGQUIT and SIGINT telling to the vm to quit
# * Dies if the vm dies (for example kernel killing because out of memory)
#
# Forks and improvements are welcome.

lpgauth

cat /erl_crash.dump | grep -2 '=proc:' | grep 'Spawned as:' | cut -d: -f2-3 | sort | uniq -c | sort -rn
  12433  cowboy_protocol:init/4
   1033  proc_lib:init_p/5
   1024  ranch_acceptor:loop/3
     16  application_master:start_it/4
     14  erlang:apply/2
     10  inet_tcp_dist:do_setup/6
      4  inet_tcp_dist:do_accept/6
      4  dlhttpc_client:request/10
      1  net_kernel:ticker/2

ferd

# Parse Erlang Crash Dumps and correlate mailbox size to the currently running
# function.
#
# Once in the procs section of the dump, all processes are displayed with
# =proc:<0.M.N> followed by a list of their attributes, which include the
# message queue length and the program counter (what code is currently
# executing).
BEGIN {
    threshold = 10000 # mailbox size
    procs = 0 # are we in the =procs entries?

ferd

f(MostLeaky).
MostLeaky = fun(N) ->
    lists:sublist(
     lists:usort(
         fun({K1,V1},{K2,V2}) -> {V1,K1} =< {V2,K2} end,
         [try
              {_,Pre} = erlang:process_info(Pid, binary),
              erlang:garbage_collect(Pid),
              {_,Post} = erlang:process_info(Pid, binary),
              {Pid, length(Post)-length(Pre)}

ferd

%% Convert a crashdump binary back into a regular binary
%% Crash dump binary:
%% =binary:CFE75808  % <- reference to refc binary
%% CA:2A31300D0A24350D0A484D5345540D0...  % <- actual binary
CDumpBin = fun(Str) ->
  [Len,Num] = string:tokens(Str, ":"),
  Src= lists:flatten(["<<16#",Num,":(16#",Len,"*8)>>."]),
  {ok, Tokens, _}=erl_scan:string(Src),
  {ok, [Form]} = erl_parse:parse_exprs(Tokens),
  {value, Val, _} = erl_eval:expr(Form, erl_eval:new_bindings()),

ferd

erlang:system_flag(scheduler_wall_time, true),
f(WallTimeDiff),
WallTimeDiff = fun(T1,T2) -> [trunc(100*((Active2-Active1)/(Total2-Total1)))/100 || {{I, Active1, Total1}, {I, Active2, Total2}} <- lists:zip(lists:sort(T1),lists:sort(T2))] end,                                                                                                                                        
f(F), put(stime, erlang:statistics(scheduler_wall_time)), 
F = fun(F,N) -> Old=get(stime), New=erlang:statistics(scheduler_wall_time), put(stime,New), io:format("rt:~p\trq:~p\t\tsched:~w~n", [element(2,erlang:statistics(runtime)), erlang:statistics(run_queue), WallTimeDiff(Old,New)]), timer:sleep(N), F(F,N) end.

%% F(F, IntervalInMS).

ferd

f(Init), f(Loop), f(Stats), f(ShowStats),
Init = fun(Delay) ->
  Ref = erlang:start_timer(Delay, self(), '#delay'),
  {{input,In},{output,Out}} = erlang:statistics(io),
  PrevGC = erlang:statistics(garbage_collection),
  {{Delay,Ref}, {In,Out}, PrevGC}
end,
Loop = fun(Self,F,N,{{D,R},{OldIn,OldOut},{OldGCs,OldWords,_}}) ->
  receive
    {timeout,R,'#delay'} ->

ferd

f(Window).

Window = fun(AttrName, Time,NumProcs) ->
 Attrs = fun(Name) ->
      [{Pid, {Attr, Curr, Init}}
       || Pid <- processes() -- [self()],
          [{_, Attr}, {_, Curr}, {_, Init}] <-
             [process_info(Pid, [Name, current_function, initial_call])]]
 end,
 F = fun() -> Attrs(AttrName) end,