Mojo::Promise

bash.txt

# Need a separate process to block to show what happens when a waiting for a non-blocking op
# 12 workers that each handle only 1 concurrent connection so that each connection can immediately be fulfilled and start the countdown

$ perl -Mojo -MTime::HiRes=time,sleep -E 'a("/#n" => sub { my $time = time; my $n = $_->param("n"); sleep $n; $_->render(inline => "<title>$n : Sleep <%= \$n %> seconds</title>", n => time - $time) })->start' prefork -w 12 -c 1
Web application available at http://127.0.0.1:3000

---

$ perl promise.pl 1 http://localhost:3000/4 http://localhost:3000/3 http://localhost:3000/2 http://localhost:3000/5 http://localhost:3000/6 http://localhost:3000/7
Getting 6 URLs starting at 1677811334.05866
Getting http://localhost:3000/6 starting after 3.00407409667969e-05
Getting http://localhost:3000/2 starting after 6.01262807846069
Getting http://localhost:3000/5 starting after 8.0180242061615
Getting http://localhost:3000/3 starting after 13.0254700183868
Getting http://localhost:3000/7 starting after 16.0332491397858
Getting http://localhost:3000/4 starting after 23.0408351421356
Done getting 6 URLs after 27.048406124115
Done getting 6 URLs after 27.0521461963654
Titles:
  6 : Sleep 6.00025391578674 seconds
  2 : Sleep 2.00024104118347 seconds
  5 : Sleep 5.00025606155396 seconds
  3 : Sleep 3.0002429485321 seconds
  7 : Sleep 7.00025081634521 seconds
  4 : Sleep 4.00020003318787 seconds

$ perl promise.pl 7 http://localhost:3000/4 http://localhost:3000/3 http://localhost:3000/2 http://localhost:3000/5 http://localhost:3000/6 http://localhost:3000/7
Getting 6 URLs starting at 1677811389.73466
Getting http://localhost:3000/5 starting after 4.69684600830078e-05
Getting http://localhost:3000/3 starting after 0.000531196594238281
Getting http://localhost:3000/6 starting after 0.00151801109313965
Getting http://localhost:3000/2 starting after 0.00247716903686523
Getting http://localhost:3000/7 starting after 0.0038151741027832
Getting http://localhost:3000/4 starting after 0.00556612014770508
Done getting 6 URLs after 7.02463006973267
Done getting 6 URLs after 7.02584218978882
Titles:
  5 : Sleep 5.00024104118347 seconds
  3 : Sleep 3.00025796890259 seconds
  6 : Sleep 6.00024700164795 seconds
  2 : Sleep 2.00023198127747 seconds
  7 : Sleep 7.00027203559875 seconds
  4 : Sleep 4.00024795532227 seconds

gistfile1.txt

$ perl promise.pl 1 5
Getting 5 URLs starting at 1677814112.0623
Getting 2.67349671630221 starting after 3.19480895996094e-05
Getting 7.58055475027298 starting after 2.67741799354553
Getting 7.06455020618088 starting after 10.2669320106506
Getting 4.69123169999499 starting after 17.3339018821716
Getting 4.97515645843897 starting after 22.0288639068604
Done getting 5 URLs after 27.0098218917847
Done getting 5 URLs after 27.0103900432587
Titles:
  2.67349671630221 : Sleep 2.67349671630221 seconds
  7.58055475027298 : Sleep 7.58055475027298 seconds
  7.06455020618088 : Sleep 7.06455020618088 seconds
  4.69123169999499 : Sleep 4.69123169999499 seconds
  4.97515645843897 : Sleep 4.97515645843897 seconds

$ perl promise.pl 5 5
Getting 5 URLs starting at 1677814146.18375
Getting 0.862842012308857 starting after 3.38554382324219e-05
Getting 7.91875325876254 starting after 0.000115871429443359
Getting 1.59643112482432 starting after 0.000144004821777344
Getting 7.22928301396243 starting after 0.000169038772583008
Getting 8.12815142049452 starting after 0.000187873840332031
Done getting 5 URLs after 8.12967205047607
Done getting 5 URLs after 8.13023591041565
Titles:
  0.862842012308857 : Sleep 0.862842012308857 seconds
  7.91875325876254 : Sleep 7.91875325876254 seconds
  1.59643112482432 : Sleep 1.59643112482432 seconds
  7.22928301396243 : Sleep 7.22928301396243 seconds
  8.12815142049452 : Sleep 8.12815142049452 seconds

$ cat promise.pl 
use Mojo::Base -strict, -signatures;
use Mojo::Collection qw(c);
use Mojo::Promise;
use Time::HiRes qw(time);

my $ua = Mojo::UserAgent->new;

my $cc = shift @ARGV;
my $urls = c(map { rand(9) } 1..$ARGV[0])->shuffle;
my @titles;
my $time = time;
warn sprintf "Getting %d URLs starting at %s\n", $urls->size, $time;
Mojo::Promise->map({concurrency => $cc}, sub {
  warn sprintf "Getting %s starting after %s\n", $_, time - $time;
  Mojo::Promise->timer($_ => "$_ : Sleep $_ seconds");
}, @$urls)->then(sub{
  warn sprintf "Done getting %d URLs after %s\n", $urls->size, time - $time;
  @titles = map { $_->[0] } @_
})->wait;
warn sprintf "Done getting %d URLs after %s\n", $urls->size, time - $time;
warn "Titles:\n";
say join "\n", map { "  $_" } @titles;

promise.pl

use Mojo::Base -strict, -signatures;
use Mojo::Collection qw(c);
use Mojo::IOLoop;
use Mojo::Promise;
use Mojo::UserAgent;
use Time::HiRes qw(time);

my $ua = Mojo::UserAgent->new;

my $cc = shift @ARGV;
my $urls = c(qw(https://mojolicious.org https://metacpan.org), @ARGV)->shuffle;
my @titles;
my $time = time;
warn sprintf "Getting %d URLs starting at %s\n", $urls->size, $time;
Mojo::Promise->map({concurrency => $cc}, sub {
  warn sprintf "Getting %s starting after %s\n", $_, time - $time;
  $ua->get_p($_)
}, @$urls)->then(sub{
  warn sprintf "Done getting %d URLs after %s\n", $urls->size, time - $time;
  @titles = map { $_->[0]->res->dom->at('title')->text } @_
})->wait;
warn sprintf "Done getting %d URLs after %s\n", $urls->size, time - $time;
warn "Titles:\n";
say join "\n", map { "  $_" } @titles;