1MCE::Hobo(3) User Contributed Perl Documentation MCE::Hobo(3)
2
3
4
6 MCE::Hobo - A threads-like parallelization module
7
9 This document describes MCE::Hobo version 1.840
10
12 use MCE::Hobo;
13
14 MCE::Hobo->init(
15 max_workers => 'auto', # default undef, unlimited
16 hobo_timeout => 20, # default undef, no timeout
17 posix_exit => 1, # default undef, CORE::exit
18 on_start => sub {
19 my ( $pid, $ident ) = @_;
20 ...
21 },
22 on_finish => sub {
23 my ( $pid, $exit, $ident, $signal, $error, @ret ) = @_;
24 ...
25 }
26 );
27
28 MCE::Hobo->create( sub { print "Hello from hobo\n" } )->join();
29
30 sub parallel {
31 my ($arg1) = @_;
32 print "Hello again, $arg1\n" if defined($arg1);
33 print "Hello again, $_\n"; # same thing
34 }
35
36 MCE::Hobo->create( \¶llel, $_ ) for 1 .. 3;
37
38 my @hobos = MCE::Hobo->list();
39 my @running = MCE::Hobo->list_running();
40 my @joinable = MCE::Hobo->list_joinable();
41 my @count = MCE::Hobo->pending();
42
43 # Joining is orderly, e.g. hobo1 is joined first, hobo2, hobo3.
44 $_->join() for @hobos;
45
46 # Joining occurs immediately as hobo(s) complete execution.
47 1 while MCE::Hobo->wait_one();
48
49 my $hobo = mce_async { foreach (@files) { ... } };
50
51 $hobo->join();
52
53 if ( my $err = $hobo->error() ) {
54 warn "Hobo error: $err\n";
55 }
56
57 # Get a hobo's object
58 $hobo = MCE::Hobo->self();
59
60 # Get a hobo's ID
61 $pid = MCE::Hobo->pid(); # $$
62 $pid = $hobo->pid();
63 $pid = MCE::Hobo->tid(); # tid is an alias for pid
64 $pid = $hobo->tid();
65
66 # Test hobo objects
67 if ( $hobo1 == $hobo2 ) {
68 ...
69 }
70
71 # Give other hobos a chance to run
72 MCE::Hobo->yield();
73 MCE::Hobo->yield(0.05);
74
75 # Return context, wantarray aware
76 my ($value1, $value2) = $hobo->join();
77 my $value = $hobo->join();
78
79 # Check hobo's state
80 if ( $hobo->is_running() ) {
81 sleep 1;
82 }
83 if ( $hobo->is_joinable() ) {
84 $hobo->join();
85 }
86
87 # Send a signal to a hobo
88 $hobo->kill('SIGUSR1');
89
90 # Exit a hobo
91 MCE::Hobo->exit(0);
92 MCE::Hobo->exit(0, @ret); # MCE::Hobo 1.827+
93
95 A Hobo is a migratory worker inside the machine that carries the
96 asynchronous gene. Hobos are equipped with "threads"-like capability
97 for running code asynchronously. Unlike threads, each hobo is a unique
98 process to the underlying OS. The IPC is managed by "MCE::Shared",
99 which runs on all the major platforms including Cygwin.
100
101 An exception was made on the Windows platform to spawn threads versus
102 children in "MCE::Hobo" 1.807 until 1.816. For consistency, the 1.817
103 release reverts back to spawning children on all supported platforms.
104
105 "MCE::Hobo" may be used as a standalone or together with "MCE"
106 including running alongside "threads".
107
108 use MCE::Hobo;
109 use MCE::Shared;
110
111 # synopsis: head -20 file.txt | perl script.pl
112
113 my $ifh = MCE::Shared->handle( "<", \*STDIN ); # shared
114 my $ofh = MCE::Shared->handle( ">", \*STDOUT );
115 my $ary = MCE::Shared->array();
116
117 sub parallel_task {
118 my ( $id ) = @_;
119 while ( <$ifh> ) {
120 printf {$ofh} "[ %4d ] %s", $., $_;
121 # $ary->[ $. - 1 ] = "[ ID $id ] read line $.\n" ); # dereferencing
122 $ary->set( $. - 1, "[ ID $id ] read line $.\n" ); # faster via OO
123 }
124 }
125
126 my $hobo1 = MCE::Hobo->new( "parallel_task", 1 );
127 my $hobo2 = MCE::Hobo->new( \¶llel_task, 2 );
128 my $hobo3 = MCE::Hobo->new( sub { parallel_task(3) } );
129
130 $_->join for MCE::Hobo->list(); # ditto: MCE::Hobo->wait_all();
131
132 # search array (total one round-trip via IPC)
133 my @vals = $ary->vals( "val =~ / ID 2 /" );
134
135 print {*STDERR} join("", @vals);
136
138 $hobo = MCE::Hobo->create( FUNCTION, ARGS )
139 $hobo = MCE::Hobo->new( FUNCTION, ARGS )
140 This will create a new hobo that will begin execution with function
141 as the entry point, and optionally ARGS for list of parameters. It
142 will return the corresponding MCE::Hobo object, or undef if hobo
143 creation failed.
144
145 FUNCTION may either be the name of a function, an anonymous
146 subroutine, or a code ref.
147
148 my $hobo = MCE::Hobo->create( "func_name", ... );
149 # or
150 my $hobo = MCE::Hobo->create( sub { ... }, ... );
151 # or
152 my $hobo = MCE::Hobo->create( \&func, ... );
153
154 $hobo = MCE::Hobo->create( { options }, FUNCTION, ARGS )
155 $hobo = MCE::Hobo->create( IDENT, FUNCTION, ARGS )
156 Options, excluding "ident", may be specified globally via the "init"
157 function. Otherwise, "ident", "hobo_timeout", and "posix_exit" may
158 be set uniquely.
159
160 The "ident" option, available since 1.827, is used by callback
161 functions "on_start" and "on_finish", for identifying the started
162 and finished process respectively.
163
164 my $hobo1 = MCE::Hobo->create( { posix_exit => 1 }, sub {
165 ...
166 } );
167
168 $hobo1->join;
169
170 my $hobo2 = MCE::Hobo->create( { hobo_timeout => 3 }, sub {
171 sleep 1 for ( 1 .. 9 );
172 } );
173
174 $hobo2->join;
175
176 if ( $hobo2->error() eq "Hobo timed out\n" ) {
177 ...
178 }
179
180 The "new()" method is an alias for "create()".
181
182 mce_async { BLOCK } ARGS;
183 mce_async { BLOCK };
184 "mce_async" runs the block asynchronously similarly to
185 "MCE::Hobo-"create()>. It returns the hobo object, or undef if hobo
186 creation failed.
187
188 my $hobo = mce_async { foreach (@files) { ... } };
189
190 $hobo->join();
191
192 if ( my $err = $hobo->error() ) {
193 warn("Hobo error: $err\n");
194 }
195
196 $hobo->join()
197 This will wait for the corresponding hobo to complete its execution.
198 In non-voided context, "join()" will return the value(s) of the
199 entry point function.
200
201 The context (void, scalar or list) for the return value(s) for
202 "join" is determined at the time of joining and mostly "wantarray"
203 aware.
204
205 my $hobo1 = MCE::Hobo->create( sub {
206 my @res = qw(foo bar baz);
207 return (@res);
208 });
209
210 my @res1 = $hobo1->join(); # ( foo, bar, baz )
211 my $res1 = $hobo1->join(); # baz
212
213 my $hobo2 = MCE::Hobo->create( sub {
214 return 'foo';
215 });
216
217 my @res2 = $hobo2->join(); # ( foo )
218 my $res2 = $hobo2->join(); # foo
219
220 $hobo1->equal( $hobo2 )
221 Tests if two hobo objects are the same hobo or not. Hobo comparison
222 is based on process IDs. This is overloaded to the more natural
223 forms.
224
225 if ( $hobo1 == $hobo2 ) {
226 print("Hobos are the same\n");
227 }
228 # or
229 if ( $hobo1 != $hobo2 ) {
230 print("Hobos differ\n");
231 }
232
233 $hobo->error()
234 Hobos are executed in an "eval" context. This method will return
235 "undef" if the hobo terminates normally. Otherwise, it returns the
236 value of $@ associated with the hobo's execution status in its
237 "eval" context.
238
239 $hobo->exit()
240 This sends 'SIGQUIT' to the hobo object, notifying hobo to exit. It
241 returns the hobo object to allow for method chaining. It is
242 important to join later if not immediately to not leave a zombie or
243 defunct process.
244
245 $hobo->exit()->join();
246 ...
247
248 $hobo->join(); # later
249
250 MCE::Hobo->exit( 0 )
251 MCE::Hobo->exit( 0, @ret )
252 A hobo can exit at any time by calling "MCE::Hobo-"exit()>.
253 Otherwise, the behavior is the same as "exit(status)" when called
254 from the main process. Current since 1.827, a worker may optionally
255 return data, to be transmitted to the parent process.
256
257 MCE::Hobo->finish()
258 This class method is called automatically by "END", but may be
259 called explicitly. An error is emitted via croak if there are active
260 hobos not yet joined.
261
262 MCE::Hobo->create( 'task1', $_ ) for 1 .. 4;
263 $_->join for MCE::Hobo->list();
264
265 MCE::Hobo->create( 'task2', $_ ) for 1 .. 4;
266 $_->join for MCE::Hobo->list();
267
268 MCE::Hobo->create( 'task3', $_ ) for 1 .. 4;
269 $_->join for MCE::Hobo->list();
270
271 MCE::Hobo->finish();
272
273 MCE::Hobo->init( options )
274 The init function accepts a list of MCE::Hobo options.
275
276 MCE::Hobo->init(
277 max_workers => 'auto', # default undef, unlimited
278 hobo_timeout => 20, # default undef, no timeout
279 posix_exit => 1, # default undef, CORE::exit
280 on_start => sub {
281 my ( $pid, $ident ) = @_;
282 ...
283 },
284 on_finish => sub {
285 my ( $pid, $exit, $ident, $signal, $error, @ret ) = @_;
286 ...
287 }
288 );
289
290 # Identification given as option or 1st argument.
291 # Current API available since 1.827.
292
293 for my $key ( 'aa' .. 'zz' ) {
294 MCE::Hobo->create( { ident => $key }, sub { ... } );
295 MCE::Hobo->create( $key, sub { ... } );
296 }
297
298 MCE::Hobo->wait_all;
299
300 Set "max_workers" if you want to limit the number of workers by
301 waiting automatically for an available slot. Specify "auto" to
302 obtain the number of logical cores via "MCE::Util::get_ncpu()".
303
304 Set "hobo_timeout", in number of seconds, if you want the hobo
305 process to terminate after some time. The default is 0 for no
306 timeout.
307
308 Set "posix_exit" to avoid all END and destructor processing.
309 Constructing MCE::Hobo inside a thread implies 1 or if present CGI,
310 FCGI, Coro, Curses, Gearman::Util, Gearman::XS, LWP::UserAgent,
311 Mojo::IOLoop, Prima, STFL, Tk, Wx, or Win32::GUI.
312
313 The callback options "on_start" and "on_finish" are called in the
314 parent process after starting a Hobo and later when terminated. The
315 arguments for the subroutines were inspired by
316 Parallel::ForkManager.
317
318 The parameters for "on_start" are the following:
319
320 - pid of the process
321 - identification (ident option or 1st arg to create)
322
323 The parameters for "on_finish" are the following:
324
325 - pid of the process
326 - program exit code
327 - identification (ident option or 1st arg to create)
328 - exit signal id
329 - error message from eval inside MCE::Hobo
330 - returned data
331
332 $hobo->is_running()
333 Returns true if a hobo is still running.
334
335 $hobo->is_joinable()
336 Returns true if the hobo has finished running and not yet joined.
337
338 $hobo->kill( 'SIG...' )
339 Sends the specified signal to the hobo. Returns the hobo object to
340 allow for method chaining. As with "exit", it is important to join
341 eventually if not immediately to not leave a zombie or defunct
342 process.
343
344 $hobo->kill('SIG...')->join();
345
346 The following is a parallel demonstration comparing "MCE::Shared"
347 against "Redis" and "Redis::Fast" on a Fedora 23 VM. Joining begins
348 after all workers have been notified to quit.
349
350 use Time::HiRes qw(time);
351
352 use Redis;
353 use Redis::Fast;
354
355 use MCE::Hobo;
356 use MCE::Shared;
357
358 my $redis = Redis->new();
359 my $rfast = Redis::Fast->new();
360 my $array = MCE::Shared->array();
361
362 sub parallel_redis {
363 my ($_redis) = @_;
364 my ($count, $quit, $len) = (0, 0);
365
366 # instead, use a flag to exit loop
367 $SIG{'QUIT'} = sub { $quit = 1 };
368
369 while () {
370 $len = $_redis->rpush('list', $count++);
371 last if $quit;
372 }
373
374 $count;
375 }
376
377 sub parallel_array {
378 my ($count, $quit, $len) = (0, 0);
379
380 # do not exit from inside handler
381 $SIG{'QUIT'} = sub { $quit = 1 };
382
383 while () {
384 $len = $array->push($count++);
385 last if $quit;
386 }
387
388 $count;
389 }
390
391 sub benchmark_this {
392 my ($desc, $num_hobos, $timeout, $code, @args) = @_;
393 my ($start, $total) = (time(), 0);
394
395 MCE::Hobo->new($code, @args) for 1..$num_hobos;
396 sleep $timeout;
397
398 # joining is not immediate; ok
399 $_->kill('QUIT') for MCE::Hobo->list();
400
401 # joining later; ok
402 $total += $_->join() for MCE::Hobo->list();
403
404 printf "$desc <> duration: %0.03f secs, count: $total\n",
405 time() - $start;
406
407 sleep 0.2;
408 }
409
410 benchmark_this('Redis ', 8, 5.0, \¶llel_redis, $redis);
411 benchmark_this('Redis::Fast', 8, 5.0, \¶llel_redis, $rfast);
412 benchmark_this('MCE::Shared', 8, 5.0, \¶llel_array);
413
414 MCE::Hobo->list()
415 Returns a list of all hobos not yet joined.
416
417 @hobos = MCE::Hobo->list();
418
419 MCE::Hobo->list_running()
420 Returns a list of all hobos that are still running.
421
422 @hobos = MCE::Hobo->list_running();
423
424 MCE::Hobo->list_joinable()
425 Returns a list of all hobos that have completed running. Thus, ready
426 to be joined without blocking.
427
428 @hobos = MCE::Hobo->list_joinable();
429
430 MCE::Hobo->max_workers([ N ])
431 Getter and setter for max_workers. Specify a number or 'auto' to
432 acquire the total number of cores via MCE::Util::get_ncpu. Specify a
433 false value to set back to no limit.
434
435 API available since 1.835.
436
437 MCE::Hobo->pending()
438 Returns a count of all hobos not yet joined.
439
440 $count = MCE::Hobo->pending();
441
442 $hobo->result()
443 Returns the result obtained by "join", "wait_one", or "wait_all". If
444 the process has not yet exited, waits for the corresponding hobo to
445 complete its execution.
446
447 use MCE::Hobo;
448 use Time::HiRes qw(sleep);
449
450 sub task {
451 my ($id) = @_;
452 sleep $id * 0.333;
453 return $id;
454 }
455
456 MCE::Hobo->create('task', $_) for ( reverse 1 .. 3 );
457
458 # 1 while MCE::Hobo->wait_one();
459
460 while ( my $hobo = MCE::Hobo->wait_one() ) {
461 my $err = $hobo->error() // 'no error';
462 my $res = $hobo->result();
463 my $pid = $hobo->pid();
464
465 print "[$pid] $err : $res\n";
466 }
467
468 Like "join" described above, the context (void, scalar or list) for
469 the return value(s) is determined at the time "result" is called and
470 mostly "wantarray" aware.
471
472 my $hobo1 = MCE::Hobo->create( sub {
473 my @res = qw(foo bar baz);
474 return (@res);
475 });
476
477 my @res1 = $hobo1->result(); # ( foo, bar, baz )
478 my $res1 = $hobo1->result(); # baz
479
480 my $hobo2 = MCE::Hobo->create( sub {
481 return 'foo';
482 });
483
484 my @res2 = $hobo2->result(); # ( foo )
485 my $res2 = $hobo2->result(); # foo
486
487 MCE::Hobo->self()
488 Class method that allows a hobo to obtain it's own MCE::Hobo object.
489
490 $hobo->pid()
491 $hobo->tid()
492 Returns the ID of the hobo.
493
494 pid: $$ process id
495 tid: $$ alias for pid
496
497 MCE::Hobo->pid()
498 MCE::Hobo->tid()
499 Class methods that allows a hobo to obtain its own ID.
500
501 pid: $$ process id
502 tid: $$ alias for pid
503
504 MCE::Hobo->wait_one()
505 MCE::Hobo->wait_all()
506 Meaningful for the manager process only, waits for one or all hobos
507 to complete execution. Afterwards, returns the corresponding
508 hobo(s). If a hobo doesn't exist, returns the "undef" value or an
509 empty list for "wait_one" and "wait_all" respectively.
510
511 The "waitone" and "waitall" methods are aliases since 1.827 for
512 backwards compatibility.
513
514 use MCE::Hobo;
515 use Time::HiRes qw(sleep);
516
517 sub task {
518 my $id = shift;
519 sleep $id * 0.333;
520 return $id;
521 }
522
523 MCE::Hobo->create('task', $_) for ( reverse 1 .. 3 );
524
525 # join, traditional use case
526 $_->join() for MCE::Hobo->list();
527
528 # wait_one, simplistic use case
529 1 while MCE::Hobo->wait_one();
530
531 # wait_one
532 while ( my $hobo = MCE::Hobo->wait_one() ) {
533 my $err = $hobo->error() // 'no error';
534 my $res = $hobo->result();
535 my $pid = $hobo->pid();
536
537 print "[$pid] $err : $res\n";
538 }
539
540 # wait_all
541 my @hobos = MCE::Hobo->wait_all();
542
543 for ( @hobos ) {
544 my $err = $_->error() // 'no error';
545 my $res = $_->result();
546 my $pid = $_->pid();
547
548 print "[$pid] $err : $res\n";
549 }
550
551 MCE::Hobo->yield( [ floating_seconds ] )
552 Prior API till 1.826.
553
554 Let this hobo yield CPU time to other hobos. By default, the class
555 method calls "sleep(0.008)" on UNIX and "sleep(0.015)" on Windows
556 including Cygwin.
557
558 MCE::Hobo->yield();
559 MCE::Hobo->yield(0.05);
560
561 # total run time: 0.25 seconds, sleep occurs in parallel
562
563 MCE::Hobo->create( sub { MCE::Hobo->yield(0.25) } ) for 1 .. 4;
564 MCE::Hobo->wait_all();
565
566 Current API available since 1.827.
567
568 Give other hobos a chance to run, optionally for given time. Yield
569 behaves similarly to MCE's interval option. It throttles hobos from
570 running too fast. A demonstration is provided in the next section
571 for fetching URLs in parallel.
572
573 # total run time: 1.00 second
574
575 MCE::Hobo->create( sub { MCE::Hobo->yield(0.25) } ) for 1 .. 4;
576 MCE::Hobo->wait_all();
577
579 This demonstration constructs two queues, two handles, starts the
580 shared-manager process if needed, and spawns four hobo workers. For
581 this demonstration, am chunking 64 URLs per job. In reality, one may
582 run with 200 workers and chunk 300 URLs on a 24-way box.
583
584 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
585 # perl demo.pl -- all output
586 # perl demo.pl >/dev/null -- mngr/hobo output
587 # perl demo.pl 2>/dev/null -- show results only
588 #
589 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
590
591 use strict;
592 use warnings;
593
594 use AnyEvent;
595 use AnyEvent::HTTP;
596 use Time::HiRes qw( time );
597
598 use MCE::Hobo;
599 use MCE::Shared;
600
601 # Construct two queues, input and return.
602
603 my $que = MCE::Shared->queue();
604 my $ret = MCE::Shared->queue();
605
606 # Construct shared handles to serialize output from many hobos
607 # writing simultaneously. This prevents garbled output.
608
609 mce_open my $OUT, ">>", \*STDOUT or die "open error: $!";
610 mce_open my $ERR, ">>", \*STDERR or die "open error: $!";
611
612 # Spawn workers early for minimum memory consumption.
613
614 MCE::Hobo->create({ posix_exit => 1 }, 'task', $_) for 1 .. 4;
615
616 # Obtain or generate input data for hobos to process.
617
618 my ( $count, @urls ) = ( 0 );
619
620 push @urls, map { "http://127.0.0.$_/" } 1..254;
621 push @urls, map { "http://192.168.0.$_/" } 1..254; # 508 URLs total
622
623 while ( @urls ) {
624 my @chunk = splice(@urls, 0, 64);
625 $que->enqueue( { ID => ++$count, INPUT => \@chunk } );
626 }
627
628 # So that workers leave the loop after consuming the queue.
629
630 $que->end();
631
632 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
633 # Loop for the manager process. The manager may do other work if
634 # need be and periodically check $ret->pending() not shown here.
635 #
636 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
637
638 my $start = time;
639
640 printf {$ERR} "Mngr - entering loop\n";
641
642 while ( $count ) {
643 my ( $result, $failed ) = $ret->dequeue( 2 );
644
645 # Remove ID from result, so not treated as a URL item.
646
647 printf {$ERR} "Mngr - received job %s\n", delete $result->{ID};
648
649 # Display the URL and the size captured.
650
651 foreach my $url ( keys %{ $result } ) {
652 printf {$OUT} "%s: %d\n", $url, length($result->{$url})
653 if $result->{$url}; # url has content
654 }
655
656 # Display URLs the hobo worker could not reach.
657
658 if ( @{ $failed } ) {
659 foreach my $url ( @{ $failed } ) {
660 print {$OUT} "Failed: $url\n";
661 }
662 }
663
664 # Decrement the count.
665
666 $count--;
667 }
668
669 MCE::Hobo->wait_all();
670
671 printf {$ERR} "Mngr - exiting loop\n\n";
672 printf {$ERR} "Duration: %0.3f seconds\n\n", time - $start;
673
674 exit;
675
676 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
677 # Hobos enqueue two items ( $result and $failed ) per each job
678 # for the manager process. Likewise, the manager process dequeues
679 # two items above. Optionally, Hobos add ID to result.
680 #
681 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
682
683 sub task {
684 my ( $id ) = @_;
685 printf {$ERR} "Hobo $id entering loop\n";
686
687 while ( my $job = $que->dequeue() ) {
688 my ( $result, $failed ) = ( { ID => $job->{ID} }, [ ] );
689
690 # Walk URLs, provide a hash and array refs for data.
691
692 printf {$ERR} "Hobo $id running job $job->{ID}\n";
693 walk( $job, $result, $failed );
694
695 # Send results to the manager process.
696
697 $ret->enqueue( $result, $failed );
698 }
699
700 printf {$ERR} "Hobo $id exiting loop\n";
701 }
702
703 sub walk {
704 my ( $job, $result, $failed ) = @_;
705
706 # Yielding is critical when running an event loop in parallel.
707 # Not doing so means that the app may reach contention points
708 # with the firewall and likely impose unnecessary hardship at
709 # the OS level. The idea here is not to have multiple workers
710 # initiate HTTP requests to a batch of URLs at the same time.
711 # Yielding in 1.827+ behaves more like scatter for the worker
712 # to run solo in a fraction of time.
713
714 MCE::Hobo->yield( 0.03 ); # MCE::Hobo 1.827
715
716 my $cv = AnyEvent->condvar();
717
718 # Populate the hash ref for URLs it could reach.
719 # Do not mix AnyEvent timeout and Hobo timeout.
720 # Choose to do the event timeout if available.
721
722 foreach my $url ( @{ $job->{INPUT} } ) {
723 $cv->begin();
724 http_get $url, timeout => 2, sub {
725 my ( $data, $headers ) = @_;
726 $result->{$url} = $data;
727 $cv->end();
728 };
729 }
730
731 $cv->recv();
732
733 # Populate the array ref for URLs it could not reach.
734
735 foreach my $url ( @{ $job->{INPUT} } ) {
736 push @{ $failed }, $url unless (exists $result->{ $url });
737 }
738
739 return;
740 }
741
742 __END__
743
744 $ perl demo.pl
745
746 Hobo 1 entering loop
747 Hobo 2 entering loop
748 Hobo 3 entering loop
749 Mngr - entering loop
750 Hobo 2 running job 2
751 Hobo 3 running job 3
752 Hobo 1 running job 1
753 Hobo 4 entering loop
754 Hobo 4 running job 4
755 Hobo 2 running job 5
756 Mngr - received job 2
757 Hobo 3 running job 6
758 Mngr - received job 3
759 Hobo 1 running job 7
760 Mngr - received job 1
761 Hobo 4 running job 8
762 Mngr - received job 4
763 http://192.168.0.1/: 3729
764 Hobo 2 exiting loop
765 Mngr - received job 5
766 Hobo 3 exiting loop
767 Mngr - received job 6
768 Hobo 1 exiting loop
769 Mngr - received job 7
770 Hobo 4 exiting loop
771 Mngr - received job 8
772 Mngr - exiting loop
773
774 Duration: 4.131 seconds
775
777 Making an executable is possible with the PAR::Packer module. On the
778 Windows platform, threads, threads::shared, and exiting via threads are
779 necessary for the binary to exit successfully.
780
781 # https://metacpan.org/pod/PAR::Packer
782 # https://metacpan.org/pod/pp
783 #
784 # pp -o demo.exe demo.pl
785 # ./demo.exe
786
787 use strict;
788 use warnings;
789
790 use if $^O eq "MSWin32", "threads";
791 use if $^O eq "MSWin32", "threads::shared";
792
793 # Include minimum dependencies for MCE::Hobo.
794 # Add other modules required by your application here.
795
796 use Storable ();
797 use Time::HiRes ();
798
799 # use IO::FDPass (); # optional: for condvar, handle, queue
800 # use Sereal (); # optional: for faster serialization
801
802 use MCE::Hobo;
803 use MCE::Shared;
804
805 # For PAR to work on the Windows platform, one must include manually
806 # any shared modules used by the application.
807
808 # use MCE::Shared::Array; # for MCE::Shared->array
809 # use MCE::Shared::Cache; # for MCE::Shared->cache
810 # use MCE::Shared::Condvar; # for MCE::Shared->condvar
811 # use MCE::Shared::Handle; # for MCE::Shared->handle, mce_open
812 # use MCE::Shared::Hash; # for MCE::Shared->hash
813 # use MCE::Shared::Minidb; # for MCE::Shared->minidb
814 # use MCE::Shared::Ordhash; # for MCE::Shared->ordhash
815 # use MCE::Shared::Queue; # for MCE::Shared->queue
816 # use MCE::Shared::Scalar; # for MCE::Shared->scalar
817
818 # Et cetera. Only load modules needed for your application.
819
820 use MCE::Shared::Sequence; # for MCE::Shared->sequence
821
822 my $seq = MCE::Shared->sequence( 1, 9 );
823
824 sub task {
825 my ( $id ) = @_;
826 while ( defined ( my $num = $seq->next() ) ) {
827 print "$id: $num\n";
828 sleep 1;
829 }
830 }
831
832 sub main {
833 MCE::Hobo->new( \&task, $_ ) for 1 .. 3;
834 MCE::Hobo->wait_all();
835 }
836
837 # Main must run inside a thread on the Windows platform or workers
838 # will fail duing exiting, causing the exe to crash. The reason is
839 # that PAR or a dependency isn't multi-process safe.
840
841 ( $^O eq "MSWin32" ) ? threads->create(\&main)->join() : main();
842
843 threads->exit(0) if $INC{"threads.pm"};
844
846 The inspiration for "MCE::Hobo" comes from wanting "threads"-like
847 behavior for processes. Both can run side-by-side including safe-use by
848 MCE workers. Likewise, the documentation resembles "threads".
849
850 The inspiration for "wait_all" and "wait_one" comes from the
851 "Parallel::WorkUnit" module.
852
854 · forks
855
856 · forks::BerkeleyDB
857
858 · Parallel::ForkManager
859
860 · Parallel::Loops
861
862 · Parallel::Prefork
863
864 · Parallel::WorkUnit
865
866 · Proc::Fork
867
868 · Thread::Tie
869
870 · threads
871
873 MCE, MCE::Shared
874
876 Mario E. Roy, <marioeroy AT gmail DOT com>
877
878
879
880perl v5.28.1 2019-01-04 MCE::Hobo(3)