PHPでアクターモデルを理解・体験しよう / Understand and experience the actor model in PHP

This presentation was given at PHP Conference Okinawa 2024.
Welcome to 
the World of the Actor Model.


Transcript

1. PHPͰΞΫλʔϞσϧΛཧղɾମݧ͠Α͏ Understand and experience the actor model in PHP phpcon okinawa 2024 yuuki takezawa a.k.a ytake
2. Pro fi le • ஛ᖒ ༗و a.k.a ytake • ઍגࣜձࣾ CTO / ΄͔ٕज़ސ໰ʢωοτϓϩςΫγϣϯζͳͲʣ • Go / Scala / Kotlin / PHP • ΞΫλʔϞσϧେ޷͖
3. A toolkit for fl exible actor models in PHP
4. Phluxor
5. Phluxor • Phluxor / Actor System • Phluxor Persistence / Event Sourcing etc.. • Phluxor Remote / Network (Experimental / WIP) • Phluxor Cluster / Virtual Actors (WIP)
6. What is The Actor Model? • 1973೥ʹൃද͞Εͨฒߦܭࢉͷ਺ֶతϞσϧͷҰछ A type of mathematical model for concurrent computation introduced in 1973. • Erlang΍ScalaͳͲͰ͓ͳ͡Έ Well-known in languages like Erlang and Scala.
7. What is The Actor Model? • ϝοηʔδΛ༻͍ͯ΍ΓऔΓΛߦ͏ Communication is performed using messages. • ΞΫλʔ Ϟσϧ͸ɺ͢΂͕ͯΞΫλʔ The actor model adopts the philosophy that everything is an actor.
8. Actor Responsibilities • ΞΫλʔΛੜ੒͢Δ Create Another Actor • ϝοηʔδΛૹ৴͢Δ Send a Message • ϝοηʔδʹద༻͢Δಈ࡞Λߦ͏ Handle Message
9. Internal State • No Share Memory • State Change -> Event, and Persistence • Immutable Message
12. Actor Reference • ͢΂ͯͷΞΫλʔ͸ΞυϨεΛ࣋ͭ All actors have an address. • ͜ͷΞυϨε͸ϢχʔΫͰࣝผ͞ΕΔ This address is unique and identi fi able. • ૹ৴ݩ΍ૹ৴ઌΛܾΊΔ͜ͱ͕Ͱ͖Δ You can specify the sender and recipient.
15. Actor Lifecycle • ͢΂ͯͷΞΫλʔ͸ϥΠϑαΠΫϧΛ࣋ͭ All actors have a lifecycle • ΞΫλʔͷఀࢭɺ࠶ىಈͳͲ including stopping, restarting, etc. • Կ΋ཁٻ͞Εͳ͍৔߹͸Կ΋͠ͳ͍ If nothing is requested of them, they do nothing.
17. Hierarchy • ΞΫλʔ͸ΞΫλʔΛੜ੒Ͱ͖Δ Actors can create actors. • ਌ࢠؔ܎͕ܗ੒͞ΕΔ Parent-child relationships are formed. • ࢠΞΫλʔʹ࢓ࣄ͕ґཔͰ͖Δ You can assign tasks to child actors.
19. Fault Tolerance • ਌ΞΫλʔ͕ࢠΞΫλʔΛ؂ಜɾ؅ཧ͢Δ੹຿Λ࣋ͭ Parent actors have the responsibility to supervise and manage child actors. • ਌ࢠؔ܎ʹͳ͍ΞΫλʔ΋؂ࢹ͢Δ͜ͱ͕Ͱ͖Δ Actors that are not in a parent-child relationship can also be monitored.
20. Fault Tolerance • ࣦഊ࣌ʹͲͷΑ͏ʹ෮چͤ͞Δ͔ΛࢦࣔͰ͖Δ You can instruct how to recover in case of failure. • ΞΫλʔͷো֐͸ଞʹ͸఻೻͠ͳ͍ Actor failures do not propagate to others.
22. <?php declare(strict_types=1); namespace Example; use Example\Message\Hello; use Phluxor\ActorSystem\Context\ContextInterface; use Phluxor\ActorSystem\Message\ActorInterface; use Phluxor\ActorSystem\Props; use Phluxor\ActorSystem\ProtoBuf\Terminated; class ParentActor implements ActorInterface { public function receive(ContextInterface $context): void { $message = $context->message(); switch (true) { case $message instanceof Hello: $ref = $context->spawn(Props::fromProducer(fn() => new ChildActor())); $context->send($ref, $message); break; case $message instanceof Terminated: $context->logger()->info('terminated', [ 'who' => $message->getWho()->getId(), 'why' => $message->getWhy(), ]); break; } } }
23. <?php declare(strict_types=1); namespace Example; use Example\Message\Hello; use Phluxor\ActorSystem\Context\ContextInterface; use Phluxor\ActorSystem\Message\ActorInterface; use Phluxor\ActorSystem\Props; use Phluxor\ActorSystem\ProtoBuf\Terminated; class ParentActor implements ActorInterface { public function receive(ContextInterface $context): void { $message = $context->message(); switch (true) { case $message instanceof Hello: $ref = $context->spawn(Props::fromProducer(fn() => new ChildActor())); $context->send($ref, $message); break; case $message instanceof Terminated: $context->logger()->info('terminated', [ 'who' => $message->getWho()->getId(), 'why' => $message->getWhy(), ]); break; } } } 1BSFOU
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24. <?php declare(strict_types=1); namespace Example; use Example\Message\Hello; use Phluxor\ActorSystem\Context\ContextInterface; use Phluxor\ActorSystem\Message\ActorInterface; use Phluxor\ActorSystem\Props; use Phluxor\ActorSystem\ProtoBuf\Terminated; class ParentActor implements ActorInterface { public function receive(ContextInterface $context): void { $message = $context->message(); switch (true) { case $message instanceof Hello: $ref = $context->spawn(Props::fromProducer(fn() => new ChildActor())); $context->send($ref, $message); break; case $message instanceof Terminated: $context->logger()->info('terminated', [ 'who' => $message->getWho()->getId(), 'why' => $message->getWhy(), ]); break; } } } $SFBUF
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25. <?php declare(strict_types=1); namespace Example; use Example\Message\Hello; use Phluxor\ActorSystem\Context\ContextInterface; use Phluxor\ActorSystem\Message\ActorInterface; use Phluxor\ActorSystem\Message\Restarting; class ChildActor implements ActorInterface { public function receive(ContextInterface $context): void { $message = $context->message(); switch (true) { case $message instanceof Restarting: $context->logger()->info('restarting...'); break; case $message instanceof Hello: $context->logger()->info('Hello ' . $message->name); $context->stop($context->self()); break; } } } $IJME
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26. <?php declare(strict_types=1); namespace Example; use Example\Message\Hello; use Phluxor\ActorSystem\Context\ContextInterface; use Phluxor\ActorSystem\Message\ActorInterface; use Phluxor\ActorSystem\Message\Restarting; class ChildActor implements ActorInterface { public function receive(ContextInterface $context): void { $message = $context->message(); switch (true) { case $message instanceof Restarting: $context->logger()->info('restarting...'); break; case $message instanceof Hello: $context->logger()->info('Hello ' . $message->name); $context->stop($context->self()); break; } } } 4UPQ
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27. <?php declare(strict_types=1); namespace Example; use Example\Message\Hello; use Phluxor\ActorSystem\Context\ContextInterface; use Phluxor\ActorSystem\Message\ActorInterface; use Phluxor\ActorSystem\Props; use Phluxor\ActorSystem\ProtoBuf\Terminated; class ParentActor implements ActorInterface { public function receive(ContextInterface $context): void { $message = $context->message(); switch (true) { case $message instanceof Hello: $ref = $context->spawn(Props::fromProducer(fn() => new ChildActor())); $context->send($ref, $message); break; case $message instanceof Terminated: $context->logger()->info('terminated', [ 'who' => $message->getWho()->getId(), 'why' => $message->getWhy(), ]); break; } } } /PUJ fi DBUJPO
    
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29. Supervision
30. <?php declare(strict_types=1); namespace Example; use Example\Message\Hello; use Phluxor\ActorSystem\Context\ContextInterface; use Phluxor\ActorSystem\Message\ActorInterface; use Phluxor\ActorSystem\Message\Restarting; class ChildActor implements ActorInterface { public function receive(ContextInterface $context): void { $message = $context->message(); switch (true) { case $message instanceof Restarting: $context->logger()->info('restarting...'); break; case $message instanceof Hello: $context->logger()->info('Hello ' . $message->name); throw new \Exception('hi, I am an exception'); break; } } } UISPX
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31. Auto Recovering / Restarting
32. Supervision • OneForOneStrategy • AllForOneStrategy • ExponentialBackoffStrategy • RestartStrategy
38. Phluxor
39. Incarnate Actor Spawn
40. ActorInterface • No Return / Only sending and receiving messages. • All actors have a receive method that receives a context. • All actors are asynchronous and independent.
41. <?php declare(strict_types=1); namespace Phluxor\ActorSystem\Message; use Phluxor\ActorSystem\Context\ContextInterface; interface ActorInterface { /** * Receives a context. * * @param ContextInterface $context The context to receive. * @return void */ public function receive(ContextInterface $context): void; }
42. Spawning Actors • spawn method is used to create a child actor or root actor. • spawnNamed method is used to create a named actor. • spawnPre fi x method is used to create an actor with a pre fi x. • When an actor is spawned, Phluxor\ActorSystem\Ref is returned.
43. use Phluxor\ActorSystem; use Phluxor\ActorSystem\Props; $system = ActorSystem::create(); $spawned = $system->root()->spawn( Props::fromProducer( fn() => new YourActor() ) ); 8IFO
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44. $context->spawnNamed( Props::fromProducer( fn() => new YourChildActor() ), 'unique-name' ); $context->spawnPrefix( Props::fromProducer( fn() => new YourChildActor() ), 'prefix-' ); "TTJHO
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45. Props • The Props are a con fi guration object used to create an actor. • Phluxor\ActorSystem\Props is a class that creates a Props object. • and more!!!!
46. Props::fromProducer(fn() => new YourActor()) Props::fromFunction( new ActorSystem\Message\ReceiveFunction( fn( ActorSystem\Context\ContextInterface $context ) => $context->message() ) ); :PV
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47. Props::fromProducer( fn() => new VoidActor(), ActorSystem\Props::withSupervisor( new ActorSystem\Strategy\OneForOneStrategy( 10, new \DateInterval('PT10S'), fn() => ActorSystem\Directive::Restart ) ) ); Props::fromProducer( fn() => new YourActor(), Props::withMailboxProducer(new ActorSystem\Mailbox\Unbounded()) ); :PV
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48. Send Message • send is a non-blocking, fi re-and-forget • request is very similar to send, Only use it when request/reply communication is required between two actors. • Futures and promises
49. $context->send($ref, new PrepareTest(['subject' => $msg->getSubject()]) ); $context->request($ref, new PrepareTest(['subject' => $msg->getSubject()]) ); $future = $context->requestFuture( $ref, new PrepareTest(['subject' => $msg->getSubject()]), 1 ); 5IF
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50. Try!
51. https://github.com/ytake/phpcon- okinawa-example
53. ֶߍͷςετྫ • ઌੜ͕ੜెʹରͯ͠ ͞Μ͢͏ͷςετΛ࣮ࢪ • ੜె͸ͦΕͧΕݸͱͯ͠໰୊Λղ͘ • ઌੜ͸ςετதʹݟकΔͳͲͷߦಈ • શͯ౴͑ͨΒςετ༻ࢴΛఏग़͢Δ
54. example (the answer sheet • Class time begins • The teacher comes to the classroom • Test begins • Write your answers on the answer sheet. • Submit test answer sheets
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57. Notice! Actors Always Run Asyncronously It doesn't look like php? :)
59. Classroom
60. readonly class ClassroomActor implements ActorInterface { // omit public function receive(ContextInterface $context): void { $msg = $context->message(); switch (true) { case $msg instanceof StartsClass: $ref = $context->spawn( Props::fromProducer( fn() => new TeacherActor( $this->subject, $this->students, $context->self() ) ) ); $context->send($ref, new PrepareTest($msg->subject)); break; case $msg instanceof FinishTest: $context->send( $this->stream, new ClassFinished($msg->subject) ); \Swoole\Coroutine::sleep(0.1); $context->stop($context->self()); break; } } }
61. readonly class ClassroomActor implements ActorInterface { // omit public function receive(ContextInterface $context): void { $msg = $context->message(); switch (true) { case $msg instanceof StartsClass: $ref = $context->spawn( Props::fromProducer( fn() => new TeacherActor( $this->subject, $this->students, $context->self() ) ) ); $context->send($ref, new PrepareTest($msg->subject)); break; case $msg instanceof FinishTest: $context->send( $this->stream, new ClassFinished($msg->subject) ); \Swoole\Coroutine::sleep(0.1); $context->stop($context->self()); break; } } } 'SPN
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62. readonly class ClassroomActor implements ActorInterface { // omit public function receive(ContextInterface $context): void { $msg = $context->message(); switch (true) { case $msg instanceof StartsClass: $ref = $context->spawn( Props::fromProducer( fn() => new TeacherActor( $this->subject, $this->students, $context->self() ) ) ); $context->send($ref, new PrepareTest($msg->subject)); break; case $msg instanceof FinishTest: $context->send( $this->stream, new ClassFinished($msg->subject) ); \Swoole\Coroutine::sleep(0.1); $context->stop($context->self()); break; } } } 4QBXO
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63. readonly class ClassroomActor implements ActorInterface { // omit public function receive(ContextInterface $context): void { $msg = $context->message(); switch (true) { case $msg instanceof StartsClass: $ref = $context->spawn( Props::fromProducer( fn() => new TeacherActor( $this->subject, $this->students, $context->self() ) ) ); $context->send($ref, new PrepareTest($msg->subject)); break; case $msg instanceof FinishTest: $context->send( $this->stream, new ClassFinished($msg->subject) ); \Swoole\Coroutine::sleep(0.1); $context->stop($context->self()); break; } } } 4FOE
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64. readonly class ClassroomActor implements ActorInterface { // omit public function receive(ContextInterface $context): void { $msg = $context->message(); switch (true) { case $msg instanceof StartsClass: $ref = $context->spawn( Props::fromProducer( fn() => new TeacherActor( $this->subject, $this->students, $context->self() ) ) ); $context->send($ref, new PrepareTest($msg->subject)); break; case $msg instanceof FinishTest: $context->send( $this->stream, new ClassFinished($msg->subject) ); \Swoole\Coroutine::sleep(0.1); $context->stop($context->self()); break; } } } 3FQMZ
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65. readonly class ClassroomActor implements ActorInterface { // omit public function receive(ContextInterface $context): void { $msg = $context->message(); switch (true) { case $msg instanceof StartsClass: $ref = $context->spawn( Props::fromProducer( fn() => new TeacherActor( $this->subject, $this->students, $context->self() ) ) ); $context->send($ref, new PrepareTest($msg->subject)); break; case $msg instanceof FinishTest: $context->send( $this->stream, new ClassFinished($msg->subject) ); \Swoole\Coroutine::sleep(0.1); $context->stop($context->self()); break; } } } 4UPQ
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67. Teacher
68. class TeacherActor implements ActorInterface { // omit public function receive(ContextInterface $context): void { $msg = $context->message(); switch (true) { case $msg instanceof PrepareTest: $context->logger()->info( sprintf("Teacher has issued a %s test", $msg->subject) ); foreach ($this->students as $student) { $ref = $context->spawnNamed( Props::fromProducer(fn() => new StudentActor()), sprintf('student-%d', $student) ); $context->send($ref->getRef(), new StartTest($msg->subject)); } break; case $msg instanceof SubmitTest: $this->endOfTests[] = $msg; if (count($this->endOfTests) === count($this->students)) { $context->send($this->replyTo, new FinishTest($this->subject)); $context->poison($context->self()); } break; } } }
69. class TeacherActor implements ActorInterface { // omit public function receive(ContextInterface $context): void { $msg = $context->message(); switch (true) { case $msg instanceof PrepareTest: $context->logger()->info( sprintf("Teacher has issued a %s test", $msg->subject) ); foreach ($this->students as $student) { $ref = $context->spawnNamed( Props::fromProducer(fn() => new StudentActor()), sprintf('student-%d', $student) ); $context->send($ref->getRef(), new StartTest($msg->subject)); } break; case $msg instanceof SubmitTest: $this->endOfTests[] = $msg; if (count($this->endOfTests) === count($this->students)) { $context->send($this->replyTo, new FinishTest($this->subject)); $context->poison($context->self()); } break; } } } 'SPN
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70. class TeacherActor implements ActorInterface { // omit public function receive(ContextInterface $context): void { $msg = $context->message(); switch (true) { case $msg instanceof PrepareTest: $context->logger()->info( sprintf("Teacher has issued a %s test", $msg->subject) ); foreach ($this->students as $student) { $ref = $context->spawnNamed( Props::fromProducer(fn() => new StudentActor()), sprintf('student-%d', $student) ); $context->send($ref->getRef(), new StartTest($msg->subject)); } break; case $msg instanceof SubmitTest: $this->endOfTests[] = $msg; if (count($this->endOfTests) === count($this->students)) { $context->send($this->replyTo, new FinishTest($this->subject)); $context->poison($context->self()); } break; } } } 4QBXO
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71. class TeacherActor implements ActorInterface { // omit public function receive(ContextInterface $context): void { $msg = $context->message(); switch (true) { case $msg instanceof PrepareTest: $context->logger()->info( sprintf("Teacher has issued a %s test", $msg->subject) ); foreach ($this->students as $student) { $ref = $context->spawnNamed( Props::fromProducer(fn() => new StudentActor()), sprintf('student-%d', $student) ); $context->send($ref->getRef(), new StartTest($msg->subject)); } break; case $msg instanceof SubmitTest: $this->endOfTests[] = $msg; if (count($this->endOfTests) === count($this->students)) { $context->send($this->replyTo, new FinishTest($this->subject)); $context->poison($context->self()); } break; } } } *OUFSOBM
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72. Student(s)
73. class StudentActor implements ActorInterface { public function receive(ContextInterface $context): void { $msg = $context->message(); if ($msg instanceof StartTest) { sleep(random_int(1, 9)); $context->logger()->info( sprintf( '%s is submitting the answer to the %s test', $context->self(), $msg->subject ) ); $context->send( $context->parent(), new SubmitTest( $msg->subject, (string)$context->self(), ) ); $context->poison($context->self()); } } }
74. class StudentActor implements ActorInterface { public function receive(ContextInterface $context): void { $msg = $context->message(); if ($msg instanceof StartTest) { sleep(random_int(1, 9)); $context->logger()->info( sprintf( '%s is submitting the answer to the %s test', $context->self(), $msg->subject ) ); $context->send( $context->parent(), new SubmitTest( $msg->subject, (string)$context->self(), ) ); $context->poison($context->self()); } } } 'SPN
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75. class StudentActor implements ActorInterface { public function receive(ContextInterface $context): void { $msg = $context->message(); if ($msg instanceof StartTest) { sleep(random_int(1, 9)); $context->logger()->info( sprintf( '%s is submitting the answer to the %s test', $context->self(), $msg->subject ) ); $context->send( $context->parent(), new SubmitTest( $msg->subject, (string)$context->self(), ) ); $context->poison($context->self()); } } } 3BOEPNMZ
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77. class StudentActor implements ActorInterface { public function receive(ContextInterface $context): void { $msg = $context->message(); if ($msg instanceof StartTest) { sleep(random_int(1, 9)); $context->logger()->info( sprintf( '%s is submitting the answer to the %s test', $context->self(), $msg->subject ) ); $context->send( $context->parent(), new SubmitTest( $msg->subject, (string)$context->self(), ) ); $context->poison($context->self()); } } } 4UVEFOU
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81. Example • Teacher -> Actor / Aggregate • Students -> Actor • Classroom -> Actor / Aggregate
84. Training
85. and more
87. In closing • It's a somewhat different programming paradigm. • It's quite dif fi cult to understand just by listening, so please try it out yourself. • Once you understand it, you can apply it to your regular programming and modeling!
88. ͍͞͝ʹ • ϓϩάϥϛϯάύϥμΠϜ͕ͪΐͬͱҧ͏΋ͷ • ฉ͚ͩ͘Ͱ͸ͳ͔ͳ͔೉͍͠ͷͰɺͥͻ৮ͬͯΈ͍ͯͩ͘͞ • ཧղͰ͖ΔͱීஈͷϓϩάϥϛϯάɺϞσϦϯάʹ΋׆͔ͤΔʂ
89. Welcome to the World of the Actor Model. Α͏ͦ͜ΞΫλʔϞσϧͷੈք΁