The example shows how some nodes could be executed several times in a cycle.
For example you want to send an email but something went wrong and the server is not available and you want to retry the operation.
mkdir ~/pvm-cycle
cd ~/pvm-cycle
composer req formapro/pvm:0.4.x-dev makasim/values:0.5.x-dev
# create such file with the code below
php cycle.php
cycle.php
failed to send email
failed to send email
failed to send email
email is sent
cycle.php
<?php
use Formapro\Pvm\DefaultBehaviorRegistry;
use Formapro\Pvm\ProcessEngine;
use Formapro\Pvm\Token;
use Formapro\Pvm\ProcessBuilder;
require_once __DIR__.'/vendor/autoload.php';
$process = (new ProcessBuilder())
->createNode('send_email', 'send_email')->end()
->createNode('email_sent', 'email_sent')->end()
->createTransition('send_email', 'send_email', 'retry')->end()
->createTransition('send_email', 'email_sent')->end()
->createStartTransition('send_email')->end()
->getProcess()
;
$engine = new ProcessEngine(new DefaultBehaviorRegistry([
'email_sent' => function(Token $token) {
echo 'email is sent'.PHP_EOL;
},
'send_email' => function(Token $token) {
$counter = $token->getValue('counter', 0);
$counter++;
$token->setValue('counter', $counter);
try {
if ($counter < $token->getValue('maxRetries')) {
throw new \LogicException('Mail server is down');
}
} catch (\Throwable $e) {
echo 'failed to send email'.PHP_EOL;
return 'retry';
}
},
]));
$token = $engine->createTokenFor($process->getStartTransition());
$token->setValue('maxRetries', rand(2, 4));
$engine->proceed($token);
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/Process.json",
"id": "60494887-cc39-43e5-ba47-4c39047a0d76",
"nodes": {
"send_email": {
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/Node.json",
"id": "send_email",
"behavior": "send_email"
},
"email_sent": {
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/Node.json",
"id": "email_sent",
"behavior": "email_sent"
}
},
"transitions": {
"058e9c00-0e88-491e-bad3-08f922f96cf2": {
"id": "058e9c00-0e88-491e-bad3-08f922f96cf2",
"weight": 1,
"async": false,
"active": true,
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
"name": "retry",
"from": "send_email",
"to": "send_email"
},
"3bae8563-2b0f-4f27-b686-4a20616fb253": {
"id": "3bae8563-2b0f-4f27-b686-4a20616fb253",
"weight": 1,
"async": false,
"active": true,
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
"from": "send_email",
"to": "email_sent"
},
"7ee26284-0952-44a2-a0d8-7e3c1c5524d1": {
"id": "7ee26284-0952-44a2-a0d8-7e3c1c5524d1",
"weight": 1,
"async": false,
"active": true,
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
"to": "send_email"
}
},
"outTransitions": {
"send_email": [
"058e9c00-0e88-491e-bad3-08f922f96cf2",
"3bae8563-2b0f-4f27-b686-4a20616fb253"
]
},
"inTransitions": {
"send_email": [
"058e9c00-0e88-491e-bad3-08f922f96cf2",
"7ee26284-0952-44a2-a0d8-7e3c1c5524d1"
],
"email_sent": [
"3bae8563-2b0f-4f27-b686-4a20616fb253"
]
},
"tokens": {
"6cdae9d7-de4a-4968-99b0-8c54e043ae67": {
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/Token.json",
"id": "6cdae9d7-de4a-4968-99b0-8c54e043ae67",
"transitions": [
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "de76e71b-da1c-46be-8715-d5da051e584e",
"transitionId": "7ee26284-0952-44a2-a0d8-7e3c1c5524d1",
"weight": 1,
"state": "opened",
"time": 16031635972293
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "3e04e0df-1720-4826-894e-115d7db71992",
"transitionId": "7ee26284-0952-44a2-a0d8-7e3c1c5524d1",
"weight": 1,
"state": "passed",
"time": 16031635972298
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "94d3deb2-b767-4406-aa7d-4930cb9ebb80",
"transitionId": "058e9c00-0e88-491e-bad3-08f922f96cf2",
"weight": 1,
"state": "opened",
"time": 16031635972301
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "68eb7c1a-c919-499f-a107-182f22ea6b6a",
"transitionId": "058e9c00-0e88-491e-bad3-08f922f96cf2",
"weight": 1,
"state": "passed",
"time": 16031635972306
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "9ec881bd-ce45-45e8-aedd-8332c333f1fb",
"transitionId": "058e9c00-0e88-491e-bad3-08f922f96cf2",
"weight": 1,
"state": "opened",
"time": 16031635972310
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "5b193997-2d95-41ed-8f97-7b6962b1b6e5",
"transitionId": "058e9c00-0e88-491e-bad3-08f922f96cf2",
"weight": 1,
"state": "passed",
"time": 16031635972315
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "381b24f3-2a58-4cad-9c3e-67acae446e9f",
"transitionId": "058e9c00-0e88-491e-bad3-08f922f96cf2",
"weight": 1,
"state": "opened",
"time": 16031635972318
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "b36fc349-7989-4e07-bdff-4f1e2a6fec23",
"transitionId": "058e9c00-0e88-491e-bad3-08f922f96cf2",
"weight": 1,
"state": "passed",
"time": 16031635972322
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "1a1dbd12-d10b-41c4-bd55-a153b9404eb4",
"transitionId": "3bae8563-2b0f-4f27-b686-4a20616fb253",
"weight": 1,
"state": "opened",
"time": 16031635972325
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "75ba0613-4cfa-4d58-8ab6-d153c5320a3e",
"transitionId": "3bae8563-2b0f-4f27-b686-4a20616fb253",
"weight": 1,
"state": "passed",
"time": 16031635972328
}
],
"maxRetries": 4,
"counter": 4
}
}
}