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": "05749845-6b48-492e-b110-f3e58483e7c9",
"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": {
"9c5d8e3c-2310-4190-ba9a-898580a54155": {
"id": "9c5d8e3c-2310-4190-ba9a-898580a54155",
"weight": 1,
"async": false,
"active": true,
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
"name": "retry",
"from": "send_email",
"to": "send_email"
},
"c000f0d9-475f-4ad9-a9b8-b0977cc4b4ee": {
"id": "c000f0d9-475f-4ad9-a9b8-b0977cc4b4ee",
"weight": 1,
"async": false,
"active": true,
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
"from": "send_email",
"to": "email_sent"
},
"dd11363c-fb03-4f01-a69b-19e57e83438f": {
"id": "dd11363c-fb03-4f01-a69b-19e57e83438f",
"weight": 1,
"async": false,
"active": true,
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
"to": "send_email"
}
},
"outTransitions": {
"send_email": [
"9c5d8e3c-2310-4190-ba9a-898580a54155",
"c000f0d9-475f-4ad9-a9b8-b0977cc4b4ee"
]
},
"inTransitions": {
"send_email": [
"9c5d8e3c-2310-4190-ba9a-898580a54155",
"dd11363c-fb03-4f01-a69b-19e57e83438f"
],
"email_sent": [
"c000f0d9-475f-4ad9-a9b8-b0977cc4b4ee"
]
},
"tokens": {
"846def2f-9458-4e58-90c7-d20fa2773964": {
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/Token.json",
"id": "846def2f-9458-4e58-90c7-d20fa2773964",
"transitions": [
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "73af28fe-66af-4bd8-b808-c77f3614fc6f",
"transitionId": "dd11363c-fb03-4f01-a69b-19e57e83438f",
"weight": 1,
"state": "opened",
"time": 15606685018049
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "cccf5fca-6f33-4109-9b0e-2d006cb344f5",
"transitionId": "dd11363c-fb03-4f01-a69b-19e57e83438f",
"weight": 1,
"state": "passed",
"time": 15606685018054
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "ae44ba62-e451-444a-9e0b-acb9f3c36fc2",
"transitionId": "9c5d8e3c-2310-4190-ba9a-898580a54155",
"weight": 1,
"state": "opened",
"time": 15606685018057
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "b54c8187-fa1e-4fa9-93f8-b0c621b69d13",
"transitionId": "9c5d8e3c-2310-4190-ba9a-898580a54155",
"weight": 1,
"state": "passed",
"time": 15606685018060
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "36bd6920-8fc7-48d2-b593-9a3c9311d983",
"transitionId": "9c5d8e3c-2310-4190-ba9a-898580a54155",
"weight": 1,
"state": "opened",
"time": 15606685018063
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "464ea29d-6a48-4f5e-ac06-d7d3a74c1a53",
"transitionId": "9c5d8e3c-2310-4190-ba9a-898580a54155",
"weight": 1,
"state": "passed",
"time": 15606685018068
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "048486e0-4f16-4f09-a97f-a2a6ddc0f292",
"transitionId": "9c5d8e3c-2310-4190-ba9a-898580a54155",
"weight": 1,
"state": "opened",
"time": 15606685018070
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "b6a10ec2-b88b-4d0e-8844-7f6c8ee14bb4",
"transitionId": "9c5d8e3c-2310-4190-ba9a-898580a54155",
"weight": 1,
"state": "passed",
"time": 15606685018074
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "9b6c132c-8ccd-4278-9baf-f3f3b2e52924",
"transitionId": "c000f0d9-475f-4ad9-a9b8-b0977cc4b4ee",
"weight": 1,
"state": "opened",
"time": 15606685018077
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "7b6ec289-383e-47f6-ab25-668154452043",
"transitionId": "c000f0d9-475f-4ad9-a9b8-b0977cc4b4ee",
"weight": 1,
"state": "passed",
"time": 15606685018080
}
],
"maxRetries": 4,
"counter": 4
}
}
}