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": "6b8ebf40-0604-4119-baf0-15f0983ad2c3",
"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": {
"079fb0e0-cc7d-45eb-b82d-ca89a3bd9f46": {
"id": "079fb0e0-cc7d-45eb-b82d-ca89a3bd9f46",
"weight": 1,
"async": false,
"active": true,
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
"name": "retry",
"from": "send_email",
"to": "send_email"
},
"10a0e2db-beb4-4aec-a9fb-3ea68a0ce992": {
"id": "10a0e2db-beb4-4aec-a9fb-3ea68a0ce992",
"weight": 1,
"async": false,
"active": true,
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
"from": "send_email",
"to": "email_sent"
},
"a2b77227-4ea6-4099-8424-700078c526c7": {
"id": "a2b77227-4ea6-4099-8424-700078c526c7",
"weight": 1,
"async": false,
"active": true,
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
"to": "send_email"
}
},
"outTransitions": {
"send_email": [
"079fb0e0-cc7d-45eb-b82d-ca89a3bd9f46",
"10a0e2db-beb4-4aec-a9fb-3ea68a0ce992"
]
},
"inTransitions": {
"send_email": [
"079fb0e0-cc7d-45eb-b82d-ca89a3bd9f46",
"a2b77227-4ea6-4099-8424-700078c526c7"
],
"email_sent": [
"10a0e2db-beb4-4aec-a9fb-3ea68a0ce992"
]
},
"tokens": {
"b7b260de-cf52-4ee9-ae52-bb6336c872d7": {
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/Token.json",
"id": "b7b260de-cf52-4ee9-ae52-bb6336c872d7",
"transitions": [
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "7773629b-9ef0-481f-bfb6-0d4ce431b980",
"transitionId": "a2b77227-4ea6-4099-8424-700078c526c7",
"weight": 1,
"state": "opened",
"time": 15968784358511
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "c5747212-31da-403a-b260-871db27a20d9",
"transitionId": "a2b77227-4ea6-4099-8424-700078c526c7",
"weight": 1,
"state": "passed",
"time": 15968784358516
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "50e413cc-cfc2-44c0-b35c-52ddf30a961c",
"transitionId": "079fb0e0-cc7d-45eb-b82d-ca89a3bd9f46",
"weight": 1,
"state": "opened",
"time": 15968784358519
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "4a52a971-0433-44a4-a65d-348d9ce60c18",
"transitionId": "079fb0e0-cc7d-45eb-b82d-ca89a3bd9f46",
"weight": 1,
"state": "passed",
"time": 15968784358525
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "9d0f61b7-ad05-4fac-9077-bbed55d3c098",
"transitionId": "079fb0e0-cc7d-45eb-b82d-ca89a3bd9f46",
"weight": 1,
"state": "opened",
"time": 15968784358573
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "951a18b6-baf5-4400-816b-e2df7f5af1ae",
"transitionId": "079fb0e0-cc7d-45eb-b82d-ca89a3bd9f46",
"weight": 1,
"state": "passed",
"time": 15968784358577
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "97088fe7-ab17-47e3-a819-c5c568dfbdb8",
"transitionId": "079fb0e0-cc7d-45eb-b82d-ca89a3bd9f46",
"weight": 1,
"state": "opened",
"time": 15968784358579
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "d2f57283-7bed-409a-a3ca-76f7bfbba61e",
"transitionId": "079fb0e0-cc7d-45eb-b82d-ca89a3bd9f46",
"weight": 1,
"state": "passed",
"time": 15968784358583
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "545cabe6-b1cf-44d3-81fc-d0b16f67c262",
"transitionId": "10a0e2db-beb4-4aec-a9fb-3ea68a0ce992",
"weight": 1,
"state": "opened",
"time": 15968784358594
},
{
"schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
"id": "cdecc00f-0c42-4b3e-895e-c4f764667428",
"transitionId": "10a0e2db-beb4-4aec-a9fb-3ea68a0ce992",
"weight": 1,
"state": "passed",
"time": 15968784358597
}
],
"maxRetries": 4,
"counter": 4
}
}
}