From b0d984b35c394a573d615baa7543a87db49149ef Mon Sep 17 00:00:00 2001
From: Kevin Bond <kevinbond@gmail.com>
Date: Mon, 8 May 2023 18:01:55 -0400
Subject: [PATCH] [Scheduler] add `JitterTrigger`

Co-authored-by: Uladzimir Tsykun <tsykun314@gmail.com>
---
 .../Component/Scheduler/RecurringMessage.php  |  6 +++
 .../Tests/Trigger/JitterTriggerTest.php       | 42 +++++++++++++++++++
 .../Scheduler/Trigger/JitterTrigger.php       | 39 +++++++++++++++++
 3 files changed, 87 insertions(+)
 create mode 100644 src/Symfony/Component/Scheduler/Tests/Trigger/JitterTriggerTest.php
 create mode 100644 src/Symfony/Component/Scheduler/Trigger/JitterTrigger.php

diff --git a/src/Symfony/Component/Scheduler/RecurringMessage.php b/src/Symfony/Component/Scheduler/RecurringMessage.php
index 4e89adc8c783a..3553e96119bf8 100644
--- a/src/Symfony/Component/Scheduler/RecurringMessage.php
+++ b/src/Symfony/Component/Scheduler/RecurringMessage.php
@@ -14,6 +14,7 @@
 use Symfony\Component\Scheduler\Exception\InvalidArgumentException;
 use Symfony\Component\Scheduler\Trigger\CronExpressionTrigger;
 use Symfony\Component\Scheduler\Trigger\DateIntervalTrigger;
+use Symfony\Component\Scheduler\Trigger\JitterTrigger;
 use Symfony\Component\Scheduler\Trigger\TriggerInterface;
 
 /**
@@ -59,6 +60,11 @@ public static function trigger(TriggerInterface $trigger, object $message): self
         return new self($trigger, $message);
     }
 
+    public function withJitter(int $maxSeconds = 60): self
+    {
+        return new self(new JitterTrigger($this->trigger, $maxSeconds), $this->message);
+    }
+
     public function getMessage(): object
     {
         return $this->message;
diff --git a/src/Symfony/Component/Scheduler/Tests/Trigger/JitterTriggerTest.php b/src/Symfony/Component/Scheduler/Tests/Trigger/JitterTriggerTest.php
new file mode 100644
index 0000000000000..52dd7d593959a
--- /dev/null
+++ b/src/Symfony/Component/Scheduler/Tests/Trigger/JitterTriggerTest.php
@@ -0,0 +1,42 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Scheduler\Tests\Trigger;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Scheduler\Trigger\JitterTrigger;
+use Symfony\Component\Scheduler\Trigger\TriggerInterface;
+
+class JitterTriggerTest extends TestCase
+{
+    public function testCanAddJitter()
+    {
+        $time = new \DateTimeImmutable();
+        $inner = $this->createMock(TriggerInterface::class);
+        $inner->method('getNextRunDate')->willReturn($time);
+
+        $trigger = new JitterTrigger($inner);
+
+        $values = array_map(
+            fn () => (int) $trigger->getNextRunDate($time)?->getTimestamp(),
+            array_fill(0, 100, null)
+        );
+
+        foreach ($values as $value) {
+            $this->assertGreaterThanOrEqual($time->getTimestamp(), $value);
+            $this->assertLessThanOrEqual($time->getTimestamp() + 60, $value);
+        }
+
+        $values = array_unique($values);
+
+        $this->assertGreaterThan(1, \count($values));
+    }
+}
diff --git a/src/Symfony/Component/Scheduler/Trigger/JitterTrigger.php b/src/Symfony/Component/Scheduler/Trigger/JitterTrigger.php
new file mode 100644
index 0000000000000..639c490c12070
--- /dev/null
+++ b/src/Symfony/Component/Scheduler/Trigger/JitterTrigger.php
@@ -0,0 +1,39 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Scheduler\Trigger;
+
+/**
+ * @author Kevin Bond <kevinbond@gmail.com>
+ */
+final class JitterTrigger implements TriggerInterface
+{
+    /**
+     * @param positive-int $maxSeconds
+     */
+    public function __construct(private readonly TriggerInterface $trigger, private readonly int $maxSeconds = 60)
+    {
+    }
+
+    public function __toString(): string
+    {
+        return sprintf('%s with 0-%d second jitter', $this->trigger, $this->maxSeconds);
+    }
+
+    public function getNextRunDate(\DateTimeImmutable $run): ?\DateTimeImmutable
+    {
+        if (!$nextRun = $this->trigger->getNextRunDate($run)) {
+            return null;
+        }
+
+        return $nextRun->add(new \DateInterval(sprintf('PT%sS', random_int(0, $this->maxSeconds))));
+    }
+}