[Scheduler] add "hashed" cron expression support

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\HashedCronExpressionTrigger;
 use Symfony\Component\Scheduler\Trigger\TriggerInterface;
 
 /**
@@ -46,6 +47,11 @@ public static function cron(string $expression, object $message): self
         return new self(CronExpressionTrigger::fromSpec($expression), $message);
     }
 
+    public static function hashedCron(string $expression, string $context, object $message): self
+    {
+        return new self(new HashedCronExpressionTrigger($expression, $context), $message);
+    }
+
     public static function trigger(TriggerInterface $trigger, object $message): self
     {
         return new self($trigger, $message);

src/Symfony/Component/Scheduler/Tests/Trigger/HashedCronExpressionTriggerTest.php

@@ -0,0 +1,59 @@
+<?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\HashedCronExpressionTrigger;
+
+final class HashedCronExpressionTriggerTest extends TestCase
+{
+    /**
+     * @dataProvider hashedExpressionProvider
+     */
+    public function testExpressionParsing(string $input, string $expected)
+    {
+        $expressionA = new HashedCronExpressionTrigger($input, 'my task');
+        $expressionB = new HashedCronExpressionTrigger($input, 'my task');
+        $expressionC = new HashedCronExpressionTrigger($input, 'another task');
+
+        $this->assertSame($expected, $expressionA->getExpression());
+        $this->assertSame($expressionB->getExpression(), $expressionA->getExpression());
+        $this->assertNotSame($expressionC->getExpression(), $expressionA->getExpression());
+    }
+
+    public static function hashedExpressionProvider(): array
+    {
+        return [
+            ['# * * * *', '56 * * * *'],
+            ['# # * * *', '56 20 * * *'],
+            ['# # # * *', '56 20 1 * *'],
+            ['# # # # *', '56 20 1 9 *'],
+            ['# # # # #', '56 20 1 9 0'],
+            ['# # 1,15 1-11 *', '56 20 1,15 1-11 *'],
+            ['# # 1,15 * *', '56 20 1,15 * *'],
+            ['#hourly', '56 * * * *'],
+            ['#daily', '56 20 * * *'],
+            ['#weekly', '56 20 * * 0'],
+            ['#weekly@midnight', '56 2 * * 0'],
+            ['#monthly', '56 20 1 * *'],
+            ['#monthly@midnight', '56 2 1 * *'],
+            ['#yearly', '56 20 1 9 *'],
+            ['#yearly@midnight', '56 2 1 9 *'],
+            ['#annually', '56 20 1 9 *'],
+            ['#annually@midnight', '56 2 1 9 *'],
+            ['#midnight', '56 2 * * *'],
+            ['#(1-15) * * * *', '12 * * * *'],
+            ['#(1-15) * * * #(3-5)', '12 * * * 5'],
+            ['#(1-15) * # * #(3-5)', '12 * 1 * 5'],
+        ];
+    }
+}

src/Symfony/Component/Scheduler/Trigger/HashedCronExpressionTrigger.php

@@ -0,0 +1,95 @@
+<?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;
+
+use Cron\CronExpression;
+use Symfony\Component\Scheduler\Exception\InvalidArgumentException;
+
+/**
+ * Use "hashed" cron expressions to describe a periodical trigger.
+ *
+ * @author Kevin Bond <kevinbond@gmail.com>
+ *
+ * @experimental
+ */
+final class HashedCronExpressionTrigger implements TriggerInterface
+{
+    private const ALIAS_MAP = [
+        '#hourly' => '# * * * *',
+        '#daily' => '# # * * *',
+        '#weekly' => '# # * * #',
+        '#weekly@midnight' => '# #(0-2) * * #',
+        '#monthly' => '# # # * *',
+        '#monthly@midnight' => '# #(0-2) # * *',
+        '#annually' => '# # # # *',
+        '#annually@midnight' => '# #(0-2) # # *',
+        '#yearly' => '# # # # *',
+        '#yearly@midnight' => '# #(0-2) # # *',
+        '#midnight' => '# #(0-2) * * *',
+    ];
+    private const RANGES = [
+        [0, 59],
+        [0, 23],
+        [1, 28],
+        [1, 12],
+        [0, 6],
+    ];
+
+    private CronExpressionTrigger $trigger;
+    private CronExpression $expression;
+
+    public function __construct(string $expression, string $context)
+    {
+        $this->trigger = new CronExpressionTrigger(
+            $this->expression = new CronExpression(self::parse($expression, $context))
+        );
+    }
+
+    public function getNextRunDate(\DateTimeImmutable $run): ?\DateTimeImmutable
+    {
+        return $this->trigger->getNextRunDate($run);
+    }
+
+    public function getExpression(): string
+    {
+        return $this->expression;
+    }
+
+    private static function parse(string $expression, string $context): string
+    {
+        $expression = self::ALIAS_MAP[$expression] ?? $expression;
+        $parts = explode(' ', $expression);
+
+        if (count($parts) !== 5) {
+            throw new InvalidArgumentException(sprintf('"%s" is an invalid cron expression.', $expression));
+        }
+
+        foreach ($parts as $position => $part) {
+            if (preg_match('#^\#(\((\d+)-(\d+)\))?$#', $part, $matches)) {
+                $parts[$position] = self::hashField(
+                    (int) ($matches[2] ?? self::RANGES[$position][0]),
+                    (int) ($matches[3] ?? self::RANGES[$position][1]),
+                    $context
+                );
+            }
+        }
+
+        return implode(' ', $parts);
+    }
+
+    private static function hashField(int $start, int $end, string $context): string
+    {
+        $possibleValues = range($start, $end);
+
+        return $possibleValues[(int) fmod(hexdec(substr(md5($context), 0, 10)), count($possibleValues))];
+    }
+}