Added a BackOffRunner that runs code with a back off strategy.

src/BackOffRunner.php

@@ -0,0 +1,53 @@
+<?php
+
+declare(strict_types=1);
+
+namespace EventSauce\BackOff;
+
+use Throwable;
+
+/**
+ * # This one is for the lazy people.
+ *
+ * This class is introduced for extremely lazy developers that can't even be bothered
+ * to write the tiniest amount of bootstrapping code, ever. LAZY! YOU'RE LAZY! BOOOO!
+ */
+class BackOffRunner
+{
+    private BackOffStrategy $strategy;
+
+    /**
+     * @var class-string<Throwable>
+     */
+    private string $retryOn;
+
+    /**
+     * @param class-string<Throwable> $retryOn
+     */
+    public function __construct(BackOffStrategy $strategy, string $retryOn = Throwable::class)
+    {
+        $this->strategy = $strategy;
+        $this->retryOn = $retryOn;
+    }
+
+    /**
+     * @return mixed
+     * @throws Throwable
+     */
+    public function run(callable $task)
+    {
+        $tries = 0;
+
+        while(true) {
+            try {
+                return $task();
+            } catch (Throwable $exception) {
+                if ( ! $exception instanceof $this->retryOn) {
+                    throw $exception;
+                }
+
+                $this->strategy->backOff(++$tries, $exception);
+            }
+        }
+    }
+}

src/BackOffRunnerTest.php

@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+namespace EventSauce\BackOff;
+
+use Exception;
+use LogicException;
+use PHPUnit\Framework\TestCase;
+use Throwable;
+
+class BackOffRunnerTest extends TestCase
+{
+    /**
+     * @test
+     */
+    public function running_a_callable_with_backoff(): void
+    {
+        $runner = new BackOffRunner(new NoWaitingBackOffStrategy(5));
+        $tries = 0;
+        $exception = null;
+
+        try {
+            $runner->run(function () use (&$tries) {
+                $tries++;
+                throw new Exception('oh no, this is terrible');
+            });
+        } catch (Throwable $throwable) {
+            $exception = $throwable;
+        }
+
+        self::assertEquals(6, $tries); // retry 5 failures + 1 final fail
+        self::assertEquals(new Exception('oh no, this is terrible'), $exception);
+    }
+    /**
+     * @test
+     */
+    public function not_matching_the_exception_type(): void
+    {
+        $runner = new BackOffRunner(new NoWaitingBackOffStrategy(5), LogicException::class);
+        $tries = 0;
+        $exception = null;
+
+        try {
+            $runner->run(function () use (&$tries) {
+                $tries++;
+                throw new Exception('oh no, this is terrible');
+            });
+        } catch (Throwable $throwable) {
+            $exception = $throwable;
+        }
+
+        self::assertEquals(1, $tries); // retry 5 failures + 1 final fail
+        self::assertEquals(new Exception('oh no, this is terrible'), $exception);
+    }
+}