Added retry

- use `RetryTrait` to handler when you would like to retry failed handlers
- for proper retry funcionality you have to use driver that supports delayed executions with `executeAt` message param

src/Dispatcher.php

@@ -108,7 +108,9 @@ public function handle(): void
         } catch (RestartException $e) {
             $this->log(LogLevel::NOTICE, 'Existing hermes dispatcher - restart');
         } catch (Exception $exception) {
-            Debugger::log($exception, Debugger::EXCEPTION);
+            if (Debugger::isEnabled()) {
+                Debugger::log($exception, Debugger::EXCEPTION);
+            }
         }
     }
 
@@ -169,12 +171,36 @@ private function handleMessage(HandlerInterface $handler, MessageInterface $mess
                 "Handler " . get_class($handler) . " throws exception - {$e->getMessage()}",
                 ['error' => $e, 'message' => $this->messageLoggerContext($message), 'exception' => $e]
             );
-            Debugger::log($e, Debugger::EXCEPTION);
+            if (Debugger::isEnabled()) {
+                Debugger::log($e, Debugger::EXCEPTION);
+            }
+
+            if (method_exists($handler, 'canRetry')) {
+                if ($message->getRetries() < $handler->maxRetry()) {
+                    $executeAt = $this->nextRetry($message);
+                    $newMessage = new Message($message->getType(), $message->getPayload(), $message->getId(), $message->getCreated(), $executeAt, $message->getRetries() + 1);
+                    $this->driver->send($newMessage);
+                }
+            }
+
             $result = false;
         }
         return $result;
     }
 
+    /**
+     * Calculate next retry
+     *
+     * Inspired by ruby sidekiq (https://github.com/mperham/sidekiq/wiki/Error-Handling#automatic-job-retry)
+     *
+     * @param MessageInterface $message
+     * @return float
+     */
+    private function nextRetry(MessageInterface $message): float
+    {
+        return microtime(true) + pow($message->getRetries(), 4) + 15 + (rand(1, 30) * ($message->getRetries() + 1));
+    }
+
     /**
      * Check if actual dispatcher has handler for given type
      *

src/Driver/RedisSetDriver.php

@@ -98,7 +98,6 @@ public function wait(Closure $callback): void
                 }
                 if ($this->redis instanceof \Redis) {
                     $messagesString = $this->redis->zRangeByScore($this->scheduleKey, '-inf', microtime(true), ['limit' => [0, 1]]);
-                    $messagesString = [];
                     if (count($messagesString)) {
                         foreach ($messagesString as $messageString) {
                             $this->redis->zRem($this->scheduleKey, $messageString);

src/Handler/EchoHandler.php

@@ -7,6 +7,8 @@
 
 class EchoHandler implements HandlerInterface
 {
+    use RetryTrait;
+
     /**
      * {@inheritdoc}
      */

src/Handler/RetryTrait.php

@@ -0,0 +1,17 @@
+<?php
+declare(strict_types=1);
+
+namespace Tomaj\Hermes\Handler;
+
+trait RetryTrait
+{
+    public function canRetry(): bool
+    {
+        return true;
+    }
+
+    public function maxRetry(): int
+    {
+        return 25;
+    }
+}

src/Message.php

@@ -23,7 +23,7 @@ class Message implements MessageInterface
     private $messageId;
 
     /**
-     * @var string
+     * @var float
      */
     private $created;
 
@@ -32,6 +32,11 @@ class Message implements MessageInterface
      */
     private $executeAt;
 
+    /**
+     * @var int
+     */
+    private $retries;
+
     /**
      * Native implementation of message.
      *
@@ -40,12 +45,18 @@ class Message implements MessageInterface
      * @var string   $messageId
      * @var float    $created   timestamp (microtime(true))
      * @var float    $executeAt timestamp (microtime(true))
+     * @var int      $retries
      */
-    public function __construct(string $type, array $payload = null, string $messageId = null, float $created = null, float $executeAt = null)
+    public function __construct(string $type, array $payload = null, string $messageId = null, float $created = null, float $executeAt = null, int $retries = 0)
     {
         $this->messageId = $messageId;
         if (!$messageId) {
-            $this->messageId = Uuid::uuid4()->toString();
+            try {
+                $this->messageId = Uuid::uuid4()->toString();
+            } catch (\Exception $e) {
+                $this->messageId = rand(10000, 99999999);
+            }
+
         }
         $this->created = $created;
         if (!$created) {
@@ -54,6 +65,7 @@ public function __construct(string $type, array $payload = null, string $message
         $this->type = $type;
         $this->payload = $payload;
         $this->executeAt = $executeAt;
+        $this->retries = $retries;
     }
 
     /**
@@ -95,4 +107,12 @@ public function getPayload(): ?array
     {
         return $this->payload;
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getRetries(): int
+    {
+        return $this->retries;
+    }
 }

src/MessageInterface.php

@@ -50,4 +50,11 @@ public function getType(): string;
      * @return array
      */
     public function getPayload(): ?array;
+
+    /**
+     * Total retries for message
+     *
+     * @return int
+     */
+    public function getRetries(): int;
 }

src/MessageSerializer.php

@@ -17,6 +17,7 @@ public function serialize(MessageInterface $message): string
                 'created' => $message->getCreated(),
                 'payload' => $message->getPayload(),
                 'execute_at' => $message->getExecuteAt(),
+                'retries' => $message->getRetries(),
             ]
         ]);
     }
@@ -32,6 +33,10 @@ public function unserialize(string $string): MessageInterface
         if (isset($message['execute_at'])) {
             $executeAt = $message['execute_at'];
         }
-        return new Message($message['type'], $message['payload'], $message['id'], $message['created'], $executeAt);
+        $retries = 0;
+        if (isset($message['retries'])) {
+            $retries = intval($message['retries']);
+        }
+        return new Message($message['type'], $message['payload'], $message['id'], $message['created'], $executeAt, $retries);
     }
 }