document shared lock keys

Author: taylorotwell

queues.md

@@ -508,7 +508,7 @@ For example, let's imagine you have a queued job that updates a user's credit sc
         return [new WithoutOverlapping($this->user->id)];
     }
 
-Any overlapping jobs will be released back to the queue. You may also specify the number of seconds that must elapse before the released job will be attempted again:
+Any overlapping jobs of the same type will be released back to the queue. You may also specify the number of seconds that must elapse before the released job will be attempted again:
 
     /**
      * Get the middleware the job should pass through.
@@ -544,9 +544,44 @@ The `WithoutOverlapping` middleware is powered by Laravel's atomic lock feature.
         return [(new WithoutOverlapping($this->order->id))->expireAfter(180)];
     }
 
-> **Warning**  
+> **Warning**
 > The `WithoutOverlapping` middleware requires a cache driver that supports [locks](/docs/{{version}}/cache#atomic-locks). Currently, the `memcached`, `redis`, `dynamodb`, `database`, `file`, and `array` cache drivers support atomic locks.
 
+<a name="sharing-lock-keys"></a>
+#### Sharing Lock Keys Across Job Classes
+
+By default, the `WithoutOverlapping` middleware will only prevent overlapping jobs of the same class. So, although two different job classes may use the same lock key, they will not be prevented from overlapping. However, you can instruct Laravel to apply the key across job classes using the `shared` method:
+
+```php
+use Illuminate\Queue\Middleware\WithoutOverlapping;
+
+class ProviderIsDown
+{
+    // ...
+
+
+    public function middleware()
+    {
+        return [
+            (new WithoutOverlapping("status:{$this->provider}"))->shared(),
+        ];
+    }
+}
+
+class ProviderIsUp
+{
+    // ...
+
+
+    public function middleware()
+    {
+        return [
+            (new WithoutOverlapping("status:{$this->provider}"))->shared(),
+        ];
+    }
+}
+```
+
 <a name="throttling-exceptions"></a>
 ### Throttling Exceptions