add shouldCancel and shouldRun

Author: QuentinGab

src/Models/Workflow.php

@@ -257,11 +257,18 @@ public function run(
         if (
             $this->isFinished() ||
             $this->isFailed() ||
-            $this->isCanceled()
+            $this->isCanceled() ||
+            ! $this->definition->shouldRun()
         ) {
             return;
         }
 
+        if ($this->definition->shouldCancel()) {
+            $this->markAsCanceled();
+
+            return;
+        }
+
         $readySteps = $this->definition
             ->steps($this)
             ->filter(function ($step, $name) {

src/WorkflowDefinition.php

@@ -27,4 +27,14 @@ public function start(): Workflow
 
         return $workflow;
     }
+
+    public function shouldCancel(): bool
+    {
+        return false;
+    }
+
+    public function shouldRun(): bool
+    {
+        return true;
+    }
 }