Add check for storage existence before creation in cache client

kcidb/cache/__init__.py

@@ -22,7 +22,22 @@ def __init__(self, bucket_name, max_store_size):
         """
         self.bucket_name = bucket_name
         self.max_store_size = max_store_size
-        self.client = storage.Client()
+        self._create_bucket_if_not_exists(bucket_name)
+
+    def _bucket_exists(self, bucket_name):
+        """Check if a GCS bucket exists."""
+        storage_client = storage.Client()
+        try:
+            storage_client.get_bucket(bucket_name)
+            return True
+        except Exception:
+            return False
+
+    def _create_bucket_if_not_exists(self, bucket_name):
+        """Create a GCS bucket if it doesn't exist."""
+        if not self._bucket_exists(bucket_name):
+            storage_client = storage.Client()
+            storage_client.create_bucket(bucket_name)
 
     @classmethod
     def _extract_content_disposition(cls, response):