feat: Async api (#60)

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

docling_serve/datamodel/engines.py

@@ -0,0 +1,30 @@
+import enum
+from typing import Optional
+
+from pydantic import BaseModel
+
+from docling_serve.datamodel.requests import ConvertDocumentsRequest
+from docling_serve.datamodel.responses import ConvertDocumentResponse
+
+
+class TaskStatus(str, enum.Enum):
+    SUCCESS = "success"
+    PENDING = "pending"
+    STARTED = "started"
+    FAILURE = "failure"
+
+
+class AsyncEngine(str, enum.Enum):
+    LOCAL = "local"
+
+
+class Task(BaseModel):
+    task_id: str
+    task_status: TaskStatus = TaskStatus.PENDING
+    request: Optional[ConvertDocumentsRequest]
+    result: Optional[ConvertDocumentResponse] = None
+
+    def is_completed(self) -> bool:
+        if self.task_status in [TaskStatus.SUCCESS, TaskStatus.FAILURE]:
+            return True
+        return False