Implement task API with input validation; implement error handling; refactoring

tofu_api/common/exceptions/__init__.py

@@ -0,0 +1 @@
+from .base import AppException

tofu_api/common/exceptions/base.py

@@ -0,0 +1,23 @@
+from typing import Optional
+
+
+class AppException(Exception):
+    """
+    Base class for application specific exceptions that can also be used as API error responses.
+    """
+    code: str = 'unspecified_error'
+    status_code: int = 400
+    message: str
+
+    def __init__(self, message: str, *, code: Optional[str] = None, status_code: Optional[int] = None):
+        if code is not None:
+            self.code = code
+        if status_code is not None:
+            self.status_code = status_code
+        self.message = message
+
+    def to_dict(self) -> dict:
+        return {
+            'code': self.code,
+            'message': self.message,
+        }