feat: typings and error propagating

Ref: #378
Signed-off-by: Tomas Dvorak <[email protected]>

python/beeai_framework/backend/chat.py

@@ -18,7 +18,7 @@
 from collections.abc import AsyncGenerator, Callable
 from typing import Annotated, Any, Literal, Self, TypeVar
 
-from pydantic import BaseModel, BeforeValidator, ConfigDict, Field, ValidationError
+from pydantic import BaseModel, BeforeValidator, ConfigDict, Field, InstanceOf, ValidationError
 
 from beeai_framework.backend.constants import ProviderName
 from beeai_framework.backend.errors import ChatModelError
@@ -95,17 +95,10 @@ class ChatModelUsage(BaseModel):
     total_tokens: int
 
 
-class ChatModelOutput:
-    def __init__(
-        self,
-        *,
-        messages: list[Message],
-        usage: ChatModelUsage | None = None,
-        finish_reason: str | None = None,
-    ) -> None:
-        self.messages = messages
-        self.usage = usage
-        self.finish_reason = finish_reason
+class ChatModelOutput(BaseModel):
+    messages: list[InstanceOf[Message]]
+    usage: InstanceOf[ChatModelUsage] | None = None
+    finish_reason: str | None = None
 
     @classmethod
     def from_chunks(cls, chunks: list) -> Self:
@@ -211,7 +204,7 @@ class DefaultChatModelStructureSchema(BaseModel):
         # TODO: validate result matches expected schema
         return ChatModelStructureOutput(object=result)
 
-    def create(self, chat_model_input: ModelLike[ChatModelInput]) -> Run:
+    def create(self, chat_model_input: ModelLike[ChatModelInput]) -> Run[ChatModelOutput]:
         input = to_model(ChatModelInput, chat_model_input)
 
         async def run_create(context: RunContext) -> ChatModelOutput:
@@ -235,11 +228,11 @@ async def run_create(context: RunContext) -> ChatModelOutput:
                 await context.emitter.emit("success", {"value": result})
                 return result
             except ChatModelError as error:
-                await context.emitter.emit("error", {input, error})
+                await context.emitter.emit("error", error)
                 raise error
-            except Exception as ex:
-                await context.emitter.emit("error", {input, ex})
-                raise ChatModelError("Model error has occurred.") from ex
+            except Exception as error:
+                await context.emitter.emit("error", error)
+                raise ChatModelError("Model error has occurred.") from error
             finally:
                 await context.emitter.emit("finish", None)