[#104] Display error message for the context window exceeded error (#105)

Changes:
- Added exception handling for `ContextWindowExceededError` in the relevant module.
- Logged the error to capture detailed error information.
- Display an error message to inform users about the error and how to resolve it.

model.py

@@ -29,6 +29,10 @@ DEFAULT_SUMMARIZE_INSTRUCTION = "Summarize the following text, maintaining the l
 DEFAULT_TRANSLATE_INSTRUCTION = "Translate the following text from {source_lang} to {target_lang}."  # pylint: disable=line-too-long
 
 
+class ContextWindowExceededError(Exception):
+  pass
+
+
 class Model:
 
   def __init__(
@@ -49,14 +53,18 @@ class Model:
     self.translate_instruction = translateInstruction or DEFAULT_TRANSLATE_INSTRUCTION  # pylint: disable=line-too-long
 
   def completion(self, messages: List, max_tokens: float = None) -> str:
-    response = litellm.completion(model=self.provider + "/" +
-                                  self.name if self.provider else self.name,
-                                  api_key=self.api_key,
-                                  api_base=self.api_base,
-                                  messages=messages,
-                                  max_tokens=max_tokens)
-
-    return response.choices[0].message.content
+    try:
+      response = litellm.completion(model=self.provider + "/" +
+                                    self.name if self.provider else self.name,
+                                    api_key=self.api_key,
+                                    api_base=self.api_base,
+                                    messages=messages,
+                                    max_tokens=max_tokens)
+
+      return response.choices[0].message.content
+
+    except litellm.ContextWindowExceededError as e:
+      raise ContextWindowExceededError() from e
 
 
 supported_models: List[Model] = [

response.py

@@ -3,6 +3,7 @@ This module contains functions for generating responses using LLMs.
 """
 
 import enum
+import logging
 from random import sample
 from typing import List
 from uuid import uuid4
@@ -11,9 +12,14 @@ from firebase_admin import firestore
 import gradio as gr
 
 from leaderboard import db
+from model import ContextWindowExceededError
 from model import Model
 from model import supported_models
 
+logging.basicConfig()
+logger = logging.getLogger(__name__)
+logger.setLevel(logging.INFO)
+
 
 def get_history_collection(category: str):
   if category == Category.SUMMARIZE.value:
@@ -81,10 +87,14 @@ def get_responses(prompt: str, category: str, source_lang: str,
       create_history(category, model.name, instruction, prompt, response)
       responses.append(response)
 
-    # TODO(#1): Narrow down the exception type.
-    except Exception as e:  # pylint: disable=broad-except
-      print(f"Error with model {model.name}: {e}")
-      raise gr.Error("Failed to get response. Please try again.")
+    except ContextWindowExceededError as e:
+      logger.exception("Context window exceeded for model %s.", model.name)
+      raise gr.Error(
+          "The prompt is too long. Please try again with a shorter prompt."
+      ) from e
+    except Exception as e:
+      logger.exception("Failed to get response from model %s.", model.name)
+      raise gr.Error("Failed to get response. Please try again.") from e
 
   model_names = [model.name for model in models]