fix(prompt-lab): app shouldn't crash when no prompts found (#53)

packages/ragbits-dev-kit/src/ragbits/dev_kit/prompt_lab/app.py

@@ -4,6 +4,7 @@
 import gradio as gr
 import jinja2
 from pydantic import BaseModel
+from rich.console import Console
 
 from ragbits.core.llms import LiteLLM
 from ragbits.core.llms.clients import LiteLLMOptions
@@ -38,28 +39,6 @@ class PromptState:
     temp_field_name: str = ""
 
 
-def load_prompts_list(pattern: str, state: gr.State) -> gr.State:
-    """
-    Fetches a list of prompts based on provided paths and updates the application state.
-
-    This function takes a path-pattern for discovering prompt definition files and uses the
-    PromptDiscovery class to discover prompts within those files. The discovered prompts are then
-    stored in the application state object.
-
-    Args:
-        pattern (str): A pattern for looking up prompt files.
-        state (gr.State): The Gradio state object to update with discovered prompts.
-
-    Returns:
-        gr.State: The updated Gradio state object containing the list of discovered prompts.
-    """
-    obj = PromptDiscovery(file_pattern=pattern)
-    discovered_prompts = list(obj.discover())
-    state.value.prompts = discovered_prompts
-
-    return state
-
-
 def render_prompt(
     index: int, system_prompt: str, user_prompt: str, state: gr.State, *args: Any
 ) -> tuple[str, str, gr.State]:
@@ -91,9 +70,7 @@ def render_prompt(
     prompt_object = prompt_class(input_data=input_data)
     state.current_prompt = prompt_object
 
-    chat_dict = {entry["role"]: entry["content"] for entry in prompt_object.chat}
-
-    return chat_dict["system"], chat_dict["user"], state
+    return prompt_object.system_message, prompt_object.user_message, state
 
 
 def list_prompt_choices(state: gr.State) -> list[tuple[str, int]]:
@@ -165,13 +142,24 @@ def lab_app(  # pylint: disable=missing-param-doc
     Launches the interactive application for listing, rendering, and testing prompts
     defined within the current project.
     """
+    prompts = PromptDiscovery(file_pattern=file_pattern).discover()
+
+    if not prompts:
+        Console(stderr=True).print(
+            f"""No prompts were found for the given file pattern: [b]{file_pattern}[/b].
+
+Please make sure that you are executing the command from the correct directory \
+or provide a custom file pattern using the [b]--file-pattern[/b] flag."""
+        )
+        return
+
     with gr.Blocks() as gr_app:
         prompt_state_obj = PromptState()
         prompt_state_obj.llm_model_name = llm_model
         prompt_state_obj.llm_api_key = llm_api_key
+        prompt_state_obj.prompts = list(prompts)
 
         prompts_state = gr.State(value=prompt_state_obj)
-        prompts_state = load_prompts_list(pattern=file_pattern, state=prompts_state)
         prompt_selection_dropdown = gr.Dropdown(
             choices=list_prompt_choices(prompts_state), value=0, label="Select Prompt"
         )