add env var for prompt template dir; error handling

src/text_generation/adapters/prompt_template_repository.py

@@ -13,10 +13,11 @@ class PromptTemplateRepository(AbstractPromptTemplateRepository):
         return os.path.join(self.templates_dir, template_filename)
 
     def get(self, id: str) -> PromptTemplate:
+        path = self._create_path_from_id(id)
         try:
-            return load_prompt(self._create_path_from_id(id))
+            return load_prompt(path)
         except Exception as e:
-            print(e)
+            print(f'Failed to load template from path "{path}":\n{e}')
             return None
     
     def add(self, id: str, prompt_template: PromptTemplate) -> None:

src/text_generation/services/nlp/text_generation_completion_service.py

@@ -186,6 +186,10 @@ class TextGenerationCompletionService(
         prompt_template = self.prompt_template_service.get(
             id=self.constants.PromptTemplateIds.PHI_3_MINI_4K_INSTRUCT_BASIC
         )
+
+        if prompt_template is None:
+            raise ValueError(f"Prompt template not found for ID: {self.constants.PromptTemplateIds.PHI_3_MINI_4K_INSTRUCT_BASIC}")
+    
         return (
             { "question": RunnablePassthrough() }
             | prompt_template