(FEAT) add centralized error handling utilty for the polymer classification app: utils/error.py

Improves code maintainability and clarity

Lays groundwork for consistent error management across the project

utils/errors.py

@@ -0,0 +1,126 @@
+"""Centralized error handling utility for the polymer classification app.
+Provides consistent error logging and graceful UI error reporting"""
+
+import streamlit as st 
+import traceback
+
+# Define a constant for error messages
+ERROR = "[ERROR]"
+
+class ErrorHandler:
+    """Centralized error handler for the application"""
+
+    @staticmethod
+    def log_error(error: Exception, context: str = "", include_traceback: bool = False) -> None:
+        """Log error to session state for display in UI"""
+        if "log_messages" not in st.session_state:
+            st.session_state["log_messages"] = []
+
+        error_msg = f"{ERROR} {context}: {str(error)}" if context else f"{ERROR} {str(error)}"
+
+        if include_traceback:
+            error_msg += f"\nTraceback: {traceback.format_exc()}"
+
+        st.session_state["log_messages"].append(error_msg)
+
+    @staticmethod
+    def log_warning(message: str, context: str = "") -> None:
+        """Log warning to session state"""
+        if "log_messages" not in st.session_state:
+            st.session_state["log_messages"] = []
+        
+        warning_msg = f"[WARNING] {context}: {message}" if context else f"[WARNING] {message}"
+        st.session_state["log_messages"].append(warning_msg)
+    
+    @staticmethod
+    def log_info(message: str, context: str = "") -> None:
+        """Log info message to session state"""
+        if "log_messages" not in st.session_state:
+            st.session_state["log_messages"] = []
+        
+        info_msg = f"[INFO] {context}: {message}" if context else f"[INFO] {message}"
+        st.session_state["log_messages"].append(info_msg)
+    
+    @staticmethod
+    def handle_file_error(filename: str, error: Exception) -> str:
+        """Handle file processing errors and return user-friendly message"""
+        ErrorHandler.log_error(error, f"File processing: {filename}")
+        
+        if isinstance(error, FileNotFoundError):
+            return f"❌ File not found: {filename}"
+        elif isinstance(error, PermissionError):
+            return f"❌ Permission denied accessing: {filename}"
+        elif isinstance(error, (ValueError, TypeError)):
+            return f"❌ Invalid file format in: {filename}. Please ensure it contains wavenumber and intensity columns."
+        else:
+            return f"❌ Error processing file: {filename}. {str(error)}"
+    
+    @staticmethod
+    def handle_inference_error(model_name: str, error: Exception) -> str:
+        """Handle model inference errors and return user-friendly message"""
+        ErrorHandler.log_error(error, f"Model inference: {model_name}")
+        
+        if "CUDA" in str(error) or "device" in str(error).lower():
+            return f"❌ Device error with model {model_name}. Falling back to CPU."
+        elif "shape" in str(error).lower() or "dimension" in str(error).lower():
+            return f"❌ Input shape mismatch for model {model_name}. Please check spectrum data format."
+        else:
+            return f"❌ Inference failed for model {model_name}: {str(error)}"
+    
+    @staticmethod
+    def handle_parsing_error(filename: str, error: Exception) -> str:
+        """Handle spectrum parsing errors and return user-friendly message"""
+        ErrorHandler.log_error(error, f"Spectrum parsing: {filename}")
+        
+        if "could not convert" in str(error).lower():
+            return f"❌ Invalid data format in {filename}. Expected numeric wavenumber and intensity columns."
+        elif "empty" in str(error).lower():
+            return f"❌ File {filename} appears to be empty or contains no valid data."
+        elif "columns" in str(error).lower():
+            return f"❌ File {filename} must contain exactly 2 columns (wavenumber, intensity)."
+        else:
+            return f"❌ Failed to parse spectrum data from {filename}: {str(error)}"
+    
+    @staticmethod
+    def clear_logs() -> None:
+        """Clear all logged messages"""
+        st.session_state["log_messages"] = []
+    
+    @staticmethod
+    def get_logs() -> list[str]:
+        """Get all logged messages"""
+        return st.session_state.get("log_messages", [])
+    
+    @staticmethod
+    def display_error_ui(error_message: str, show_details: bool = False) -> None:
+        """Display error in Streamlit UI with optional details"""
+        st.error(error_message)
+        
+        if show_details and st.session_state.get("log_messages"):
+            with st.expander("Error Details", expanded=False):
+                for msg in st.session_state["log_messages"][-5:]:  # Show last 5 log entries
+                    st.text(msg)
+
+def safe_execute(func, *args, error_context: str = "", show_error: bool = True, **kwargs):
+    """
+    Safely execute a function with error handling
+    
+    Args:
+        func: Function to execute
+        *args: Arguments for the function
+        error_context: Context description for error logging
+        show_error: Whether to show error in UI
+        **kwargs: Keyword arguments for the function
+    
+    Returns:
+        Tuple of (result, success_flag)
+    """
+    try:
+        result = func(*args, **kwargs)
+        return result, True
+    except Exception as e:
+        ErrorHandler.log_error(e, error_context)
+        if show_error:
+            error_msg = f"Error in {error_context}: {str(e)}" if error_context else str(e)
+            st.error(error_msg)
+        return None, False