Replace print statements with structured logging

.gitignore

@@ -0,0 +1,25 @@
+# Build artifacts
+*.egg-info/
+dist/
+build/
+*.pyc
+__pycache__/
+
+# IDE
+.vscode/
+.idea/
+
+# Virtual environments
+venv/
+env/
+.env
+
+# Test artifacts
+.pytest_cache/
+.coverage
+htmlcov/
+*.png
+
+# OS files
+.DS_Store
+Thumbs.db

LOGGING.md

@@ -0,0 +1,135 @@
+# Logging in SpyDE
+
+## Overview
+
+SpyDE uses Python's built-in `logging` module for all application output. All `print()` statements have been replaced with appropriate logging calls to provide better control and visibility into application behavior.
+
+## Configuration
+
+Logging is configured centrally in `spyde/logging_config.py` and initialized when the application starts in `main_window.py:main()`.
+
+### Setting Log Level
+
+There are two ways to set the logging level:
+
+#### 1. Via the GUI (Recommended)
+
+Use the menu: **View → Set Log Level** and select from:
+- **DEBUG**: Show all diagnostic information
+- **INFO**: Show general informational messages (default)
+- **WARNING**: Show only warnings and errors
+- **ERROR**: Show only errors
+- **CRITICAL**: Show only critical errors
+
+The log level can be changed at any time while the application is running, and changes take effect immediately.
+
+#### 2. Via Environment Variable
+
+- **LOG_LEVEL**: Set the logging level at startup (DEBUG, INFO, WARNING, ERROR, CRITICAL)
+  - Default: `INFO` in production
+  - For debugging, set `LOG_LEVEL=DEBUG`
+
+Example:
+```bash
+export LOG_LEVEL=DEBUG
+spyde
+```
+
+## Usage in Code
+
+### Creating a Logger
+
+Each module should create its own logger at the module level:
+
+```python
+import logging
+
+logger = logging.getLogger(__name__)
+```
+
+### Logging Messages
+
+Use appropriate logging levels:
+
+```python
+# Debug - Detailed diagnostic information
+logger.debug("Processing data with shape: %s", data.shape)
+
+# Info - General informational messages
+logger.info("Signal loaded: %s", signal)
+
+# Warning - Something unexpected but not critical
+logger.warning("Could not find tool button for action %s", action_name)
+
+# Error - An error occurred but the application can continue
+logger.error("Plot update failed: %s", result)
+
+# Critical - A serious error that may prevent the application from continuing
+logger.critical("Unable to initialize Dask client")
+```
+
+### Exception Logging
+
+For exceptions, use `logger.exception()` inside an except block:
+
+```python
+try:
+    process_data()
+except Exception as e:
+    logger.exception("Failed to process data: %s", e)
+    raise
+```
+
+This automatically includes the traceback in the log output.
+
+## Best Practices
+
+1. **Use string formatting with %**: Instead of f-strings, use `%s` placeholders
+   ```python
+   # Good
+   logger.info("Loading file: %s", filename)
+
+   # Avoid
+   logger.info(f"Loading file: {filename}")
+   ```
+   This is more efficient because string formatting only happens if the log level is enabled.
+
+2. **Choose appropriate log levels**:
+   - `DEBUG`: Detailed information for diagnosing problems
+   - `INFO`: Confirmation that things are working as expected
+   - `WARNING`: Something unexpected happened, but the software is still working
+   - `ERROR`: A serious problem occurred
+   - `CRITICAL`: The program may be unable to continue
+
+3. **No print statements**: Use logging instead. Print statements should only be used in:
+   - Example scripts that demonstrate usage
+   - Test output that should always be visible
+
+4. **Third-party library logging**: Overly verbose third-party loggers are suppressed in `logging_config.py` to reduce noise.
+
+## Testing Logging
+
+To verify logging is working in a module:
+
+```python
+import os
+os.environ['LOG_LEVEL'] = 'DEBUG'
+
+from spyde.logging_config import setup_logging
+setup_logging()
+
+# Your code with logging calls
+```
+
+## Output Format
+
+The default log format is:
+```
+%(asctime)s - %(name)s - %(levelname)s - %(message)s
+```
+
+Example output:
+```
+2025-11-04 15:04:16 - spyde.main_window - INFO - Starting Dask LocalCluster with 4 workers
+2025-11-04 15:04:16 - spyde.signal_tree - DEBUG - Created Signal Tree with root signal: <Signal>
+```

spyde/__init__.py

@@ -1,5 +1,8 @@
 from importlib.resources import files
 import yaml
+import logging
+
+logger = logging.getLogger(__name__)
 
 # Load the configuration .yaml files at package initialization
 
@@ -10,7 +13,7 @@
     "r", encoding="utf-8"
 ) as f:
     METADATA_WIDGET_CONFIG = yaml.safe_load(f)
-print(METADATA_WIDGET_CONFIG)
+logger.debug("Loaded metadata widget config: %s", METADATA_WIDGET_CONFIG)
 
 __all__ = ["TOOLBAR_ACTIONS", "METADATA_WIDGET_CONFIG"]
 

spyde/actions/base.py

@@ -1,4 +1,5 @@
 from typing import TYPE_CHECKING
+import logging
 
 if TYPE_CHECKING:
     from spyde.drawing.toolbars.rounded_toolbar import RoundedToolBar
@@ -7,6 +8,8 @@
 
 from PySide6 import QtWidgets
 
+logger = logging.getLogger(__name__)
+
 ZOOM_STEP = 0.8
 
 
@@ -138,7 +141,7 @@ def toggle_navigation_plots(
     #    current_buttons[add_button_name] = add_button
 
     if toolbar.action_widgets.get(action_name, None) is None:
-        print(f"Adding toolbar action widget: {action_name}")
+        logger.debug("Adding toolbar action widget: %s", action_name)
         toolbar.add_action_widget(action_name, group, layout)
 
     if toggle is not None:
@@ -233,7 +236,7 @@ def tree2buttons(tree):
         layout = toolbar.action_widgets[action_name]["layout"]
 
     if toolbar.action_widgets.get(action_name, None) is None:
-        print(f"Adding toolbar action widget: {action_name}")
+        logger.debug("Adding toolbar action widget: %s", action_name)
         toolbar.add_action_widget(action_name, group, layout)
 
     if toggle is not None: