Adding a GC memory cleanup (releases cached libxml memory and others) (#3079)

changedetectionio/__init__.py

@@ -144,6 +144,15 @@ def main():
 
     signal.signal(signal.SIGTERM, sigshutdown_handler)
     signal.signal(signal.SIGINT, sigshutdown_handler)
+    
+    # Custom signal handler for memory cleanup
+    def sigusr_clean_handler(_signo, _stack_frame):
+        from changedetectionio.gc_cleanup import memory_cleanup
+        logger.info('SIGUSR1 received: Running memory cleanup')
+        return memory_cleanup(app)
+    
+    # Register the SIGUSR1 signal handler
+    signal.signal(signal.SIGUSR1, sigusr_clean_handler)
 
     # Go into cleanup mode
     if do_cleanup:

changedetectionio/flask_app.py

@@ -447,6 +447,16 @@ def changedetection_app(config=None, datastore_o=None):
 
     import changedetectionio.blueprint.watchlist as watchlist
     app.register_blueprint(watchlist.construct_blueprint(datastore=datastore, update_q=update_q, queuedWatchMetaData=queuedWatchMetaData), url_prefix='')
+    
+    # Memory cleanup endpoint
+    @app.route('/gc-cleanup', methods=['GET'])
+    @login_optionally_required
+    def gc_cleanup():
+        from changedetectionio.gc_cleanup import memory_cleanup
+        from flask import jsonify
+
+        result = memory_cleanup(app)
+        return jsonify({"status": "success", "message": "Memory cleanup completed", "result": result})
 
     # @todo handle ctrl break
     ticker_thread = threading.Thread(target=ticker_thread_check_time_launch_checks).start()

changedetectionio/gc_cleanup.py

@@ -0,0 +1,162 @@
+#!/usr/bin/env python3
+
+import ctypes
+import gc
+import re
+import psutil
+import sys
+import threading
+import importlib
+from loguru import logger
+
+def memory_cleanup(app=None):
+    """
+    Perform comprehensive memory cleanup operations and log memory usage
+    at each step with nicely formatted numbers.
+    
+    Args:
+        app: Optional Flask app instance for clearing Flask-specific caches
+        
+    Returns:
+        str: Status message
+    """
+    # Get current process
+    process = psutil.Process()
+    
+    # Log initial memory usage with nicely formatted numbers
+    current_memory = process.memory_info().rss / 1024 / 1024
+    logger.debug(f"Memory cleanup started - Current memory usage: {current_memory:,.2f} MB")
+
+    # 1. Standard garbage collection - force full collection on all generations
+    gc.collect(0)  # Collect youngest generation
+    gc.collect(1)  # Collect middle generation
+    gc.collect(2)  # Collect oldest generation
+
+    # Run full collection again to ensure maximum cleanup
+    gc.collect()
+    current_memory = process.memory_info().rss / 1024 / 1024
+    logger.debug(f"After full gc.collect() - Memory usage: {current_memory:,.2f} MB")
+    
+
+    # 3. Call libc's malloc_trim to release memory back to the OS
+    libc = ctypes.CDLL("libc.so.6")
+    libc.malloc_trim(0)
+    current_memory = process.memory_info().rss / 1024 / 1024
+    logger.debug(f"After malloc_trim(0) - Memory usage: {current_memory:,.2f} MB")
+    
+    # 4. Clear Python's regex cache
+    re.purge()
+    current_memory = process.memory_info().rss / 1024 / 1024
+    logger.debug(f"After re.purge() - Memory usage: {current_memory:,.2f} MB")
+
+    # 5. Reset thread-local storage
+    # Create a new thread local object to encourage cleanup of old ones
+    threading.local()
+    current_memory = process.memory_info().rss / 1024 / 1024
+    logger.debug(f"After threading.local() - Memory usage: {current_memory:,.2f} MB")
+
+    # 6. Clear sys.intern cache if Python version supports it
+    try:
+        sys.intern.clear()
+        current_memory = process.memory_info().rss / 1024 / 1024
+        logger.debug(f"After sys.intern.clear() - Memory usage: {current_memory:,.2f} MB")
+    except (AttributeError, TypeError):
+        logger.debug("sys.intern.clear() not supported in this Python version")
+    
+    # 7. Clear XML/lxml caches if available
+    try:
+        # Check if lxml.etree is in use
+        lxml_etree = sys.modules.get('lxml.etree')
+        if lxml_etree:
+            # Clear module-level caches
+            if hasattr(lxml_etree, 'clear_error_log'):
+                lxml_etree.clear_error_log()
+            
+            # Check for _ErrorLog and _RotatingErrorLog objects and clear them
+            for obj in gc.get_objects():
+                if hasattr(obj, '__class__') and hasattr(obj.__class__, '__name__'):
+                    class_name = obj.__class__.__name__
+                    if class_name in ('_ErrorLog', '_RotatingErrorLog', '_DomainErrorLog') and hasattr(obj, 'clear'):
+                        try:
+                            obj.clear()
+                        except (AttributeError, TypeError):
+                            pass
+                    
+                    # Clear Element objects which can hold references to documents
+                    elif class_name in ('_Element', 'ElementBase') and hasattr(obj, 'clear'):
+                        try:
+                            obj.clear()
+                        except (AttributeError, TypeError):
+                            pass
+            
+            current_memory = process.memory_info().rss / 1024 / 1024
+            logger.debug(f"After lxml.etree cleanup - Memory usage: {current_memory:,.2f} MB")
+
+        # Check if lxml.html is in use
+        lxml_html = sys.modules.get('lxml.html')
+        if lxml_html:
+            # Clear HTML-specific element types
+            for obj in gc.get_objects():
+                if hasattr(obj, '__class__') and hasattr(obj.__class__, '__name__'):
+                    class_name = obj.__class__.__name__
+                    if class_name in ('HtmlElement', 'FormElement', 'InputElement',
+                                    'SelectElement', 'TextareaElement', 'CheckboxGroup',
+                                    'RadioGroup', 'MultipleSelectOptions', 'FieldsDict') and hasattr(obj, 'clear'):
+                        try:
+                            obj.clear()
+                        except (AttributeError, TypeError):
+                            pass
+
+            current_memory = process.memory_info().rss / 1024 / 1024
+            logger.debug(f"After lxml.html cleanup - Memory usage: {current_memory:,.2f} MB")
+    except (ImportError, AttributeError):
+        logger.debug("lxml cleanup not applicable")
+    
+    # 8. Clear JSON parser caches if applicable
+    try:
+        # Check if json module is being used and try to clear its cache
+        json_module = sys.modules.get('json')
+        if json_module and hasattr(json_module, '_default_encoder'):
+            json_module._default_encoder.markers.clear()
+            current_memory = process.memory_info().rss / 1024 / 1024
+            logger.debug(f"After JSON parser cleanup - Memory usage: {current_memory:,.2f} MB")
+    except (AttributeError, KeyError):
+        logger.debug("JSON cleanup not applicable")
+    
+    # 9. Force Python's memory allocator to release unused memory
+    try:
+        if hasattr(sys, 'pypy_version_info'):
+            # PyPy has different memory management
+            gc.collect()
+        else:
+            # CPython - try to release unused memory
+            ctypes.pythonapi.PyGC_Collect()
+            current_memory = process.memory_info().rss / 1024 / 1024
+            logger.debug(f"After PyGC_Collect - Memory usage: {current_memory:,.2f} MB")
+    except (AttributeError, TypeError):
+        logger.debug("PyGC_Collect not supported")
+    
+    # 10. Clear Flask-specific caches if applicable
+    if app:
+        try:
+            # Clear Flask caches if they exist
+            for key in list(app.config.get('_cache', {}).keys()):
+                app.config['_cache'].pop(key, None)
+            
+            # Clear Jinja2 template cache if available
+            if hasattr(app, 'jinja_env') and hasattr(app.jinja_env, 'cache'):
+                app.jinja_env.cache.clear()
+            
+            current_memory = process.memory_info().rss / 1024 / 1024
+            logger.debug(f"After Flask cache clear - Memory usage: {current_memory:,.2f} MB")
+        except (AttributeError, KeyError):
+            logger.debug("No Flask cache to clear")
+    
+    # Final garbage collection pass
+    gc.collect()
+    libc.malloc_trim(0)
+    
+    # Log final memory usage
+    final_memory = process.memory_info().rss / 1024 / 1024
+    logger.info(f"Memory cleanup completed - Final memory usage: {final_memory:,.2f} MB")
+    return "cleaned"