Add helper funcs for debugging (#10997)

* Add helper funcs for debugging

* Exclude from coverage

* Raise error if not in debug

* Raise error if not in DEBUG mode

.gitignore

@@ -37,6 +37,11 @@ local_settings.py
 *.backup
 *.old
 
+# Files generated by profiling tools
+*.prof
+*.log
+*.sql
+
 # Files used for testing
 inventree-demo-dataset/
 inventree-data/

src/backend/InvenTree/InvenTree/profiling.py

@@ -0,0 +1,130 @@
+"""Helper functions for profiling InvenTree code.
+
+A set of decorators to assist with profiling functions and logging,
+which implement oft-repeated patterns used during development and debugging.
+
+Note: These functions are not to be used in production code.
+"""
+
+from functools import wraps
+
+
+def ensure_debug():
+    """Ensure that InvenTree is running in DEBUG mode."""
+    from django.conf import settings
+
+    if not settings.DEBUG:
+        raise RuntimeError('Profiling functions can only be used in DEBUG mode!')
+
+
+def time_function(func):  # pragma: no cover
+    """Decorator to time a function's execution duration.
+
+    Args:
+        func: Function to be timed
+    """
+
+    @wraps(func)
+    def wrapper(*args, **kwargs):
+        import time
+
+        ensure_debug()
+
+        start_time = time.time()
+        result = func(*args, **kwargs)
+        end_time = time.time()
+
+        duration = end_time - start_time
+        print(f"Function '{func.__name__}' executed in {duration:.6f} seconds.")
+
+        return result
+
+    return wrapper
+
+
+def profile_function(filename='profile.prof'):  # pragma: no cover
+    """Decorator to profile a function using cProfile.
+
+    Args:
+        func: Function to be profiled
+        filename: Output filename for the profiling data
+    """
+
+    def decorator(func):
+
+        @wraps(func)
+        def wrapper(*args, **kwargs):
+            import cProfile
+            import io
+            import pstats
+
+            ensure_debug()
+
+            pr = cProfile.Profile()
+            pr.enable()
+
+            result = func(*args, **kwargs)
+
+            pr.disable()
+            s = io.StringIO()
+            sortby = pstats.SortKey.CUMULATIVE
+            ps = pstats.Stats(pr, stream=s).sort_stats(sortby)
+            ps.dump_stats(filename)
+            print(s.getvalue())
+
+            return result
+
+        return wrapper
+
+    return decorator
+
+
+def log_slow_queries(
+    threshold: float = 0.01, n: int = 5, log_to_file: bool = True
+):  # pragma: no cover
+    """Decorator to log slow database queries in a Django view function.
+
+    Args:
+        func: Function to be decorated
+        threshold: Time threshold (in seconds) for logging slow queries
+        n: Number of slowest queries to log
+        log_to_file: Whether to log to a file or print to console
+    """
+
+    def decorator(func):
+
+        @wraps(func)
+        def wrapper(*args, **kwargs):
+            from django.db import connection
+
+            ensure_debug()
+
+            result = func(*args, **kwargs)
+
+            slow_queries = [
+                q for q in connection.queries if float(q.get('time', 0)) >= threshold
+            ]
+            slow_queries.sort(key=lambda x: float(x.get('time', 0)), reverse=True)
+
+            log_entries = []
+            for query in slow_queries[:n]:
+                log_entry = f'Time: {query["time"]}s | SQL: {query["sql"]}'
+                log_entries.append(log_entry)
+
+            if log_entries:
+                log_message = '\n'.join(log_entries)
+                if log_to_file:
+                    with open('slow_queries.log', 'w', encoding='utf-8') as f:
+                        f.write(f'Slow queries detected:\n{log_message}\n')
+                else:
+                    print(f'Slow queries detected:\n{log_message}')
+
+            return result
+
+        return wrapper
+
+    return decorator
+
+
+# Raise an exception if this file is imported outside of DEBUG mode
+ensure_debug()