1 files changed, 68 insertions, 0 deletions
diff --git a/tracing.py b/tracing.py
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+# Copyright (C) 2011  Lars Wirzenius <liw@liw.fi>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+
+'''Python debubbing log messages.
+
+This module provides a couple of functions for logging debug messages.
+It is sometimes practical to add a lot of debugging log messages to a
+program, but having them enabled all the time results in very large
+log files. Also, logging that much takes quite a bit of time.
+
+This module provides a way to turn such debugging or tracing messages
+on and off, based on the filename they occur in. For example:
+
+    import tracing
+    
+    tracing.trace_add_pattern('foobar')
+    tracing.trace_add_pattern('yeehaa')
+    
+    ...
+    
+    tracing.trace('start procedure')
+    tracing.trace('arg1=%s' % arg1)
+    tracing.trace('arg2=%s' % arg2)
+    
+Only calls that happen in files whose names contain 'foobar' or
+'yeehaa' will actually be logged. Pattern matching is based on
+substring checking only, no globbing or regexps, sorry.
+
+'''
+
+
+import logging
+import traceback
+
+
+trace_patterns = []
+
+
+def trace_add_pattern(pattern):
+    trace_patterns.append(pattern)
+    
+    
+def trace_clear_patterns():
+    del trace_patterns[:]
+
+
+def trace(msg):
+    frames = traceback.extract_stack(limit=2)
+    filename, lineno, funcname, text = frames[0]
+    for pattern in trace_patterns:
+        if pattern in filename:
+            logging.debug('%s:%s:%s: %s' % (filename, lineno, funcname, msg))
+            break
+