From 91c6ab63a8de9a6dd6169bc8d4beaf996d324aec Mon Sep 17 00:00:00 2001
From: Neil Williams <neil@reddit.com>
Date: Mon, 10 Sep 2012 17:39:10 -0700
Subject: [PATCH] Locks: Pare down the traceback stored in the lock cache.

This reduces the size of the traceback data stored in the lock caches by
an order of magnitude. It is intended to help with the drastic imbalance
in lock cache network usage.
---
 r2/r2/lib/lock.py        |  5 +++--
 r2/r2/lib/utils/utils.py | 14 ++++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/r2/r2/lib/lock.py b/r2/r2/lib/lock.py
index dabf812b4..8b07b4180 100644
--- a/r2/r2/lib/lock.py
+++ b/r2/r2/lib/lock.py
@@ -24,10 +24,11 @@ from __future__ import with_statement
 from time import sleep
 from datetime import datetime
 from threading import local
-from traceback import format_stack
 import os
 import socket
 
+from r2.lib.utils import simple_traceback
+
 # thread-local storage for detection of recursive locks
 locks = local()
 
@@ -58,7 +59,7 @@ class MemcacheLock(object):
     def __enter__(self):
         start = datetime.now()
 
-        my_info = (reddit_host, reddit_pid, ''.join(format_stack()))
+        my_info = (reddit_host, reddit_pid, simple_traceback())
 
         #if this thread already has this lock, move on
         if self.key in self.locks:
diff --git a/r2/r2/lib/utils/utils.py b/r2/r2/lib/utils/utils.py
index b9ba1a5f3..dd4daffe4 100644
--- a/r2/r2/lib/utils/utils.py
+++ b/r2/r2/lib/utils/utils.py
@@ -20,7 +20,9 @@
 # Inc. All Rights Reserved.
 ###############################################################################
 
+import os
 import base64
+import traceback
 
 from urllib import unquote_plus
 from urllib2 import urlopen
@@ -1426,3 +1428,15 @@ def parse_http_basic(authorization_header):
     except TypeError:
         raise RequirementException
     return require_split(auth_data, 2, ":")
+
+
+def simple_traceback():
+    """Generate a pared-down traceback that's human readable but small."""
+
+    stack_trace = traceback.extract_stack(limit=7)[:-2]
+    return "\n".join(":".join((os.path.basename(filename),
+                               function_name,
+                               str(line_number),
+                              ))
+                     for filename, line_number, function_name, text
+                     in stack_trace)