From 49af9b4e1a5ca3cc9eda8c6554d66480d449e313 Mon Sep 17 00:00:00 2001
From: Henrik Levkowetz <henrik@levkowetz.com>
Date: Thu, 23 Feb 2017 11:48:55 +0000
Subject: [PATCH] Added an affirm(statement_string) function, which acts like
 an assert, and lets us trigger an email message with traceback when the
 statement to affirm is False.  Use instead of assert if we still want the
 server to produce a response, even if something is seriously wrong.  -
 Legacy-Id: 12901

---
 ietf/utils/log.py | 48 ++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 37 insertions(+), 11 deletions(-)

diff --git a/ietf/utils/log.py b/ietf/utils/log.py
index ad783ca85..871e10870 100644
--- a/ietf/utils/log.py
+++ b/ietf/utils/log.py
@@ -1,20 +1,21 @@
 # Copyright The IETF Trust 2007, All Rights Reserved
 
-try:
-    import syslog
-    logger = syslog.syslog
-except ImportError:                     # import syslog will fail on Windows boxes
-    import logging
-    logging.basicConfig(filename='tracker.log',level=logging.INFO)
-    logger = logging.info
-
-    pass
-    
+import logging
 import inspect
 import os.path
 
+try:
+    import syslog
+    logfunc = syslog.syslog
+except ImportError:                     # import syslog will fail on Windows boxes
+    logging.basicConfig(filename='tracker.log',level=logging.INFO)
+    logfunc = logging.info
+    pass
+
 from django.conf import settings
 
+import debug                            # pyflakes:ignore
+
 def getclass(frame):
     cls = None
     argnames, varargs, varkw, defaults  = inspect.getargvalues(frame)
@@ -31,6 +32,7 @@ def getcaller():
     return (pmodule, pclass, pfunction, pfile, pline)
 
 def log(msg):
+    "Uses syslog by preference.  Logs the given calling point and message."
     if settings.SERVER_MODE == 'test':
         return
     if isinstance(msg, unicode):
@@ -45,6 +47,30 @@ def log(msg):
             where = " in " + func + "()"
     except IndexError:
         file, line, where = "/<UNKNOWN>", 0, ""
-    logger("ietf%s(%d)%s: %s" % (file, line, where, msg))
+    logfunc("ietf%s(%d)%s: %s" % (file, line, where, msg))
 
 
+
+logger = logging.getLogger('django')
+
+def affirm(statement):
+    """
+    This acts like an assertion.  It uses the django logger in order to send
+    the failed assertion and a backtrace as for an internal server error.
+
+    """
+    class Traceback():
+        pass
+    frame = inspect.stack()[1][0]
+    value = eval(statement, frame.f_globals, frame.f_locals)
+    if not value:
+        if settings.DEBUG is True:
+            raise AssertionError(statement)
+        else:
+            # build a simulated traceback object
+            tb = Traceback()
+            tb.tb_frame = frame
+            tb.tb_lasti = None
+            tb.tb_lineno = frame.f_lineno
+            tb.tb_next = None
+            logger.error("AssertionError: '%s'", statement, exc_info=(AssertionError, statement, tb), extra=frame.f_locals)