X on zobjtrace

To know through which ZODB object A another ZODB object B is accessed.

zobjtrace

+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# Copyright (C) 2018-2020  Nexedi SA and Contributors.
+#                          Kirill Smelkov <kirr@nexedi.com>
+#
+# This program is free software: you can Use, Study, Modify and Redistribute
+# it under the terms of the GNU General Public License version 3, or (at your
+# option) any later version, as published by the Free Software Foundation.
+#
+# You can also Link and Combine this program with other software covered by
+# the terms of any of the Free Software licenses or any of the Open Source
+# Initiative approved licenses and Convey the resulting work. Corresponding
+# source of such a combination shall include the source code for all other
+# software used.
+#
+# This program is distributed WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+#
+# See COPYING file for full licensing terms.
+# See https://www.nexedi.com/licensing for rationale and options.
+"""zobjtrace is python interpreter that traces ZODB object access.
+
+XXX
+"""
+
+from __future__ import print_function, absolute_import
+
+
+# patch Persistent to trace access
+import persistent
+origPersistent = persistent.Persistent
+
+# TracePersistent is Persistent that traces through which persistent object an
+# persistent object was accessed.
+class TracePersistent(origPersistent):
+
+    def __getattribute__(self, name):
+        obj = origPersistent.__getattribute__(self, name)
+        if isinstance(obj, origPersistent):
+            traceAccess('get .%s' % name, self, obj)
+        return obj
+
+    def __setattr__(self, name, value):
+        origPersistent.__setattr__(self, name, value)
+        if isinstance(value, origPersistent):
+            traceAccess('set .%s' % name, self, value)
+
+    # XXX __delattr__
+
+    # XXX __getitem__ ?
+    # XXX __setitem__
+
+    # XXX __delitem__
+    # XXX __missing__
+
+    # XXX __iter__
+    # XXX __reversed__
+
+    # XXX __contains__
+
+
+    # XXX __get__/__set__/__delete__ ?
+
+persistent.Persistent = TracePersistent
+
+# XXX patch BTrees to trace item access
+
+
+# traceAccess traces access from persistent object a to b.
+def traceAccess(op, a, b):
+    assert isinstance(a, origPersistent)
+    assert isinstance(b, origPersistent)
+    #print('%s\tobj<%s|%s> -> obj<%s|%s>' %
+    #        (op, oidstr(a._p_oid), typeof(a), oidstr(b._p_oid), typeof(b)))
+    print('%s\t%s(%s) -> %s(%s)' %
+            (op, oidstr(a._p_oid), typeof(a), oidstr(b._p_oid), typeof(b)))
+
+
+# oidstr returns string representation of object ID.
+# it is either %d(ID) or ø if oid was not yet assigned.
+def oidstr(oid):
+    if oid is None:
+        return 'ø'
+    return '%d' % u64(oid)
+
+# u64 = ZODB.utils.u64, but we don't want to preimport ZODB yet
+import struct
+_oid_struct = struct.Struct('>Q')
+def u64(oid):
+    assert isinstance(oid, bytes)
+    assert len(oid) == 8
+    return _oid_struct.unpack(oid)[0]
+
+
+# typeof returns fully qualified type of object.
+def typeof(obj): # -> str
+    typ = type(obj)
+    return "%s.%s" % (typ.__module__, typ.__name__)
+
+
+
+# tail to pymain with already patched Persistent
+import sys
+from gpython import pymain
+
+def main():
+    # XXX sys.executable = sys.argv[0]
+    pymain(sys.argv[1:])
+
+
+if __name__ == '__main__':
+    main()