1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
|
# Authors:
# Jason Gerard DeRose <jderose@redhat.com>
#
# Copyright (C) 2008 Red Hat
# see file 'COPYING' for use and warranty information
#
# 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; version 2 only
#
# 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
"""
Base classes for all backed-end plugins.
"""
import threading
import plugable
from errors2 import PublicError, InternalError, CommandError
from request import context, Connection, destroy_context
class Backend(plugable.Plugin):
"""
Base class for all backend plugins.
"""
__proxy__ = False # Backend plugins are not wrapped in a PluginProxy
class Connectible(Backend):
# Override in subclass:
connection_klass = None
def connect(self, *args, **kw):
"""
Create thread-local connection.
"""
if hasattr(context, self.name):
raise StandardError(
"connection 'context.%s' already exists in thread %r" % (
self.name, threading.currentThread().getName()
)
)
if not issubclass(self.connection_klass, Connection):
raise ValueError(
'%s.connection_klass must be a request.Connection subclass' % self.name
)
conn = self.connection_klass(*args, **kw)
setattr(context, self.name, conn)
assert self.conn is conn.conn
def isconnected(self):
"""
Return ``True`` if thread-local connection on `request.context` exists.
"""
return hasattr(context, self.name)
def __get_conn(self):
"""
Return thread-local connection.
"""
if not hasattr(context, self.name):
raise AttributeError('no context.%s in thread %r' % (
self.name, threading.currentThread().getName())
)
return getattr(context, self.name).conn
conn = property(__get_conn)
class Executioner(Backend):
def execute(self, name, *args, **options):
error = None
try:
if name not in self.Command:
raise CommandError(name=name)
result = self.Command[name](*args, **options)
except PublicError, e:
error = e
except StandardError, e:
self.exception(
'non-public: %s: %s', e.__class__.__name__, str(e)
)
error = InternalError()
destroy_context()
if error is None:
return result
assert isinstance(error, PublicError)
raise error
|