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
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
|
# Copyright (C) 2001-2008 by the Free Software Foundation, Inc.
#
# 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 2
# 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.
"""Reading and writing message objects and message metadata.
"""
# enqueue() and dequeue() are not symmetric. enqueue() takes a Message
# object. dequeue() returns a email.Message object tree.
#
# Message metadata is represented internally as a Python dictionary. Keys and
# values must be strings. When written to a queue directory, the metadata is
# written into an externally represented format, as defined here. Because
# components of the Mailman system may be written in something other than
# Python, the external interchange format should be chosen based on what those
# other components can read and write.
#
# Most efficient, and recommended if everything is Python, is Python marshal
# format. Also supported by default is Berkeley db format (using the default
# bsddb module compiled into your Python executable -- usually Berkeley db
# 2), and rfc822 style plain text. You can write your own if you have other
# needs.
import os
import sha
import time
import email
import errno
import cPickle
import marshal
from Mailman import mm_cfg
from Mailman import Utils
from Mailman import Message
from Mailman.Logging.Syslog import syslog
# 20 bytes of all bits set, maximum sha.digest() value
shamax = 0xffffffffffffffffffffffffffffffffffffffffL
try:
True, False
except NameError:
True = 1
False = 0
# This flag causes messages to be written as pickles (when True) or text files
# (when False). Pickles are more efficient because the message doesn't need
# to be re-parsed every time it's unqueued, but pickles are not human readable.
SAVE_MSGS_AS_PICKLES = True
# Small increment to add to time in case two entries have the same time. This
# prevents skipping one of two entries with the same time until the next pass.
DELTA = .0001
# We count the number of times a file has been moved to .bak and recovered.
# In order to prevent loops and a message flood, when the count reaches this
# value, we move the file to the shunt queue as a .psv.
MAX_BAK_COUNT = 3
class Switchboard:
def __init__(self, whichq, slice=None, numslices=1, recover=False):
self.__whichq = whichq
# Create the directory if it doesn't yet exist.
# FIXME
omask = os.umask(0) # rwxrws---
try:
try:
os.mkdir(self.__whichq, 0770)
except OSError, e:
if e.errno <> errno.EEXIST: raise
finally:
os.umask(omask)
# Fast track for no slices
self.__lower = None
self.__upper = None
# BAW: test performance and end-cases of this algorithm
if numslices <> 1:
self.__lower = ((shamax+1) * slice) / numslices
self.__upper = (((shamax+1) * (slice+1)) / numslices) - 1
if recover:
self.recover_backup_files()
def whichq(self):
return self.__whichq
def enqueue(self, _msg, _metadata={}, **_kws):
# Calculate the SHA hexdigest of the message to get a unique base
# filename. We're also going to use the digest as a hash into the set
# of parallel qrunner processes.
data = _metadata.copy()
data.update(_kws)
listname = data.get('listname', '--nolist--')
# Get some data for the input to the sha hash
now = time.time()
if SAVE_MSGS_AS_PICKLES and not data.get('_plaintext'):
protocol = 1
msgsave = cPickle.dumps(_msg, protocol)
else:
protocol = 0
msgsave = cPickle.dumps(str(_msg), protocol)
hashfood = msgsave + listname + `now`
# Encode the current time into the file name for FIFO sorting in
# files(). The file name consists of two parts separated by a `+':
# the received time for this message (i.e. when it first showed up on
# this system) and the sha hex digest.
#rcvtime = data.setdefault('received_time', now)
rcvtime = data.setdefault('received_time', now)
filebase = `rcvtime` + '+' + sha.new(hashfood).hexdigest()
filename = os.path.join(self.__whichq, filebase + '.pck')
tmpfile = filename + '.tmp'
# Always add the metadata schema version number
data['version'] = mm_cfg.QFILE_SCHEMA_VERSION
# Filter out volatile entries
for k in data.keys():
if k.startswith('_'):
del data[k]
# We have to tell the dequeue() method whether to parse the message
# object or not.
data['_parsemsg'] = (protocol == 0)
# Write to the pickle file the message object and metadata.
omask = os.umask(007) # -rw-rw----
try:
fp = open(tmpfile, 'w')
try:
fp.write(msgsave)
cPickle.dump(data, fp, protocol)
fp.flush()
os.fsync(fp.fileno())
finally:
fp.close()
finally:
os.umask(omask)
os.rename(tmpfile, filename)
return filebase
def dequeue(self, filebase):
# Calculate the filename from the given filebase.
filename = os.path.join(self.__whichq, filebase + '.pck')
backfile = os.path.join(self.__whichq, filebase + '.bak')
# Read the message object and metadata.
fp = open(filename)
# Move the file to the backup file name for processing. If this
# process crashes uncleanly the .bak file will be used to re-instate
# the .pck file in order to try again.
os.rename(filename, backfile)
try:
msg = cPickle.load(fp)
data = cPickle.load(fp)
finally:
fp.close()
if data.get('_parsemsg'):
msg = email.message_from_string(msg, Message.Message)
return msg, data
def finish(self, filebase, preserve=False):
bakfile = os.path.join(self.__whichq, filebase + '.bak')
try:
if preserve:
psvfile = os.path.join(mm_cfg.BADQUEUE_DIR, filebase + '.psv')
# Create the directory if it doesn't yet exist.
# Copied from __init__.
omask = os.umask(0) # rwxrws---
try:
try:
os.mkdir(mm_cfg.BADQUEUE_DIR, 0770)
except OSError, e:
if e.errno <> errno.EEXIST: raise
finally:
os.umask(omask)
os.rename(bakfile, psvfile)
else:
os.unlink(bakfile)
except EnvironmentError, e:
syslog('error', 'Failed to unlink/preserve backup file: %s',
bakfile)
def files(self, extension='.pck'):
times = {}
lower = self.__lower
upper = self.__upper
for f in os.listdir(self.__whichq):
# By ignoring anything that doesn't end in .pck, we ignore
# tempfiles and avoid a race condition.
filebase, ext = os.path.splitext(f)
if ext <> extension:
continue
when, digest = filebase.split('+')
# Throw out any files which don't match our bitrange. BAW: test
# performance and end-cases of this algorithm. MAS: both
# comparisons need to be <= to get complete range.
if lower is None or (lower <= long(digest, 16) <= upper):
key = float(when)
while times.has_key(key):
key += DELTA
times[key] = filebase
# FIFO sort
keys = times.keys()
keys.sort()
return [times[k] for k in keys]
def recover_backup_files(self):
# Move all .bak files in our slice to .pck. It's impossible for both
# to exist at the same time, so the move is enough to ensure that our
# normal dequeuing process will handle them. We keep count in
# _bak_count in the metadata of the number of times we recover this
# file. When the count reaches MAX_BAK_COUNT, we move the .bak file
# to a .psv file in the shunt queue.
for filebase in self.files('.bak'):
src = os.path.join(self.__whichq, filebase + '.bak')
dst = os.path.join(self.__whichq, filebase + '.pck')
fp = open(src, 'rb+')
try:
try:
msg = cPickle.load(fp)
data_pos = fp.tell()
data = cPickle.load(fp)
except Exception, s:
# If unpickling throws any exception, just log and
# preserve this entry
syslog('error', 'Unpickling .bak exception: %s\n'
+ 'preserving file: %s', s, filebase)
self.finish(filebase, preserve=True)
else:
data['_bak_count'] = data.setdefault('_bak_count', 0) + 1
fp.seek(data_pos)
if data.get('_parsemsg'):
protocol = 0
else:
protocol = 1
cPickle.dump(data, fp, protocol)
fp.truncate()
fp.flush()
os.fsync(fp.fileno())
if data['_bak_count'] >= MAX_BAK_COUNT:
syslog('error',
'.bak file max count, preserving file: %s',
filebase)
self.finish(filebase, preserve=True)
else:
os.rename(src, dst)
finally:
fp.close()
|
