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
|
# Copyright (C) 2009 W. Trevor King <wking@drexel.edu>
#
# 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.
"""
Functions for running external commands in subprocesses.
"""
from subprocess import Popen, PIPE
import sys
import libbe
from encoding import get_encoding
if libbe.TESTING == True:
import doctest
_MSWINDOWS = sys.platform == 'win32'
_POSIX = not _MSWINDOWS
if _POSIX == True:
import os
import select
class CommandError(Exception):
def __init__(self, command, status, stdout=None, stderr=None):
strerror = ['Command failed (%d):\n %s\n' % (status, stderr),
'while executing\n %s' % command]
Exception.__init__(self, '\n'.join(strerror))
self.command = command
self.status = status
self.stdout = stdout
self.stderr = stderr
def invoke(args, stdin=None, stdout=PIPE, stderr=PIPE, expect=(0,),
cwd=None, unicode_output=True, verbose=False, encoding=None):
"""
expect should be a tuple of allowed exit codes. cwd should be
the directory from which the command will be executed. When
unicode_output == True, convert stdout and stdin strings to
unicode before returing them.
"""
if cwd == None:
cwd = '.'
if verbose == True:
print >> sys.stderr, '%s$ %s' % (cwd, ' '.join(args))
try :
if _POSIX:
q = Popen(args, stdin=PIPE, stdout=stdout, stderr=stderr, cwd=cwd)
else:
assert _MSWINDOWS==True, 'invalid platform'
# win32 don't have os.execvp() so have to run command in a shell
q = Popen(args, stdin=PIPE, stdout=stdout, stderr=stderr,
shell=True, cwd=cwd)
except OSError, e:
raise CommandError(args, status=e.args[0], stderr=e)
stdout,stderr = q.communicate(input=stdin)
status = q.wait()
if unicode_output == True:
if encoding == None:
encoding = get_encoding()
if stdout != None:
stdout = unicode(stdout, encoding)
if stderr != None:
stderr = unicode(stderr, encoding)
if verbose == True:
print >> sys.stderr, '%d\n%s%s' % (status, stdout, stderr)
if status not in expect:
raise CommandError(args, status, stdout, stderr)
return status, stdout, stderr
class Pipe (object):
"""
Simple interface for executing POSIX-style pipes based on the
subprocess module. The only complication is the adaptation of
subprocess.Popen._comminucate to listen to the stderrs of all
processes involved in the pipe, as well as the terminal process'
stdout. There are two implementations of Pipe._communicate, one
for MS Windows, and one for POSIX systems. The MS Windows
implementation is currently untested.
>>> p = Pipe([['find', '/etc/'], ['grep', '^/etc/ssh$']])
>>> p.stdout
'/etc/ssh\\n'
>>> p.status
1
>>> p.statuses
[1, 0]
>>> p.stderrs # doctest: +ELLIPSIS
[...find: ...: Permission denied..., '']
"""
def __init__(self, cmds, stdin=None):
# spawn processes
self._procs = []
for cmd in cmds:
if len(self._procs) != 0:
stdin = self._procs[-1].stdout
self._procs.append(Popen(cmd, stdin=stdin, stdout=PIPE, stderr=PIPE))
self.stdout,self.stderrs = self._communicate(input=None)
# collect process statuses
self.statuses = []
self.status = 0
for proc in self._procs:
self.statuses.append(proc.wait())
if self.statuses[-1] != 0:
self.status = self.statuses[-1]
# Code excerpted from subprocess.Popen._communicate()
if _MSWINDOWS == True:
def _communicate(self, input=None):
assert input == None, 'stdin != None not yet supported'
# listen to each process' stderr
threads = []
std_X_arrays = []
for proc in self._procs:
stderr_array = []
thread = Thread(target=proc._readerthread,
args=(proc.stderr, stderr_array))
thread.setDaemon(True)
thread.start()
threads.append(thread)
std_X_arrays.append(stderr_array)
# also listen to the last processes stdout
stdout_array = []
thread = Thread(target=proc._readerthread,
args=(proc.stdout, stdout_array))
thread.setDaemon(True)
thread.start()
threads.append(thread)
std_X_arrays.append(stdout_array)
# join threads as they die
for thread in threads:
thread.join()
# read output from reader threads
std_X_strings = []
for std_X_array in std_X_arrays:
std_X_strings.append(std_X_array[0])
stdout = std_X_strings.pop(-1)
stderrs = std_X_strings
return (stdout, stderrs)
else:
assert _POSIX==True, 'invalid platform'
def _communicate(self, input=None):
read_set = []
write_set = []
read_arrays = []
stdout = None # Return
stderr = None # Return
if self._procs[0].stdin:
# Flush stdio buffer. This might block, if the user has
# been writing to .stdin in an uncontrolled fashion.
self._procs[0].stdin.flush()
if input:
write_set.append(self._procs[0].stdin)
else:
self._procs[0].stdin.close()
for proc in self._procs:
read_set.append(proc.stderr)
read_arrays.append([])
read_set.append(self._procs[-1].stdout)
read_arrays.append([])
input_offset = 0
while read_set or write_set:
try:
rlist, wlist, xlist = select.select(read_set, write_set, [])
except select.error, e:
if e.args[0] == errno.EINTR:
continue
raise
if self._procs[0].stdin in wlist:
# When select has indicated that the file is writable,
# we can write up to PIPE_BUF bytes without risk
# blocking. POSIX defines PIPE_BUF >= 512
chunk = input[input_offset : input_offset + 512]
bytes_written = os.write(self.stdin.fileno(), chunk)
input_offset += bytes_written
if input_offset >= len(input):
self._procs[0].stdin.close()
write_set.remove(self._procs[0].stdin)
if self._procs[-1].stdout in rlist:
data = os.read(self._procs[-1].stdout.fileno(), 1024)
if data == '':
self._procs[-1].stdout.close()
read_set.remove(self._procs[-1].stdout)
read_arrays[-1].append(data)
for i,proc in enumerate(self._procs):
if proc.stderr in rlist:
data = os.read(proc.stderr.fileno(), 1024)
if data == '':
proc.stderr.close()
read_set.remove(proc.stderr)
read_arrays[i].append(data)
# All data exchanged. Translate lists into strings.
read_strings = []
for read_array in read_arrays:
read_strings.append(''.join(read_array))
stdout = read_strings.pop(-1)
stderrs = read_strings
return (stdout, stderrs)
if libbe.TESTING == True:
suite = doctest.DocTestSuite()
|
