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
|
# Copyright (C) 2011, 2012 Lars Wirzenius
# Copyright (C) 2012 Codethink Limited
#
# 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.
import errno
import fcntl
import logging
import os
import select
import subprocess
import cliapp
def runcmd(argv, *args, **kwargs):
'''Run external command or pipeline.
Example: ``runcmd(['grep', 'foo'], ['wc', '-l'],
feed_stdin='foo\nbar\n')``
Return the standard output of the command.
Raise ``cliapp.AppException`` if external command returns
non-zero exit code. ``*args`` and ``**kwargs`` are passed
onto ``subprocess.Popen``.
'''
if 'ignore_fail' in kwargs:
ignore_fail = kwargs['ignore_fail']
del kwargs['ignore_fail']
else:
ignore_fail = False
exit, out, err = runcmd_unchecked(argv, *args, **kwargs)
if exit != 0:
msg = 'Command failed: %s\n%s' % (' '.join(argv), err)
if ignore_fail:
logging.info(msg)
else:
logging.error(msg)
raise cliapp.AppException(msg)
return out
def runcmd_unchecked(argv, *argvs, **kwargs):
'''Run external command or pipeline.
Return the exit code, and contents of standard output and error
of the command.
See also ``runcmd``.
'''
argvs = [argv] + list(argvs)
logging.debug('run external command: %s' % repr(argvs))
def pop_kwarg(name, default):
if name in kwargs:
value = kwargs[name]
del kwargs[name]
return value
else:
return default
feed_stdin = pop_kwarg('feed_stdin', '')
pipe_stdin = pop_kwarg('stdin', subprocess.PIPE)
pipe_stdout = pop_kwarg('stdout', subprocess.PIPE)
pipe_stderr = pop_kwarg('stderr', subprocess.PIPE)
try:
pipeline = _build_pipeline(argvs,
pipe_stdin,
pipe_stdout,
pipe_stderr,
kwargs)
return _run_pipeline(pipeline, feed_stdin, pipe_stdin,
pipe_stdout, pipe_stderr)
except OSError, e: # pragma: no cover
if e.errno == errno.ENOENT and e.filename is None:
e.filename = argv[0]
raise e
else:
raise
def _build_pipeline(argvs, pipe_stdin, pipe_stdout, pipe_stderr, kwargs):
procs = []
for i, argv in enumerate(argvs):
if i == 0 and i == len(argvs) - 1:
stdin = pipe_stdin
stdout = pipe_stdout
stderr = pipe_stderr
elif i == 0:
stdin = pipe_stdin
stdout = subprocess.PIPE
stderr = pipe_stderr
elif i == len(argv) - 1:
stdin = procs[-1].stdout
stdout = pipe_stdout
stderr = pipe_stderr
else:
stdin = procs[-1].stdout
stdout = subprocess.PIPE
stderr = pipe_stderr
p = subprocess.Popen(argv, stdin=stdin, stdout=stdout,
stderr=stderr, close_fds=True, **kwargs)
procs.append(p)
return procs
def _run_pipeline(procs, feed_stdin, pipe_stdin, pipe_stdout, pipe_stderr):
logging.debug('PIPE=%d' % subprocess.PIPE)
logging.debug('STDOUT=%d' % subprocess.STDOUT)
logging.debug('pipe_stdin=%s' % repr(pipe_stdin))
logging.debug('pipe_stdout=%s' % repr(pipe_stdout))
logging.debug('pipe_stderr=%s' % repr(pipe_stderr))
stdout_eof = False
stderr_eof = False
out = []
err = []
pos = 0
io_size = 1024
def set_nonblocking(fd):
logging.debug('set nonblocking fd=%d' % fd)
flags = fcntl.fcntl(fd, fcntl.F_GETFL, 0)
flags = flags | os.O_NONBLOCK
fcntl.fcntl(fd, fcntl.F_SETFL, flags)
if feed_stdin and pipe_stdin == subprocess.PIPE:
set_nonblocking(procs[0].stdin.fileno())
if pipe_stdout == subprocess.PIPE:
set_nonblocking(procs[-1].stdout.fileno())
if pipe_stderr == subprocess.PIPE:
set_nonblocking(procs[-1].stderr.fileno())
def still_running():
for p in procs:
p.poll()
for p in procs:
if p.returncode is None:
return True
if pipe_stdout == subprocess.PIPE and not stdout_eof:
return True
if pipe_stderr == subprocess.PIPE and not stderr_eof:
return True # pragma: no cover
return False
while still_running():
rlist = []
if not stdout_eof and pipe_stdout == subprocess.PIPE:
rlist.append(procs[-1].stdout)
if not stderr_eof and pipe_stderr == subprocess.PIPE:
rlist.append(procs[-1].stderr)
wlist = []
if pipe_stdin == subprocess.PIPE and pos < len(feed_stdin):
wlist.append(procs[0].stdin)
if rlist or wlist:
r, w, x = select.select(rlist, wlist, [])
else:
break # Let's not busywait waiting for processes to die.
if procs[0].stdin in w and pos < len(feed_stdin):
data = feed_stdin[pos : pos+io_size]
procs[0].stdin.write(data)
pos += len(data)
if pos >= len(feed_stdin):
procs[0].stdin.close()
if procs[-1].stdout in r:
data = procs[-1].stdout.read(io_size)
if data:
out.append(data)
else:
stdout_eof = True
if procs[-1].stderr in r:
data = procs[-1].stderr.read(io_size)
if data:
err.append(data)
else:
stderr_eof = True
while still_running():
for p in procs:
if p.returncode is None:
logging.debug('Waiting for child pid=%d to terminate' % p.pid)
p.wait()
return procs[-1].returncode, ''.join(out), ''.join(err)
|
