1 # Copyright (C) 2009-2010 W. Trevor King <wking@drexel.edu>
3 # This program is free software: you can redistribute it and/or modify
4 # it under the terms of the GNU General Public License as published by
5 # the Free Software Foundation, either version 3 of the License, or
6 # (at your option) any later version.
8 # This program is distributed in the hope that it will be useful,
9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 # GNU General Public License for more details.
13 # You should have received a copy of the GNU General Public License
14 # along with this program. If not, see <http://www.gnu.org/licenses/>.
16 # The author may be contacted at <wking@drexel.edu> on the Internet, or
17 # write to Trevor King, Drexel University, Physics Dept., 3141 Chestnut St.,
18 # Philadelphia PA 19104, USA.
20 """Functions for running external commands in subprocesses.
23 from subprocess import Popen, PIPE
27 class CommandError(Exception):
28 """Represent errors in command execution.
30 Instances are picklable (for passing through `multiprocessing.Queue`\s).
33 >>> a = CommandError('somefunc', 1, '', 'could not find "somefunc"')
34 >>> x = pickle.dumps(a)
35 >>> b = pickle.loads(x)
38 could not find "somefunc"
43 def __init__(self, command=None, status=None, stdout=None, stderr=None):
44 self.command = command
48 Exception.__init__(self, self.__str__())
50 def __getstate__(self):
53 def __setstate__(self, data):
54 self.__dict__.update(data)
58 "Command failed (%s):\n %s\n" % (self.status, self.stderr),
59 "while executing\n %s" % self.command,
63 def invoke(cmd_string, stdin=None, expect=(0,), cwd=None, verbose=False):
65 expect should be a tuple of allowed exit codes. cwd should be
66 the directory from which the command will be executed.
71 print >> sys.stderr, "%s$ %s" % (cwd, cmd_string)
73 if sys.platform != "win32" and False:
74 q = Popen(cmd_string, stdin=PIPE, stdout=PIPE, stderr=PIPE, cwd=cwd)
76 # win32 don't have os.execvp() so have to run command in a shell
77 q = Popen(cmd_string, stdin=PIPE, stdout=PIPE, stderr=PIPE,
80 raise CommandError(cmd_string, status=e.args[0], stdout="", stderr=e)
81 stdout,stderr = q.communicate(input=stdin)
84 print >> sys.stderr, "%d\n%s%s" % (status, stdout, stderr)
85 if status not in expect:
86 raise CommandError(cmd_string, status, stdout, stderr)
87 return status, stdout, stderr