[Python-checkins] python/dist/src/Lib subprocess.py,1.11,1.12

[astrand at users.sourceforge.net]

Update of /cvsroot/python/python/dist/src/Lib
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv24099/d

Modified Files:
	subprocess.py 
Log Message:
New subprocess utility function: check_call. Closes #1071764.

Index: subprocess.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/subprocess.py,v
retrieving revision 1.11
retrieving revision 1.12
diff -u -d -r1.11 -r1.12
--- subprocess.py	5 Dec 2004 20:15:36 -0000	1.11
+++ subprocess.py	1 Jan 2005 09:36:34 -0000	1.12
@@ -133,6 +133,15 @@
 
     retcode = call(["ls", "-l"])
 
+check_call(*popenargs, **kwargs):
+    Run command with arguments.  Wait for command to complete.  If the
+    exit code was zero then return, otherwise raise
+    CalledProcessError.  The CalledProcessError object will have the
+    return code in the errno attribute.
+
+    The arguments are the same as for the Popen constructor.  Example:
+
+    check_call(["ls", "-l"])
 
 Exceptions
 ----------
@@ -148,6 +157,9 @@
 
 A ValueError will be raised if Popen is called with invalid arguments.
 
+check_call() will raise CalledProcessError, which is a subclass of
+OSError, if the called process returns a non-zero return code.
+
 
 Security
 --------
@@ -363,6 +375,13 @@
 import types
 import traceback
 
+# Exception classes used by this module.
+class CalledProcessError(OSError):
+    """This exception is raised when a process run by check_call() returns
+    a non-zero exit status.  The exit status will be stored in the
+    errno attribute.  This exception is a subclass of
+    OSError."""
+
 if mswindows:
     import threading
     import msvcrt
@@ -393,7 +412,7 @@
     import fcntl
     import pickle
 
-__all__ = ["Popen", "PIPE", "STDOUT", "call"]
+__all__ = ["Popen", "PIPE", "STDOUT", "call", "check_call", "CalledProcessError"]
 
 try:
     MAXFD = os.sysconf("SC_OPEN_MAX")
@@ -428,6 +447,25 @@
     return Popen(*popenargs, **kwargs).wait()
 
 
+def check_call(*popenargs, **kwargs):
+    """Run command with arguments.  Wait for command to complete.  If
+    the exit code was zero then return, otherwise raise
+    CalledProcessError.  The CalledProcessError object will have the
+    return code in the errno attribute.
+
+    The arguments are the same as for the Popen constructor.  Example:
+
+    check_call(["ls", "-l"])
+    """
+    retcode = call(*popenargs, **kwargs)
+    cmd = kwargs.get("args")
+    if cmd is None:
+        cmd = popenargs[0]
+    if retcode:
+        raise CalledProcessError(retcode, "Command %s returned non-zero exit status" % cmd)
+    return retcode
+
+
 def list2cmdline(seq):
     """
     Translate a sequence of arguments into a command line