New subprocess utility function: check_call. Closes #1071764.
diff --git a/Doc/lib/libsubprocess.tex b/Doc/lib/libsubprocess.tex
index 308c1dd..5a2a835 100644
--- a/Doc/lib/libsubprocess.tex
+++ b/Doc/lib/libsubprocess.tex
@@ -120,7 +120,7 @@
\subsubsection{Convenience Functions}
-This module also defines one shortcut function:
+This module also defines two shortcut functions:
\begin{funcdesc}{call}{*popenargs, **kwargs}
Run command with arguments. Wait for command to complete, then
@@ -133,6 +133,18 @@
\end{verbatim}
\end{funcdesc}
+\begin{funcdesc}{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
+\member{errno} attribute.
+
+The arguments are the same as for the Popen constructor. Example:
+
+\begin{verbatim}
+ check_call(["ls", "-l"])
+\end{verbatim}
+\end{funcdesc}
\subsubsection{Exceptions}
@@ -149,6 +161,10 @@
A \exception{ValueError} will be raised if \class{Popen} is called
with invalid arguments.
+check_call() will raise \exception{CalledProcessError}, which is a
+subclass of \exception{OSError}, if the called process returns a
+non-zero return code.
+
\subsubsection{Security}
diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 40b04fe..da0c31b 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -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
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index b26d40c..52f4d47 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -44,6 +44,22 @@
"import sys; sys.exit(47)"])
self.assertEqual(rc, 47)
+ def test_check_call_zero(self):
+ # check_call() function with zero return code
+ rc = subprocess.check_call([sys.executable, "-c",
+ "import sys; sys.exit(0)"])
+ self.assertEqual(rc, 0)
+
+ def test_check_call_nonzero(self):
+ # check_call() function with non-zero return code
+ try:
+ subprocess.check_call([sys.executable, "-c",
+ "import sys; sys.exit(47)"])
+ except subprocess.CalledProcessError, e:
+ self.assertEqual(e.errno, 47)
+ else:
+ self.fail("Expected CalledProcessError")
+
def test_call_kwargs(self):
# call() function with keyword args
newenv = os.environ.copy()