green: subprocess: Popen.wait accepts new `timeout` kwarg

As in Python 3.3 http://docs.python.org/3.3/library/subprocess.html#subprocess.Popen.wait
https://bitbucket.org/eventlet/eventlet/issue/89/add-a-timeout-argument-to-subprocesspopen
https://bitbucket.org/eventlet/eventlet/pull-request/30

2 files changed, 51 insertions, 3 deletions

diff --git a/eventlet/green/subprocess.py b/eventlet/green/subprocess.py
index c1cc9b3..4e93836 100644
--- a/eventlet/green/subprocess.py
+++ b/eventlet/green/subprocess.py
@@ -1,5 +1,6 @@
 import errno
 import new
+import time
 
 import eventlet
 from eventlet import greenio
@@ -10,6 +11,23 @@ from eventlet.green import select
 patcher.inject('subprocess', globals(), ('select', select))
 subprocess_orig = __import__("subprocess")
 
+
+if getattr(subprocess_orig, 'TimeoutExpired', None) is None:
+    # Backported from Python 3.3.
+    # https://bitbucket.org/eventlet/eventlet/issue/89
+    class TimeoutExpired(Exception):
+        """This exception is raised when the timeout expires while waiting for
+        a child process.
+        """
+        def __init__(self, cmd, output=None):
+            self.cmd = cmd
+            self.output = output
+
+        def __str__(self):
+            return ("Command '%s' timed out after %s seconds" %
+                    (self.cmd, self.timeout))
+
+
 # This is the meat of this module, the green version of Popen.
 class Popen(subprocess_orig.Popen):
     """eventlet-friendly version of subprocess.Popen"""
@@ -21,9 +39,10 @@ class Popen(subprocess_orig.Popen):
     # non-blocking I/O, don't even bother overriding it on Windows.
     if not subprocess_orig.mswindows:
         def __init__(self, args, bufsize=0, *argss, **kwds):
+            self.args = args
             # Forward the call to base-class constructor
             subprocess_orig.Popen.__init__(self, args, 0, *argss, **kwds)
-            # Now wrap the pipes, if any. This logic is loosely borrowed from 
+            # Now wrap the pipes, if any. This logic is loosely borrowed from
             # eventlet.processes.Process.run() method.
             for attr in "stdin", "stdout", "stderr":
                 pipe = getattr(self, attr)
@@ -32,14 +51,18 @@ class Popen(subprocess_orig.Popen):
                     setattr(self, attr, wrapped_pipe)
         __init__.__doc__ = subprocess_orig.Popen.__init__.__doc__
 
-    def wait(self, check_interval=0.01):
+    def wait(self, timeout=None, check_interval=0.01):
         # Instead of a blocking OS call, this version of wait() uses logic
         # borrowed from the eventlet 0.2 processes.Process.wait() method.
+        if timeout is not None:
+            endtime = time.time() + timeout
         try:
             while True:
                 status = self.poll()
                 if status is not None:
                     return status
+                if timeout is not None and time.time() > endtime:
+                    raise TimeoutExpired(self.args)
                 eventlet.sleep(check_interval)
         except OSError, e:
             if e.errno == errno.ECHILD:
@@ -52,7 +75,7 @@ class Popen(subprocess_orig.Popen):
 
     if not subprocess_orig.mswindows:
         # don't want to rewrite the original _communicate() method, we
-        # just want a version that uses eventlet.green.select.select() 
+        # just want a version that uses eventlet.green.select.select()
         # instead of select.select().
         try:
             _communicate = new.function(subprocess_orig.Popen._communicate.im_func.func_code,
diff --git a/tests/subprocess_test.py b/tests/subprocess_test.py
new file mode 100644
index 0000000..b323ffa
--- /dev/null
+++ b/tests/subprocess_test.py
@@ -0,0 +1,25 @@
+import eventlet
+from eventlet.green import subprocess
+import eventlet.patcher
+import os
+import sys
+import time
+original_subprocess = eventlet.patcher.original('subprocess')
+
+
+def test_subprocess_wait():
+	# https://bitbucket.org/eventlet/eventlet/issue/89
+	# In Python 3.3 subprocess.Popen.wait() method acquired `timeout`
+	# argument.
+	# RHEL backported it to their Python 2.6 package.
+	p = subprocess.Popen([sys.executable,
+	                     "-c", "import time; time.sleep(0.5)"])
+	ok = False
+	t1 = time.time()
+	try:
+		p.wait(timeout=0.1)
+	except subprocess.TimeoutExpired:
+		ok = True
+	tdiff = time.time() - t1
+	assert ok == True, 'did not raise subprocess.TimeoutExpired'
+	assert 0.1 <= tdiff <= 0.2, 'did not stop within allowed time'