fix examples/processes.py to use gevent.subprocess

examples/processes.py

 #!/usr/bin/env python
-"""An example on how to communicate with a subprocess.
-
-Written by Marcus Cavanaugh.
-See http://groups.google.com/group/gevent/browse_thread/thread/7fca7230db0509f6
-where it was first posted.
-"""
-
 import gevent
-from gevent import socket
-
-import subprocess
-import errno
-import sys
-import os
-import fcntl
-
-
-def popen_communicate(args, data=''):
-    """Communicate with the process non-blockingly."""
-    p = subprocess.Popen(args, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
-    fcntl.fcntl(p.stdin, fcntl.F_SETFL, os.O_NONBLOCK)  # make the file nonblocking
-    fcntl.fcntl(p.stdout, fcntl.F_SETFL, os.O_NONBLOCK)  # make the file nonblocking
-
-    bytes_total = len(data)
-    bytes_written = 0
-    while bytes_written < bytes_total:
-        try:
-            # p.stdin.write() doesn't return anything, so use os.write.
-            bytes_written += os.write(p.stdin.fileno(), data[bytes_written:])
-        except IOError:
-            ex = sys.exc_info()[1]
-            if ex.args[0] != errno.EAGAIN:
-                raise
-            sys.exc_clear()
-        socket.wait_write(p.stdin.fileno())
-
-    p.stdin.close()
-
-    chunks = []
-
-    while True:
-        try:
-            chunk = p.stdout.read(4096)
-            if not chunk:
-                break
-            chunks.append(chunk)
-        except IOError:
-            ex = sys.exc_info()[1]
-            if ex[0] != errno.EAGAIN:
-                raise
-            sys.exc_clear()
-        socket.wait_read(p.stdout.fileno())
+from gevent import subprocess
 
-    p.stdout.close()
-    return ''.join(chunks)
 
+# run 2 jobs in parallel
+p1 = subprocess.Popen(['uname'], stdout=subprocess.PIPE)
+p2 = subprocess.Popen(['finger'], stdout=subprocess.PIPE)
 
-if __name__ == '__main__':
-    # run 2 jobs in parallel
-    job1 = gevent.spawn(popen_communicate, 'uname')
-    job2 = gevent.spawn(popen_communicate, 'netstat')
+job1 = gevent.spawn(p1.stdout.read)
+job2 = gevent.spawn(p2.stdout.read)
 
-    # wait for them to complete. stop waiting after 2 seconds
-    gevent.joinall([job1, job2], timeout=5)
+# wait for them to complete. stop waiting after 2 seconds
+gevent.joinall([job1, job2], timeout=5)
 
-    # print the results (if available)
-    if job1.ready():
-        print ('finger: %s bytes: %s' % (len(job1.value or ''), repr(job1.value)[:50]))
-    else:
-        print ('finger: job is still running')
-    if job2.ready():
-        print ('netstat: %s bytes: %s' % (len(job2.value or ''), repr(job2.value)[:50]))
-    else:
-        print ('netstat: job is still running')
+# print the results (if available)
+if job1.ready():
+    print ('finger: %s bytes: %s' % (len(job1.value or ''), repr(job1.value)[:50]))
+else:
+    print ('finger: job is still running')
+if job2.ready():
+    print ('netstat: %s bytes: %s' % (len(job2.value or ''), repr(job2.value)[:50]))
+else:
+    print ('netstat: job is still running')