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From: Stephen Hansen on 17 Jun 2010 18:16
On 6/17/10 3:06 PM, Laurent Verweijen wrote:
>>
>> In your other thread you include an actual traceback:
>>
>> Traceback (most recent call last):
>> File "subchronous_test.py", line 5, in <module>
>> send_all(str(p), n)
>> File "/home/Somelauw/asynchronous.py", line 145, in send_all
>> while len(data):
>> TypeError: object of type 'int' has no len()
>>
>> The first argumetn to send_all should be the actual Popen subclass. The
>> second should be a string to send. I think that line really is intended
>> to be:
>>
>> send_all(p, str(n)) # assuming 'n' is say, the number 5.
>>
>
> You are right, I swapped the parameters, but even if I correct it, it
> still gives the second error.
>

General rule of thumb: its best to never use the word "still" when it
comes to debugging Python and exceptions, unless you are absolutely
certain the exception is precisely the same.

I don't doubt that you may still get an exception on send_all; but there
is no way you're getting the *same* exception (that specific type error:
attempting to call len() on an integer) if you corrected your arguments.

You're getting the EOFError, because you're never sending anything to
the subprocess. You're not getting anything from the subprocess because
it never receives anything to send back. And apparently there's an error
on send, which is causing that problem, but that error is...?

--

Stephen Hansen
... Also: Ixokai
... Mail: me+list/python (AT) ixokai (DOT) io
... Blog: http://meh.ixokai.io/

From: Laurent Verweijen on 18 Jun 2010 11:47
Op donderdag 17-06-2010 om 15:16 uur [tijdzone -0700], schreef Stephen
Hansen:
> On 6/17/10 3:06 PM, Laurent Verweijen wrote:
> >>
> >> In your other thread you include an actual traceback:
> >>
> >> Traceback (most recent call last):
> >> File "subchronous_test.py", line 5, in <module>
> >> send_all(str(p), n)
> >> File "/home/Somelauw/asynchronous.py", line 145, in send_all
> >> while len(data):
> >> TypeError: object of type 'int' has no len()
> >>
> >> The first argumetn to send_all should be the actual Popen subclass. The
> >> second should be a string to send. I think that line really is intended
> >> to be:
> >>
> >> send_all(p, str(n)) # assuming 'n' is say, the number 5.
> >>
> >
> > You are right, I swapped the parameters, but even if I correct it, it
> > still gives the second error.
> >
>
> General rule of thumb: its best to never use the word "still" when it
> comes to debugging Python and exceptions, unless you are absolutely
> certain the exception is precisely the same.
>
> I don't doubt that you may still get an exception on send_all; but there
> is no way you're getting the *same* exception (that specific type error:
> attempting to call len() on an integer) if you corrected your arguments.
>
> You're getting the EOFError, because you're never sending anything to
> the subprocess. You're not getting anything from the subprocess because
> it never receives anything to send back. And apparently there's an error
> on send, which is causing that problem, but that error is...?
>
My last post, contains the output after I fixed swapping the parameters
and everything you said.

I think there is still a problem with output that gets blocked.
Couldn't it be just that the output which gets blocked is causing this
error?

Anyway here is the output again:

python subchronous_test.py




Traceback (most recent call last):
File "increment.py", line 8, in <module>
n = int(raw_input(str(n))) + 1
EOFError: EOF when reading a line

close failed in file object destructor:
Error in sys.excepthook:

Original exception was:



And here are all 3 files concatenated:

# subchronous_test
import sys
from asynchronous import *
p = Popen(["python", "increment.py"], stdin=PIPE, stdout=PIPE, stderr =
sys.stderr)

for n in [5, 7, 10, 4]:
send_all(p, str(n))
print(recv_some(p))


# increment.py
import sys, traceback

try:
n = 0
while True:
n = int(raw_input(str(n))) + 1
except:
print >>sys.stderr, traceback.format_exc()


# asynchronous.py
## {{{ http://code.activestate.com/recipes/440554/ (r10)
import os
import subprocess
import errno
import time
import sys

PIPE = subprocess.PIPE

if subprocess.mswindows:
from win32file import ReadFile, WriteFile
from win32pipe import PeekNamedPipe
import msvcrt
else:
import select
import fcntl

class Popen(subprocess.Popen):
def recv(self, maxsize=None):
return self._recv('stdout', maxsize)

def recv_err(self, maxsize=None):
return self._recv('stderr', maxsize)

def send_recv(self, input='', maxsize=None):
return self.send(input), self.recv(maxsize),
self.recv_err(maxsize)

def get_conn_maxsize(self, which, maxsize):
if maxsize is None:
maxsize = 1024
elif maxsize < 1:
maxsize = 1
return getattr(self, which), maxsize

def _close(self, which):
getattr(self, which).close()
setattr(self, which, None)

if subprocess.mswindows:
def send(self, input):
if not self.stdin:
return None

try:
x = msvcrt.get_osfhandle(self.stdin.fileno())
(errCode, written) = WriteFile(x, input)
except ValueError:
return self._close('stdin')
except (subprocess.pywintypes.error, Exception), why:
if why[0] in (109, errno.ESHUTDOWN):
return self._close('stdin')
raise

return written

def _recv(self, which, maxsize):
conn, maxsize = self.get_conn_maxsize(which, maxsize)
if conn is None:
return None

try:
x = msvcrt.get_osfhandle(conn.fileno())
(read, nAvail, nMessage) = PeekNamedPipe(x, 0)
if maxsize < nAvail:
nAvail = maxsize
if nAvail > 0:
(errCode, read) = ReadFile(x, nAvail, None)
except ValueError:
return self._close(which)
except (subprocess.pywintypes.error, Exception), why:
if why[0] in (109, errno.ESHUTDOWN):
return self._close(which)
raise

if self.universal_newlines:
read = self._translate_newlines(read)
return read

else:
def send(self, input):
if not self.stdin:
return None

if not select.select([], [self.stdin], [], 0)[1]:
return 0

try:
written = os.write(self.stdin.fileno(), input)
except OSError, why:
if why[0] == errno.EPIPE: #broken pipe
return self._close('stdin')
raise

return written

def _recv(self, which, maxsize):
conn, maxsize = self.get_conn_maxsize(which, maxsize)
if conn is None:
return None

flags = fcntl.fcntl(conn, fcntl.F_GETFL)
if not conn.closed:
fcntl.fcntl(conn, fcntl.F_SETFL, flags| os.O_NONBLOCK)

try:
if not select.select([conn], [], [], 0)[0]:
return ''

r = conn.read(maxsize)
if not r:
return self._close(which)

if self.universal_newlines:
r = self._translate_newlines(r)
return r
finally:
if not conn.closed:
fcntl.fcntl(conn, fcntl.F_SETFL, flags)

message = "Other end disconnected!"

def recv_some(p, t=.1, e=1, tr=5, stderr=0):
if tr < 1:
tr = 1
x = time.time()+t
y = []
r = ''
pr = p.recv
if stderr:
pr = p.recv_err
while time.time() < x or r:
r = pr()
if r is None:
if e:
raise Exception(message)
else:
break
elif r:
y.append(r)
else:
time.sleep(max((x-time.time())/tr, 0))
return ''.join(y)

def send_all(p, data):
while len(data):
sent = p.send(data)
if sent is None:
raise Exception(message)
data = buffer(data, sent)

if __name__ == '__main__':
if sys.platform == 'win32':
shell, commands, tail = ('cmd', ('dir /w', 'echo HELLO WORLD'),
'\r\n')
else:
shell, commands, tail = ('sh', ('ls', 'echo HELLO WORLD'), '\n')

a = Popen(shell, stdin=PIPE, stdout=PIPE)
print recv_some(a),
for cmd in commands:
send_all(a, cmd + tail)
print recv_some(a),
send_all(a, 'exit' + tail)
print recv_some(a, e=0)
a.wait()
## end of http://code.activestate.com/recipes/440554/ }}}


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