CODEWITHSUNDEEP
pythonfile
webminal.org
webminal.org

Reputation: 47296

How to fail with error message "Too many open files in python"

I created 10000 files - my default limit was " ulimit -n 1024" - I expected following script to fail with a message like "Too many files open" , but it didn't fail. (/tmp/files has 10000 files)

Any thoughts on where am i going wrong? 

import os
listfiles=os.listdir('/tmp/files')
count=0
f=''
for file in listfiles:
        fn=f+str(count)
        fn=open(file,'w')
        fn.write('hello')
        print 'file=',file
        count=count+1

print count

Upvotes: 1

Views: 1594

Answers (3)

Not_a_Golfer
Not_a_Golfer

Reputation: 49265

You loop brings each file object out of scope, so they are quickly closed, and you don't have more than 1 alive at any time (technically you might have because of GC delay). Just append each file object to a global list and you'll be good crashing your script! :)

Upvotes: 2

Ignacio Vazquez-Abrams
Ignacio Vazquez-Abrams

Reputation: 799310

Rebinding fn causes the reference count of the old object to drop to 0, causing it to be reaped. Append the files to a list instead.

Upvotes: 2

John La Rooy
John La Rooy

Reputation: 304433

for file in listfiles:
        fn = f+str(count)    # what is this supposed to do?
        fn = open(file,'w')  # old file handle gets garbage collected and closed
        fn.write('hello')
        print 'file=',file
        count = count + 1

Every time you rebind fn the previous file gets closed. It's possible that in jython for example the file doesn't get closed immediately, but it very likely will still be garbarge collected and closed before you exceed the 1024 file limit

Try storing the file objects in a list like this:

import os
listfiles = os.listdir('/tmp/files')
count = 0
f = ''
fn = []
for file in listfiles:
        fn.append(open(file,'w'))
        fn[-1].write('hello')
        print 'file=',file
        count = count + 1

print count

Upvotes: 2

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