Add Handles count functionality (Windows)

[giampaolo]

From [email protected] on August 11, 2011 12:40:01

It is often need to count/monitor a handles opened by process.
Now use Pythoncom for this. Code example:

def getHandleCount(self):
    pid = self.PID
    try:
        pythoncom.CoInitializeEx(pythoncom.COINIT_MULTITHREADED)
    except pythoncom.com_error:
        # already initialized.
        pass
    if psutil.pid_exists(pid):
        proc_name = psutil.Process(pid).name
        print proc_name
        strComputer = "."
        objWMIService = win32com.client.Dispatch("WbemScripting.SWbemLocator")
        objSWbemServices = objWMIService.ConnectServer(strComputer,"root\cimv2")
        colItems = objSWbemServices.ExecQuery("SELECT * FROM 
Win32_PerfFormattedData_PerfProc_Process")
        for objItem in colItems:
            if objItem.IDProcess != pid:
                continue
            if objItem.HandleCount != None:
                self.HandleCount = objItem.HandleCount
                return objItem.HandleCount
    else:
        self.HandleCount = 0
        return 0

Original issue: http://code.google.com/p/psutil/issues/detail?id=195

[giampaolo]

From g.rodola on August 19, 2011 11:24:47

I originally added this feature as a private method for testing purposes: 
https://code.google.com/p/psutil/source/detail?r=979 ...then removed it because 
the test was not reliable: 
https://code.google.com/p/psutil/source/detail?r=1056 I wasn't sure whether it 
would have been useful (that's why it was private).
Out of curiosity: what do you need this for?

[giampaolo]

From [email protected] on September 10, 2011 23:40:13

I am a QA. I've used it for monitor resources leaks. Handles count leaks are 
very important for my customer. Currently this only one feature that I use not 
from psutil.
In any case, thanks for your work.

[giampaolo]

From g.rodola on October 22, 2011 04:45:14

Status: WaitingForReview
Labels: -Type-Defect Type-Enhancement OpSys-Windows

[giampaolo]

From [email protected] on October 31, 2011 08:44:36

Windows uses handles for references to operating system objects. Objects like 
threads, files, and sockets all get handles.

Being able to keep a handle count in windows can be vital as a reported 
statistic under windows. There are many places in windows software where a 
handle leak can be used to identify a file that wasn't closed, or a socket that 
wasnt cleaned up properly, etc. Using these numbers a programmer can then look 
at the currently opened handles using a tool like process explorer to track 
down what type of object is leaking and fix the problem.

The only request I would make for the old code is changing "handlers" to "handles".

[giampaolo]

From g.rodola on April 21, 2012 10:56:24

This is now committed in r1291 .
As for my previous comment:

> [...] I removed it because the test was not reliable

I think the test was not accurate. I rewrote it here: 
https://code.google.com/p/psutil/source/browse/trunk/test/_windows.py?spec=svn1291&r=1291#218
 ...and it seems to work now.
Very sporadically it fails but I suppose that's because Windows might need 
sometime to actually close the process handle.

Summary: Add Handles count functionality (Windows)
Status: FixedInSVN
Labels: Milestone-0.5.0

[giampaolo]

From g.rodola on June 27, 2012 11:54:03

0.5.0 is finally out. Closing out as fixed.

Status: Fixed

[giampaolo]

From g.rodola on March 02, 2013 04:02:37

Updated csets after the SVN -> Mercurial migration: r1291 == revision 
d37b3525b133