I am trying to parse my local FTP logfile and decipher the logs, then act on that to block anyone trying to login as administrator...

It was working good on a test computer, but then on a production server i receive errors like the following:

So, before i get into posting the code, or part of it (it's many pages), has anyone out there been able to successfully read an active log file with system.io.filestream commands?

Never really a good idea to try to open files with another open file handle on them. Either copy the active file to a temp file (and delete if after) or start some kind of log rotation.

Acceptable?

Try to use tail.exe. If it is able to access the file then you could probably use a String Reader to read the file, but you need to open in share read mode.

Understand this relies on the process that has that log open to have opened it in shared read.

I understand tail.exe, and that's a good idea, but that's not exactly what we need.
I know that IIS log analyzers like deepmetrix and awstats dont seem to have a problem polling the IIS/FTP logs for a website regularly, and I still don't see why this isn't possible.

Here's the code we're using to open the logfile:

function openfile([string] $filename, [int] $offset, [ref] $filestreamInput, [ref] $streamReader)
{
if ([system.io.file]::exists($filename))
{
#write-host "openfile: $file exists"
}
else
{
write-host "openfile: $file does not exist"
return -1
}

$filestreamInput.Value = new-object system.io.filestream($filename,
[system.io.filemode]::open,
[system.io.fileaccess]::read,
[system.io.fileshare]::read)

$streamReader.Value = new-object system.io.streamreader($filestreamInput.value)

if ($offset -gt 0)
{
write-host "openfile: setting start position to " + $offset
$filestreamInput.Value.Position = $offset
}

write-host ("openfile: $file length " + $filestreamInput.Value.Length)
return $filestreamInput.Value.Length
}

function closefile ($filestreamInput, $streamReader)
{
if ($streamReader)
{
$streamReader.Close()
}
if ($filestreamInput)
{
$filestreamInput.Close()
}
}


I appreciate your help and I am sure there is a way to make this work if other programs can!

I dont see a way to edit my last post, so forgive me for the double posting of code, it seems the quote button duplicates text.

I wasnt suggesting using Tail.exe for anything other than testing how the log file is open. There are several modes a file can be open in. If it is not open in shared read you will not be able to read it until the process releases the file.

I will look at your code and see if I can help.

I appreciate your help!

by the way, tail.exe seems to work just fine on the logfile.

See if this helps
http://www.codeplex.com/PsObject/Thread/View.aspx?ThreadId=7637