I created simple nagios plugin check_log.ps1 to check log file on windows machine. It works in way that make copy content of log and in next time look for specified string in difference between copy of log and original log file.
The problem is that sometimes in random moments check_log.ps1 locks log file so it cause stop of the application which create log file.
Generally plugin use original log file in two places
# compare content of $Logfile and $Oldlog, save diff to $tempdiff
Compare-Object -ReferenceObject (Get-Content -Path $Logfile) -DifferenceObject (Get-Content -Path $Oldlog) | Select-Object -Property InputObject > $tempdiff
# override file $Oldlog using conetent of $Logfile
Copy-Item $Logfile $Oldlog
I make test. In one PS session I run while($true) { [string]"test" >> C:\test\test.log }, in second session I run plugin C:\test\check_log.ps1 C:\test\test.log C:\test\Old_log.log test
I'm not fully sure if my test is correct but I think that Copy-Item command cause problem. When I comment this line in script I don't see any errors in terminals. I tested some custom functions to copy file which I found in internet but I din't find solution for my problem.
Do you have an idea how to make it work fully?
if you think the copy-item is locking the file, try reading the content and then saving it to another location. Something like this:
Get-Content $Logfile | Set-Content $Oldlog