extract filename and data from file - powershell

Question

I have hourly log files from the past couple of months and i would like to export the data to MS Charts.
I've managed to get the data out, but having problems with getting the date on the x axis of the Chart.
The file name of the log file contains the date and i've tried using the creatation date or last write time. The closest i've got is to count the number of logs then divide by 24, but the dates it generates does not match up with the data.
Any ideas please?
Everything works as expected, but i cant get the X Axis to display the correct dates. in theory, it should calculate the 11 June as the start date, and the end date is yesterday's date.
the format of the file it reads from is
HealthCheck Wed 10 Sep 2014 - 05.00 AM.log
Ideally, I would like to get the date from the file name. I dont want to rely on calculations on when the file was written as this is prone to errors.
[void][Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")
[void][System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms.DataVisualization")
$Farm = "XAccess"
#gets files from yesterday
$Date = Get-Date #-Uformat %x
$Date = ($Date).adddays(-1)
$Date = $Date.ToString("M/d/yyyy")
$files = get-childitem "c:\$Farm*.log" | Where{$_.LastWriteTime -lt $date}
$ActiveSessions = Select-String -path $files '(?<=^"*Total Active Sessions: )\d+(?=)'|
ForEach-Object {$_.Matches[0].Value}
#Calculates numbers of days
$datapoints = $ActiveSessions.count/24
#== Creates Chart ==#
# create chart object
$Chart = New-object System.Windows.Forms.DataVisualization.Charting.Chart
$Chart.Width = 1600
$Chart.Height = 800
# create a chartarea to draw on and add to chart
$ChartArea = New-Object System.Windows.Forms.DataVisualization.Charting.ChartArea
$Chart.ChartAreas.Add($ChartArea)
[void]$Chart.Series.Add("Data")
$Chart.ChartAreas["ChartArea1"].AxisX.Interval = 24
$Chart.ChartAreas["ChartArea1"].AxisX.LabelStyle.Angle = -40
$Chart.ChartAreas["ChartArea1"].AxisY.Interval = 5
$Chart.ChartAreas["ChartArea1"].AxisY.title = "Active Sessions"
$chart.Series.Add('ChartArea1')
# add a data point for each server
foreach ($session in $ActiveSessions)
{
$dp1 = new-object System.Windows.Forms.DataVisualization.Charting.DataPoint(0, $session)
$dp1.AxisLabel = (get-date).adddays(-"$datapoints").tostring("ddd dd MMM")
$datapoints = $datapoints - 0.0416666666666667
$Chart.Series["Data"].Points.Add($dp1)
}
# set the title to the date and time
$title = new-object System.Windows.Forms.DataVisualization.Charting.Title
$Chart.Titles.Add( $title )
$Chart.Titles[0].Font = "Arial,13pt"
$Chart.Titles[0].Text = "Year to Date sessions for $Farm"
# save the chart to a file
$Chart.SaveImage("C:\$Farm Farm.png","png")

Answer 1

Ok, so you want the date from the file. No problem, we can do that. Let's start with how best to do it... We have options (as usual) to choose from. Wait, I'm getting ahead of myself. Where do we want to define it? Well, simplest place I can think of is anyplace that you are looping through the files in question and getting other data, so we can keep everything properly associated. So, it looks like the lines that you assign $ActiveSessions is going to be our best bet.
Now, back to how to get the date. We could use the SubString method, but that just seems messy to me when we have a defined format for the text. Personally I'd rather do a regex match. So what I see in the file name is a three letter day abbreviation, then a 1-2 digit day, a three letter month, and a four digit year. After that there's a hyphen, and two digit hour, period, two digit minute, and the AM/PM designator.
So, as far as [datetime] formats go that's ddd d MMM yyyy - hh.mm tt. We'll get back to that. How to extract the date? Oh right, a regex. Here's how I'd get that:
([regex]"\w{3} \d{1,2} \w{3} \d{4} - \d{2}\.\d{2} (?:AM|PM)").matches($_.Filename).value
That declares the pattern as a regex object, and then uses it's Matches() method, and get the value of the match. So we have the date, now to actually make it usable. Here's where we get back to that DateTime format. We can use the [DateTime]::ParseExact() method to get the date time, even with the strange formatting. Now we are going to be getting it in the ForEach loop, and are extracting the date from the FileName property of the object that Select-String is feeding the loop. Here's what it will look like:
[datetime]::ParseExact(([regex]"\w{3} \d{1,2} \w{3} \d{4} - \d{2}\.\d{2} (?:AM|PM)").matches($_.Filename).value,"ddd d MMM yyyy - hh.mm tt",$null)
Ok, that actually gives us a nice usable datetime object. So that ForEach loop is already spitting back the active sessions, and $ActiveSessions is an array of strings. Let's change that a little and make it an array of objects, and each object will have two properties now, Sessions and Date. So the inside of the ForEach loop has to make an object with those properties. Easiest way (with PowerShell v3 or higher, I'll show you the hard way if you are running an old version of PowerShell and need me to) is:
[PSCustomObject][Ordered]#{
'Sessions'=$_.Matches[0].Value
'Date'=[datetime]::ParseExact(([regex]"\w{3} \d{1,2} \w{3} \d{4} - \d{2}\.\d{2} (?:AM|PM)").matches($_.Filename).value,"ddd d MMM yyyy - hh.mm tt",$null)
}
That makes the whole $ActiveSessions = line look like:
$ActiveSessions = Select-String -path $files '(?<=^"*Total Active Sessions: )\d+(?=)'|
ForEach-Object {[PSCustomObject][Ordered]#{
'Sessions'=$_.Matches[0].Value
'Date'=[datetime]::ParseExact(([regex]"\w{3} \d{1,2} \w{3} \d{4} - \d{2}\.\d{2} (?:AM|PM)").matches($_.Filename).value,"ddd d MMM yyyy - hh.mm tt",$null)
}
}
Only thing that leaves is to change where that variable is referenced:
foreach ($session in $ActiveSessions)
{
$dp1 = new-object System.Windows.Forms.DataVisualization.Charting.DataPoint(0, $session.session)
$dp1.AxisLabel = $Session.Date.tostring("ddd dd MMM")
$Chart.Series["Data"].Points.Add($dp1)
}
That should do it for you.

Answer 2

I tried using regex but could not get pass the error i mentioned.
so after a bit more research, i decided exporting the creation date of the file and the data i needed into a CSV file, then creating the chart from that. So this is the code i used to get the data in to csv:
$files = get-childitem "c:\$farm*.log" | sort CreationTime
Foreach ($file in $files)
{
$FileCreation = $file.CreationTime.Date.ToString('ddd dd MMM yyyy')
$ActiveSessions = Select-String -path $file '(?<=^"*Total Active Sessions: )\d+(?=)' | ForEach-Object {$_.Matches[0].Value}
Add-Content d:\licInUse.csv "$FileCreation,$ActiveSessions"
}
# processing the Data
$Processes = Import-Csv -path d:\licInUse.csv -Delimiter ',' -Header "Date","Count"
$DateNames = #(foreach($Date in $Processes){$Date.Date})
$SessionCount = #(foreach($Date in $Processes){$Date.Count})
then used the following to plot the data
$Chart.Series["Data"].Points.DataBindXY($DateNames, $SessionCount)