CBTr.Net Tech Dump

I’m recently reading up on Regular Expression and was having some issue getting the data I need. I have a html text file that has the following as its content:

Source code

<tbody>
<tr><td class="n"><a href="../">Parent Directory</a>/</td><td class="m"></td><td class="s">- </td><td class="t">Directory</td></tr>
<tr><td class="n"><a href="20091103/">20091103</a>/</td><td class="m">2009-Dec-29 19:31:07</td><td class="s">- </td><td class="t">Directory</td></tr>
<tr><td class="n"><a href="20100116/">20100116</a>/</td><td class="m">2010-Jan-30 01:54:24</td><td class="s">- </td><td class="t">Directory</td></tr>
<tr><td class="n"><a href="20100130/">20100130</a>/</td><td class="m">2010-Mar-26 05:31:56</td><td class="s">- </td><td class="t">Directory</td></tr>
<tr><td class="n"><a href="20100730/">20100730</a>/</td><td class="m">2010-Aug-08 15:59:47</td><td class="s">- </td><td class="t">Directory</td></tr>
<tr><td class="n"><a href="latest/">latest</a>/</td><td class="m">2010-Aug-05 03:46:25</td><td class="s">- </td><td class="t">Directory</td></tr>
</tbody>

The only part of this html file I need is the YYYYMMDD section between between <a href=”…”></a>. I tried a few ways of stripping out the desire date as using Powershell’s -match but I found that -match has its own shortcoming and was frustrating the hell out of me. I went to a co-worker of mine who excel in regular expression and he threw my regex syntax into Regulator and it would give me the result I want, so I know my criteria is correct but Powershell doesn’t like it or not showing me what I want.

Thus, I ended up using the .Net regex class and was able to get my desire result:

Source code

$c = gc ".\Desktop\powershell\local_site.txt"
([regex]'<a\s+href=\"\d+/?\">(\d+)</a>').matches($c) | foreach {$_.Groups[1].Captures}

Without the foreach loop, you will get a listing that look like this:

Source code

Groups   : {20091103, 20091103}
Success  : True
Captures : {20091103}
Index    : 1301
Length   : 32
Value    : 20091103
...
...

I found this addin for Visual Studio this evening. Ever since I started to write powershell code, I was wondering when Microsoft was going to incorporate powershell into Visual Studio. The addin can be found here.

In SQL 2008, there’s a built in SQL job named: Syspolicy_purge_history. This sucker’s job is to purge your job history every day so that it doesn’t pile up on your server. In the past, it would take forever to get the SQL job log because it has to read all those past job run. By default, this job purge your SQL job once a day, sometimes making it rather hard to try to identify how long a job took to complete.

Use the following command to see the duration:

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SELECT current_value
FROM msdb.dbo.syspolicy_configuration
WHERE name = N'HistoryRetentionInDays';

Then use the following store proc to change the value:

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exec msdb.dbo.sp_syspolicy_set_config_history_retention [ @value = ] value

A while back, a dev lead came over and asked me if I can write a script to monitor a file. Check to see if the file is older than 30minutes. If it is older than 30 minutes, an email should be to sent to a certain people and distribution list. I came up with the following.

Source code

# Get file properties n compare time difference
$hotlist = get-item "\path\to\file\filename.txt"
$now = [datetime]::now
$diff = $now - $hotlist.LastWriteTime
write-output "Time Diff: " $diff.Minutes
if ($diff.Minutes -ge 30)
{
    "sending mail"
    send-email $emailaddress `
    " - filename.txt is older than 30 minutes" `
    "Please open a ticket to address/investigate why the txt file is older than 30 minutes. The location of the file is: \path\to\file"
    # Keep checking the file until it is -lt 5 minutes
    do
    {
        "checking timestamp"
        sleep 60
        $hotlist = get-item "\path\to\file\filename.txt"
        $now = [datetime]::now
        $diff = $now - $hotlist.LastWriteTime
    }
    until ($diff.Minutes -lt 5)
    {
        "sending green email"
        send-email $emailaddress `
        " - filename.txt up-to-date" `
        "The txt file has been updated less than 1 minute ago"
    }
}

The send-email is a function I wrote which utilize powershell’s Send-MailMessage cmdlet.

On my SQL server, I wrote a stored procedure that ping servers and if the result come back as “request not found” an email will be sent. It is a pretty ugly looking script, use of temp table, memory table, etc, and was slated to run every 45 seconds. Looking at the system recompiled plan, this stored procedure dominated the list. Not that it was doing anything to the server because it was an ops server, meaning it is lightly used. Heck, I hardly log onto that server now a days.

Keen on converting anything I can into powershell, I wrote a little function to ping servers. The following function will take one or more servers. Using a foreach loop to run thru the array, any server w/ statusCode != 0, an email will be sent, using the send-mail function I wrote.

Source code

function ping-server([string[]]$servers = $(throw "Nothing to Ping!"), $emailaddress = $(throw "empty email list!"))
{
	foreach($server in $servers)
	{
		$result = get-wmiobject win32_pingStatus -f "address = '$($server)'"
		if ($result.StatusCode -ne 0)
		{
		send-email $emailaddress "$($server) is unavailable " "."
		}
	}
}

The send-email is a function I put together yesterday. You can find it here at the bottom of the post.

Source code

Usage:
#import the function
. .\ping_server.ps1
#declaring variables
$servers = get-content "d:\listOfServers.txt"
$emailaddress = "abc@xyz.com","def@xyz.com"
#making use of the function
ping-server $servers $emailaddress