Now that I have a reliable and programmatic way of adding a one-time maintenance window in PRTG, I wanted to be able to provide this functionality to end users responsible over their specific set of sensors. Since I have experience with C# Asp.net, and didn’t have the luxury of time learning something new (Asp.net Core, doing it entirely in Javascript, etc) I continued down that path.

Going through my requirements as I built and fine-tuned it, this is what I ended up with:

• Must use Windows Authentication
• Provide functionality to select a “logical group” that is a pre-defined set of objects for applying the maintenance window
• Be able to edit these “logical groups” outside of the code base, preferably in a simple static file
• Be able to restrict from view and selection certain “logical groups” depending on Active Directory group membership of the user viewing the site.
• Allow user to supply 2 datetime values, with validation that they exist, and end datetime is later than start datetime
• Allow user to supply conditional parameters for additional objects to include
• Display results of the operation for the user
• Email results of the operation to specific recipients

I started with this post from Jeff Murr, which detailed how to use asp.net to call a PowerShell script, and return some output. This really formed the basis of what I built.

I started by trying to use Jeff’s code as-is, as a proof-of-concept. One of the immediate problems I ran into was getting my project to recognize the system.automation reference. It kept throwing this error:

The type or namespace name 'Automation' does not exist in the namespace 'System.Management' (are you missing an assembly reference?)

I eventually came across this blog post that contained a comment with the resolution for me:

You have to add:
Microsoft PowerShell version (5/4/3/..) Reference Assembly.

You can search for "PowerShell" in NuGet Packages Manager search bar

Once I had done this, the project could be built and I had a functional method of executing PowerShell from my site.

Building out the framework of the site was simple, and I utilized some new learning on CSS FlexBox to layout my conditional panels as I wanted to.

I decided to use an XML file as the data source for my “logical grouping” of information; intending that team members will be able to simply modify and push changes without having to understand anything related to the code. The XML file looks like this:

<?xml version="1.0" standalone="yes"?>
<types>
  <type Id ="0" Code ="None">
  </type>
  <type Id ="1" Code ="Client1">
    <TimeZone>MST</TimeZone>
    <emailaddress>notificationlist@domain.com,notificationlist2@domain.com</emailaddress>
  </type>
  <type Id ="2" Code ="Client2">
    <TimeZone>MST</TimeZone>
    <emailaddress>notificationlist@domain.com,notificationlist2@domain.com</emailaddress>
  </type>
  <type Id ="3" Code ="Client3">
    <TimeZone>MST</TimeZone>
    <emailaddress>notificationlist@domain.com,notificationlist2@domain.com</emailaddress>
  </type>
</types>

Another issue I had was with choosing a good date/time control. The out-of-the-box ones are clearly inadequate, so I decided to use a jQuery timepicker. jQuery and client-side scripts are a little unfamiliar to me, so I spent quite a bit of time tinkering to get it just right, when in reality it should have only been a brief effort.

In order to get my PowerShell script to run, and return Out-String values back to the page, I had to add: UnobtrusiveValidationMode=”None”. I did this at the top of page declaration, but it could have been done in web.config as well. Without this, when the page attempted to run the PowerShell Invoke-WebRequest, it did so under the user context of my IIS Application Pool, and it tried to run the Internet Explorer first-run wizard. Adding UnobtrusiveValidationMode bypassed this requirement.

Another unique thing I wanted to do was be able to manipulate the location of the PowerShell script and other things like disabling email notifications if I was testing during debug on my local machine. To do that, I used an IF statement to test for HttpContext.Current.Request.IsLocal.

Here’s what the site looks like:

You can find the GitHub repository of this code here: https://github.com/jeffwmiles/PrtgMaintenanceWindow

I recently had a need to provide capability for adding one-time maintenance windows in PRTG for a specific set of objects.

I found this post on the PRTG forums as a starting point. I also needed to learn how to authenticate an API request in PowerShell, which Paessler has provided a KB article on.

Part of my requirements were conditional logic, to say “Pause these sensors, and maybe pause these other ones too if desired”. I used a Switch parameter in my PowerShell script to accomplish this.

One of the remaining downsides of this script is that it requires pre-knowledge of the exact object IDs from PRTG. These are easy to find, by navigating to the object you desire, and looking at the URL which will display it.

I also want to be able to call this script from a website with user-specified parameters, but that will be for a future post.

Here’s my script, which can be called like this:

$start = get-date
$end = (get-date).AddMinutes(5)
.\PrtgMaintenanceWindow.ps1 -MaintStartTime $start -MaintEndTime $end -IncludProdWebServers -IncludeTestWebServers

Full Script:

param(
    [Parameter(Mandatory = $true)] [datetime]$MaintStartTime,
    [Parameter(Mandatory = $true)] [datetime]$MaintEndTime,
    [Switch]$IncludeProdWebServers,
    [Switch]$IncludeTestWebServers
)
 
# Use $Global parameters so they can be used inside the Function without repeating
$Global:prtgAuth = 'username=PRTGUSERNAME&passhash=GENERATEDHASHVALUE'
$Global:prtgServer = 'https://FQDN.OF.PRTG'
$Global:MaintStart = '{0:yyyy-MM-dd-HH-mm-ss}' -f $MaintStartTime
$Global:MaintEnd = '{0:yyyy-MM-dd-HH-mm-ss}' -f $MaintEndTime
 
$ServicesID = @("OBJECTID") # Group containing devices & sensors that I want to control
$ProdWebServersID = @("13152", "13153", "13149", "13150") # Individual Devices to conditionally apply a maintenance window to
$TestWebServersID = @("13219", "13221", "13220", "13222")
 
# Function that can be called multiple times, after passing in an ObjectID.
function ApplyMaintenanceWindow {
    param(
        [int]$objectid
    )
    # Apply Start Time of Maintenance Window
    $startattempt = Invoke-WebRequest "$prtgServer/api/setobjectproperty.htm?id=$objectid&name=maintstart&value=$MaintStart&$prtgAuth" -UseBasicParsing
 
    # Display the output as successful if HTTP200 response code received. Using Out-String for future integration purposes with website. 
    if ($startattempt.StatusCode -eq "200") {
        $message = "Object ID: $objectid - Maintenance window set to start at $MaintStart"
        $message | out-string
    }
    # Apply End Time of Maintenance Window
    $endattempt = Invoke-WebRequest "$prtgServer/api/setobjectproperty.htm?id=$objectid&name=maintend&value=$MaintEnd&$prtgAuth" -UseBasicParsing
    if ($endattempt.StatusCode -eq "200") {
        $message = "Object ID: $objectid - Maintenance window set to end at $MaintEnd"
        $message | out-string
    }
    # Enable Maintenance Window for the object
    $enableattempt = Invoke-WebRequest "$prtgServer/api/setobjectproperty.htm?id=$objectid&name=maintenable&value=1&$prtgAuth" -UseBasicParsing
    if ($enableattempt.StatusCode -eq "200") {
        $message = "Object ID: $objectid - Maintenance window enabled"
        $message | out-string
    }
}
 
# Add maintenance Window for Client Services
# Do this always, with the parameters supplied
foreach ($id in $ClientServicesID) {
    ApplyMaintenanceWindow -objectid $id
}
 
#If necessary, add maintenance window for ProdWebServers
# Do this conditionally, if the switch is provided
if ($IncludeProdWebServers.IsPresent) {
    foreach ($id in $ClientProdWebServersID) {
        ApplyMaintenanceWindow -objectid $id
    }
}
 
#If necessary, add maintenance window for TestWebServers
# Do this conditionally, if the switch is provided
if ($IncludeTestWebServers.IsPresent) {
    foreach ($id in $ClientTestWebServersID) {
        ApplyMaintenanceWindow -objectid $id
    }
}