AKA: Microsoft.Windows.TimedScript.DiscoveryProvider

If you are following these VSAE Fragment posts in order, you’ll see they are tied together in the same example management pack. This fragment demonstrates the timed script discovery provider, and discovers the application component class discussed in the previous post.

What does it do?

This discovery uses a script to read a local csv file (c:\ScomSkills.csv). The file is expected to have two entries, separated by a comma. Doesn’t matter what the entries are, as they will simply be discovered as class properties.

One thing I’d like to callout here is the discovery of Entity\DisplayName, highlighted below. It is important to discover PrincipalName or NetbiosName for Entity\DisplayName, because this is what the source will be when monitors targeting this class generate an alert. Ever see an alert generated by "c:" or "Windows Server 2008"? Not very useful while looking at a long list of alerts in the console, and doesn’t help much if you have other processes that are expecting computer name values for source. This is also discussed here.

<ManagementPackFragment SchemaVersion="2.0" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Monitoring>
    <Discoveries>
      <Discovery ID="SCOMskills.Demo.TimedScript.Discovery" ConfirmDelivery="false" Enabled="true" Priority="Normal" Remotable="true" Target="SCOMskills.Demo.LocalApplication.Class">
        <Category>Discovery</Category>
        <DiscoveryTypes>
          <DiscoveryClass TypeID="SCOMskills.Demo.ApplicationComponent.Class">
            <Property TypeID="SCOMskills.Demo.ApplicationComponent.Class" PropertyID="CsvField1"/>
            <Property TypeID="SCOMskills.Demo.ApplicationComponent.Class" PropertyID="CsvField2"/>
            <Property TypeID="System!System.Entity" PropertyID="DisplayName"/>
          </DiscoveryClass>
        </DiscoveryTypes>
        <DataSource ID="DS" TypeID="Windows!Microsoft.Windows.TimedScript.DiscoveryProvider">
          <IntervalSeconds>60</IntervalSeconds>
          <SyncTime/>
          <ScriptName>SCOMskills.Demo.Discovery.vbs</ScriptName>
          <Arguments>$MPElement$ $Target/Id$ $Target/Host/Property[Type="Windows!Microsoft.Windows.Computer"]/PrincipalName$ c:\ScomSkillsDemo.csv</Arguments>
          <ScriptBody>
            <![CDATA[
Option Explicit

Dim oArgs
Set oArgs = WScript.Arguments
if oArgs.Count < 4 Then
   Wscript.Quit -1
End If

Dim SourceID, ManagedEntityId, TargetComputer, SourceFile

SourceId = oArgs(0)
ManagedEntityId = oArgs(1)
TargetComputer = oArgs(2)
SourceFile = oArgs(3)

Dim oAPI, oDiscoveryData, oInst
Set oAPI = CreateObject("MOM.ScriptAPI")
set oDiscoveryData = oAPI.CreateDiscoveryData(0, SourceId, ManagedEntityId)

Dim oFso, oFile, aField
Set oFso = CreateObject("Scripting.FileSystemObject")

If (oFso.FileExists(SourceFile)) Then
Set oFile = oFso.OpenTextFile(SourceFile)
aField = split(oFile.ReadLine,",")

set oInst = oDiscoveryData.CreateClassInstance("$MPElement[Name='SCOMskills.Demo.ApplicationComponent.Class']$")
call oInst.AddProperty("$MPElement[Name='Windows!Microsoft.Windows.Computer']/PrincipalName$", TargetComputer)
call oInst.AddProperty("$MPElement[Name='SCOMskills.Demo.ApplicationComponent.Class']/CsvField1$", aField(0))
call oInst.AddProperty("$MPElement[Name='SCOMskills.Demo.ApplicationComponent.Class']/CsvField2$", aField(1))
call oInst.AddProperty("$MPElement[Name='System!System.Entity']/DisplayName$", TargetComputer)
call oDiscoveryData.AddInstance(oInst)

Else

Wscript.Quit -1

End If

Call oAPI.Return(oDiscoveryData) 
]]>
          </ScriptBody>
          <TimeoutSeconds>30</TimeoutSeconds>
        </DataSource>
      </Discovery>
    </Discoveries>
  </Monitoring>
  <LanguagePacks>
    <LanguagePack ID="ENU" IsDefault="true">
      <DisplayStrings>
        <DisplayString ElementID="SCOMskills.Demo.TimedScript.Discovery">
          <Name>SCOMskills Timed Script Discovery</Name>
        </DisplayString>
      </DisplayStrings>
    </LanguagePack>
  </LanguagePacks>
</ManagementPackFragment>

AKA: Microsoft.Windows.ApplicationComponent

Here is another post in the VSAE Fragment category, building on the Microsoft Windows Local Application class in the previous example. This is another common class type to use while authoring a custom management pack, as discuss here. Use this class to discover components hosted on your custom Local Application class. This could also be considered a type (or server role) of the hosting class.

What does it do?

Discovers a component (or type/role) that is hosted by the seed class discovered in the previous example. You will notice here the highlighted hosting relationship also needs to be discovered, since this isn’t automatically included in the Microsoft Windows Application Component class type.  Monitors targeting this class will not automatically rollup to the Windows computer, so long as you do not create a dependency or hosting relationship on local application. This class requires a relationship with it’s base class, which is typically the seed class. If the seed class is local application, then it will automatically rollup to windows computer, and in some cases this is not what you want. In many cases, you might want to target your base class, which would be targeting Windows operating system (more on that later – look at the best practices category).

<ManagementPackFragment SchemaVersion="2.0" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <TypeDefinitions>
    <EntityTypes>
      <ClassTypes>
        <ClassType ID="SCOMskills.Demo.ApplicationComponent.Class" Abstract="false" Accessibility="Public" Base="Windows!Microsoft.Windows.ApplicationComponent" Hosted="true" Singleton="false">
          <Property ID="CsvField1" Key="false" Type="string"/>
          <Property ID="CsvField2" Key="false" Type="string"/>
        </ClassType>
      </ClassTypes>
      <RelationshipTypes>
        <RelationshipType ID="LocalApplicationHostsApplicationComponent" Base="System!System.Hosting" Accessibility="Public">
          <Source ID="LocalApplication" Type="SCOMskills.Demo.LocalApplication.Class"/>
          <Target ID="ApplicationComponent" Type="SCOMskills.Demo.ApplicationComponent.Class"/>
        </RelationshipType>
      </RelationshipTypes>
    </EntityTypes>
  </TypeDefinitions>
  <LanguagePacks>
    <LanguagePack ID="ENU" IsDefault="true">
      <DisplayStrings>
        <DisplayString ElementID="SCOMskills.Demo.ApplicationComponent.Class">
          <Name>SCOMskills Application Component Class</Name>
        </DisplayString>
        <DisplayString ElementID="SCOMskills.Demo.ApplicationComponent.Class" SubElementID="CsvField1">
          <Name>CSV Field 1</Name>
        </DisplayString>
        <DisplayString ElementID="SCOMskills.Demo.ApplicationComponent.Class" SubElementID="CsvField2">
          <Name>CSV Field 2</Name>
        </DisplayString>
        <DisplayString ElementID="LocalApplicationHostsApplicationComponent">
          <Name>Local Application class hosts Application Component class</Name>
        </DisplayString>
      </DisplayStrings>
    </LanguagePack>
  </LanguagePacks>
</ManagementPackFragment>