Launch Condition, custom action and property - wix

Question

I have this problem with wix installer not installing our application IISversion >=10. It works on IISVersion <10.
I found this link on github. https://github.com/wixtoolset/issues/issues/5276
This link suggests adding a custom action which returns ActionResult.Success if IISRegistryversion is >= IISRequiredVersion.
But I am getting the following error. The error happens after this in the log
Doing action: LaunchConditions
Action start 12:46:02: LaunchConditions.
Either the variable is not being set or custom action is not being called.
I have some logging in the custom action but its not logging anything even with verbose on.
How do make sure the launch condition/ custom action is being called before this condition is evaluated? Can anyone suggest please?
This is how Product.wxs looks
<InstallExecuteSequence>
<Custom Action="CA.DS.CreateScriptDirCommand" Before="InstallFinalize">
<![CDATA[NOT Installed AND (&Feature.DatabaseServer.Database = 3)]]>
</Custom>
<Custom Action="Iis.CheckInstalledVersion.SetProperty" Before="LaunchConditions" >
<![CDATA[NOT Installed AND &Feature.WebServer.WebServices = 3]]>
</Custom>
<Custom Action="Iis.CheckInstalledVersion" After="Iis.CheckInstalledVersion.SetProperty" >
<![CDATA[NOT Installed AND &Feature.WebServer.WebServices = 3]]>
</Custom>
</InstallExecuteSequence>
<Condition Message="This application requires IIS [Iis.RequiredVersion] or higher. Please run this installer again on a server with the correct IIS version.">
<![CDATA[Iis.IsRequiredVersion > 0]]>
</Condition>
<Fragment>
<CustomAction Id='Iis.CheckInstalledVersion.SetProperty' Property='Iis.CheckInstalledVersion' Execute='immediate' Value='' />
<!--Note: Changed "Execute" from "deferred" to "immediate", to avoid error "LGHT0204: ICE77: Iis.CheckInstalledVersion is a in-script custom action. It must be sequenced in between the InstallInitialize action and the InstallFinalize action in the InstallExecuteSequence table"-->
<!--Note: Changed "Impersonate" from "no" to "yes", to avoid warning "LGHT1076: ICE68: Even though custom action 'Iis.CheckInstalledVersion' is marked to be elevated (with attribute msidbCustomActionTypeNoImpersonate), it will not be run with elevated privileges because it's not deferred (with attribute msidbCustomActionTypeInScript)"-->
<CustomAction Id='Iis.CheckInstalledVersion' BinaryKey='B.WixCA' DllEntry='CheckInstalledIISVersion' Execute='immediate' Return='check' Impersonate='yes' />
<Component
</Component>
</Fragment>
[CustomAction]
public static ActionResult CheckInstalledIISVersion(Session session)
{
try
{
session.Log("* Starting to check installed IIS version");
const int IisRequiredVersion = 7;
string IISMajorVersionFromRegistry = session["IISMAJORVERSION"];
session.Log(string.Format("*!*! DEBUG; CheckInstalledIisVersion; IIS major version: {0}", IISMajorVersionFromRegistry));
string iisMajorVersionNumeric = IISMajorVersionFromRegistry.Replace("#", string.Empty);
int iisMajorVersion = int.Parse(iisMajorVersionNumeric, CultureInfo.InvariantCulture);
bool isRequiredVersion = iisMajorVersion >= IisRequiredVersion;
// Setting the required version as a custom property, so that it can be used in the condition message
session["IIs.RequiredVersion"] = IisRequiredVersion.ToString(CultureInfo.InvariantCulture);
// Setting the results of the check as "bool"
session["Iis.IsRequiredVersion"] = isRequiredVersion ? "1" : "0";
return ActionResult.Success;
}
catch (Exception ex)
{
session.Log(string.Format("CheckInstalledIisVersion; Error occured SC: {0}", ex.Message));
return ActionResult.Failure;
}
}
It works without the condition. The condition gets executed before

Answer 1

The feature check Feature.WebServer.WebServices = 3 isn't going to work because the feature "to be installed" state isn't set until after costing (and often choosing the feature in the feature dialogs). So the CA isn't being called.
You probably need to rethink this and force the check for IIS after CostFinalize, and then perhaps warn then that IIS is not installed/running etc. So you'd do the search for IIS unconditionally to set the property and not use it as a launch condition. Then give the warning if &Feature.WebServer.WebServices = 3 and the IIS version is too low.
See feature action condition documentation and the reference to CostFinalize:
https://msdn.microsoft.com/en-us/library/windows/desktop/aa368012(v=vs.85).aspx