Executing Custom Action after adding system variable in Wix - wix

Question

I am adding system variables and then i want to execute custom actions, that depends on those variables. The variables are being added correctly, but the scripts are exiting ( because at that time variables are not there yet ), depsite the fact I am using "After Install Files". Here is my code:
<?xml version="1.0" encoding="UTF-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi"
xmlns:util="http://schemas.microsoft.com/wix/UtilExtension">
<Product Id="*" Name="DataBaseds_Service_Installer" Language="1033" Version="1.0.0.0" Manufacturer="" UpgradeCode="3875ce89-3886-4cbf-b132-01f947ac7a08">
<Package InstallerVersion="200" Compressed="yes" InstallScope="perMachine" />
<MajorUpgrade DowngradeErrorMessage="A newer version of [ProductName] is already installed." />
<MediaTemplate EmbedCab="yes" />
<CustomAction Id="NssmUnzip" Directory="INSTALLFOLDER" Execute="deferred" Impersonate="no" ExeCommand="cmd.exe /c "unzip.exe nssm-2.24.zip -d "%TANGO_ROOT%\bin" "" Return="ignore" />
<CustomAction Id="Tango_db" Directory="INSTALLFOLDER" Execute="deferred" Impersonate="no" ExeCommand="[INSTALLFOLDER]create-tangodb.bat" Return="ignore" />
<CustomAction Id ="Baseds_Service" Directory="INSTALLFOLDER" Execute="deferred" Impersonate="no" ExeCommand="[INSTALLFOLDER]Tango-DataBaseds.bat" Return="ignore" />
<CustomAction Id="UninstallService" Directory="INSTALLFOLDER" Execute="deferred" Impersonate="no" ExeCommand="[INSTALLFOLDER]Remove_Baseds_Service.bat" Return="ignore" />
<InstallExecuteSequence>
<Custom Action="NssmUnzip" After="InstallFiles">NOT Installed</Custom>
<Custom Action="Tango_db" After="NssmUnzip">NOT Installed</Custom>
<Custom Action="Baseds_Service" After="Tango_db">NOT Installed</Custom>
<Custom Action="UninstallService" After="InstallInitialize"> Installed and Not REINSTALL</Custom>
</InstallExecuteSequence>
<Property Id="DIRR">
<RegistrySearch Id="aaa" Root="HKCU"
Key="Software\corp\Tango"
Name="Directory"
Type="directory"/>
</Property>
<Feature Id="ProductFeature" Title="DataBaseds_Service_Installer" Level="1">
<ComponentRef Id="MYSQL_Path"/>
<ComponentRef Id="MYSQL_USER"/>
<ComponentRef Id="MYSQL_PASSWORD"/>
<ComponentGroupRef Id="Components" />
</Feature>
<Directory Id="TARGETDIR" Name="SourceDir">
<Directory Id="ProgramFilesFolder">
<Directory Id="INSTALLFOLDER" Name="DataBaseds_Service_Installer" />
</Directory>
</Directory>
<ComponentGroup Id="Components" Directory="INSTALLFOLDER">
<Component Id="NSSM" Guid="54CEB76C-6974-4071-96E9-EF5AD1937BD4">
<File Source="nssm-2.24.zip" KeyPath="yes" />
<File Source="Tango-DataBaseds.bat" KeyPath="no"/>
<File Source="Remove_Baseds_Service.bat" KeyPath="no"/>
<File Source="create-tangodb.bat" KeyPath="no"/>
</Component>
<Component Id="unzip" Guid="E10EE17A-AA5A-416B-82DF-37532281116C">
<File Source="unzip.exe" KeyPath="yes"/>
</Component>
</ComponentGroup>
<DirectoryRef Id="TARGETDIR">
<Component Id="MYSQL_USER" Guid="D05C8155-8421-4AEB-9A19-5016DAFAED19">
<Environment Id="MYSQL_USER" Name="MYSQL_USER" Value="root" Permanent="no" Part="last" Action="set" System="yes" />
</Component>
<Component Id="MYSQL_PASSWORD" Guid="222C7887-1E4D-4DC2-B429-A3F18F707FA3">
<Environment Id="MYSQL_PASSWORD" Name="MYSQL_PASSWORD" Value="tango" Permanent="no" Part="last" Action="set" System="yes" />
</Component>
<Component Id="MYSQL_Path" Guid="34D14695-1803-4D7E-AD65-3C9011D019CE">
<Environment Id="PATH" Name="PATH" Value="[DIRR]bin" Permanent="no" Part="last" Action="set" System="yes" />
</Component>
</DirectoryRef>
</Product>
</Wix>
Am I doing something wrong?
Greetings

Answer 1

There are two general issues with environment variables in Windows Installer:
When they are set they don't just automatically show up for running programs because Windows Installer doesn't send the "environment variables have changed" broadcast message until the end of the install. If you run a program AFTER that it will pick up the new values.
There is no reason for any running processes to pick them up unless they have a message loop and are prepared to deal with the (I think) WM_WININICHANGE message and reload the environment.
So none of your custom actions are going to pick up the new variables because they haven't been broadcast to the system yet and "committed". And yes, it's better to find another way to pass the data to the programs.

Answer 2

Phil is not wrong.
But here is my solution, if anyone will ever have the same problem:
Even though as Phil says: "system variables are not set during an installation:
Windows Installer doesn't send the environment variables have changed broadcast message until the end of the install, they are stored inside variable ( "DIRR" in this example) when you are reading the registry:
<Property Id="DIRR">
<RegistrySearch Id="aaa" Root="HKCU"
Key="Software\corp\Tango"
Name="Directory"
Type="directory"/>
</Property>
So you can run a script and pass them as argument:
<CustomAction Id="Tango_db" Directory="INSTALLFOLDER" Execute="deferred" Impersonate="no" ExeCommand="[INSTALLFOLDER]create-tangodb.bat ****"[DIRR]bin"****" Return="ignore" />
These way your batch file has access to the system variables, despite the fact that ther are not yet set in the system.
Hope that this helps :)