Windows Environment variables in ModelBuilder

[curtvprice]

It sure would be great to access Windows environment variables in ModelBuilder as builtin model variables. For example %COMPUTERNAME% %USERNAME% or user defined ones set in the Windows Control Panel or in a startup script. I realize one can do this with Calculate Value calling os.environ["COMPUTERNAME"], but this would be easier.

Way back in the 20th century, in ArcInfo Workstation AML, we could access windows env variables like AML variables with %COMPUTERNAME%. In that environment, if a windows environment variable conflicted with an AML variable, the AML variable would always take precedence to avoid confusion. I think that would be a good way to do it in ModelBuilder too.

A very common use case for me is constructing path names, so for example %TEMP%\%USERNAME%_%t%

[ShitijMehta]

Thanks Curtis for this idea!

Please can you share a few more use cases when you would want to use these Windows environment variables in a model to construct a path instead of using environment variables or data paths directly?
User profile specific? 

Thank You!

[curtvprice]

examples of windows environment variables. 

If the variable didn't exist the expected behavior would what is is now when you specify a variable that does not exist, ie you get the literal "%VAR%" unmodified.

Path to create a folder in TEMP for the model to log information:

Create Folder, folder: %TEMP% name:%COMPUTERNAME%_%USERNAME%

Access the 1:24K quads in the ArcMap folder: MakeFeaturesLayer %AGSDESKTOPJAVA%\\Reference Systems\World Time Zones.shp  quads

Find out it ArcMap is installed: CalculateValue arcpy.Exists(r"%AGSDESKTOPJAVA%")

Find out if ArcInfo Workstation is installed (haha) CalculateValue arcpy.Exists(r"%ARCHOME%")

Write a status info table to %APPDATA%\ESRI folder TableToTable %logtable% %APPDATA%\ESRI\log%t%.dbf

If expression to find out whether we have more than two processors: %NUMBER_OF_PROCESSORS% > 2

Access user defined variable (set by user in control panel) lay, MY_LOGPATH   %MY_LOGPATH%

To get a quick list of environment variables open a windows cmd window and enter: set

[curtvprice]

It occurred to me that it's pretty easy to get these with an arcpy method, so maybe it's a matter of documenting this functionality for use with Calculate Value:

Executing (Calculate Value): CalculateValue arcpy.GetSystemEnvironment("AGSDESKTOPJAVA") # Variant
Start Time: Wednesday, November 11, 2020 8:18:36 PM
Value = C:\Program Files (x86)\ArcGIS\Desktop10.7\
Succeeded at Wednesday, November 11, 2020 8:18:36 PM (Elapsed Time: 0.00 seconds)

[ChristophKoschmieder]

I also would like this feature to be integrated to the "normal" GP tool dialog! This would be a great thing for example to get dynamic parameter values for geoprocessing tools configured in tasks steps in ArcGIS Pro.