Can't run python scripts in Jenkins

The fact that "demo.py" gives the message '...is not recognized as an internal or external command' doesn't convince me that your script is recognized as executable. If I type 'turkey.abc' into a command prompt window I get the same error, and I don't have a tool for executing '.abc' files.

I see two possibilities here:

1) In batch scripts, executable extensions sometimes must appear in an environment variable called PATHEXT.

In the Jenkins batch script, add a "set" command near the top of the script to dump the environment variables for your running script into your Jenkins build log (you can remove the set command after this is debugged). Run the build. Look not only for the definition of PATH, but also at PATHEXT. Is ".py" one of the extensions listed there?

I have experienced this problem with Perl scripts. However, I'm wimping out on claiming this definitely since in testing on my Windows 10 home PC I am successfully executing .py scripts even without it being in PATHEXT, so it's something to try but it may not be this.

2) Another possibility is that the environment in which your service is running is different than the environment you get when you open a command prompt on your desktop (because the Jenkins service runs as a different user than the one you log in as.)

Adding "set" to your Jenkins batch commands will help debugging this too, since it will show you the environment your Jenkins script is running in. Then you can examine PATH to see if your script folder is being found.

It is also possible that the file associations for Python were installed for your user only, not for all users (i.e., in HKEY_CURRENT_USER in the registry instead of HKEY_LOCAL_MACHINE). That is harder to dump into your Jenkins log - the 'reg' command would do it, but it will take you a number of tries to get everything you need. You might be able to figure it out by just examining the registry. Search for ".py" - if it occurs in HKEY_LOCAL_MACHINE that is not it; if it occurs in HKEY_CURRENT_USER that is at least part of the problem.

I don't know if this will fix your issue but you shouldn't have a relative path in your PATH environment variable.

Can you try again after having removing .\Scripts from the PATH variable? (don't forget to open a fresh new terminal do get the new %PATH% value)

The problem is that your PATH variable doesn't include the paths of you python scripts. You need the full path of the Scripts directory. Not the relative path .\Scripts.