How to set up vsvars32 environment variables?

Question

Hi,

I'm struggling with setting my scons environment variables for visual studio 2008.
Normally I do following:

%VS90COMNTOOLS%vsvars32.bat

or 

call %VS90COMNTOOLS%vsvars32.bat

And this works in my shell.

I try to do that in python using subprocess

subprocess.call([os.environ['VS90COMNTOOLS']+r"\vsvars32.bat"])

output:

d:\N\workspace>scons test
scons: Reading SConscript files ...
Setting environment for using Microsoft Visual Studio 2008 x86 tools.
KeyError: 'INCLUDE':

above invokes batch process, but environment variables are not inherited from it to my 'master process.

When i use:

subprocess.call([os.environ['VS90COMNTOOLS']+r"\vsvars32.bat"])

I get:

d:\N\workspace>scons test
scons: Reading SConscript files ...
WindowsError: [Error 2] The system cannot find the file specified:
  File "D:\N\workspace\SConstruct", line 17:
    subprocess.Popen(["call ", os.environ['VS90COMNTOOLS']+r"\vsvars32.bat"])
  File "C:\Python26\lib\subprocess.py", line 595:
    errread, errwrite)
  File "C:\Python26\lib\subprocess.py", line 821:
    startupinfo)

How to achieve that?

Answer 1

Write a batch file that runs vsvars32.bat and then outputs the values in the form VARNAME=value, then have your Python script parse the values and inject them into os.environ.

Answer 2

In addition to the previous answer. An excerpt of my SConstruct:

for key in ['INCLUDE','LIB']:
    if os.environ.has_key(key):
        env.Prepend(ENV = {key.upper():os.environ[key]})

Please take care that variable names in Python are case-sensitive. Ensure that your env['ENV'] dict has no duplicate variable names with different case, otherwise the Windows shell will only see one variant of the variable.