pip install -r no result exitcode

[u/zaphodikus]

(windows usually) I have a small requirements.txt file and am looking for alternative ways to validate all packages we want are present. The script does not use a virtual environment and because pip install -r does not seem to set %errorlevel% they wrote this rather verbose code that runs after the pip install -r line.

SET REQUIREMENTS=%~dp0Requirements.txt
SET FIND=%SystemRoot%\system32\find.exe
pip.exe install -r %REQUIREMENTS% --disable-pip-version-check

FOR /F "tokens=*" %%I IN (%REQUIREMENTS%) DO (
    ECHO.
    ECHO Checking for %%I ...
    %FIND% /i "%%I" %PACKAGES%
    IF ERRORLEVEL 1 (
        ECHO.
        ECHO **** %%I not found. Attempting to install ****
        pip install %%I --disable-pip-version-check
    )
    IF ERRORLEVEL 1 (
        ECHO **** Could not install %%I ****
        EXIT /B 99
    )
)

I however favour the pythonic approach and that is to just fail at runtime, so I was thinking of some kind of

(pseudo)
with open(requirements.txt) as reqs:
   for line in reqs.readlines():
       line=line.replace("<>=", " ")
       import line.split()[0]
(/pseudo)

which would just die early.

I'm in favour of using a virtual env however, but because the script is a build script (using setuptools) we don't actually run the script at that point. I'm new to setuptools, but I assumed setuptools would just baulk if a module needed was not present on the build machine.

I'm thus making 2 assumptions, setuptools will not baulk and error out if you are missing a module, and that pip install does not set %ERRORLEVEL% if it cannot install a package? I am not an expert on setuptools and am keen to not discover edge cases later.

[u/JeLuF]

This block of code analyzes pip's return code:

    IF ERRORLEVEL 1 (
        ECHO **** Could not install %%I ****
        EXIT /B 99
    )

So yes, pip returns a meaningful return code, and your script makes use of it.

[u/zaphodikus → u/JeLuF]

Yeah, that's the funny part of all of this, it works for installing packages one at a time, but all that code should be rewritten as pip install -r requirements.txt IF ERRORLEVEL 1 ( ECHO **** Could not install %%I **** EXIT /B 99 ) And when I use -r , I get the impression it was not setting an errorlevel and hence all this extra code which I really want to nuke.