How to obtain arguments passed to setup.py from pip with '--install-option'?

Question

I am using pip 1.4.1, attempting to install a package from a local path, for example:

pip install /path/to/my/local/package

This does what

Answer 1

It works well and also documented.

from setuptools.command.install import install

class InstallCommand(install):             
    user_options = install.user_options + [
        ('engine=', None, ''),
    ]                                      

    def initialize_options(self):          
        install.initialize_options(self)   
        self.engine = None  

    def finalize_options(self):                   
        print("value of engine is", self.engine)
        install.finalize_options(self)            

    def run(self):                                
        print(self.engine)                       
        install.run(self)                         

setup(
...
cmdclass={'install': InstallCommand}
...
)

One of common mistakes is to pass setup options to pip like you pass it to setup directly. Use options from pip like that:

pip install . --install-option="--engine=rabbitmq"

But this way is a wrong way:

pip install . --install-option="--engine rabbitmq"

Absence of equal sign causes well known error:

error: option --engines rabbitmq not recognized