When running Python model adapters within FEWS, Python should be installed on your system and the dependencies (Python packages) of your adapter as well. The proposed way to do this is to:

• work in virtual environment
• organize model adapter code as python package

• make sure that all dependencies are listed in the setup.py of the package, to allow straightforward installation

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environment environment

Working with virtual environment

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More information on installation and use can be found in the documentation:

• virtualenv

install with:

pip install virtualenv

• virtualenvwrapper

install with:

pip install virtualenvwrapper

...

pip install virtualenvwrapper-win

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package package

Create Python package

The python scaffold package (https://pypi.python.org/pypi/Scaffold/0.1.3) helps to create a proper directory structure for your package, following the structure as explained in http://www.scotttorborg.com/python-packaging/minimal.html

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For packages under development, we can also install the package with a symlink, so that changes to the source files will be immediately available to other users of the package on our system:

python setup.py develop

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adjustsetup adjustsetup

Adjusting setup.py

The setup.py file is used for meta information of the package and for the requirements. The initial setup.py file, as created by scaffold, looks like this:

try:
    from setuptools import setup
except ImportError:
    from distutils.core import setup

config = {
    'description': 'My Project',
    'author': 'My Name',
    'url': 'URL to get it at.',
    'download_url': 'Where to download it.',
    'author_email': 'My email.',
    'version': '0.1',
    'install_requires': ['nose'],
    'packages': ['projectname'],
    'scripts': [],
    'name': 'projectname'
}

setup(**config)

The config dictionary has to be adjusted in order to describe the actual information on the package and the author(s). The field install_requires should include a list with the requirements of the package. All packages listed in there will be installed when installing your package with:

python setup.py develop