From virtualenv, pip freeze > requirements.txt give TONES of garbage! How to trim it out?

That is one thing that has bugged me too quite a bit. This happens when you create a virtualenv without the --no-site-packages flag.

There are a couple of things you can do:

1. Create virtualenv with the --no-site-packages flag.
2. When installing apps, dont run pip install <name> directly, instead, add the library to your requirements.txt first, and then install the requirements. This is slower but makes sure your requirements are updated.
3. Manually delete libraries you dont need. A rule of thumb i follow for this is to add whatever is there in my INSTALLED_APPS, and database adapters. Most other required libraries will get installed automatically because of dependencies. I know its silly, but this is what I usually end up doing.

— Edit —

I’ve since written a couple of scripts to help manage this. The first runs pip freeze and adds the found library to a provided requirements file, the other, runs pip install, and then adds it to the requirements file.

function pipa() {
    # Adds package to requirements file.
    # Usage: pipa <package> <path to requirements file>
    package_name=$1
    requirements_file=$2
    if [[ -z $requirements_file ]]
    then
        requirements_file="./requirements.txt"
    fi
    package_string=`pip freeze | grep -i $package_name`
    current_requirements=`cat $requirements_file`
    echo "$current_requirements\n$package_string" | LANG=C sort | uniq > $requirements_file
}

function pipia() {
    # Installs package and adds to requirements file.
    # Usage: pipia <package> <path to requirements file>
    package_name=$1
    requirements_file=$2
    if [[ -z $requirements_file ]]
    then
        requirements_file="./requirements.txt"
    fi
    pip install $package_name
    pipa $package_name $requirements_file
}