A simple wrapper around `pex`. For self-contained python scripts.

pexed

#!/usr/bin/env sh

requirements=$1
script=$2

exec pex $requirements -- $script

Install to /usr/bin/pexed.

An example script using pexed:

#!/usr/bin/pexed flask flask_restful
from flask import Flask
from flask_restful import Resource, Api

app = Flask(__name__)
api = Api(app)


class HelloWorld(Resource):
    def get(self):
        return {'hello': 'world'}


api.add_resource(HelloWorld, '/')

if __name__ == '__main__':
    app.run()

This wrapper around pex is needed because of the way shebangs pass everything after the cmd (ie flask flask_restful) as a single string, rather than splitting them into arguments, as you might expect.
[source]

pex smartly caches your requirements, so the second time you run the script, there's no delay, and pinning is supported by pex (requests==2.18.4)

A general-purpose solution to this is https://github.com/jordansissel/shebang