Basic reusable server base, using Flask-based WSGI application served asynchronously w/ gevent.pywsgi

kirksrv.py

"""Basic reusable server base, using Flask-based WSGI application served
   asynchronously with gevent.pywsgi; provides a nice template / starting point
   that I've reused several dozen times.
"""

import os
import flask
from gevent import pywsgi

MOD_PATH, _ = os.path.split(os.path.abspath(__file__))
_, MOD_NAME = os.path.split(MOD_PATH)
APP = flask.Flask(MOD_NAME)

@APP.route("/", methods=["GET"])
def index():
    """Flask-like endpoints are easily identifiable and access request
       information via flask.request ; might be useful in the near-future to
       provide more examples of things like reading request body data,
       websockets, query arguments, path-matching, request headers, etc. I do
       use the three-element tuple return format here, partly as an example but
       also because I've found it very helpful to explicitly declare response
       codes and header fields in many different situations.
    """
    return "Hey.", 200, {"Content-Type": "text/plain"}
    
def main():
    """Launching via command line, by default entry point, will start pywsgi
       with the module-defined Flask app. Environmental variables can be used
       to override port and host used (useful for container-based services).
       The APP module-level symbol can be customized to programmatically extend
       the service from outside the module, if desired, but most use cases will
       copy-and-paste this file to extend/define their own service.
    """
    host = os.getenv("SERVICE_HOST", "0.0.0.0")
    port = int(os.getenv("SERVICE_PORT", 5000))
    print("Starting %s client hosting at %s:%u..." % (MOD_NAME, host, port))
    pywsgi.WSGIServer((host, port), APP).serve_forever()

if __name__ == "__main__":
    main()