kernels.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import logging
import os

from distutils.version import LooseVersion

import IPython
from IPython.html.utils import url_path_join

try:
    if LooseVersion(IPython.__version__) < LooseVersion('3.0'):
        raise ImportError("kernel service requires IPython ≥ 3.0, found %s" % IPython.__version__)
except TypeError:
    pass

import tornado
import tornado.options
from tornado import httpserver
from tornado import web

from tornado.log import app_log

from IPython.kernel.kernelspec import KernelSpecManager

from IPython.html.services.kernels.kernelmanager import MappingKernelManager
from IPython.html.services.kernels.handlers import default_handlers as kernels_handlers
from IPython.html.services.kernelspecs.handlers import default_handlers as kernelspecs_handlers

default_handlers = kernels_handlers + kernelspecs_handlers
        
def fix_base_path(base_path):
    if not base_path.startswith('/'):
        base_path = '/' + base_path
    if not base_path.endswith('/'):
        base_path = base_path + '/'
    return base_path

class WebApp(web.Application):
    def __init__(self, kernel_manager, settings):
        base_path = settings['base_path']

        handlers = [ tuple([url_path_join(base_path, handler[0])] + list(handler[1:]))  for handler in default_handlers ]

        super(WebApp, self).__init__(handlers, **settings)

def main():
    tornado.options.define('base_path', default='/',
            help="Base path for the server (e.g. /jupyter/)"
    )
    tornado.options.define('port', default=8000,
            help="Port to serve on, defaults to 8000"
    )

    tornado.options.parse_command_line()
    opts = tornado.options.options

    kernel_manager = MappingKernelManager()

    # Start the default kernel automatically
    kernel_id = kernel_manager.start_kernel()

    base_path = fix_base_path(opts.base_path)

    # Loosey goosey
    headers = {
            "Access-Control-Allow-Origin": "*",
            "Content-Security-Policy": "",
    }

    allow_origin='*'
    allow_origin_pat=''

    from jinja2 import Environment, FileSystemLoader
    template_path=IPython.html.DEFAULT_TEMPLATE_PATH_LIST
    env = Environment(loader=FileSystemLoader(template_path))

    settings = dict(
        cookie_secret=os.environ.get('COOKIE_SECRET', 'secret'),
        cookie_name='ignored',
        kernel_manager=kernel_manager,
        base_path=base_path,
        headers=headers,
        allow_origin=allow_origin,
        allow_origin_pat=allow_origin_pat,
        kernel_spec_manager=KernelSpecManager(),

        static_path=IPython.html.DEFAULT_STATIC_FILES_PATH,
        static_file_path=[IPython.html.DEFAULT_STATIC_FILES_PATH],

        jinja2_env=env,
    )

    app = WebApp(kernel_manager, settings)
    server = httpserver.HTTPServer(app)
    server.listen(opts.port)
    app_log.info("Serving at http://127.0.0.1:{}{}api/kernels".format(opts.port, base_path))
    try:
        tornado.ioloop.IOLoop.instance().start()
    except KeyboardInterrupt:
        app_log.info("Interrupted...")
    finally:
        kernel_manager.shutdown_all()


if __name__ == '__main__':
    main()