remove all CLI args from default Spawner implementation

use only env variables, which are safer to ignore and easier to handle in multiple ways

docs/source/changelog.md

@@ -899,7 +899,7 @@ Bugfixes on 0.6:
 
 ### [0.6.0] - 2016-04-25
 
-- JupyterHub has moved to a new `jupyterhub` namespace on GitHub and Docker. What was `juptyer/jupyterhub` is now `jupyterhub/jupyterhub`, etc.
+- JupyterHub has moved to a new `jupyterhub` namespace on GitHub and Docker. What was `jupyter/jupyterhub` is now `jupyterhub/jupyterhub`, etc.
 - `jupyterhub/jupyterhub` image on DockerHub no longer loads the jupyterhub_config.py in an ONBUILD step. A new `jupyterhub/jupyterhub-onbuild` image does this
 - Add statsd support, via `c.JupyterHub.statsd_{host,port,prefix}`
 - Update to traitlets 4.1 `@default`, `@observe` APIs for traits

jupyterhub/singleuser/mixins.py

@@ -10,6 +10,7 @@ with JupyterHub authentication mixins enabled.
 # Distributed under the terms of the Modified BSD License.
 import asyncio
 import json
+import logging
 import os
 import random
 import warnings
@@ -48,6 +49,17 @@ from ..utils import make_ssl_context
 from ..utils import url_path_join
 
 
+def _bool_env(key):
+    """Cast an environment variable to bool
+
+    0, empty, or unset is False; All other values are True.
+    """
+    if os.environ.get(key, "") in {"", "0"}:
+        return False
+    else:
+        return True
+
+
 # Authenticate requests with the Hub
 
 
@@ -268,6 +280,10 @@ class SingleUserNotebookAppMixin(Configurable):
     def _user_changed(self, change):
         self.log.name = change.new
 
+    @default("default_url")
+    def _default_url(self):
+        return os.environ.get("JUPYTERHUB_DEFAULT_URL", "/tree/")
+
     hub_host = Unicode().tag(config=True)
 
     hub_prefix = Unicode('/hub/').tag(config=True)
@@ -350,7 +366,26 @@ class SingleUserNotebookAppMixin(Configurable):
         """,
     ).tag(config=True)
 
-    @validate('notebook_dir')
+    @default("disable_user_config")
+    def _default_disable_user_config(self):
+        return _bool_env("JUPYTERHUB_DISABLE_USER_CONFIG")
+
+    @default("root_dir")
+    def _default_root_dir(self):
+        if os.environ.get("JUPYTERHUB_ROOT_DIR"):
+            proposal = {"value": os.environ["JUPYTERHUB_ROOT_DIR"]}
+            # explicitly call validator, not called on default values
+            return self._notebook_dir_validate(proposal)
+        else:
+            return os.getcwd()
+
+    # notebook_dir is used by the classic notebook server
+    # root_dir is the future in jupyter server
+    @default("notebook_dir")
+    def _default_notebook_dir(self):
+        return self._default_root_dir()
+
+    @validate("notebook_dir", "root_dir")
     def _notebook_dir_validate(self, proposal):
         value = os.path.expanduser(proposal['value'])
         # Strip any trailing slashes
@@ -366,6 +401,13 @@ class SingleUserNotebookAppMixin(Configurable):
             raise TraitError("No such notebook dir: %r" % value)
         return value
 
+    @default('log_level')
+    def _log_level_defaul(self):
+        if _bool_env("JUPYTERHUB_DEBUG"):
+            return logging.DEBUG
+        else:
+            return logging.INFO
+
     @default('log_datefmt')
     def _log_datefmt_default(self):
         """Exclude date from default date format"""

jupyterhub/spawner.py

@@ -797,8 +797,27 @@ class Spawner(LoggingConfigurable):
             'activity',
         )
         env['JUPYTERHUB_BASE_URL'] = self.hub.base_url[:-4]
+
         if self.server:
+            base_url = self.server.base_url
+            if self.ip or self.port:
+                self.server.ip = self.ip
+                self.server.port = self.port
             env['JUPYTERHUB_SERVICE_PREFIX'] = self.server.base_url
+        else:
+            # this should only occur in mock/testing schenarios
+            base_url = '/'
+
+        if self.ip or self.port:
+            # specify JUPYTERHUB_SERVICE_URL *if* ip or port is specified
+            # TODO: set this always?
+            # Prior to 2.0, leaving 'ip' or 'port' unset meant letting the subprocess default be used
+            # setting via a URL means we cannot specify explicit ip or port without specifying *both*
+            # this results in a changed default behavior of specifying only report
+            # specifying ip='' *explicitly*, which is the same as all interfaces, instead of localhost
+            s = 's' if self.internal_ssl else ''
+            bind_url = f"http{s}://{self.ip}:{self.port}{base_url}"
+            env["JUPYTERHUB_SERVICE_URL"] = bind_url
 
         # Put in limit and guarantee info if they exist.
         # Note that this is for use by the humans / notebook extensions in the
@@ -818,6 +837,20 @@ class Spawner(LoggingConfigurable):
             env['JUPYTERHUB_SSL_CERTFILE'] = self.cert_paths['certfile']
             env['JUPYTERHUB_SSL_CLIENT_CA'] = self.cert_paths['cafile']
 
+        if self.notebook_dir:
+            notebook_dir = self.format_string(self.notebook_dir)
+            env["JUPYTERHUB_ROOT_DIR"] = notebook_dir
+
+        if self.default_url:
+            default_url = self.format_string(self.default_url)
+            env["JUPYTERHUB_DEFAULT_URL"] = default_url
+
+        if self.debug:
+            env["JUPYTERHUB_DEBUG"] = "1"
+
+        if self.disable_user_config:
+            env["JUPYTERHUB_DISABLE_USER_CONFIG"] = "1"
+
         # env overrides from config. If the value is a callable, it will be called with
         # one parameter - the current spawner instance - and the return value
         # will be assigned to the environment variable. This will be called at
@@ -829,7 +862,6 @@ class Spawner(LoggingConfigurable):
                 env[key] = value(self)
             else:
                 env[key] = value
-
         return env
 
     async def get_url(self):
@@ -996,24 +1028,16 @@ class Spawner(LoggingConfigurable):
         """Return the arguments to be passed after self.cmd
 
         Doesn't expect shell expansion to happen.
+
+        .. versionchanged:: 2.0
+            Prior to 2.0, JupyterHub passed some options such as
+            ip, port, and default_url to the command-line.
+            JupyterHub 2.0 no longer builds any CLI args
+            other than `Spawner.cmd` and `Spawner.args`.
+            All values that come from jupyterhub itself
+            will be passed via environment variables.
         """
-        args = []
+        return self.args
-
-        if self.notebook_dir:
-            notebook_dir = self.format_string(self.notebook_dir)
-            args.append('--notebook-dir=%s' % _quote_safe(notebook_dir))
-        if self.default_url:
-            default_url = self.format_string(self.default_url)
-            args.append(
-                '--SingleUserNotebookApp.default_url=%s' % _quote_safe(default_url)
-            )
-
-        if self.debug:
-            args.append('--debug')
-        if self.disable_user_config:
-            args.append('--disable-user-config')
-        args.extend(self.args)
-        return args
 
     def run_pre_spawn_hook(self):
         """Run the pre_spawn_hook if defined"""
@@ -1269,6 +1293,11 @@ class LocalProcessSpawner(Spawner):
     Note: This spawner does not implement CPU / memory guarantees and limits.
     """
 
+    @default('ip')
+    def _default_ip(self):
+        """Listen on localhost by default for local processes"""
+        return '127.0.0.1'
+
     interrupt_timeout = Integer(
         10,
         help="""

jupyterhub/tests/mocksu.py

@@ -11,10 +11,10 @@ Handlers and their purpose include:
 - ArgsHandler: allowing retrieval of `sys.argv`.
 
 """
-import argparse
 import json
 import os
 import sys
+from urllib.parse import urlparse
 
 from tornado import httpserver
 from tornado import ioloop
@@ -36,7 +36,8 @@ class ArgsHandler(web.RequestHandler):
         self.write(json.dumps(sys.argv))
 
 
-def main(args):
+def main():
+    url = urlparse(os.environ["JUPYTERHUB_SERVICE_URL"])
     options.logging = 'debug'
     log.enable_pretty_logging()
     app = web.Application(
@@ -50,10 +51,11 @@ def main(args):
 
     if key and cert and ca:
         ssl_context = make_ssl_context(key, cert, cafile=ca, check_hostname=False)
+        assert url.scheme == "https"
 
     server = httpserver.HTTPServer(app, ssl_options=ssl_context)
-    log.app_log.info("Starting mock singleuser server at 127.0.0.1:%s", args.port)
+    log.app_log.info(f"Starting mock singleuser server at {url.hostname}:{url.port}")
-    server.listen(args.port, '127.0.0.1')
+    server.listen(url.port, url.hostname)
     try:
         ioloop.IOLoop.instance().start()
     except KeyboardInterrupt:
@@ -61,7 +63,4 @@ def main(args):
 
 
 if __name__ == '__main__':
-    parser = argparse.ArgumentParser()
+    main()
-    parser.add_argument('--port', type=int)
-    args, extra = parser.parse_known_args()
-    main(args)

jupyterhub/tests/test_api.py

@@ -565,10 +565,17 @@ async def test_spawn(app):
     r = await async_requests.get(ujoin(url, 'args'), **kwargs)
     assert r.status_code == 200
     argv = r.json()
-    assert '--port' in ' '.join(argv)
+    assert '--port' not in ' '.join(argv)
+    # we pass no CLI args anymore:
+    assert len(argv) == 1
     r = await async_requests.get(ujoin(url, 'env'), **kwargs)
     env = r.json()
-    for expected in ['JUPYTERHUB_USER', 'JUPYTERHUB_BASE_URL', 'JUPYTERHUB_API_TOKEN']:
+    for expected in [
+        'JUPYTERHUB_USER',
+        'JUPYTERHUB_BASE_URL',
+        'JUPYTERHUB_API_TOKEN',
+        'JUPYTERHUB_SERVICE_URL',
+    ]:
         assert expected in env
     if app.subdomain_host:
         assert env['JUPYTERHUB_HOST'] == app.subdomain_host