indicate that REST API timestamps are UTC

use iso8601 Z suffix for UTC timestamps

use dateutil to parse dates from proxy, as well

even though CHP uses iso8601 UTC timestamps, we no longer assume CHP, so use more general parsing

in our db we are stuck with naïve datetime objects, so use those internally.
But ensure we put 'Z' on timestamps we ship externally

jupyterhub/apihandlers/auth.py

@@ -8,7 +8,7 @@ import json
 from urllib.parse import quote
 
 from oauth2.web.tornado import OAuth2Handler
-from tornado import web, gen
+from tornado import web
 
 from .. import orm
 from ..user import User

jupyterhub/apihandlers/base.py

@@ -10,7 +10,7 @@ from tornado import web
 
 from .. import orm
 from ..handlers import BaseHandler
-from ..utils import url_path_join
+from ..utils import isoformat, url_path_join
 
 class APIHandler(BaseHandler):
 
@@ -103,7 +103,7 @@ class APIHandler(BaseHandler):
         last_activity = user.last_activity
         # don't call isoformat if last_activity is None
         if last_activity:
-            last_activity = last_activity.isoformat()
+            last_activity = isoformat(last_activity)
 
         model = {
             'kind': 'user',
@@ -122,7 +122,7 @@ class APIHandler(BaseHandler):
             for name, spawner in user.spawners.items():
                 last_activity = spawner.orm_spawner.last_activity
                 if last_activity:
-                    last_activity = last_activity.isoformat()
+                    last_activity = isoformat(last_activity)
                 if spawner.ready:
                     servers[name] = s = {
                         'name': name,

jupyterhub/app.py

@@ -8,7 +8,7 @@ import asyncio
 import atexit
 import binascii
 from concurrent.futures import ThreadPoolExecutor
-from datetime import datetime
+from datetime import datetime, timezone
 from getpass import getuser
 import logging
 from operator import itemgetter
@@ -22,8 +22,8 @@ from urllib.parse import urlparse
 if sys.version_info[:2] < (3, 3):
     raise ValueError("Python < 3.3 not supported: %s" % sys.version)
 
+from dateutil.parser import parse as parse_date
 from jinja2 import Environment, FileSystemLoader, PrefixLoader, ChoiceLoader
-
 from sqlalchemy.exc import OperationalError
 
 from tornado.httpclient import AsyncHTTPClient
@@ -50,7 +50,7 @@ from .services.service import Service
 
 from . import crypto
 from . import dbutil, orm
-from .user import User, UserDict
+from .user import UserDict
 from .oauth.store import make_provider
 from ._data import DATA_FILES_PATH
 from .log import CoroutineLogFormatter, log_request
@@ -59,7 +59,6 @@ from .traitlets import URLPrefix, Command
 from .utils import (
     maybe_future,
     url_path_join,
-    ISO8601_ms, ISO8601_s,
     print_stacks, print_ps_info,
 )
 # classes for config
@@ -1581,10 +1580,11 @@ class JupyterHub(Application):
             if spawner is None:
                 self.log.warning("Found no spawner for route: %s", route)
                 continue
-            try:
-                dt = datetime.strptime(route_data['last_activity'], ISO8601_ms)
-            except Exception:
-                dt = datetime.strptime(route_data['last_activity'], ISO8601_s)
+            dt = parse_date(route_data['last_activity'])
+            if dt.tzinfo:
+                # strip timezone info to naïve UTC datetime
+                dt = dt.astimezone(timezone.utc).replace(tzinfo=None)
+
             if user.last_activity:
                 user.last_activity = max(user.last_activity, dt)
             else:

jupyterhub/handlers/base.py

@@ -26,7 +26,7 @@ from ..spawner import LocalProcessSpawner
 from ..utils import maybe_future, url_path_join
 from ..metrics import (
     SERVER_SPAWN_DURATION_SECONDS, ServerSpawnStatus,
-    PROXY_ADD_DURATION_SECONDS, ProxyAddStatus
+    PROXY_ADD_DURATION_SECONDS, ProxyAddStatus,
 )
 
 # pattern for the authentication token header

jupyterhub/user.py

@@ -10,7 +10,6 @@ from oauth2.error import ClientNotFoundError
 from sqlalchemy import inspect
 from tornado import gen
 from tornado.log import app_log
-from traitlets import HasTraits, Any, Dict, default
 
 from .utils import maybe_future, url_path_join
 

jupyterhub/utils.py

@@ -6,6 +6,7 @@
 import asyncio
 from binascii import b2a_hex
 import concurrent.futures
+from datetime import datetime, timezone
 import random
 import errno
 import hashlib
@@ -15,7 +16,6 @@ import os
 import socket
 import sys
 import threading
-from threading import Thread
 import uuid
 import warnings
 
@@ -39,6 +39,16 @@ ISO8601_ms = '%Y-%m-%dT%H:%M:%S.%fZ'
 ISO8601_s = '%Y-%m-%dT%H:%M:%SZ'
 
 
+def isoformat(dt):
+    """Render a datetime object as an ISO 8601 UTC timestamp
+
+    Naïve datetime objects are assumed to be UTC
+    """
+    if dt.tzinfo:
+        dt = dt.astimezone(timezone.utc).replace(tzinfo=None)
+    return dt.isoformat() + 'Z'
+
+
 def can_connect(ip, port):
     """Check if we can connect to an ip:port.
 

requirements.txt

@@ -4,6 +4,7 @@ tornado>=4.1
 jinja2
 pamela
 python-oauth2>=1.0
+python-dateutil
 SQLAlchemy>=1.1
 requests
 prometheus_client>=0.0.21