Fix HTTP response hanging if system time set back. Closes #802

CHANGES.txt

@@ -31,6 +31,10 @@
 - Zope ``trackrefs``, a debugging tool that was included in the ``tests``
  directory but hadn't been used for years, has been removed.
 
+- Fixed an issue where `supervisord` could hang when responding to HTTP
+ requests (including `supervisorctl` commands) if the system time was set
+ back after `supervisord` was started.
+
 3.3.0 (2016-05-14)
 ------------------
 

supervisor/http.py

@@ -334,17 +334,16 @@ class deferring_http_channel(http_server.http_channel):
  # order to spew tail -f output faster (speculative)
  ac_out_buffer_size = 4096
 
- delay = False
- writable_check = time.time()
+ delay = 0 # seconds
+ last_writable_check = time.time()
 
  def writable(self, t=time.time):
  now = t()
  if self.delay:
  # we called a deferred producer via this channel (see refill_buffer)
- last_writable_check = self.writable_check
- elapsed = now - last_writable_check
- if elapsed > self.delay:
- self.writable_check = now
+ elapsed = now - self.last_writable_check
+ if (elapsed > self.delay) or (elapsed < 0):
+ self.last_writable_check = now
  return True
  else:
  return False
@@ -901,4 +900,3 @@ def __init__(self, dict, handler, realm='default'):
  auth_handler.__init__(self, dict, handler, realm)
  # override the authorizer with one that knows about SHA hashes too
  self.authorizer = encrypted_dictionary_authorizer(dict)
-

supervisor/tests/test_http.py

@@ -312,7 +312,7 @@ def test_more_noproducer(self):
  producer = self._makeOne(None, None)
  self.assertEqual(producer.more(), '')
 
-class Test_deferring_http_request(unittest.TestCase):
+class DeferringHttpRequestTests(unittest.TestCase):
  def _getTargetClass(self):
  from supervisor.http import deferring_http_request
  return deferring_http_request
@@ -428,6 +428,57 @@ def test_done_http_09(self):
  inst.done()
  self.assertTrue(channel.closed)
 
+class DeferringHttpChannelTests(unittest.TestCase):
+ def _getTargetClass(self):
+ from supervisor.http import deferring_http_channel
+ return deferring_http_channel
+
+ def _makeOne(self):
+ return self._getTargetClass()(
+ server=None,
+ conn=None,
+ addr=None
+ )
+
+ def test_defaults_delay_and_last_writable_check_time(self):
+ channel = self._makeOne()
+ self.assertEqual(channel.delay, 0)
+ self.assertTrue(channel.last_writable_check > 0)
+
+ def test_writable_with_delay_is_False_if_elapsed_lt_delay(self):
+ channel = self._makeOne()
+ channel.delay = 2
+ channel.last_writable_check = _NOW
+ later = _NOW + 1
+ self.assertFalse(channel.writable(t=lambda: later))
+ self.assertEqual(channel.last_writable_check, _NOW)
+
+ def test_writable_with_delay_is_False_if_elapsed_eq_delay(self):
+ channel = self._makeOne()
+ channel.delay = 2
+ channel.last_writable_check = _NOW
+ later = _NOW + channel.delay
+ self.assertFalse(channel.writable(t=lambda: later))
+ self.assertEqual(channel.last_writable_check, _NOW)
+
+ def test_writable_with_delay_is_True_if_elapsed_gt_delay(self):
+ channel = self._makeOne()
+ channel.delay = 2
+ channel.last_writable_check = _NOW
+ later = _NOW + channel.delay + 0.1
+ self.assertTrue(channel.writable(t=lambda: later))
+ self.assertEqual(channel.last_writable_check, later)
+
+ def test_writable_with_delay_is_True_if_system_time_goes_backwards(self):
+ channel = self._makeOne()
+ channel.delay = 2
+ channel.last_writable_check = _NOW + 3600 # last check was in the future
+ later = _NOW
+ self.assertTrue(channel.writable(t=lambda: later))
+ self.assertEqual(channel.last_writable_check, later)
+
+_NOW = 1470085990
+
 class EncryptedDictionaryAuthorizedTests(unittest.TestCase):
  def _getTargetClass(self):
  from supervisor.http import encrypted_dictionary_authorizer