Don't report negative uptime for a process if system time changes

Refs Supervisor#281
Refs Supervisor#458
Refs Supervisor#533
Refs Supervisor#552
Refs Supervisor#618

(cherry picked from commit 1c2ea90)

Author: mnaberez

supervisor/rpcinterface.py

@@ -627,6 +627,8 @@ def _interpretProcessInfo(self, info):
             start_dt = datetime.datetime(*time.gmtime(start)[:6])
             now_dt = datetime.datetime(*time.gmtime(now)[:6])
             uptime = now_dt - start_dt
+            if uptime.total_seconds() < 0: # system time set back
+                uptime = datetime.timedelta(0)
             desc = 'pid %s, uptime %s' % (info['pid'], uptime)
 
         elif state in (ProcessStates.FATAL, ProcessStates.BACKOFF):

supervisor/tests/test_rpcinterfaces.py

@@ -1210,6 +1210,19 @@ def test__interpretProcessInfo(self):
         description = interface._interpretProcessInfo(stopped2)
         self.assertEqual(description, 'Not started')
 
+    def test__interpretProcessInfo_doesnt_report_negative_uptime(self):
+        supervisord = DummySupervisor()
+        interface = self._makeOne(supervisord)
+        from supervisor.process import ProcessStates
+        running = {'name': 'running',
+                   'pid': 42,
+                   'state': ProcessStates.RUNNING,
+                   'start': _NOW + 10, # started in the future
+                   'stop': None,
+                   'now': _NOW}
+        description = interface._interpretProcessInfo(running)
+        self.assertEqual(description, 'pid 42, uptime 0:00:00')
+
     def test_getProcessInfo(self):
         from supervisor.process import ProcessStates