[tor-commits] [arm/master] Only supporting a single resource tracker

[atagar at torproject.org]

commit 0c36c50b981c4a5d87eb82a26007cf4bd338dd31
Author: Damian Johnson <atagar at torproject.org>
Date:   Sun Oct 20 19:24:46 2013 -0700

    Only supporting a single resource tracker
    
    Swapping us over to a singleton. Code still sucks, but getting closer.
---
 arm/graphing/resourceStats.py |    2 +-
 arm/headerPanel.py            |    6 ++++--
 arm/starter.py                |   10 +++++-----
 arm/util/sysTools.py          |   28 +++++++++++-----------------
 4 files changed, 21 insertions(+), 25 deletions(-)

diff --git a/arm/graphing/resourceStats.py b/arm/graphing/resourceStats.py
index d4d71c4..843ef41 100644
--- a/arm/graphing/resourceStats.py
+++ b/arm/graphing/resourceStats.py
@@ -42,7 +42,7 @@ class ResourceStats(graphPanel.GraphStats):
 
     primary, secondary = 0, 0
     if self.queryPid:
-      resourceTracker = sysTools.getResourceTracker(self.queryPid, True)
+      resourceTracker = sysTools.getResourceTracker()
 
       if resourceTracker and not resourceTracker.lastQueryFailed():
         primary, _, secondary, _ = resourceTracker.getResourceUsage()
diff --git a/arm/headerPanel.py b/arm/headerPanel.py
index bf8a98e..b27a858 100644
--- a/arm/headerPanel.py
+++ b/arm/headerPanel.py
@@ -414,7 +414,8 @@ class HeaderPanel(panel.Panel, threading.Thread):
 
         isChanged = False
         if self.vals["tor/pid"]:
-          resourceTracker = sysTools.getResourceTracker(self.vals["tor/pid"])
+          resourceTracker = sysTools.getResourceTracker()
+          resourceTracker.set_process(self.vals["tor/pid"])
           isChanged = self._lastResourceFetch != resourceTracker.run_counter()
 
         if isChanged or currentTime - self._lastUpdate >= 20:
@@ -560,7 +561,8 @@ class HeaderPanel(panel.Panel, threading.Thread):
 
     # ps or proc derived resource usage stats
     if self.vals["tor/pid"]:
-      resourceTracker = sysTools.getResourceTracker(self.vals["tor/pid"])
+      resourceTracker = sysTools.getResourceTracker()
+      resourceTracker.set_process(self.vals["tor/pid"])
 
       if resourceTracker.lastQueryFailed():
         self.vals["stat/%torCpu"] = "0"
diff --git a/arm/starter.py b/arm/starter.py
index 16dc348..e728bfb 100644
--- a/arm/starter.py
+++ b/arm/starter.py
@@ -286,17 +286,17 @@ def _shutdown_daemons():
   # joins on utility daemon threads - this might take a moment since the
   # internal threadpools being joined might be sleeping
 
-  resource_trackers = arm.util.sysTools.RESOURCE_TRACKERS.values()
+  resource_tracker = arm.util.sysTools.getResourceTracker() if arm.util.sysTools.getResourceTracker().is_alive() else None
   connection_resolver = arm.util.tracker.get_connection_resolver() if arm.util.tracker.get_connection_resolver().is_alive() else None
 
-  for tracker in resource_trackers:
-    tracker.stop()
+  if resource_tracker:
+    resource_tracker.stop()
 
   if connection_resolver:
     connection_resolver.stop()  # sets halt flag (returning immediately)
 
-  for tracker in resource_trackers:
-    tracker.join()
+  if resource_tracker:
+    resource_tracker.join()
 
   if connection_resolver:
     connection_resolver.join()  # joins on halted resolver
diff --git a/arm/util/sysTools.py b/arm/util/sysTools.py
index d6baef0..e2ec45e 100644
--- a/arm/util/sysTools.py
+++ b/arm/util/sysTools.py
@@ -10,7 +10,7 @@ import arm.util.tracker
 
 from stem.util import conf, log, proc, str_tools, system
 
-RESOURCE_TRACKERS = {}  # mapping of pids to their resource tracker instances
+RESOURCE_TRACKER = None
 
 # Runtimes for system calls, used to estimate cpu usage. Entries are tuples of
 # the form:
@@ -56,26 +56,17 @@ def getSysCpuUsage():
   runtimeSum = sum([entry[1] for entry in RUNTIMES])
   return runtimeSum / SAMPLING_PERIOD
 
-def getResourceTracker(pid, noSpawn = False):
+def getResourceTracker():
   """
-  Provides a running singleton ResourceTracker instance for the given pid.
-
-  Arguments:
-    pid     - pid of the process being tracked
-    noSpawn - returns None rather than generating a singleton instance if True
+  Singleton for tracking the resource usage of our tor process.
   """
 
-  if pid in RESOURCE_TRACKERS:
-    tracker = RESOURCE_TRACKERS[pid]
-    if tracker.isAlive(): return tracker
-    else: del RESOURCE_TRACKERS[pid]
+  global RESOURCE_TRACKER
+
+  if RESOURCE_TRACKER is None:
+    RESOURCE_TRACKER = ResourceTracker()
 
-  if noSpawn: return None
-  tracker = ResourceTracker()
-  tracker.set_process(pid)
-  RESOURCE_TRACKERS[pid] = tracker
-  tracker.start()
-  return tracker
+  return RESOURCE_TRACKER
 
 class ResourceTracker(arm.util.tracker.Daemon):
   """
@@ -140,6 +131,9 @@ class ResourceTracker(arm.util.tracker.Daemon):
     return self._failureCount != 0
 
   def task(self):
+    if self._procss_pid is None:
+      return
+
     timeSinceReset = time.time() - self.lastLookup
 
     newValues = {}