Rate Watcher: Improve locking behavior in corner cases

desbma · Nov 12, 2016 · ed57e3a · ed57e3a
1 parent 970747a
commit ed57e3a
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Showing 2 changed files with 8 additions and 4 deletions.
diff --git a/requirements.txt b/requirements.txt
@@ -1,6 +1,6 @@
 appdirs>=1.4.0
 cssselect>=0.9.1
-lockfile>=0.12.2
+lockfile==0.12.2
 lxml>=3.3.3,<4.0.0
 mutagen>=1.31
 pillow>=2.7.0

diff --git a/sacad/rate_watcher.py b/sacad/rate_watcher.py
@@ -11,7 +11,8 @@
 import lockfile
 
 
-MIN_WAIT_TIME_S = 0.05
+MIN_WAIT_TIME_S = 0.01
+SUSPICIOUS_LOCK_AGE_S = 120
 
 
 class WaitNeeded(Exception):
@@ -81,7 +82,10 @@ def _getLock(self):
       try:
         plock.acquire(timeout=0)
       except (lockfile.LockTimeout, lockfile.AlreadyLocked):
-        # TODO detect and break locks of dead processes
+        # detect and break locks of dead processes
+        lock_age = time.time() - os.path.getmtime(plock.lock_file)
+        if lock_age > SUSPICIOUS_LOCK_AGE_S:
+          plock.break_lock()
         tlock.release()
       except:
         tlock.release()
@@ -91,5 +95,5 @@ def _getLock(self):
     return False
 
   def _releaseLock(self):
-    __class__.thread_locks[self.domain].release()
     lockfile.FileLock(os.path.join(self.lock_dir, self.domain)).release()
+    __class__.thread_locks[self.domain].release()