[Zconfig] SVN: ZConfig/trunk/ fix race condition problem with emit when reopening logs

[Fred Drake]

Log message for revision 124374:
  fix race condition problem with emit when reopening logs
  (https://bugs.launchpad.net/zconfig/+bug/481512; patch by Henning Eggers)

Changed:
  U   ZConfig/trunk/NEWS.txt
  U   ZConfig/trunk/ZConfig/components/logger/loghandler.py
  U   ZConfig/trunk/ZConfig/components/logger/tests/test_logger.py

-=-
Modified: ZConfig/trunk/NEWS.txt
===================================================================
--- ZConfig/trunk/NEWS.txt	2012-02-11 05:40:21 UTC (rev 124373)
+++ ZConfig/trunk/NEWS.txt	2012-02-11 06:04:50 UTC (rev 124374)
@@ -6,7 +6,9 @@
 ZConfig 2.9.1 (unreleased)
 --------------------------
 
+- Make FileHandler.reopen thread safe.
 
+
 ZConfig 2.9.0 (2011-03-22)
 --------------------------
 

Modified: ZConfig/trunk/ZConfig/components/logger/loghandler.py
===================================================================
--- ZConfig/trunk/ZConfig/components/logger/loghandler.py	2012-02-11 05:40:21 UTC (rev 124373)
+++ ZConfig/trunk/ZConfig/components/logger/loghandler.py	2012-02-11 06:04:50 UTC (rev 124374)
@@ -84,8 +84,12 @@
         _remove_from_reopenable(self._wr)
 
     def reopen(self):
-        self.stream.close()
-        self.stream = open(self.baseFilename, self.mode)
+        self.acquire()
+        try:
+            self.stream.close()
+            self.stream = open(self.baseFilename, self.mode)
+        finally:
+            self.release()
 
 
 class Win32FileHandler(FileHandler):

Modified: ZConfig/trunk/ZConfig/components/logger/tests/test_logger.py
===================================================================
--- ZConfig/trunk/ZConfig/components/logger/tests/test_logger.py	2012-02-11 05:40:21 UTC (rev 124373)
+++ ZConfig/trunk/ZConfig/components/logger/tests/test_logger.py	2012-02-11 06:04:50 UTC (rev 124374)
@@ -537,7 +537,24 @@
                 logger.removeHandler(handler)
                 handler.close()
 
+    def test_filehandler_reopen_thread_safety(self):
+        # The reopen method needs to do locking to avoid a race condition
+        # with emit calls. For simplicity we replace the "acquire" and
+        # "release" methods with dummies that record calls to them.
 
+        fn = self.mktemp()
+        h = self.handler_factory(fn)
+
+        calls = []
+        h.acquire = lambda: calls.append("acquire")
+        h.release = lambda: calls.append("release")
+
+        h.reopen()
+        h.close()
+
+        self.assertEqual(calls, ["acquire", "release"])
+
+
 class TestReopeningRotatingLogfiles(TestReopeningLogfilesBase):
 
     _sampleconfig_template = """