file filter-backends: stability fix for sporadically errors - always close file handle, otherwise may be locked (prevent log-rotate, etc.)

fail2ban/server/filter.py

@@ -799,6 +799,8 @@ class FileFilter(Filter):
 		if log is None:
 			logSys.error("Unable to get failures in " + filename)
 			return False
+		# We should always close log (file), otherwise may be locked (log-rotate, etc.)
+		try:
 			# Try to open log file.
 			try:
 				has_content = log.open()
@@ -830,17 +832,14 @@ class FileFilter(Filter):
 					logSys.exception(e)
 					return False
 
-		# yoh: has_content is just a bool, so do not expect it to
-		# change -- loop is exited upon break, and is not entered at
-		# all if upon container opening that one was empty.  If we
-		# start reading tested to be empty container -- race condition
-		# might occur leading at least to tests failures.
-		while has_content:
+			if has_content:
+				while not self.idle:
 					line = log.readline()
 					if not line or not self.active:
 						# The jail reached the bottom or has been stopped
 						break
 					self.processLineAndAdd(line)
+		finally:
 			log.close()
 		db = self.jail.database
 		if db is not None: