multiprocessing.Lock access to ManagerLog.write

rational: otherwise sub-processes sometimes write over each other

cloudtask/session.py

@@ -27,6 +27,8 @@
 
 import re
 
+from multiprocessing import Lock
+
 def makedirs(path, mode=0750):
     try:
         os.makedirs(path, mode)
@@ -141,11 +143,16 @@ def __getattr__(self, attr):
     class ManagerLog:
         def __init__(self, path):
             self.fh = file(path, "a", 1)
+            self.lock = Lock()
 
         def write(self, buf):
-            self.fh.write(buf)
-            sys.stdout.write(buf)
-            sys.stdout.flush()
+            self.lock.acquire()
+            try:
+                self.fh.write(buf)
+                sys.stdout.write(buf)
+                sys.stdout.flush()
+            finally:
+                self.lock.release()
 
         def __getattr__(self, attr):
             return getattr(self.fh, attr)