add pid to log

src/backend.py

@@ -8,7 +8,8 @@ import ConfigParser
 DEBUG=0
 
 def log(msg):
-    sys.stderr.write('backend: %s\n' % msg)
+    sys.stderr.write('backend (%s): %s\n' % (os.getpid(), msg))
+
 
 def write(*l):
     args=len(l)
@@ -24,6 +25,7 @@ def write(*l):
     sys.stdout.write('\n')
     sys.stdout.flush()
 
+
 def get_next():
     if DEBUG: log('reading now')
     l = sys.stdin.readline()