From d928641f7afde57ac012f9915dc44ebf5292c060 Mon Sep 17 00:00:00 2001
From: bernat <none>
Date: Tue, 22 Mar 2005 09:17:28 +0100
Subject: [PATCH] Backoff exponentiel pour tenter de robtenir le lock.

darcs-hash:20050322081728-d1718-a0c77f2ee05294f513cab9599ed62dce7f81c97a.gz
---
 gestion/lock.py | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/gestion/lock.py b/gestion/lock.py
index e08d6798..991a735c 100755
--- a/gestion/lock.py
+++ b/gestion/lock.py
@@ -11,12 +11,13 @@ import os,string,time,sys, affich_tools
 from commands import getoutput
 from user_tests import getuser
 from fcntl import lockf, LOCK_EX, LOCK_NB, LOCK_UN
-import errno
+import errno, random
 
-def wait_lock(lock_name, lock_comment='', d=None):
+def wait_lock(lock_name, lock_comment='', d=None, retry=0.2):
     """Attend la disponibilité d'un lock en utilisant le framework Twisted.
 
     Si d est de type Deferred, on est en mode asynchrone.
+    retry permet de réessayer dans `retry' secondes.
     """
     from twisted.internet import reactor, defer
     try:
@@ -44,8 +45,9 @@ def wait_lock(lock_name, lock_comment='', d=None):
         if not d:
             # On est en mode synchrone, on va passer en asynchrone
             d = defer.Deferred()
-        # On essaie de nouveau dans 200 ms.
-        reactor.callLater(0.2, wait_lock, lock_name, lock_comment, d)
+        # On essaie de nouveau plus tard
+        newretry = min(retry * 2, 4) + random.random() * 0.1 * retry
+        reactor.callLater(retry, wait_lock, lock_name, lock_comment, d, newretry)
         return d
 
 def make_lock(lock_name, lock_comment='',nowait=0, quiet=False) :