add decorator to retry failed requests

weboob/tools/decorators.py

@@ -0,0 +1,49 @@
+# -*- coding: utf-8 -*-
+
+# Copyright(C) 2010  Christophe Benz
+# 
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, version 3 of the License.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+import logging
+import time
+
+
+__all__ = ['retry']
+
+
+def retry(ExceptionToCheck, tries=4, delay=3, backoff=2):
+    """
+    Retry decorator
+    from http://www.saltycrane.com/blog/2009/11/trying-out-retry-decorator-python/
+    original from http://wiki.python.org/moin/PythonDecoratorLibrary#Retry
+    """
+    def deco_retry(f):
+        def f_retry(*args, **kwargs):
+            mtries, mdelay = tries, delay
+            try_one_last_time = True
+            while mtries > 1:
+                try:
+                    return f(*args, **kwargs)
+                    try_one_last_time = False
+                    break
+                except ExceptionToCheck, e:
+                    logging.debug(u'%s, Retrying in %d seconds...' % (e, mdelay))
+                    time.sleep(mdelay)
+                    mtries -= 1
+                    mdelay *= backoff
+            if try_one_last_time:
+                return f(*args, **kwargs)
+            return
+        return f_retry # true decorator
+    return deco_retry