Attachment 890842 Details for Bug 1091404 – atomic cache write patch

[patch] atomic cache write patch

0001-cache.py-limit-cache-writing-window-limit-chance-of-.patch (text/plain), 1.61 KB, created by Ales Zelinka on 2014-04-29 14:40:36 UTC

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Creator: Ales Zelinka

Created: 2014-04-29 14:40:36 UTC

Size: 1.61 KB

patch

obsolete

>From 36d246d5f69d90f659bfa54262a548ef4719f4b1 Mon Sep 17 00:00:00 2001
>From: Ales Zelinka <azelinka@redhat.com>
>Date: Tue, 29 Apr 2014 16:39:41 +0200
>Subject: [PATCH] cache.py: limit cache writing window, limit chance of cache
> corruption
>
>---
> source/cache.py | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
>diff --git a/source/cache.py b/source/cache.py
>index 217c9f2..c7572bc 100644
>--- a/source/cache.py
>+++ b/source/cache.py
>@@ -114,6 +114,7 @@ import gzip
> import pickle
> import atexit
> import datetime
>+import tempfile
> import xmlrpclib
> import nitrate.immutable as immutable
> import nitrate.mutable as mutable
>@@ -263,11 +264,18 @@ class Cache(object):
> 
>         # Dump the cache object into file
>         try:
>-            output_file = gzip.open(self._filename, 'wb')
>+            # Use temporary file to minimize the time during which
>+            # is the real cache inconsistent
>+            output_file=tempfile.NamedTemporaryFile(mode='wb',
>+                    delete=False,prefix="nitrate-cache.",
>+                    dir=os.path.dirname(self._filename))
>+            log.debug("Temporary cache file {0}".format(output_file.name))
>+            output_file = gzip.open(output_file.name, 'wb')
>             log.debug("Saving persistent cache into {0}".format(
>                     self._filename))
>             pickle.dump(data, output_file)
>             output_file.close()
>+            os.rename(output_file.name,self._filename)
>             log.debug("Persistent cache successfully saved")
>         except IOError, error:
>             log.error("Failed to save persistent cache ({0})".format(error))
>-- 
>1.8.3.1
>

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Attachments on bug 1091404: 890809 | 890842