diff options
Diffstat (limited to 'main/utils.py')
| -rw-r--r-- | main/utils.py | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/main/utils.py b/main/utils.py index ae446ab..d7681cb 100644 --- a/main/utils.py +++ b/main/utils.py @@ -5,6 +5,12 @@ except ImportError: from django.core.cache import cache from django.utils.hashcompat import md5_constructor +CACHE_TIMEOUT = 1800 +INVALIDATE_TIMEOUT = 15 + +CACHE_PACKAGE_KEY = 'cache_package_latest' +CACHE_NEWS_KEY = 'cache_news_latest' + def cache_function_key(func, args, kwargs): raw = [func.__name__, func.__module__, args, kwargs] pickled = pickle.dumps(raw, protocol=pickle.HIGHEST_PROTOCOL) @@ -40,7 +46,23 @@ def clear_cache_function(func, args, kwargs): key = cache_function_key(func, args, kwargs) cache.delete(key) -#utility to make a pair of django choices +# utility to make a pair of django choices make_choice = lambda l: [(str(m), str(m)) for m in l] +# These are in here because we would be jumping around in some import circles +# and hoops otherwise. The only thing currently using these keys is the feed +# caching stuff. + +def refresh_package_latest(**kwargs): + # We could delete the value, but that could open a race condition + # where the new data wouldn't have been committed yet by the calling + # thread. Instead, explicitly set it to None for a short amount of time. + # Hopefully by the time it expires we will have committed, and the cache + # will be valid again. See "Scaling Django" by Mike Malone, slide 30. + cache.set(CACHE_PACKAGE_KEY, None, INVALIDATE_TIMEOUT) + +def refresh_news_latest(**kwargs): + # same thoughts apply as in refresh_package_latest + cache.set(CACHE_NEWS_KEY, None, INVALIDATE_TIMEOUT) + # vim: set ts=4 sw=4 et: |