gddo-server: Use memcache to cache HTTP transport.

The memcache underneath is using the gomemcache package, which can be
used both as a standalone app or in App Engine. The cache will reduce a
significant amount of HTTP requests we make when updating packages. Most
of the requests are to GitHub. So this change will save a lot against
GitHub rate limits.

Change-Id: I46c7c4bd658b7b2ab18ca67e8c8d25549181dfb4
Reviewed-by: Alan Donovan <>
Reviewed-by: Andrew Gerrand <>
3 files changed