Use to wind down a running app when needed.
Limits the max-age to the contents of the
WIND_DOWN file, and salts the ETags to unsure clients see different deployments as having different contents.
require "rack/cache_buster" … use Rack::CacheBuster, APP_VERSION, WIND_DOWN_TIME
require "rack/cache_buster" … use Rack::CacheBuster::Rails
Before you deploy (capistrano):
Add this to your
begin gem "rack-cache-buster" require 'rack_cache_buster_recipes' rescue LoadError puts "\n\n*** Please gem install rack-cache-buster before trying to deploy.\n\n" end # set :wind_down_time, 60*60 # defaults to 1hr
… wait 1 hr …
Before you deploy (other):
Find the maximum cache duration for all pages in your app, start this process with at least that amount time before you deploy.
Create a WIND_DOWN file in the app root of all your app servers.
Restart all instances (touch tmp/restart.txt will be fine for passenger apps).
Once all the caches should have expired you can deploy as normal.
If you are using Rack::Cache, you can safely put the CacheBuster below it in the stack, but only if you clear Rack::Cache's cache upon deploy.
This is actually the recommended approach as it will prevent the increased amount of hits between
WIND_DOWN_TIME and your actual deployment from making it through to your app.