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
Add this to your deploy.rb
:
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
Then:
cap cache:winddown
… wait 1 hr …
cap deploy:migrations
… profit!
-
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.