This works fine provided you only have a single instance of your app running, otherwise that timestamp may be different for each instance, causing the etags to change depending on which instance is serving each request - therefore defeating the whole point of them.
If you want to handle this properly, you’ll want to use something like the current Git checkout hash, or a timestamp persisted in a file (I believe Capistrano does this) - then the ENV[“RAILS_APP_VERSION”] variable is more suitable (purely semantics). I’m not sure either of those methods are available for Heroku though…
ryantownsend —
I’ve just confirmed Capistrano does indeed do this… it prints a revision hash into a file, see:
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This works fine provided you only have a single instance of your app running, otherwise that timestamp may be different for each instance, causing the etags to change depending on which instance is serving each request - therefore defeating the whole point of them.
If you want to handle this properly, you’ll want to use something like the current Git checkout hash, or a timestamp persisted in a file (I believe Capistrano does this) - then the ENV[“RAILS_APP_VERSION”] variable is more suitable (purely semantics). I’m not sure either of those methods are available for Heroku though…
I’ve just confirmed Capistrano does indeed do this… it prints a revision hash into a file, see:
(echo 603cee4906d2f7c43b6911e3ba2534cc82593d14 > /path/to/app/releases/20120730094816/REVISION)This command will be the same, executed across all servers so it’s safe to use in your initializer.
So here’s what I’d do:
revision_file = Rails.root.join("REVISION") if File.exist?(revision_file) ENV["RAILS_APP_VERSION"] = File.read(revision_file) endPost a comment