Displaying Deployment Date and Time and Git Revision Number in Rails Views

I had a need to display the deployment date and time (timestamp) and the current revision/version number in the footer of all our pages in our Rails application. Our users always were asking "Did you update the web site?"

Thanks to capistrano, the deployment tool, this turned out to be fairly easy. Capistrano already collects the deployed version and places it into a file named REVISION in the deployment directory. The contents hold whatever is reported by your version control software. For git, this is a SHA1 hash.

For the deployment timestamp, thankfully capistrano uses a timestamp for the deployment directory name. So we can just parse the path, looking for the timestamp.

Below is the helper code, please let me know if there's a better way.

[sourcecode language='ruby']
# pulls from the capistrano directory structure
def deploy_timestamp
if Rails.env.production?
RAILS_ROOT.split('/').last
else
"Undeployed"
end
end

def deploy_version
if Rails.env.production?
File.read("#{RAILS_ROOT}/REVISION")
else
"DEV - " + `git rev-parse HEAD`
end
end
[/sourcecode]

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