Getting svn version info from inside rails application

Rails
1

hi,

who has an example of how to retrieve svn-version information from
inside a rails application.

i’d like to display this information to the user, so that he can
report a bug relating to the version number.

retrieving should be quick as it is displayed on every view.

many thanks in advance,
siegi

2

You could parse the results of svn info then store it in a cached
class variable in your ApplicationHelper. In production mode, svn info would only be called once.

def svn_revision
(@@svn_revision rescue false) or
@@svn_revision = svn info.scan(/Revision: (\d+)/)[0][0]
end

Hacky, but…

3

On Apr 23, 2007, at 8:10 AM, eden li wrote:

many thanks in advance,
siegi

If you’re deploying with capistrano and have a revisions.log, you can
use something like this:

Layout:


<%= application_revision %>

<%= Time.now %>

Helper:
def application_revision
" ver. #{RevisionNumber.from_log}" rescue ‘’
end

From lib/revision_number.rb: Note that this uses the file-tail gem
to simplify getting the last line of the log file:

revision_number.rb

Copyright (c) 2007 Rob B.

Rob [at] AgileConsultingLLC.com

Rob_Biedenharn [at] alum.mit.edu

Permission is hereby granted, free of charge, to any person

obtaining a copy

of this software and associated documentation files (the

“Software”), to

deal in the Software without restriction, including without

limitation the

rights to use, copy, modify, merge, publish, distribute,

sublicense, and/or

sell copies of the Software, and to permit persons to whom the

Software is

furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be

included in

all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND,

EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT

SHALL THE

AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,

ARISING FROM,

OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

DEALINGS IN THE

SOFTWARE.

require ‘rubygems’
require ‘file/tail’

require ‘logger’

class RevisionNumber
@@logger = Logger.new(STDERR)
@@logger.level = ENV[‘RAILS_ENV’] == ‘development’ ?
Logger::DEBUG : Logger::INFO
@@logger.debug “Loading #{self}”

@@revision = {}

def self.from_log name=‘revisions.log’, forced=false
return @@revision[name] if @@revision.has_key?(name) && ! forced

 starting_dir = Dir.pwd
 begin
   @@logger.debug "Starting in #{Dir.pwd} to look for #{name}"
   this_dir = Dir.pwd
   until File.exists?(name) || this_dir == '/'
     Dir.chdir '..'
     @@logger.debug "Not found; moving up to #{Dir.pwd}"
     break if this_dir == Dir.pwd # I.e., Windows "c:/.." => "c:/"
     this_dir = Dir.pwd
   end

   begin
     @@logger.debug "In #{Dir.pwd}, ready to open #{name}..."

     rev = File.open(name) do |f|
       f.extend(File::Tail)
       f.backward(1).gets.match(/(\d+) \d{14}$/)[1]
     end
   rescue
     rev = 'indeterminant'
   else
     rev = 'unknown' if rev.nil?
   end
 ensure
   Dir.chdir(starting_dir)
 end

 @@revision[name] = rev

end
end

4

You might use a metadata file, accessible to the app, which includes
the svn revision, and then have that revision managed by svn’s
‘Revision’ keyword substitution:

http://svnbook.red-bean.com/nightly/en/
svn.advanced.props.special.keywords.html

-faisal

5

A variation:

In environment.rb

APP_REVISION = IO.popen(“svn info”).readlines[4] rescue “not found”

In your views/layout :

I place that line at the very bottom of layouts => I can quickly check
what version has been deployed withouth showing to the users who don’t
care.

Alain

6

If you’re deploying with capistrano and have a revisions.log, you can

revisions.log is phased out in Capistrano 2.x
see:
http://www.capify.org/upgrade

Alain

7

On Apr 23, 2007, at 2:27 AM, siegi wrote:

hi,

who has an example of how to retrieve svn-version information from
inside a rails application.

i’d like to display this information to the user, so that he can
report a bug relating to the version number.

retrieving should be quick as it is displayed on every view.

Hope you still need this, I’m a few days behind on reading the forums.

Here’s what I use, assuming you have svnversion in your path:

class ApplicationController < ActionController::Base
def svn_revision
@svn_revision ||= svnversion ..gsub(/^.*:/, ‘’).gsub(/[MS]/,
‘’).to_i
end
helper_method :svn_revision
end

That caches the revision number for the life of the Ruby process, so
it should be fast.

Brad