module AppRevision

Returns the current application git commit SHA. Will look first in the APP_REVISION environment variable, then in the REVISION file written by Capsitrano, then in the Git history and lastly will return 'unknown' will be returned

Constants

ENV_VARS
VERSION

Public Class Methods

current() click to toggle source

Calls `determine_current` with memoization.

# File lib/app_revision.rb, line 15
def self.current
  @current ||= determine_current
end

determine_current() click to toggle source

Performs version detection in the following order: APP_REVISION -> REVISION file -> git -> “unknown” and returns the current commit/revision SHA as a String

# File lib/app_revision.rb, line 22
def self.determine_current
  detected_rev_str = read_from_env || read_from_revision_file || determine_from_git_rev || unknown_revision
  up_to_newline(detected_rev_str)
end

Private Class Methods

determine_from_git_rev() click to toggle source

# File lib/app_revision.rb, line 37
def self.determine_from_git_rev
  cmd_output = `git rev-parse --verify HEAD`.strip
  return cmd_output if cmd_output =~ /^[a-f\d]{40}$/
end

read_from_env() click to toggle source

# File lib/app_revision.rb, line 42
def self.read_from_env
  ENV_VARS.each do |envvar|
    envvar_value = ENV.fetch(envvar, '').strip
    return envvar_value unless envvar_value.empty?
  end
  nil
end

read_from_revision_file() click to toggle source

# File lib/app_revision.rb, line 50
def self.read_from_revision_file
  my_directory = File.dirname(__FILE__)
  my_location = File.split(File.expand_path(my_directory))
  begin
    File.read(File.join(my_location + ['REVISION'])).chomp
  rescue Errno::ENOENT
    my_location.pop # Remove the last path part and try again
    if my_location.empty?
      return nil
    else
      retry
    end
  end
end

unknown_revision() click to toggle source

# File lib/app_revision.rb, line 33
def self.unknown_revision
  'unknown'
end

up_to_newline(str) click to toggle source

# File lib/app_revision.rb, line 29
def self.up_to_newline(str)
  str.scan(/[a-z0-9\-]+/)[0]
end