"how to backup a local git repository?" Code Answer

i started hacking away a bit on yar's script and the result is on github, including man pages and install script:

https://github.com/najamelan/git-backup

installation:

git clone "https://github.com/najamelan/git-backup.git"
cd git-backup
sudo ./install.sh

welcoming all suggestions and pull request on github.

#!/usr/bin/env ruby
#
# for documentation please sea man git-backup(1)
#
# todo:
# - make it a class rather than a function
# - check the standard format of git warnings to be conform
# - do better checking for git repo than calling git status
# - if multiple entries found in config file, specify which file
# - make it work with submodules
# - propose to make backup directory if it does not exists
# - depth feature in git config (eg. only keep 3 backups for a repo - like rotate...)
# - testing



# allow calling from other scripts
def git_backup


# constants:
git_dir_name    = '.git'          # just to avoid magic "strings"
filename_suffix = ".git.bundle"   # will be added to the filename of the created backup


# test if we are inside a git repo
`git status 2>&1`

if $?.exitstatus != 0

   puts 'fatal: not a git repository: .git or at least cannot get zero exit status from "git status"'
   exit 2


else # git status success

   until        file::directory?( dir.pwd + '/' + git_dir_name )             
            or  file::directory?( dir.pwd                      ) == '/'


         dir.chdir( '..' )
   end


   unless file::directory?( dir.pwd + '/.git' )

      raise( 'fatal: directory still not a git repo: ' + dir.pwd )

   end

end


# git-config --get of version 1.7.10 does:
#
# if the key does not exist git config exits with 1
# if the key exists twice in the same file   with 2
# if the key exists exactly once             with 0
#
# if the key does not exist       , an empty string is send to stdin
# if the key exists multiple times, the last value  is send to stdin
# if exaclty one key is found once, it's value      is send to stdin
#


# get the setting for the backup directory
# ----------------------------------------

directory = `git config --get backup.directory`


# git config adds a newline, so remove it
directory.chomp!


# check exit status of git config
case $?.exitstatus

   when 1 : directory = dir.pwd[ /(.+)/[^/]+/, 1]

            puts 'warning: could not find backup.directory in your git config file. please set it. see "man git config" for more details on git configuration files. defaulting to the same directroy your git repo is in: ' + directory

   when 2 : puts 'warning: multiple entries of backup.directory found in your git config file. will use the last one: ' + directory

   else     unless $?.exitstatus == 0 then raise( 'fatal: unknown exit status from git-config: ' + $?.exitstatus ) end

end


# verify directory exists
unless file::directory?( directory )

   raise( 'fatal: backup directory does not exists: ' + directory )

end


# the date and time prefix
# ------------------------

prefix           = ''
prefix_date      = time.now.strftime( '%f'       ) + ' - ' # %f = yyyy-mm-dd
prefix_time      = time.now.strftime( '%h:%m:%s' ) + ' - '
add_date_default = true
add_time_default = false

prefix += prefix_date if git_config_bool( 'backup.prefix-date', add_date_default )
prefix += prefix_time if git_config_bool( 'backup.prefix-time', add_time_default )



# default bundle name is the name of the repo
bundle_name = dir.pwd.split('/').last

# set the name of the file to the first command line argument if given
bundle_name = argv[0] if( argv[0] )


bundle_name = file::join( directory, prefix + bundle_name + filename_suffix )


puts "backing up to bundle #{bundle_name.inspect}"


# git bundle will print it's own error messages if it fails
`git bundle create #{bundle_name.inspect} --all --remotes`


end # def git_backup



# helper function to call git config to retrieve a boolean setting
def git_config_bool( option, default_value )

   # get the setting for the prefix-time from git config
   config_value = `git config --get #{option.inspect}`

   # check exit status of git config
   case $?.exitstatus

      # when not set take default
      when 1 : return default_value

      when 0 : return true unless config_value =~ /(false|no|0)/i

      when 2 : puts 'warning: multiple entries of #{option.inspect} found in your git config file. will use the last one: ' + config_value
               return true unless config_value =~ /(false|no|0)/i

      else     raise( 'fatal: unknown exit status from git-config: ' + $?.exitstatus )

   end
end

# function needs to be called if we are not included in another script
git_backup if __file__ == $0