post-receive hook for marley

post-receive.rb

#!/usr/bin/env ruby
#based on /usr/share/doc/git-core/contrib/hooks/post-receive-email

require 'syslog'
 
MARLEY_DIR="/home/git/marley"

def log(msg)
  Syslog.open
  Syslog.debug(msg)
  Syslog.close
end

def parse_rev(old_rev, new_rev, ref_name)
  raise ArgumentError,  "need all parameters" unless old_rev && new_rev && ref_name
  
	oldrev=`git rev-parse #{old_rev}`
	newrev=`git rev-parse #{new_rev}`

	# --- Interpret
	# 0000->1234 (create)
	# 1234->2345 (update)
	# 2345->0000 (delete)
	if oldrev =~ /\A0*\E/
		change_type="create"
	else
		if newrev =~ /\A0*\E/
			change_type="delete"
		else
			change_type="update"
		end
	end
    
	# --- Get the revision types
	newrev_type=`git cat-file -t #{newrev}`.to_s.strip
	oldrev_type=`git cat-file -t #{oldrev}`.to_s.strip
	
	case change_type
    when "create", "update":
		  rev=newrev
		  rev_type=newrev_type		
	  when "delete":
		  rev=oldrev
		  rev_type=oldrev_type		
	end

	case ref_name
    when %r{refs/tags/(\w+)}:
	    refname_type  = rev_type == 'commit' ? 'tag' : 'annotated tag'
	    short_refname = $1
    when %r{refs/(heads|remotes)/(\w+)}:
      refname_type  = $1 == 'heads' ? 'branch' : 'tracking branch'
      short_refname = $2
	  else
	    raise ArgumentError, "unknown ref_name: '#{ref_name}'"
  end
	{
	  :refname_type  => refname_type,
	  :short_refname => short_refname,
	  :rev_type => rev_type,
	  :rev => rev
	}
end

def update_marley(dir, commit)
  if commit[:rev_type] == 'commit' && commit[:short_refname] == 'zegoggles'
	  log "updating blog with commit rev: #{commit[:rev]}"	  
	  print <<-`EOC`
      unset GIT_DIR
      cd #{dir} && git pull origin #{commit[:short_refname]} && touch tmp/restart.txt
    EOC
    $?
  else
    0
  end
end

if $0 == __FILE__
  # Allow dual mode: run from the command line just like the update hook, or if no arguments are given then run as a hook script  
  commit_info = if ARGV.size == 3
    parse_rev(ARGV[0], ARGV[1], ARGV[2])
  else
    stdin = STDIN.read
    if stdin.scan(/^([0-9a-z]+)\s([0-9a-z]+)\s(.+)$/) 
      parse_rev($1, $2, $3)
    else
      raise ArgumentError, "invalid git hook received: #{stdin.strip}"
    end
  end    
  exit(update_marley(MARLEY_DIR, commit_info))
end