mysqlfs.rb

mysqlfs.rb

#!/usr/bin/ruby
#
#  Quick proof of concept hack to get a MySQL Filesystem working via FUSE.
#
#  Once mounted you can view all database tables and their contents.
#
#  NB:  Assumes mysqldump will run with: --user='root' --pass=''
#
#  Documentation:
#
#        http://www.debian-administration.org/articles/619
#
# Steve
# --
#


require 'fusefs'


class MySQLDIR

  # login credentials for MySQL
  attr_reader :username, :password


  #
  #  Constructor here is where you change the username
  # and password.
  #
  def initialize( username = "root", password = "" )
    @username = username
    @password = password
  end



  #
  #  Find all databases
  #
  def get_databases()
    `mysql --batch  --user=#{@username} --pass='#{@password}' -e "show databases"  | grep -v ^Database\$`.split("\n")
  end



  #
  #  Show the tables for the named database
  #
  def get_tables(db)

    # strip the leading "/"
    if ( db =~ /^\/(.*)/ )
      db=$1
    end
    `mysql --batch --user='#{@username}' --pass='#{@password}' #{db} -e "show tables" | grep -v ^Tables_in_#{db}\$`.split("\n")
  end



  #
  #  Read the contents of a path, two versions:
  #
  #  contents(/)       => Show databases
  #  contents(/dbname) => Show tables in database "dbname"
  #
  def contents(path)
    if ( path == "/" )
      get_databases()
    else
      names = get_tables( path )
      results = Array.new
      names.each do |name|
        results.push( "#{name}.sql" )
        results.push( "#{name}.data" )
      end
      results
    end
  end



  #
  #  Is the given path a directory?
  #
  def directory?(path)
    paths = get_databases()
    paths.each do |db|
      return true if ( "/#{db}" == path )
    end
    nil
  end



  #
  #  Always true is fine.  Oddly enough.
  #
  def file?(path)
      true
  end



  #
  #  Read a file
  #
  # either:
  #
  #  database-name/table-name.sql  => Table structure
  #  database-name/table-name.data => Table structure + data
  #
  def read_file(path)

    # reading "dbname/table" == dumping structure.
    if ( path =~ /^\/([^\/]+)\/(.*)$/ )
      db=$1
      tbl=$2

      if ( tbl =~ /(.*)\.sql$/i )
        `mysqldump --user='#{@username}' --pass='#{@password}' #{db} #{$1} --no-data`
      elsif (tbl =~ /(.*)\.data$/i )
        `mysqldump --user='#{@username}' --pass='#{@password}' #{db} #{$1}`
      else
        nil
      end
    end
  end
end




#
#  Make sure we have a mount-point
#
if ( ! File.directory?( "/mysql" ) )
  puts "/mysql doesn't exist"
  exit
end

#
#  Make sure we're root
#
if ( ENV["USER"] != "root" )
  puts "Run me as root, please"
  exit
end

#
#  Load the module - which might not be present.
#
Kernel.system( "modprobe fuse    2>/dev/null >/dev/null" )


#
#  Setup & run.
#
dir = MySQLDIR.new()
FuseFS.set_root(dir)
FuseFS.mount_to "/mysql", "allow_other"
FuseFS.run