#!/usr/bin/env ruby

# -------------------------------------------------------------------------- */
# Copyright 2002-2012, OpenNebula Project Leads (OpenNebula.org)             #
# Licensed under the Apache License, Version 2.0 (the "License"); you may    */
# not use this file except in compliance with the License. You may obtain    */
# a copy of the License at                                                   */
#                                                                            */
# http://www.apache.org/licenses/LICENSE-2.0                                 */
#                                                                            */
# Unless required by applicable law or agreed to in writing, software        */
# distributed under the License is distributed on an "AS IS" BASIS,          */
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   */
# See the License for the specific language governing permissions and        */
# limitations under the License.                                             */
# -------------------------------------------------------------------------- */

# ----------------------------------------------------------------------------
# Set up the environment for the driver
# ----------------------------------------------------------------------------

ONE_LOCATION = ENV["ONE_LOCATION"]

if !ONE_LOCATION
    RUBY_LIB_LOCATION = "/usr/lib/one/ruby"
    VAR_LOCATION      = "/var/lib/one"
else
    RUBY_LIB_LOCATION = ONE_LOCATION + "/lib/ruby"
    VAR_LOCATION      = ONE_LOCATION + "/var"
end

$: << RUBY_LIB_LOCATION

require "OpenNebulaDriver"
require 'getoptlong'
require 'base64'
require 'rexml/document'

# This class provides basic messaging and logging functionality
# to implement Datastore Drivers. A datastore driver
# is a program (or a set of) that  specialize the OpenNebula behavior
# by interfacing with specific infrastructure storage solutions.
class DatastoreDriver < OpenNebulaDriver

    # Image Driver Protocol constants
    ACTION = {
        :cp    => "CP",
        :rm    => "RM",
        :mkfs  => "MKFS",
        :log   => "LOG",
        :stat  => "STAT",
        :clone => "CLONE"
    }

    # Register default actions for the protocol
    def initialize(ds_type, options={})
        @options={
            :concurrency => 10,
            :threaded => true,
            :retries => 0,
            :local_actions => {
                ACTION[:stat] => nil,
                ACTION[:cp]   => nil,
                ACTION[:rm]   => nil,
                ACTION[:mkfs] => nil,
                ACTION[:clone]=> nil
            }
        }.merge!(options)

        super("datastore/", @options)

        if ds_type == nil
            @types = Dir["#{@local_scripts_path}/*/"].map do |d|
                d.split('/')[-1]
            end
        elsif ds_type.class == String
            @types = [ds_type]
        else
            @types = ds_type
        end

        register_action(ACTION[:cp].to_sym,   method("cp"))
        register_action(ACTION[:rm].to_sym,   method("rm"))
        register_action(ACTION[:mkfs].to_sym, method("mkfs"))
        register_action(ACTION[:stat].to_sym, method("stat"))
        register_action(ACTION[:clone].to_sym,method("clone"))
    end

    ############################################################################
    # Image Manager Protocol Actions (generic implementation)
    ############################################################################

    def cp(id, drv_message)
        ds = get_ds_type(drv_message)
        do_image_action(id, ds, :cp, "#{drv_message} #{id}")
    end

    def rm(id, drv_message)
        ds = get_ds_type(drv_message)
        do_image_action(id, ds, :rm, "#{drv_message} #{id}")
    end

    def mkfs(id, drv_message)
        ds = get_ds_type(drv_message)
        do_image_action(id, ds, :mkfs, "#{drv_message} #{id}")
    end

    def stat(id, drv_message)
        ds = get_ds_type(drv_message)
        do_image_action(id, ds, :stat, "#{drv_message} #{id}")
    end

    def clone(id, drv_message)
        ds = get_ds_type(drv_message)
        do_image_action(id, ds, :clone, "#{drv_message} #{id}")
    end

    private

    def is_available?(ds, id, action)
        if @types.include?(ds)
            return true
        else
            send_message(ACTION[action], RESULT[:failure], id,
                "Datastore driver '#{ds}' not available")
            return false
        end
    end

    def do_image_action(id, ds, action, arguments)
        return if not is_available?(ds,id,action)

        path = File.join(@local_scripts_path, ds)
        cmd  = File.join(path, ACTION[action].downcase)

        cmd << " " << arguments

        rc = LocalCommand.run(cmd, log_method(id))

        result, info = get_info_from_execution(rc)

        send_message(ACTION[action], result, id, info)
    end

    def get_ds_type(drv_message)
        message = Base64.decode64(drv_message)
        xml_doc = REXML::Document.new(message)

        dsxml = xml_doc.root.elements['/DS_DRIVER_ACTION_DATA/DATASTORE/DS_MAD']
        dstxt = dsxml.text if dsxml

        return dstxt
    end
end

################################################################################
################################################################################
# DatastoreDriver Main program
################################################################################
################################################################################

opts = GetoptLong.new(
    [ '--threads',  '-t', GetoptLong::OPTIONAL_ARGUMENT ],
    [ '--ds-types', '-d', GetoptLong::OPTIONAL_ARGUMENT ]
)

ds_type = nil
threads = 15

begin
    opts.each do |opt, arg|
        case opt
            when '--threads'
                threads = arg.to_i
            when '--ds-types'
                ds_type = arg.split(',').map {|a| a.strip }
        end
    end
rescue Exception => e
    exit(-1)
end

ds_driver = DatastoreDriver.new(ds_type, :concurrency => threads)
ds_driver.start_driver
