amahi/platform

# Amahi Home Server
# Copyright (C) 2007-2013 Amahi
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License v3
# (29 June 2007), as published in the COPYING file.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# file COPYING for more details.
# 
# You should have received a copy of the GNU General Public
# License along with this program; if not, write to the Amahi
# team at http://www.amahi.org/ under "Contact Us."

require 'platform'
require 'command'

class Server < ApplicationRecord

    # CAUTION - this class *assumes* new servers are created
    # started and enabled at boot time as services!

    PID_PATH = "/var/run"

    validates_uniqueness_of :name
    validates_presence_of :name

    before_save  :before_save_hook
    after_create  :create_hook
    after_destroy  :destroy_hook

    def self.create_default_servers
        Server.create(:name => 'smb', :pidfile => Platform.file_name(:samba_pid), :comment => I18n.t('file_server_samba'))
        r = "# WARNING - This file was automatically generated on #{Time.now}\n" \
            "\nset daemon 30\n" \
            "include #{Platform.file_name(:monit_dir)}/logging\n" \
            "include #{Platform.file_name(:monit_dir)}/*.conf\n"
        fname = TempCache.unique_filename "server-conf"
        f = File.new fname, "w"
        f.write r
        c = Command.new("cp -f #{f.path} #{Platform.file_name(:monit_conf)}")
        c.submit("rm -f #{f.path}")
        c.submit("chmod 644 #{Platform.file_name(:monit_log)}")
        c.submit Platform.watchdog_restart_command
        c.execute
        f.close
    end

    def pids
        estimate_pids
    end

    def do_start
        c = Command.new start_cmd
        c.execute
    end

    def do_stop
        c = Command.new stop_cmd
        c.execute
    end

    def do_restart
        c = Command.new stop_cmd
        c.submit start_cmd
        c.execute
    end

    def stopped?
        pids.empty?
    end

    def running?
        !stopped?
    end

    # in some cases, some server names have many instances, named with @, e.g. openvpn@amahi
    def clean_name
        name.gsub /@/, '-'
    end

protected

    def pid_file
        tmp = self.pidfile || (self.name + ".pid")
        (tmp =~ /^\//) ? tmp : File.join(PID_PATH, tmp)
    end

    def start_cmd
        Platform.service_start_command(name)
    end

    def stop_cmd
        Platform.service_stop_command(name)
    end

    def enable_cmd
        Platform.service_enable_command(name)
    end

    def disable_cmd
        Platform.service_disable_command(name)
    end

    def destroy_hook
        c = Command.new("rm -f #{File.join(Platform.file_name(:monit_dir), Platform.service_name(name))}.conf")
        c.submit Platform.watchdog_restart_command
        c.submit disable_cmd
        c.submit stop_cmd
        c.execute
    end

    def cmd_file
        "# WARNING - This file was automatically generated on #{Time.now}\n"    \
        "check process #{self.clean_name} with pidfile \"#{self.pid_file}\"\n"    \
            "\tstart program = \"#{self.start_cmd}\"\n"                \
            "\tstop  program = \"#{self.stop_cmd}\"\n"
    end

    def monit_file_add
        fname = TempCache.unique_filename "server-#{self.name}"
        open(fname, "w") { |f| f.write cmd_file }
        c = Command.new "cp -f #{fname} #{File.join(Platform.file_name(:monit_dir), Platform.service_name(self.name))}.conf"
        c.submit "rm -f #{fname}"
        c.submit Platform.watchdog_restart_command
        c.execute
    end

    def monit_file_remove
        c = Command.new("rm -f #{File.join(Platform.file_name(:monit_dir), Platform.service_name(name))}.conf")
        # FIXME - this conrestart does not help on ubuntu, as there is no such thing
        c.submit Platform.watchdog_restart_command
        c.execute
    end

    def service_enable
        c = Command.new enable_cmd
        c.execute
    end

    def service_disable
        c = Command.new disable_cmd
        c.execute
    end

    def before_save_hook
        if monitored_changed?
            monitored ? monit_file_add : monit_file_remove
            # DEBUG RAILS_DEFAULT_LOGGER.info "* * * MONITORED CHANGED to #{monitored}"
        end
        if start_at_boot_changed?
            start_at_boot ? service_enable : service_disable
            # DEBUG RAILS_DEFAULT_LOGGER.info "* * * START_AT_BOOT CHANGED to #{start_at_boot}"
        end
    end

    def create_hook
        c = Command.new enable_cmd
        c.submit start_cmd
        c.execute
        monit_file_add
    end

    # estimate the status of the PIDs
    def estimate_pids
        pf = pid_file
        ret = []
        begin
            # check if the pid file is there
            if File.exists?(pf) && File.readable?(pf)
                # check the pid file and check for the process existance
                open(pf) do |p|
                    list = p.readlines.map{ |line| line.gsub(/\n/, '').split(' ') }.flatten
                    ret = list.map{|pid| File.exists?("/proc/#{pid}") ? pid : nil }.compact
                end
            end
        rescue
            # something went wrong
        end
        return ret unless ret.empty?

        # use pgrep instead - fails in many cases, but
        # it's *some fallback*
        begin
            IO.popen("pgrep #{Platform.service_name name}") do |p|
                ret = p.readlines.map {|pid| pid.gsub(/\n/, '')}
            end
            return ret unless ret.empty?
            # third fallback -- wtf??
            IO.popen("pgrep #{name}") do |p|
                ret = p.readlines.map {|pid| pid.gsub(/\n/, '')}
            end
        rescue
            []
        end
        ret
    end

end