mountmgr

#!/usr/bin/ruby
require 'json'
require 'tempfile'
require 'logger'
require 'open3'

LOCK_FILE = '/run/mountmgr.lock'
LOG_FILE = '/var/log/mountmgr.log'

ENV['PATH'] = '/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin'
ENV['SSH_AUTH_SOCK'] = '/var/lib/auth-keys/sockets/default'
ENV['SDC_KEY_ID'] = %x{ssh-add -l}.split[1]
ENV['SDC_ACCOUNT'] = %x{hostname}.strip

def sh(cmd, input: nil, check: true)
  $log.info("CMD: #{cmd}")
  $logfile.flush
  outlines = []
  Open3.popen3(cmd) do |stdin, stdout, stderr, waiter|
    stdin.write(input) if not input.nil?
    stdin.close
    fds = [stdout, stderr]
    loop do
      rs, _, _ = IO.select(fds)
      rs.each do |fd|
        if fd.eof?
          fds.delete(fd)
          next
        end
        line = fd.readline.chomp
        if fd == stdout and line != ''
          outlines << line
          $log.info('> ' + line)
        elsif fd == stderr
          $log.error('> ' + line)
        end
      end
      break if fds.empty?
    end
    exit_status = waiter.value
    if exit_status != 0 and check
      raise Exception.new("Command '#{cmd}' exited with status #{exit_status}")
    end
  end
  outlines
end

$lock = File.open(LOCK_FILE, File::CREAT)
$lock.flock(File::LOCK_EX)

#$logfile = File.open(LOG_FILE, File::WRONLY | File::APPEND | File::CREAT | File::SYNC)
$logfile = STDERR
$log = Logger.new($logfile)
$log.level = Logger::DEBUG

digest = nil

loop do
  uri = 'https://comp4703-control.uqcloud.net/nfs/exports'
  uri += "/#{digest}" if digest
  $log.debug("requesting #{uri}")
  obj = nil
  begin
    data = sh("sdc-curl -s #{uri}")
    obj = JSON.parse(data.join("\n"), :symbolize_names => true)
  rescue Exception
    sleep 1
    next
  end
  next unless obj[:digest]
  next if digest == obj[:digest]
  digest = obj[:digest]
  $log.debug("digest is now #{digest}")

  oldf = File.new('/etc/exports')
  newf = Tempfile.new('.exports', '/etc')
  until oldf.eof?
    line = oldf.readline
    if line =~ /^\s*#/
      newf.puts line
    elsif line =~ /^\s*#\s*KEEP/
      newf.puts line
      newf.puts oldf.readline
    end
  end
  oldf.close
  obj[:mounts].each do |mount|
    newf.puts "/storage/home/#{mount[:username]}\t\t#{mount[:mountip]}/32(rw,sync,crossmnt)"
    newf.puts "/storage/conda/#{mount[:username]}\t\t#{mount[:mountip]}/32(rw,sync,crossmnt)"
    newf.puts "/storage/cache/#{mount[:username]}\t\t#{mount[:mountip]}/32(rw,sync,crossmnt)"
  end
  newf.chmod(0644)
  newf.close

  diff = %x{diff -u /etc/exports #{newf.path}}
  $log.debug("diff = #{diff}")

  File.rename(newf.path, '/etc/exports')
  $log.debug("rebuilt exports")

  sh('exportfs -ra')
end