#!/bin/bash
# set|unset server to read-only mode
# variables:
# src = ip address or socket 
# login|password or /root/.my.cnf
# status=off|on
set -e

DEFAULT_CONF=/root/.my.cnf # can set login and password from file
DEFAULT_CONF_USAGE=0

LOGDIR=/opt/webdir/logs
[[ ! -d $LOGDIR ]] && mkdir -m 750 $LOGDIR
TMPDIR=/tmp
[[ -d /dev/shm ]] && TMPDIR=/dev/shm
TMPFILE=$TMPDIR/.$(date +%s)_bx_mysql_$$

save_log(){
  message=$1
  log_file=$LOGDIR/readonly_mysql.log

  printf "%-15s: %s\n" "$(date +%Y/%m/%d:%H:%M:%S)" "$message" >> $log_file
}

# print error message
error_message_and_exit() {
  e_message=$1
  save_log "$e_message"
  echo "{\"changed\":false,\"failed\":true,\"msg\":\"$e_message\"}"
  [[ -f $TMPFILE ]] && rm -f $TMPFILE
  exit 1
}

# print ok message
ok_message_and_exit() {
  o_message=$1
  save_log "$o_message"
  echo "{\"changed\":true,\"msg\":\"$o_message\"}"
  [[ -f $TMPFILE ]] && rm -f $TMPFILE
  exit 0
}

# test mandatory option and print error if not exists
test_variables() {
  for desc in "src=$src" "login=$login" "password=$password" "status=$status"; do
    var=$(echo $desc | cut -d'=' -f1)
    val=$(echo $desc | cut -d'=' -f2)

    if [[ -z "$val" ]]; then
      # test if login and password needed variables  
      if [[ ( "$var" == "login" ) || ( "$var" == "password" ) ]]; then
        if [[ ! -f "$DEFAULT_CONF" ]]; then
          error_message_and_exit "option $var= is mandatory, you must define it or set in $DEFAULT_CONF file"
        fi
        DEFAULT_CONF_USAGE=1  
      else
        error_message_and_exit "option $var= is mandatory, you must define it"
      fi
    fi
  done
}

set_mysql_mode(){
  save_log "start set read-only mode to $status"

  if [[ $DEFAULT_CONF_USAGE -eq 1 ]]; then
    src_mysql_cmd="mysql --defaults-file=$DEFAULT_CONF"
    save_log " usage default config $DEFAULT_CONF"
  else
    src_mysql_cmd="mysql --user=$login --password=$password"
    save_log " usage login and password"
  fi


  if [[ $(echo $src | grep -c '^/') -gt 0 ]]; then
    src_mysql_cmd=$src_mysql_cmd" --socket=$src"
  else
    src_mysql_cmd=$src_mysql_cmd" --host=$src"
  fi

  if [[ $(echo "$status" | grep -iwc 'ON') -gt 0 ]]; then
    $src_mysql_cmd -e "FLUSH TABLES WITH READ LOCK; SET GLOBAL read_only = ON;" > $TMPFILE 2>&1
    save_log "$src_mysql_cmd -e \"FLUSH TABLES WITH READ LOCK; SET GLOBAL read_only = ON;\""
    if [[ $? -gt 0 ]]; then
      error_message_and_exit "mysql cmd return error: $(head -1 $TMPFILE)"
    fi
  elif [[ $(echo "$status" | grep -iwc 'OFF') -gt 0 ]]; then
    $src_mysql_cmd -e "SET GLOBAL read_only = OFF; UNLOCK TABLES;" > $TMPFILE 2>&1
    if [[ $? -gt 0 ]]; then
      error_message_and_exit "mysql cmd return error: $(head -1 $TMPFILE)"
    fi
  else
    error_message_and_exit "option status can be ON or OFF"
  fi

  ok_message_and_exit "set mysql to status=$status"

}

# get options from file
source ${1}

test_variables

set_mysql_mode