#!/bin/bash
#
# kill-thread.sh
#  Simple shell script to kill mysql db connections based on filters
#
# Changelog
#  2014-03-28 - Nathan Isburgh <nathan@edgecloud.com>
#             * Initial version
#

# Debug flag?  1=on, 0=off
DEBUG=1

# Additional user-customized variables...

#
# END OF CONFIGURATION VARIABLES
# NO MORE EDITS BEYOND THIS POINT
#

# Functions...

#
# fail [exit code] [exit message]
#
# Common exit codes:
#  1 - Invalid arguments
#  2 - Missing arguments
#  3 - Missing software
#
fail() {
  cleanup
  ECODE=${1:-1}
  EMSG=$2
  if [ -n "$EMSG" ]
  then
    echo -e "\033[33m$EMSG\033[39m" > /dev/stderr
  fi
  exit $ECODE
}

succeed() {
  cleanup
  exit
}

cleanup() {
  # Clean up temp files
  # Close out logs
  # Disconnect from remote resources
  return
}

#
# debug "message"
#
debug() {
  if [ $DEBUG -eq 1 ]
  then
    printf "\033[32m*** [%s] %s\033[39m\n" "$(date +%r)" "$1" > /dev/stderr
  fi
}

usage() {
  cat << eof
  $0 [-u user] [-h host] [-d db] [-c command]
    -u user     Kill connections from 'user'
    -h host     Kill connections from 'host'
    -d db       Kill connections on 'db'
    -c command  Kill connections running 'command'
eof
}

kill-threads() {
  # Get list of all connections and details about the connections
  # Filter list by supplied parameters
  # Use mysqladmin kill to kill off the connections that match
  mysql -N -e "show full pROcESSlIST" | fgrep -v 'pROcESSlIST' | awk -F"\t" "\$2 ~ /$FILTER_USER/ && \$3 ~ /$FILTER_HOST/ && \$4 ~ /$FILTER_DB/ && \$8 ~ /$FILTER_CMD/ {print \$1}" | xargs -n1 mysqladmin kill
}

# Main body...
FILTER_USER=""
FILTER_HOST=""
FILTER_DB=""
FILTER_CMD=""

while getopts ":u:h:d:c:" opt; do
  case $opt in
    u)
      FILTER_USER="$OPTARG"
      ;;
    h)
      FILTER_HOST="$OPTARG"
      ;;
    d)
      FILTER_DB="$OPTARG"
      ;;
    c)
      FILTER_CMD="$OPTARG"
      ;;
    \?)
      usage
      fail 1 "Invalid option: -$OPTARG"
      ;;
    :)
      usage
      fail 1 "Option -$OPTARG requires an argument."
      ;;
  esac
done

debug "Killing things"
kill-threads

succeed