#!/bin/bash
# es-maintenance-script.sh
# Notes:
# - https://www.elastic.co/guide/en/elasticsearch/guide/current/retiring-data.html
# - http://tech.superhappykittymeow.com/?p=296
# 
# Author: Gabriel C <shellcooking@gmail.com>

# Display instructions
help()
{
cat << EOF

es-maintenance-script.sh

Deletes old indexes and closes indexes until yesterday.

USAGE: ./es-maintenance-script.sh [opt]

Opt:
-help       Show this message
-i          Indices to keep (default: 20)
-es         ES Url (default: http://localhost:9200)
-prefix     Consistent index name (default: logstash)
-l          Log file for execution

EOF
}

# Default values
ES="http://localhost:9200"
KEEP=20
PREFIX="logstash"

# Pattern for dates
RE_D="^[0-9]+$"

while getopts ":i:e:prefix:l:help" flag
do
  case "$flag" in
    help)
      help
      exit 0
      ;;
    i)
      if [[ $OPTARG =~ $RE_D ]]; then
        KEEP=$OPTARG
      else
        echo -e "${ERROR} Indexes to keep must be an integer.\n"
        exit 1
      fi
      ;;
    es)
      ES=$OPTARG
      ;;
    prefix)
      PREFIX=$OPTARG
      ;;
    l)
      LOGFILE=$OPTARG
      ;;
    ?)
      help
      exit 1
      ;;
  esac
done

# Get the indices
INDICES=`curl -s "${ES}/_cat/indices?v" | awk '/'$PREFIX'/{match($0, /[:blank]*('$PREFIX'.[^ ]+)[:blank]*/, m); print m[1];}' | sort -r`
if [ -z "$INDICES" ]; then
  echo "No indices returned containing '${PREFIX}' from ${ES}."
  exit 1
fi

if [ -n "$LOGFILE" ] && ! [ -e $LOGFILE ]; then
  touch $LOGFILE
fi

declare -a INDEX=($INDICES)

# Closing indices
if [ ${#INDEX[@]} -gt 1 ]; then
    MAX=`expr ${KEEP} - 1`
    for index in `seq 1 $MAX`; do
        index=${INDEX[index]}
        if [ -n "$index" ]; then
            echo `date "+[%Y-%m-%d %H:%M] "`" Closing index: $index."
            curl -s -XPOST "${ES}/$index/_close" > /dev/null
            if [ ! -z "$LOGFILE" ]; then
                echo `date "+[%Y-%m-%d %H:%M] "`" Closing index: $index." >> $LOGFILE
            fi
        fi
    done
else
    echo "No indices to close"
fi

# Deleting indices
if [ ${#INDEX[@]} -gt $KEEP ]; then
    for index in ${INDEX[@]:$KEEP}; do
        if [ -n "$index" ]; then
            echo `date "+[%Y-%m-%d %H:%M] "`" Deleting index: $index."
            curl -s -XDELETE "${ES}/$index" > /dev/null
            if [ ! -z "$LOGFILE" ]; then
                echo `date "+[%Y-%m-%d %H:%M] "`" Deleting index: $index." >> $LOGFILE
            fi
        fi
    done
else
    echo "No indices to delete"
fi

exit 0