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[membash] BASH script which may be used to interact with memcache. All main memcache functions are supported. #memcache
#!/bin/bash
# Gist: 11375877
# Url: https://gist.github.com/goodevilgenius/11375877
#
# All memcache functions are supported.
#
# Can also be sourced from other scripts, e.g.
# source membash.sh
# MCSERVER="localhost"
# MCPORT=11211
# foobar=$(mc_get foobar)
# [ -z "$foobar" ] && foobar="default value"
# mc_set foobar 0 "$foobar"
# original author: wumin, https://gist.github.com/ri0day/1538831
# updated by goodevilgenius to support debian-based systems, support more
# functions, and be more user-friendly
mc_usage() {
format_usage="membash: a memcache library for BASH \n\
https://gist.github.com/goodevilgenius/11375877\n\n\
Usage:\n
\t $(basename "$0") [-hp] command [arguments] \n \
\t [-h]\t memcached hostname or ip. \n \
\t [-p]\t memcached port. \n\n\
Commands: \n \
\t usage (print this help) \n \
\t set/add/replace/append/prepend key exptime value \n \
\t touch key exptime \n \
\t incr/decr key value \n \
\t get key \n \
\t delete key [time] \n \
\t stats \n \
\t list_all_keys"
echo -e $format_usage
}
mc_help() { mc_usage;}
mc_sendmsg() { echo -e "$*\r" | nc $MCSERVER $MCPORT;}
mc_stats() { mc_sendmsg "stats";}
mc_get_last_items_id() {
LastID=$(mc_sendmsg "stats items"|tail -n 2|head -n 1|awk -F':' '{print $2}')
echo $LastID
}
mc_list_all_keys() {
:>/dev/shm/mc_all_keys_${MCSERVER}_${MCPORT}.txt
max_item_num=$(mc_get_last_items_id)
for i in `seq 1 $max_item_num`
do
mc_sendmsg "stats cachedump $i 0" | awk '{print $2}'
done >>/dev/shm/mc_all_keys_${MCSERVER}_${MCPORT}.txt
sed -i '/^$/d' /dev/shm/mc_all_keys_${MCSERVER}_${MCPORT}.txt
cat /dev/shm/mc_all_keys_${MCSERVER}_${MCPORT}.txt
}
mc_get() { mc_sendmsg "get $1" | awk "/^VALUE $1/{a=1;next}/^END/{a=0}a" ;}
mc_touch() {
key="$1"
shift
let exptime="$1"
shift
mc_sendmsg "touch $key $exptime"
}
mc_doset() {
command="$1"
shift
key="$1"
shift
let exptime="$1"
shift
val="$*"
let bytes=$(echo -n "$val"|wc -c)
mc_sendmsg "$command $key 0 $exptime $bytes\r\n$val"
}
mc_set() { mc_doset set "$@";}
mc_add() { mc_doset add "$@";}
mc_replace() { mc_doset replace "$@";}
mc_append() { mc_doset append "$@";}
mc_prepend() { mc_doset prepend "$@";}
mc_delete() { mc_sendmsg delete "$*";}
mc_incr() { mc_sendmsg incr "$*";}
mc_decr() { mc_sendmsg decr "$*";}
mc_superpurge() {
mc_list_all_keys > /dev/null
if [ ! -z "/dev/shm/mc_all_keys_${MCSERVER}_${MCPORT}.txt" ];then
grep "$1" /dev/shm/mc_all_keys_${MCSERVER}_${MCPORT}.txt >/dev/shm/temp.swap.${MCSERVER}_${MCPORT}.txt
fi
while read keys
do
mc_sendmsg "delete ${keys}"
done </dev/shm/temp.swap.${MCSERVER}_${MCPORT}.txt
rm -rf /dev/shm/temp.swap.${MCSERVER}_${MCPORT}.txt
}
if [ "$(basename "$0" .sh)" = "membash" ]
then
MCSERVER="localhost"
MCPORT=11211
while getopts "h:p:" flag
do
case $flag in
h)
MCSERVER=${OPTARG:="localhost"}
;;
p)
MCPORT=${OPTARG:="11211"}
;;
\?)
echo "Invalid option: $OPTARG" >&2
;;
esac
done
command="${@:$OPTIND:1}"
[ -z "$command" ] && command="usage"
let OPTIND++
mc_$command "${@:$OPTIND}"
exit $?
fi
@FabiusChiang

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FabiusChiang commented Mar 1, 2018

Thank you very much!

@IslandLife

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IslandLife commented Mar 22, 2018

Chking this script with shellcheck shows this comment

script if [ ! -z /dev/shm/mc_all_keys_${MCSERVER}_${MCPORT}.txt ];then
^-- SC2157: Argument to -z is always false due to literal strings.

and indeed the man page for test says

   -z STRING
          the length of STRING is zero

So the question is .. is -z the correct operator?

@IslandLife

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IslandLife commented Mar 22, 2018

When I invoke this script interactively with a single argument like "stats" it produces the result but does not close the connection.
I have to use control-C to exit. Everything else is ignored (including the nc command quit)

Perhaps you want to use a HERE statement where the passed argument is expanded and quit appended.
That way the connection closes after doing the required command.
Example
#!/usr/bin/env bash

set -u

command="stats"
nc "myhostname" 11211 << END_OF_INPUT
$command
quit
END_OF_INPUT

@IslandLife

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IslandLife commented Mar 22, 2018

mc_sendmsg() { nc "$MCSERVER" "$MCPORT" << END_OF_MSG
$*
quit

END_OF_MSG

perhaps..
}

@IslandLife

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IslandLife commented Mar 22, 2018

Or even allow multiple commands enclosing each one in quotes if they have spaces like "stat" "second cmd" ... "stat"
#!/usr/bin/env bash
#
set -u
#
arr_command=( $@ )
( IFS=$'\n'; echo "${arr_command[]}" )
nc "myservername" 11211 << END_OF_INPUT
$( IFS=$'\n'; echo "${arr_command[
]}" )
quit
END_OF_INPUT

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