memcached_dump.sh

#!/bin/bash

# Dumps memcached data from one server and restores on another.
# Useful for copying production data to staging.
# 
# Generates a ./user_ids file with the users that were copied and an ./error file for errors. 
# The user_ids file can be plugged into the JMeter RTS load generator.
#
# Takes a maximum number of entries to copy. If unspecified it copies everything.
#
# Usage:
#  ./memcached_dump source dest [max]
#  ./memcached_dump.sh "rts-cache01.sliad.dataxu.net:1760" "test-rts-cache01.us01.dataxu.net:1760" 1000

SOURCE=$1
DEST=$2
MAX=$3

if [[ -z $SOURCE || -z $DEST ]]; then
  echo 'Usage: ./memcached_dump [source] [dest]'
  echo 'Example: ./memcached_dump.sh "rts-cache01.sliad.dataxu.net:1760" "test-rts-cache01.us01.dataxu.net:1760" 1000'
  exit 1
fi

echo "Dumping ${SOURCE} to ${DEST}"
if [[ -n $MAX ]]; then
  echo "Copying at most ${MAX} entries"
else
  echo "Copying all entries!"
fi

DATA_DIR=/tmp/memcached_dump

rm -rf ${DATA_DIR}
mkdir -p ${DATA_DIR}

echo "Dumping..."
export MEMCACHED_SERVERS=${SOURCE}
if [[ -n $MAX ]]; then
  dump_cmd="memcdump | head -${MAX}"
else
  dump_cmd="memcdump"
fi

eval "${dump_cmd}" | xargs -n1 -i bash -c "memccat {} --file ${DATA_DIR}/{} && echo {}" >./user_ids 2>error

echo "`du -sh ${DATA_DIR}`"

echo "Restoring..."
export MEMCACHED_SERVERS=${DEST}
find ${DATA_DIR} -type f -exec memccp {} \;

echo "Done!"
exit 0