Bash script for redis key migration

redis-migrate.sh

#!/usr/bin/env bash

######
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
# TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
# CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.
######

######
###	Migrates the keys responding to the pattern specified on the command line, using DUMP/RESTORE, supports authentication differently from MIGRATE
######

PATTERN=$1
# add -a before passwords
SOURCE_PASSWORD=""
SOURCE_PORT=6379
SOURCE_SCHEMA=0
# add -a before passwords
TARGET_PASSWORD=""
TARGET_PORT=6379
TARGET_SCHEMA=4

# log file
LOG_FILE="redis-migrate.log"

# iteration
START=0
COUNT=10000

# ttl
TTL=7889400

WAIT_COUNT=$2

if [[ -z "$PATTERN" ]]; then
	echo -e "Please provide a KEYS matcher, like *~cache"
	exit 1
fi

echo "*** Migrating keys matching $PATTERN"

M_COUNT=0
while true; do
    echo " ** starting from $START counts $COUNT"
    redis-cli ${SOURCE_PASSWORD} -p ${SOURCE_PORT} SCAN ${START} MATCH ${PATTERN} COUNT ${COUNT} | while read KEY; do
        [[ ${KEY} == ERR* ]] && echo "*** Keys matched with $PATTERN TTL updated to $TTL and migrated to destination db." && exit
        [[ ${KEY} == 0 ]] && continue
        # Get TTL for the key in the source
        KEY_TTL=`redis-cli ${SOURCE_PASSWORD} -p ${SOURCE_PORT} TTL "$KEY"`
        # Check if the key is immortal
        if [[ ${KEY_TTL} -lt 1 ]]; then
            echo "  * set expiration and migrate: $KEY"
            # Set TTL for the key in the source
            redis-cli ${SOURCE_PASSWORD} -p ${SOURCE_PORT} EXPIRE "$KEY" ${TTL} >> ${LOG_FILE} 2>&1
            redis-cli --raw -p ${SOURCE_PORT} -n ${SOURCE_SCHEMA} ${SOURCE_PASSWORD} DUMP "$KEY" | head -c -1 | redis-cli -x -p ${TARGET_PORT} -n ${TARGET_SCHEMA} ${TARGET_PASSWORD} RESTORE "$KEY" ${TTL}  >> ${LOG_FILE} 2>&1
            echo "Dump/Restore \"$KEY\", ttl $TTL" >> ${LOG_FILE} 2>&1
            M_COUNT=$((M_COUNT+1))
        fi
        if [[ $((M_COUNT%WAIT_COUNT)) -eq 0 ]]; then
            sleep 1
        fi
    done

    START=$((COUNT + START))
done

echo "Exiting."