migrate-redis-without-migrate.sh

# This script migrates keys from a redis instance to another using only redis-cli
# This is necessary if you're migrating from a redis instance where MIGRATE command is removed
#   such as heroku or aws elasticache

# Caveat & Notes:
# • Does not preserve expiry time or ttl
# • Slow, copies keys sequentially, took about 5 minutes for 500 keys

set -Eueo pipefail

SOURCE_HOST=ec2-12-34-567-890.eu-west-1.compute.amazonaws.com
SOURCE_PORT=12345
SOURCE_DB=0
SOURCE_AUTH=6a0f0731d84afa4082031e3a72354991

TARGET_HOST=containers-us-west-123.railway.app
TARGET_PORT=12345
TARGET_DB=0
TARGET_AUTH=286755fad04869ca523320acce0dc6a4

function redis-source() {
  REDISCLI_AUTH="$SOURCE_AUTH" redis-cli -h $SOURCE_HOST -p $SOURCE_PORT -n $SOURCE_DB $@
}

function redis-target() {
  REDISCLI_AUTH="$TARGET_AUTH" redis-cli -h $TARGET_HOST -p $TARGET_PORT -n $TARGET_DB $@
}

# Check Connection
printf "Source Redis PING... "
redis-source PING
printf "Target Redis PING... "
redis-target PING

REDISCLI_AUTH="$SOURCE_AUTH" redis-cli -h $SOURCE_HOST -p $SOURCE_PORT -n $SOURCE_DB keys \* | while read key; do
  printf "$key... "
  redis-source --raw DUMP $key | head -c-1 | redis-target -x RESTORE $key 0
done