roxy

This redis protocol service will act as a redis service and mirror the commands between two redis servers. Used for zero downtime migration.

Through mirroring we can we can migrate between Redis instances without downtime when replication is not an option (e.x ElasticCache), or do capacity check in a safe way. Commands will mirror in the second redis in an async and non-fatal way.

Diagram

Demo

Note: you will only need docker to test the setup

# Start the main redis server
$ docker run --rm --name redis-main -p 6379:6379 redis
# Start the mirror redis server
$ docker run --rm --name redis-mirror -p 6381:6379 redis

# complile and run the mirror service in docker
$ docker run -ti --rm -v $PWD/:/ws --workdir /ws -p 6380:6380 golang:1 go run *.go \
     -redis1 host.docker.internal:6379 -redis2 host.docker.internal:6381 -addr :6380


# connect to the redis-mirror service (6380)
$ docker run -ti --rm --entrypoint /usr/local/bin/redis-cli redis -h host.docker.internal -p 6380 SET KEY VAL
OK
$ docker run -ti --rm --entrypoint /usr/local/bin/redis-cli redis -h host.docker.internal -p 6380 GET KEY
"VAL"

# check the value in the main server
$ docker run -ti --rm --entrypoint /usr/local/bin/redis-cli redis -h host.docker.internal -p 6379 GET KEY
"VAL"
# check the value in the mirror server
$ docker run -ti --rm --entrypoint /usr/local/bin/redis-cli redis -h host.docker.internal -p 6381 GET KEY
"VAL"