How to add caching

Background

Sourcegraph is backed by two Redis caches, redis-cache and redis-store.

redis-cache should be favored as the two instances are to be consolidated into one.

Usage

Engineers are welcome to cache data as they see fit.

The cache instances are instantiated in internal/redispool. You can use the rcache package to read and write data to and from redis-cache, which you are also welcome to add to.

Troubleshooting local redis access

A simple way to test your caching locally is through the redis-cli. You can install it using brew if you do not have it:

brew install redis

You might run into the following error with sg after installing:

❌ Start Redis
   failed to write to Redis at 127.0.0.1:6379: MISCONF Redis is configured to save RDB snapshots, but it's currently unable to persist to disk. Commands that may modify the data set are disabled, because this instance is configured to report errors during writes if RDB snapshotting fails (stop-writes-on-bgsave-error option). Please check the Redis logs for details about the RDB error.

Potential solutions for this are:

  1. Restarting Redis (e.g. brew services restart redis)
  2. Changing the config to stop writes:
redis-cli 
> config set stop-writes-on-bgsave-error no
> exit