REDIS.md

Redis

Each time an API call is made, Dory queries GitHub to discover the author and published date of each post — for these cases it's important that you are authenticating with GitHub otherwise default rate limits apply. However by introducing Redis into the mix, those queries are cached using a TTL defined in the dory.yml configuration.

By default Dory doesn't connect to Redis — it instead waits until REDIS_HOST has been defined as an environment variable before any connection is attempted.

Setting up Heroku

Using Redis on Heroku requires finding a provider — we have a choice of which provider we use, but for the remainder of the article we'll use Redis Cloud as these provide the most space — 30MB — for free. Once you have applied Redis Cloud to your Heroku app, you will need to rename the environment variable Heroku has just added to REDIS_HOST.

Redis Cloud provides 30MB which should be more than sufficient for Dory, however you are able to pay or even introduce your own Redis instance as long as it's accessible remotely.

Development

For development you can use the Redis instance on Heroku — or you could opt to install Redis locally. You simply need to have the REDIS_HOST in your list of environment variables.

However using Redis is purely optional, and without Redis configured locally each API call will simply query GitHub — and although slightly slower than cached Redis responses, may well be preferred for your development environment.

By default all Redis keys are cached for 120 seconds — you can change this by modifying cacheExpiration from the dory.yml configuration.

Summary

• You can log onto your remote Redis host by the details listed on RedisLabs.
• Issue the KEYS * command to display all cached GitHub keys;
• Use each key with GET to display its cached content;
• Use TTL to see when each key is set to expire;
• Use FLUSHALL to remove all keys from the Redis instance;