Heroku buildpack: Redis

This is a Heroku buildpack that allows an application to use an stunnel to connect securely to Heroku Redis. It is meant to be used in conjunction with other buildpacks.

Usage

First you need to set this buildpack as your initial buildpack with:

$ heroku buildpacks:set https://github.com/mcity/heroku-buildpack-redis

Then you can add other buildpack(s) to compile your code like so:

$ heroku buildpacks:add https://github.com/heroku/heroku-buildpack-ruby.git

Choose the correct buildpack(s) for the language(s) used in your application.

For more information on using multiple buildpacks check out this devcenter article.

Next, for each process that should connect to Redis securely, you will need to preface the command in your Procfile with bin/start-stunnel. In this example, we want the web process to use a secure connection to Heroku Redis. The worker process doesn't interact with Redis, so bin/start-stunnel was not included:

$ cat Procfile
web:    bin/start-stunnel bundle exec unicorn -p $PORT -c ./config/unicorn.rb -E $RACK_ENV
worker: bundle exec rake worker

We're then ready to deploy to Heroku with an encrypted connection between the dynos and Heroku Redis:

$ git push heroku master
...
-----> Fetching custom git buildpack... done
-----> Multipack app detected
=====> Downloading Buildpack: https://github.com/heroku/heroku-buildpack-redis.git
=====> Detected Framework: stunnel
       Using stunnel version: 5.02
       Using stack version: cedar
-----> Fetching and vendoring stunnel into slug
-----> Moving the configuration generation script into app/bin
-----> Moving the start-stunnel script into app/bin
-----> stunnel done
=====> Downloading Buildpack: https://github.com/heroku/heroku-buildpack-ruby.git
=====> Detected Framework: Ruby/Rack
-----> Using Ruby version: ruby-2.2.2
-----> Installing dependencies using Bundler version 1.7.12
...

Configuration

The buildpack will install and configure stunnel to connect to REDIS_URL over a SSL connection. Prepend bin/start-stunnel to any process in the Procfile to run stunnel alongside that process.

Stunnel settings

Some settings are configurable through app config vars at runtime:

• STUNNEL_HOSTPORT: The host and port for the destination endpoint (Redis). ie. cache.mvillage.um.city:6380
• REDIS_URL: Include the username (optional) and password for the destination redis instance. Point at localhost:6380, which will be the Stunnel endpoint on your Dyno. ie. redis://:@localhost:6380

Troubleshooting

Redis URLs without a username

This buildpack assumes that every URL is with username and password. As Redis does not support usernames but only passwords you may encounter a problem here. Just invent a username and put it in your URL.

redis://:password@example.com:6379
=> Invent username (here "h")
redis://h:password@example.com:6379