Online rails configuration generator using etcd as source data
Latest commit 0252857 Apr 29, 2016 @rubenfonseca Refactored flag usage.


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by Ruben Fonseca (rubenfonseca)

Online rails configuration generator using etcd as source data.



  • Bring the power of etcd live changes to your Rails app
  • Everytime there's a change on an etcd dir, your Rails config files are updated and processes are restarted
  • Written in Go so no runtime dependency on your production servers
  • Extendable system to support more rendererers (turns etcd data into files) and reloaders (reloads Rails processes)
  • Currently supported renderers:
    • YAML - renderes the etcd data to a .yml file
  • Currently supported reloaders:
    • Touch - touches tmp/restart.txt for passenger compatible servers.


$ go install
$ rails-configd -h

Example usage

First you have to set the data on your etcd cluster. Let's try to configure the database on our production rails app.

$ export DIR=rails_app01/database/production
$ etcdctl set $DIR/host
$ etcdctl set $DIR/adapter pg
$ etcdctl set $DIR/database db01
$ etcdctl set $DIR/username dbuser

Then, next to each Rails app, you should run a rails-configd daemon:

$ rails-configd --etcd http://localhost:4001 --etcd-dir /rails_app01 \
                --renderer yaml --yaml-file config/database.yml \
                --reloader touch

This will read from etcd under /rails_app01 directory and build the config/database.yml file. After this, any change to a key under the etcd-dir directory will trigger the generation of a new database.yml file, and reload the rails server by touching tmp/restart.txt.


Why another daemon to do this?

I believe this daemon does only one thing and does it right. I don't want to add another responsability to Rails. Also, since this is written in Go, you can distribute a binary to all your platforms with no runtime dependencies (aka: bundle install...)

But, what if I have more than one config file on my Rails app?

I also do :) Then the sollution is to run one rails-configd daemon for each file. Each daemon will read form a different etcd directory, and you can control the output file with the param yaml-file. Don't worry about resources, go daemons like this use very little memory :-)

But I'm running this super awesome application server that doesn't support reloading by touching tmp/restart.txt!

Then pachtes are welcome :) There's a reloader interface on the code that you can implement with your own reloading method!

Project details


rails-configd uses semantic versioning.


rails-configd is under MIT license. See the LICENSE file for details.