Setting environment variable at runtime in Rails

Question

I have running rails application. I cannot restart the server.

I have an environment variable that I need to change. I tried to do it through the rails console

ENV['SCORE'] = "123"

It updates variable for the current rails c session:

ENV['SCORE']
=> "123"

But has no effect on the variable that application is using.

Is there a way to permanently change environment variable at runtime?

Your rails server and your rails console are two separate processes. Objects are not shared between them and ENV is no exception. — Stefan
– Stefan, Commented Sep 8, 2014 at 11:29

zeeraw · Accepted Answer · 2014-09-08 13:17:15Z

4

If you want to share data between processes you typically use some kind of storage. In this situation, an in-memory key/value storage like Redis (http://redis.io/) seems optimal for your use case.

Install and run Redis, then put the gem in your Gemfile.

gem "redis"

In your code connect to the database

require "redis"

client = Redis.new
client.set("score", 123)

client.get("score")
# => "123"

client.incr("score")
# => "124"

answered Sep 8, 2014 at 13:17

zeeraw

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Comments

javiyu · Accepted Answer · 2014-09-08 10:59:20Z

0

If you create an initializer with that code

ENV['SCORE'] = "123"

the value will persist.

answered Sep 8, 2014 at 10:59

javiyu

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2 Comments

Alex Smolov Over a year ago

I will need to restart my server then. I am wondering if there is solution for running application?

zeeraw Over a year ago

Modifying an environment variable in one server thread won't change it for others.

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