Getting DB Configuration from require - ruby

Question

Right now I've got a simple Sinatra app that connects to a DB.
Right now I have the connection strings hard-coded inside the repo itself. My aim is to return the connection information from a different file (which will eventually be outside the repo).
This is what I've tried so far:
app.rb
class MySinatraApp < Sinatra::Application
configure do
conf = require_relative 'configuration'
# set public dirs, sessions, etc.
set :mongourl, conf[:mongourl]
set :mongodb, conf[:mongodb]
end
end
...And finally in the configuration.rb
env = ENV['RACK_ENV'].to_sym
case env
when :production
return {
"mongourl" => 'mongodb://localhost/prod',
"mongodb" => 'prod'
}
when :development
return {
"mongourl" => 'mongodb://localhost/dev',
"mongodb" => 'prod'
}
else
return {
"mongourl" => 'mongodb://localhost/test',
"mongodb" => 'test'
}
end
The idea would be to just return whatever hash I need to use, however when I attempt the above, it errors out with these errors:
<my_project_dir>/configuration.rb: <my_project_dir>/configuration.rb:9: Invalid return (SyntaxError)
<my_project_dir>/configuration.rb:16: Invalid return
<my_project_dir>/configuration.rb:21: Invalid return
From the error, you are unable to return the way I'm doing it now. I am assuming this is because it isn't in a function call of some sort? How do people normally include configuration files in Ruby/ Sinatra?

Answer 1

You’re right that you can’t do this because you can’t return from a required file in this way (at least not at the moment). Your solution is using a top level constant rather than a global (global variables look like $foo, constants look like Foo or FOO) but it pretty much amounts to the same thing.
A common solution to doing configuration like this in Sinatra is with ConfigFile from Sinatra-contrib.
Create a config Yaml file:
production:
mongourl: mongodb://localhost/prod
mongodb: prod
develepment:
mongourl: mongodb://localhost/dev
mongodb: prod
test:
mongourl: mongodb://localhost/test
mongodb: test
Then in your Sinatra file (install the sinatra-contrib gem first):
require 'sinatra'
require 'sinatra/config_file'
config_file 'path/to/config.yml'
The settings from the config file will now be available according to the whatever environment is running.
Another way to do this kind of thing is to put all the configuration data into environment variables and then access them with ENV. Doing this prevents you from accidentally checking in production credentials to your version control, but it means you have to manage all the config vars somehow. Have a look at dotenv or Foreman for tools that can help with this if you want to go this way.

Answer 2

If anyone has a better way of including DB connection strings, please share!
I'm not going to say this is a better way, but I do it this way because it's simple.
More or less it's the same as sinatra/config_file.
So you have your config file with the different values for each environment
$cat config.yaml
development:
mongourl: mongodb://localhost/test
mongodb: dev
production:
mongourl: mongodb://localhost/test
mongodb: prod
And now just use it:
configure do
env = ENV['RACK_ENV']
AppConfig = YAML.load_file(File.expand_path("../config.yaml", File.dirname(__FILE__)))[env]
set :mongourl, AppConfig['mongourl']
set :mongodb, AppConfig['mongodb']
end

Answer 3

It would seem I can just declare a variable in the root of the require'ed file, it automatically is global (I think). In either case, this is how I changed the files to work:
app.rb
class MySinatraApp < Sinatra::Application
configure do
require_relative 'configuration'
# set public dirs, sessions, etc.
set :mongourl, CONFIG["mongourl"]
set :mongodb, CONFIG["mongodb"]
end
end
configuration.rb
env = ENV['RACK_ENV'].to_sym
case env
when :production
CONFIG = {
"mongourl" => 'mongodb://localhost/prod',
"mongodb" => 'prod'
}
when :development
CONFIG = {
"mongourl" => 'mongodb://localhost/dev',
"mongodb" => 'prod'
}
else
CONFIG = {
"mongourl" => 'mongodb://localhost/test',
"mongodb" => 'test'
}
end
Not a super-big fan of having connection strings being in a global variable, but it will work for now I think. If anyone has a better way of including DB connection strings, please share!