How to include a YAML file inside a YAML file in Ruby

Question

Is there a custom tag in YAML for ruby to include a YAML file inside a YAML file?

#E.g.:  
--- !include
filename: another.yml

A similar question was asked some time ago and there was no relevant answer.

I am wondering if there is some custom tag for Ruby similar to this one for Python.

Answer 1

If you are in Rails, YAML can include ERB.

Combine that together, and here is how you can use <%= %> to include one file from another:

database.yml

<% if File.exists?('/tmp/mysql.sock') %>
<%= IO.read('config/database.mysql.yml') %>
<% else %>
<%= IO.read('config/database.sqlite.yml') %>
<% end %>

database.sqlite.yml

sqlite: &defaults
  adapter: sqlite3
  pool: 5
  timeout: 5000

development:
  <<: *defaults
  database: db/development.sqlite3

test:
  <<: *defaults
  database: db/test.sqlite3

production:
  <<: *defaults
  database: db/production.sqlite3

database.mysql.yml

development:
  adapter: mysql2
  # ... the rest of your mysql configuration ...