String Interpolation in escaped erb tag

Question

I have a ERB(database.yml.erb) file template for database.yml for rendering using chef 11.10

I want to have an output(after rendering in chef) in database.yml, like below:

default: &default
  adapter: mysql2
  username: <%= ENV['diff_db_user'] || <username> %>
  password: <%= ENV['diff_db_password'] || <password> %>
  ...

In the above yaml, I expect the values <username> and <password> are substituted from @node[:database][:username] & @node[:database][:password]

So, the reason I wanted to do this is, to use a different password just by setting the environment variable while running a rake job like db migration

So, I tried the above with using escaping the erb tag as mentioned in How do I escape the ERB tag in ERB but in the output yml I could see the value is not substituted, it just prints the variable itself

for example I had an erb like this:

default: &default
      adapter: mysql2
      username: <%%= ENV['diff_db_user'] || @node[:database][:username] %>
      password: <%%= ENV['diff_db_password'] || @node[:database][:password] %>
      ...

The output I'm getting for it is:

default: &default
  adapter: mysql2
  username: <%= ENV['diff_db_user'] || @node[:database][:username] %>
  password: <%= ENV['diff_db_password'] || @node[:database][:password] %>
  ...

So, wanted to know is there any other way for to get printed like the one I initially mentioned at the top, when using template in chef to render the erb to yml

@SebastianPalma : I have edited the question and added the output I got — sarathprasath, Jun 07 '20 at 08:31

score 0 · Answer 1 · answered Jun 07 '20 at 09:29

0

You could add another item in database.yml

development_with_password:      
  adapter: mysql2
  username: 
  password:

and call it in your rake task e.g.

RAILS_ENV=development_with_password rails db:migrate

answered Jun 07 '20 at 09:29

Eyeslandic

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score 0 · Answer 2 · answered Jun 07 '20 at 11:06

Something like this?! You need yo use nested <% %> tags, escaping the outer ones. Also don't forget the quotes.

username: <%%= ENV['diff_db_user'] || "<%= @node[:database][:username] %>" %>
password: <%%= ENV['diff_db_password'] || "<%= @node[:database][:password] %>" %>

String Interpolation in escaped erb tag

2 Answers2