How to solve an error in Heroku's config/database.yml file "mapping values are not allowed in this context"
heroku, heroku-postgres, psych, ruby, sinatra
Solution
Okay after some more research I have worked out the problem. Sigh.
On my local machine I am loading my database configuration as follows:
dbconfig = YAML::load(File.open(File.join("config","database.yml")))
but because the `yml` file that Heroku generates is actually an `ERB` file in disguise, I need to parse it first.
Changing the above line to:
dbconfig = YAML.load(ERB.new(File.read(File.join("config","database.yml"))).result)
works a treat.
Problem
I'm deploying an app to Heroku and it's mostly fine but for this error ``` mapping values are not allowed in this context at line 22 column 13 (Psych::SyntaxError) ``` The line they are referring to is line 22 of the database.yml file that Heroku itself is writing over my own file, as per standard practice. Jumping into `heroku run bash` and taking a look at the file in question: ``` <% require 'cgi' require 'uri' begin uri = URI.parse(ENV["DATABASE_URL"]) rescue URI::InvalidURIError raise "Invalid DATABASE_URL" end raise "No RACK_ENV or RAILS_ENV found" unless ENV["RAILS_ENV"] || ENV["RACK_ENV"] def attribute(name, value, force_string = false) if value value_string = if force_string '"' + value + '"' else value end "#{name}: #{value_string}" else "" end end adapter = uri.scheme adapter = "postgresql" if adapter == "postgres" database = (uri.path || "").split("/")[1] username = uri.user password = uri.password host = uri.host port = uri.port params = CGI.parse(uri.query || "") %> <%= ENV["RAILS_ENV"] || ENV["RACK_ENV"] %>: <%= attribute "adapter", adapter %> <%= attribute "database", database %> <%= attribute "username", username %> <%= attribute "password", password, true %> <%= attribute "host", host %> <%= attribute "port", port %> <% params.each do |key, value| %> <%= key %>: <%= value.first %> <% end %> ``` Line 22 is ``` "#{name}: #{value_string}" ``` Any suggestions as to how to resolve this problem?