Rails: No connection pool for ActiveRecord::Base

Question

I\'m trying to use rails 4.2.6 to develop an app. I\'m trying to use postgres for database. Server starts fine but when I try loading a page it throws this \"No connection p

Answer 1

In my case, the config/database.yml was taking variables from the environment:

# ...
test:
  <<: *default
  database: <%= ENV.fetch("DB_NAME") %>_test
  username: <%= ENV.fetch("DB_USER") %>
  password: <%= ENV.fetch("DB_PASS") %>
# ...

The error was coming when the new terminal window where I was running the bundle exec rails spec did not have those variables initialized.

Doing,

$ export DB_NAME=mydb
$ export DB_USER=myuser
$ export DB_PASS=mypass
$ bundle exec rails spec

fixed the issue.