Rails does not consider `DATABASE_URL` in the `test` environment?

Question

I'm using docker-compose to create two services for my Rails application:

• web - the actual Rails/web app
• db - A postgres container running postgres 11.5

I'm running both services locally with RAILS_ENV=development .

As a one-time manual step I want to The very first time I try to run rake db:create to create the database. However, I get a postgres connection error:

docker-compose up --build --no-start
docker-compose run --rm web bundle exec rake db:create

RAILS_ENV=development bundle exec rake db:create
Created database 'feeder_development'
could not connect to server: Connection refused
  Is the server running on host "localhost" (127.0.0.1) and accepting
  TCP/IP connections on port 5432?
could not connect to server: Cannot assign requested address
  Is the server running on host "localhost" (::1) and accepting
  TCP/IP connections on port 5432?
Couldn't create 'feeder_test' database. Please check your configuration.
rake aborted!
PG::ConnectionBad: could not connect to server: Connection refused
  Is the server running on host "localhost" (127.0.0.1) and accepting
  TCP/IP connections on port 5432?
could not connect to server: Cannot assign requested address
  Is the server running on host "localhost" (::1) and accepting
  TCP/IP connections on port 5432?
/app/vendor/bundle/ruby/2.5.0/gems/pg-0.18.4/lib/pg.rb:45:in `initialize'
/app/vendor/bundle/ruby/2.5.0/gems/pg-0.18.4/lib/pg.rb:45:in `new'
/app/vendor/bundle/ruby/2.5.0/gems/pg-0.18.4/lib/pg.rb:45:in `connect'
/app/vendor/bundle/ruby/2.5.0/gems/activerecord-5.2.2/lib/active_record/connection_adapters/postgresql_adapter.rb:692:in `connect'
/app/vendor/bundle/ruby/2.5.0/gems/activerecord-5.2.2/lib/active_record/connection_adapters/postgresql_adapter.rb:223:in `initialize'
/app/vendor/bundle/ruby/2.5.0/gems/activerecord-5.2.2/lib/active_record/connection_adapters/postgresql_adapter.rb:48:in `new'
/app/vendor/bundle/ruby/2.5.0/gems/activerecord-5.2.2/lib/active_record/connection_adapters/postgresql_adapter.rb:48:in `postgresql_connection'
/app/vendor/bundle/ruby/2.5.0/gems/activerecord-5.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:811:in `new_connection'

As you can see, it successfully created the development database, but failed on creating the test database

(The db:create tasks automatically creates test and development databases together even when the environment is development )

Here is my database.yml .

default: &default
  adapter: postgresql
  encoding: utf8
  host: localhost
  min_messages: warning
  pool: 5
  timeout: 5000

test:
  <<: *default
  database: feeder_test

development:
  <<: *default
  database: feeder_development

According to theRails guides , you can override the above config by specifying a DATABASE_URL , which I set as:

DATABASE_URL=postgres://feeder:password123@db/

So from what I can tell -

1. Rails merges the DATABASE_URL info with the database.yml info when trying to create the development database. All is good.

2. Rails does NOT consider the DATABASE_URL at all when creating the test database. It uses ONLY the database.yml info, which is why it's looking for a psql connection on localhost .

So - is there a way to get Rails to respect my DATABASE_URL ENV on the test environment?

Answer 1

I'm pretty sure you can put ERB into the database.yml file, so I'd suggest changing test to

test:
  <<: *default
  database: <%= ENV['DATABASE_URL'] || 'feeder_test' %>

Answer 2

in your database.yml set url to ENV['DATABASE_URL'] and leave other keys as defaults:

test:
  url: <%= ENV['DATABASE_URL'] %>
  database: app_test
  host: 127.0.0.1

DATABASE_URL='postgresql://192.168.0.2/' rails runner 'puts ActiveRecord::Base.configurations.to_json' | jq '.test'
{
  "database": "app_test",
  "host": "192.168.0.2",
  "adapter": "postgresql"
}

Notice that database name left unchanged but host has been overwritten.