Setting the correct database connection on production with Render

While deploying a Rails 8 app on Render today, I faced this issue in the deployment log: ActiveRecord::ConnectionNotEstablished: connection to server on socket "/var/run/postgresql/.s.PGSQL.5432" failed: No such file or directory (ActiveRecord::ConnectionNotEstablished) Is the server running locally and accepting connections on that socket? Caused by: PG::ConnectionBad: connection to server on socket "/var/run/postgresql/.s.PGSQL.5432" failed: No such file or directory (PG::ConnectionBad) Is the server running locally and accepting connections on that socket? Tasks: TOP => db:migrate (See full trace by running task with --trace) ==> Pre-deploy has failed ==> Exited with status 1 That was confusing because I did deploy my Render app with a database connection. But I did the logical thing which was: Check the database existed on Render and was connected via the Environment Variables to my deployed web service. It was! Go to the config/database.yml and see what the connection was expecting... In the config/database.yml, I found: # ... production: primary: &primary_production

Mar 13, 2025 - 19:35

Setting the correct database connection on production with Render

While deploying a Rails 8 app on Render today, I faced this issue in the deployment log:

ActiveRecord::ConnectionNotEstablished: connection to server on socket "/var/run/postgresql/.s.PGSQL.5432" failed: No such file or directory (ActiveRecord::ConnectionNotEstablished)
    Is the server running locally and accepting connections on that socket?
Caused by:
PG::ConnectionBad: connection to server on socket "/var/run/postgresql/.s.PGSQL.5432" failed: No such file or directory (PG::ConnectionBad)
    Is the server running locally and accepting connections on that socket?
Tasks: TOP => db:migrate
(See full trace by running task with --trace)
==> Pre-deploy has failed
==> Exited with status 1

That was confusing because I did deploy my Render app with a database connection.

But I did the logical thing which was:

Check the database existed on Render and was connected via the Environment Variables to my deployed web service. It was!
Go to the config/database.yml and see what the connection was expecting...

In the config/database.yml, I found:

# ...
production:
  primary: &primary_production
    <<: *default
    database: news_production
    username: news
    password: <%= ENV["NEWS_DATABASE_PASSWORD"] %>
# ...

Oops! By default, when I created my app Rails 8 app with rails new ..., it set the production database.

But what I actually want in those lines is:

# ...
production:
  primary: &primary_production
    <<: *default
    url: <%= ENV["DATABASE_URL"] %>
# ...

I made that change, pushed a commit, and the app is up and running!