I am trying to push my Docker container into Heroku and I keep having this error when I try to do heroku run rake db:migrate:

PG::ConnectionBad: could not translate host name "db" to address: Name or service not known

I have been searching around and added: POSTGRES_HOST_AUTH_METHOD: trust to my docker-compose.yml and also kept the same names for the environment in both docker-compose.yml and database.yml, but it keeps giving the same error and I am quite lost.

This is the docker-compose.yml:

version: "3.8"

services:
  db:
    image: postgres
    environment:
      POSTGRES_HOST_AUTH_METHOD: trust
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
    volumes:
      - ./tmp/db:/var/lib/postgresql/data
  web:
    build: .
    command: bash -c "rm -f tmp/pids/server.pid && bundle exec rails s -p 3000 -b '0.0.0.0'"
    volumes:
      - .:/myapp
    ports:
      - "3000:3000"
    depends_on:
      - db
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
      POSTGRES_HOST: db
      RAILS_ENV: production

This is the database.yml:

default: &default
  adapter: postgresql
  encoding: unicode
  host: db
  username: user
  password: password
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>

development:
  <<: *default
  database: _rails_ecommerce_site_development

test:
  <<: *default
  database: _rails_ecommerce_site_test

production:
  <<: *default
  database: _rails_ecommerce_site_production

And these are the logs from heroku logs --tail:

2022-04-19T11:07:38.574966 00:00 heroku[web.1]: Starting process with command `rails server -b 0.0.0.0`
2022-04-19T11:07:42.805650 00:00 app[web.1]: => Booting Puma
2022-04-19T11:07:42.805662 00:00 app[web.1]: => Rails 6.0.4.4 application starting in production
2022-04-19T11:07:42.805662 00:00 app[web.1]: => Run `rails server --help` for more startup options
2022-04-19T11:07:44.787345 00:00 app[web.1]: Puma starting in single mode...
2022-04-19T11:07:44.787369 00:00 app[web.1]: * Version 4.3.10 (ruby 2.6.6-p146), codename: Mysterious Traveller
2022-04-19T11:07:44.787370 00:00 app[web.1]: * Min threads: 5, max threads: 5
2022-04-19T11:07:44.787370 00:00 app[web.1]: * Environment: production
2022-04-19T11:07:44.787625 00:00 app[web.1]: * Listening on tcp://0.0.0.0:24849
2022-04-19T11:07:44.787902 00:00 app[web.1]: Use Ctrl-C to stop
2022-04-19T11:07:45.114352 00:00 heroku[web.1]: State changed from starting to up
2022-04-19T11:07:47.793790 00:00 heroku[router]: at=info method=GET path="/" host=xxxx.herokuapp.com request_id=0368ded8-ba57-474b-b540-4f23292881d1 fwd="119.105.11.94" dyno=web.1 connect=0ms service=109ms status=500 bytes=1827 protocol=https
2022-04-19T11:08:36.612997 00:00 app[api]: Starting process with command `rake db:migrate` by user xxxxx
2022-04-19T11:09:06.965267 00:00 heroku[run.7786]: State changed from starting to up
2022-04-19T11:09:07.057271 00:00 heroku[run.7786]: Awaiting client
2022-04-19T11:09:07.084913 00:00 heroku[run.7786]: Starting process with command `rake db:migrate`
2022-04-19T11:09:12.164888 00:00 heroku[run.7786]: State changed from up to complete
2022-04-19T11:09:11.892289 00:00 heroku[run.7786]: Process exited with status 1

Is there anything I am missing here? How could I fix it? Thanks!

CodePudding user response：

Solved!

So, basically we need to add the Postgres add-on in Heroku. The steps are here (https://betterprogramming.pub/how-to-containerize-and-deploy-apps-with-docker-and-heroku-b1c49e5bc070) but basically:

1. Navigate to Heroku and click on the app you created.
2. In Resources, search “postgres” and click on the Heroku Postgres.
3. Add it to your app. Click Provision.

And REALLY important, in the database.yml of the project the production should have this: url: <%= ENV['DATABASE_URL'] %>. In my case:

production:
  <<: *default
  database: _rails_ecommerce_site_production
  url: <%= ENV['DATABASE_URL'] %>

The <%= ENV['DATABASE_URL'] %> will be given by Heroku once we add the Postgresql add-on