Run `rails db:setup` in Docker with schema in structure.sql

Question

I have a new Rails app that I am planning to deploy in a Docker container. We are using structure.sql instead of schema.rb . In my local setup (using a docker-compose file, with Postgres in a separate container), when I run rails db:setup , I get the following error:

rails aborted!
failed to execute:
psql -q -f /rails/db/structure.sql cappy_dev

Please check the output above for any errors and make sure that `psql` is installed in your PATH and has proper permissions.

/usr/local/bundle/gems/activerecord-5.0.2/lib/active_record/tasks/postgresql_database_tasks.rb:99:in `run_cmd'
/usr/local/bundle/gems/activerecord-5.0.2/lib/active_record/tasks/postgresql_database_tasks.rb:71:in `structure_load'
/usr/local/bundle/gems/activerecord-5.0.2/lib/active_record/tasks/database_tasks.rb:213:in `structure_load'
/usr/local/bundle/gems/activerecord-5.0.2/lib/active_record/tasks/database_tasks.rb:226:in `load_schema'
/usr/local/bundle/gems/activerecord-5.0.2/lib/active_record/tasks/database_tasks.rb:253:in `block in load_schema_current'
/usr/local/bundle/gems/activerecord-5.0.2/lib/active_record/tasks/database_tasks.rb:292:in `block in each_current_configuration'
/usr/local/bundle/gems/activerecord-5.0.2/lib/active_record/tasks/database_tasks.rb:291:in `each'
/usr/local/bundle/gems/activerecord-5.0.2/lib/active_record/tasks/database_tasks.rb:291:in `each_current_configuration'
/usr/local/bundle/gems/activerecord-5.0.2/lib/active_record/tasks/database_tasks.rb:252:in `load_schema_current'
/usr/local/bundle/gems/activerecord-5.0.2/lib/active_record/railties/databases.rake:306:in `block (3 levels) in <top (required)>'
/usr/local/bundle/gems/activerecord-5.0.2/lib/active_record/railties/databases.rake:310:in `block (3 levels) in <top (required)>'
/usr/local/bundle/gems/railties-5.0.2/lib/rails/commands/rake_proxy.rb:14:in `block in run_rake_task'
/usr/local/bundle/gems/railties-5.0.2/lib/rails/commands/rake_proxy.rb:11:in `run_rake_task'
/usr/local/bundle/gems/railties-5.0.2/lib/rails/commands/commands_tasks.rb:51:in `run_command!'
/usr/local/bundle/gems/railties-5.0.2/lib/rails/commands.rb:18:in `<top (required)>'
bin/rails:9:in `require'
bin/rails:9:in `<main>'
Tasks: TOP => db:structure:load
(See full trace by running task with --trace)

This makes sense because my Rails container only has Ruby and Rails-related tools, and does not have Postgres or pqsl, which are in the Postgres container.

How do I run rails db:setup (or db:migrate or other tasks) if I don't have psql, pg_dump, and other Postgres tools in my Rails container?

UPDATE: Here is my docker-compose file:

version: '3'
services:
  postgres:
    image: postgres:9.6
    volumes:
      - cappy-data:/var/lib/postgresql/data
    ports:
      - '5432:5432'
    environment:
      POSTGRES_PASSWORD: postgres

  cappy:
    image: REDACTED.dkr.ecr.us-east-1.amazonaws.com/cappy:latest
    build:
      context: .
    command: rails s -p 3000 -b '0.0.0.0'
    depends_on:
      - postgres
    volumes:
      - .:/rails
    ports:
      - "3000:3000"
    links:
      - "postgres:postgres"
    environment:
      RAILS_ENV: development

volumes:
  cappy-data:

I don't think this file is the problem though-- db:setup can create the database, it just can't load the structure.sql because it can't seem to find psql .

Answer 1

I tried a couple of things--running rails db:create and then db:migrate would have worked to get the local database set up, but it would not have worked in the long run because when you run rails db:migrate , at the end of the task it dumps the schema. With Postgres, and with schema_format set to :sql (which is what generates the structure.sql file), the rake task relies on Postgres tools like psql and pg_dump.

In the end, the best way to handle it was to add postgresql-client (don't need the whole server) to the Rails Docker image. It has the tools it needs right at hand and everything works fine.