Changing sqlite to PostgreSQL in ruby on rails

Question

I am using win 7 with docker and in docker I am using ruby on rails, I did an application that works very well with sqlite3 but when I try to upload to Heroku, Heroku gave me an error that it is not supported sqlite3 so I had to change my app database to PostgreSQL and I did the following changes: in my Gemfile I commented gem sqlite3:

# Use sqlite3 as the database for Active Record
#gem 'sqlite3'
#posgresql
gem 'pg'

second i did a "bundle install" and then a docker-compuse build

then in my database.yml:

BEFORE:

default: &default
  adapter: sqlite3
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  timeout: 5000

development:
  <<: *default
  database: db/development.sqlite3

# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
  <<: *default
  database: db/test.sqlite3

production:
  <<: *default
  database: db/production.sqlite3

after the changes:

development:
  adapter: postgresql
  database: my_database_development
  pool: 5
  timeout: 5000

test:
  adapter: postgresql
  database: my_database_test
  pool: 5
  timeout: 5000

production:
  adapter: postgresql
  database: my_database_production
  pool: 5
  timeout: 5000

so when i tried to create a new datebase with "rake db:create" docker gave me the next error:

 $ docker-compose run web rails db:create
Starting grupo43_postgres_1 ... done
could not connect to server: No such file or directory
        Is the server running locally and accepting
        connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
Couldn't create database for {"adapter"=>"postgresql", "database"=>"my_database_
development", "pool"=>5, "timeout"=>5000}
rails aborted!
PG::ConnectionBad: could not connect to server: No such file or directory
        Is the server running locally and accepting
        connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
/usr/local/bundle/gems/pg-1.0.0/lib/pg.rb:56:in `initialize'
/usr/local/bundle/gems/pg-1.0.0/lib/pg.rb:56:in `new'
/usr/local/bundle/gems/pg-1.0.0/lib/pg.rb:56:in `connect'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/connection_adapters/
postgresql_adapter.rb:697:in `connect'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/connection_adapters/
postgresql_adapter.rb:221:in `initialize'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/connection_adapters/
postgresql_adapter.rb:38:in `new'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/connection_adapters/
postgresql_adapter.rb:38:in `postgresql_connection'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/connection_adapters/
abstract/connection_pool.rb:759:in `new_connection'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/connection_adapters/
abstract/connection_pool.rb:803:in `checkout_new_connection'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/connection_adapters/
abstract/connection_pool.rb:782:in `try_to_checkout_new_connection'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/connection_adapters/
abstract/connection_pool.rb:743:in `acquire_connection'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/connection_adapters/
abstract/connection_pool.rb:500:in `checkout'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/connection_adapters/
abstract/connection_pool.rb:374:in `connection'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/connection_adapters/
abstract/connection_pool.rb:931:in `retrieve_connection'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/connection_handling.
rb:116:in `retrieve_connection'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/connection_handling.
rb:88:in `connection'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/tasks/postgresql_dat
abase_tasks.rb:10:in `connection'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/tasks/postgresql_dat
abase_tasks.rb:19:in `create'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/tasks/database_tasks
.rb:117:in `create'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/tasks/database_tasks
.rb:137:in `block in create_current'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/tasks/database_tasks
.rb:305:in `block in each_current_configuration'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/tasks/database_tasks
.rb:302:in `each'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/tasks/database_tasks
.rb:302:in `each_current_configuration'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/tasks/database_tasks
.rb:136:in `create_current'
/usr/local/bundle/gems/activerecord-5.1.6/lib/active_record/railties/databases.r
ake:27:in `block (2 levels) in <top (required)>'
/usr/local/bundle/gems/railties-5.1.6/lib/rails/commands/rake/rake_command.rb:21
:in `block in perform'
/usr/local/bundle/gems/railties-5.1.6/lib/rails/commands/rake/rake_command.rb:18
:in `perform'
/usr/local/bundle/gems/railties-5.1.6/lib/rails/command.rb:46:in `invoke'
/usr/local/bundle/gems/railties-5.1.6/lib/rails/commands.rb:16:in `<top (require
d)>'
/example/bin/rails:9:in `require'
/example/bin/rails:9:in `<top (required)>'
/usr/local/bundle/gems/spring-2.0.2/lib/spring/client/rails.rb:28:in `load'
/usr/local/bundle/gems/spring-2.0.2/lib/spring/client/rails.rb:28:in `call'
/usr/local/bundle/gems/spring-2.0.2/lib/spring/client/command.rb:7:in `call'
/usr/local/bundle/gems/spring-2.0.2/lib/spring/client.rb:30:in `run'
/usr/local/bundle/gems/spring-2.0.2/bin/spring:49:in `<top (required)>'
/usr/local/bundle/gems/spring-2.0.2/lib/spring/binstub.rb:31:in `load'
/usr/local/bundle/gems/spring-2.0.2/lib/spring/binstub.rb:31:in `<top (required)
>'
/example/bin/spring:15:in `require'
/example/bin/spring:15:in `<top (required)>'
bin/rails:3:in `load'
bin/rails:3:in `<main>'
Tasks: TOP => db:create
(See full trace by running task with --trace)

i found different solution but for linux and mac, all i could inform here is that maybe the problem is because i have to delete some file that i didn t know where i can find with windows or with docker :(, all the information i found is here: PG::ConnectionBad - could not connect to server: Connection refused

this is my docker-compose.yml file:

version: '3'
services:
  postgres:
    image: postgres:10.3
    ports:
      - "3000"
  web:
    build: .
    env_file:
      - .env
    command: bash -c "(bundle check || bundle install) && bundle exec rails s -p 3000 -b '0.0.0.0'"
    volumes:
      - .:/example
    ports:
      - "3000:3000"
    depends_on:
      - postgres

Answer 1

Make sure you have installed PostgreSQL in your machine and add a helpful tool called pgAdmin, then update the database.yml file like below

default: &default
  adapter: postgresql
  encoding: unicode
  username: postgres
  password: xxxxx #<-- which you have defiend while installing postgresql
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>

development:
  <<: *default
  database: project_development

test:
  <<: *default
  database: project_test

production:
  <<: *default
  database: project_production
  username: username
  password: <%= ENV['PROJECT_DATABASE_PASSWORD'] %>

and gem pg use in your Gemfile like gem 'pg', '~> 0.20.0' with this version then run bundle install

rake db:create
rake db:migrate

for Heroku

heroku run rake db:migrate

and you can use rails command instead of rake if your rails version is rails > 5.0.0