rake db:schema:dump is not producing schema for all databases - mysql

Question

I have this project and I need to integrate a bunch of databases into my Rails project.
This is the database configuration that I have to work with.
$ nano config/database.yml
production:
adapter: mysql2
reconnect: true
pool: 5
username: user_xyz
password: 123456
database: database1
host: localhost
database_2:
adapter: mysql2
reconnect: false
pool: 5
username: user_xyz
password: 123456
database: database2
host: 192.168.2.100
database_3:
adapter: mysql2
reconnect: false
pool: 5
username: user_xyz
password: 123456
database: database3
host: 192.168.2.101
database_4:
adapter: mysql2
reconnect: false
database: database4
pool: 5
username: user_xyz
password: 123456
host: 192.168.2.102
I need to update the schema inside db/schema.rb but unfortunately it's only producing the schema for production (database1).
$ RAILS_ENV=production bundle exec rake db:schema:dump
I can't just run this as it complains:
$ bundle exec rake db:schema:dump
rake aborted!
database configuration does not specify adapter
What do I need to do to get all of these databases into db/schema.rb?

Answer 1

Austio's answer is a good one. Here is some extra detail on how to implement a solution. Create a new rake file, e.g., lib/tasks/schema_dump.rake, and add the following contents:
namespace :db do
namespace :schema do
desc 'dumps the schema of database_1 to db/schema_db1.rb'
task :dump_db1 => :environment do
ActiveRecord::Base.establish_connection 'database_4'
File.open(Rails.root.join('db', 'schema_db1.rb'), 'w') do |file|
ActiveRecord::SchemaDumper.dump ActiveRecord::Base.connection, file
end
end
end
end
Now when you run rake db:schema:dump it'll dump the schema of your primary database to db/schema.rb (like traditional Rails). But when you run rake db:schema:dump_db1, it'll dump the schema of your database_1 block into db/schema_db1.rb.
You can create similar tasks for your other database blocks and have a schema file for each database.

Answer 2

You will need to establish a connection to each database that you would like to schema dump on. Here is example for database_4
ActiveRecord::Base.establish_connection 'database_4'
Then when you run schema dump, it will dump the current database you have a connection with. I'm not sure if the rake task has arguments to copy it to a different file name, so you may have to rename the file.