Support direct database URL for startup migrations

README.md

@@ -76,6 +76,8 @@ docker run --name docuseal -p 3000:3000 -v.:/data docuseal/docuseal
 
 By default DocuSeal docker container uses an SQLite database to store data and configurations. Alternatively, it is possible to use PostgreSQL or MySQL databases by specifying the `DATABASE_URL` env variable.
 
+When using PostgreSQL providers that offer a pooled connection string for application traffic and a direct connection string for schema changes, keep `DATABASE_URL` set to the application connection and set `MIGRATION_DATABASE_URL` to the direct connection string. This lets DocuSeal run startup migrations, such as adding `NOT NULL` constraints, outside transaction poolers that do not support all migration operations.
+
 #### Docker Compose
 
 Download docker-compose.yml into your private server:

config/initializers/migrate.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require Rails.root.join('lib/migration_database_url')
+
 Rails.configuration.to_prepare do
-  ActiveRecord::Tasks::DatabaseTasks.migrate if ENV['RAILS_ENV'] == 'production' && ENV['RUN_MIGRATIONS'] != 'false'
+  MigrationDatabaseUrl.migrate if ENV['RAILS_ENV'] == 'production' && ENV['RUN_MIGRATIONS'] != 'false'
 end

lib/migration_database_url.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module MigrationDatabaseUrl
+  module_function
+
+  def migrate
+    migration_database_url = ENV.fetch('MIGRATION_DATABASE_URL', '').to_s
+
+    return ActiveRecord::Tasks::DatabaseTasks.migrate if migration_database_url.empty?
+
+    app_database_config = ActiveRecord::Base.connection_db_config
+
+    ActiveRecord::Base.establish_connection(migration_database_url)
+    ActiveRecord::Tasks::DatabaseTasks.migrate
+  ensure
+    ActiveRecord::Base.establish_connection(app_database_config) if app_database_config
+  end
+end

spec/lib/migration_database_url_spec.rb

@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+require Rails.root.join('lib/migration_database_url')
+
+RSpec.describe MigrationDatabaseUrl do
+  around do |example|
+    original_env = ENV.to_hash
+
+    example.run
+  ensure
+    ENV.replace(original_env)
+  end
+
+  describe '.migrate' do
+    it 'runs migrations with the application database when no migration URL is configured' do
+      ENV.delete('MIGRATION_DATABASE_URL')
+
+      expect(ActiveRecord::Base).not_to receive(:establish_connection)
+      expect(ActiveRecord::Tasks::DatabaseTasks).to receive(:migrate)
+
+      described_class.migrate
+    end
+
+    it 'uses MIGRATION_DATABASE_URL for migrations and restores the application database' do
+      original_config = Object.new
+      migration_database_url = 'postgres://user:***@ep-direct.us-east-1.aws.neon.tech/docuseal?sslmode=require'
+      connections = []
+
+      ENV['MIGRATION_DATABASE_URL'] = migration_database_url
+
+      allow(ActiveRecord::Base).to receive(:connection_db_config).and_return(original_config)
+      allow(ActiveRecord::Base).to receive(:establish_connection) { |config| connections << config }
+
+      expect(ActiveRecord::Tasks::DatabaseTasks).to receive(:migrate)
+
+      described_class.migrate
+
+      expect(connections).to eq([migration_database_url, original_config])
+    end
+
+    it 'restores the application database when migration fails' do
+      original_config = Object.new
+      migration_database_url = 'postgres://user:***@ep-direct.us-east-1.aws.neon.tech/docuseal?sslmode=require'
+      connections = []
+
+      ENV['MIGRATION_DATABASE_URL'] = migration_database_url
+
+      allow(ActiveRecord::Base).to receive(:connection_db_config).and_return(original_config)
+      allow(ActiveRecord::Base).to receive(:establish_connection) { |config| connections << config }
+      allow(ActiveRecord::Tasks::DatabaseTasks).to receive(:migrate).and_raise(ActiveRecord::StatementInvalid)
+
+      expect { described_class.migrate }.to raise_error(ActiveRecord::StatementInvalid)
+      expect(connections).to eq([migration_database_url, original_config])
+    end
+  end
+end