Adapt `SchemaMigrations::Context` to support config

This adds a support for `schema_migrations_path`
in a similar way to `migrations_paths`
for managing database configs.

doc/development/database/multiple_databases.md

@@ -61,7 +61,6 @@ development:
     adapter: postgresql
     encoding: unicode
     database: gitlabhq_development_ci
-    migrations_paths: db/ci_migrate
     host: /path/to/gdk/postgresql
     pool: 10
     prepared_statements: false
@@ -82,7 +81,6 @@ test: &test
     adapter: postgresql
     encoding: unicode
     database: gitlabhq_test_ci
-    migrations_paths: db/ci_migrate
     host: /path/to/gdk/postgresql
     pool: 10
     prepared_statements: false

lib/gitlab/database/schema_migrations/context.rb

@@ -6,17 +6,14 @@ module Gitlab
       class Context
         attr_reader :connection
 
+        DEFAULT_SCHEMA_MIGRATIONS_PATH = "db/schema_migrations"
+
         def initialize(connection)
           @connection = connection
         end
 
         def schema_directory
-          @schema_directory ||=
-            if ActiveRecord::Base.configurations.primary?(database_name)
-              File.join(db_dir, 'schema_migrations')
-            else
-              File.join(db_dir, "#{database_name}_schema_migrations")
-            end
+          @schema_directory ||= Rails.root.join(database_schema_migrations_path).to_s
         end
 
         def versions_to_create
@@ -32,8 +29,8 @@ module Gitlab
           @database_name ||= @connection.pool.db_config.name
         end
 
-        def db_dir
-          @db_dir ||= Rails.application.config.paths["db"].first
+        def database_schema_migrations_path
+          @connection.pool.db_config.configuration_hash[:schema_migrations_path] || DEFAULT_SCHEMA_MIGRATIONS_PATH
         end
       end
     end

spec/lib/gitlab/database/schema_migrations/context_spec.rb

@@ -3,7 +3,8 @@
 require 'spec_helper'
 
 RSpec.describe Gitlab::Database::SchemaMigrations::Context do
-  let(:connection) { ActiveRecord::Base.connection }
+  let(:connection_class) { ActiveRecord::Base }
+  let(:connection) { connection_class.connection }
 
   let(:context) { described_class.new(connection) }
 
@@ -12,15 +13,67 @@ RSpec.describe Gitlab::Database::SchemaMigrations::Context do
       expect(context.schema_directory).to eq(File.join(Rails.root, 'db/schema_migrations'))
     end
 
-    context 'multiple databases' do
-      let(:connection) { Ci::CiDatabaseRecord.connection }
+    context 'CI database' do
+      let(:connection_class) { Ci::CiDatabaseRecord }
 
       it 'returns a directory path that is database specific' do
         skip_if_multiple_databases_not_setup
 
+        expect(context.schema_directory).to eq(File.join(Rails.root, 'db/schema_migrations'))
+      end
+    end
+
+    context 'multiple databases' do
+      let(:connection_class) do
+        Class.new(::ApplicationRecord) do
+          self.abstract_class = true
+
+          def self.name
+            'Gitlab::Database::SchemaMigrations::Context::TestConnection'
+          end
+        end
+      end
+
+      let(:configuration_overrides) { {} }
+
+      before do
+        connection_class.establish_connection(
+          ActiveRecord::Base
+            .connection_pool
+            .db_config
+            .configuration_hash
+            .merge(configuration_overrides)
+        )
+      end
+
+      after do
+        connection_class.remove_connection
+      end
+
+      context 'when `schema_migrations_path` is configured as string' do
+        let(:configuration_overrides) do
+          { "schema_migrations_path" => "db/ci_schema_migrations" }
+        end
+
+        it 'returns a configured directory path that' do
+          skip_if_multiple_databases_not_setup
+
           expect(context.schema_directory).to eq(File.join(Rails.root, 'db/ci_schema_migrations'))
         end
       end
+
+      context 'when `schema_migrations_path` is configured as symbol' do
+        let(:configuration_overrides) do
+          { schema_migrations_path: "db/ci_schema_migrations" }
+        end
+
+        it 'returns a configured directory path that' do
+          skip_if_multiple_databases_not_setup
+
+          expect(context.schema_directory).to eq(File.join(Rails.root, 'db/ci_schema_migrations'))
+        end
+      end
+    end
   end
 
   describe '#versions_to_create' do