1 files changed, 205 insertions, 0 deletions
diff --git a/spec/tasks/gitlab/db/validate_config_rake_spec.rb b/spec/tasks/gitlab/db/validate_config_rake_spec.rb
new file mode 100644
index 00000000000..0b2c844a91f
--- /dev/null
+++ b/spec/tasks/gitlab/db/validate_config_rake_spec.rb
@@ -0,0 +1,205 @@
+# frozen_string_literal: true
+
+require 'rake_helper'
+
+RSpec.describe 'gitlab:db:validate_config', :silence_stdout do
+  before :all do
+    Rake.application.rake_require 'active_record/railties/databases'
+    Rake.application.rake_require 'tasks/seed_fu'
+    Rake.application.rake_require 'tasks/gitlab/db/validate_config'
+
+    # empty task as env is already loaded
+    Rake::Task.define_task :environment
+  end
+
+  context "when validating config" do
+    let(:main_database_config) do
+      Rails.application.config.load_database_yaml
+        .dig('test', 'main')
+        .slice('adapter', 'encoding', 'database', 'username', 'password', 'host')
+        .symbolize_keys
+    end
+
+    let(:additional_database_config) do
+      # Use built-in postgres database
+      main_database_config.merge(database: 'postgres')
+    end
+
+    around do |example|
+      with_reestablished_active_record_base(reconnect: true) do
+        with_db_configs(test: test_config) do
+          example.run
+        end
+      end
+    end
+
+    shared_examples 'validates successfully' do
+      it 'by default' do
+        expect { run_rake_task('gitlab:db:validate_config') }.not_to output(/Database config validation failure/).to_stderr
+        expect { run_rake_task('gitlab:db:validate_config') }.not_to raise_error
+      end
+
+      it 'for production' do
+        allow(Gitlab).to receive(:dev_or_test_env?).and_return(false)
+
+        expect { run_rake_task('gitlab:db:validate_config') }.not_to output(/Database config validation failure/).to_stderr
+        expect { run_rake_task('gitlab:db:validate_config') }.not_to raise_error
+      end
+
+      it 'always re-establishes ActiveRecord::Base connection to main config' do
+        run_rake_task('gitlab:db:validate_config')
+
+        expect(ActiveRecord::Base.connection_db_config.configuration_hash).to include(main_database_config) # rubocop: disable Database/MultipleDatabases
+      end
+
+      it 'if GITLAB_VALIDATE_DATABASE_CONFIG is set' do
+        stub_env('GITLAB_VALIDATE_DATABASE_CONFIG', '1')
+        allow(Gitlab).to receive(:dev_or_test_env?).and_return(false)
+
+        expect { run_rake_task('gitlab:db:validate_config') }.not_to output(/Database config validation failure/).to_stderr
+        expect { run_rake_task('gitlab:db:validate_config') }.not_to raise_error
+      end
+
+      context 'when finding the initializer fails' do
+        where(:raised_error) { [ActiveRecord::NoDatabaseError, ActiveRecord::ConnectionNotEstablished, PG::ConnectionBad] }
+        with_them do
+          it "does not raise an error for #{params[:raised_error]}" do
+            allow(ActiveRecord::Base.connection).to receive(:select_one).and_raise(raised_error) # rubocop: disable Database/MultipleDatabases
+
+            expect { run_rake_task('gitlab:db:validate_config') }.not_to output(/Database config validation failure/).to_stderr
+            expect { run_rake_task('gitlab:db:validate_config') }.not_to raise_error
+          end
+        end
+      end
+    end
+
+    shared_examples 'raises an error' do |match|
+      it 'by default' do
+        expect { run_rake_task('gitlab:db:validate_config') }.to raise_error(match)
+      end
+
+      it 'for production' do
+        allow(Gitlab).to receive(:dev_or_test_env?).and_return(false)
+
+        expect { run_rake_task('gitlab:db:validate_config') }.to raise_error(match)
+      end
+
+      it 'always re-establishes ActiveRecord::Base connection to main config' do
+        expect { run_rake_task('gitlab:db:validate_config') }.to raise_error(match)
+
+        expect(ActiveRecord::Base.connection_db_config.configuration_hash).to include(main_database_config) # rubocop: disable Database/MultipleDatabases
+      end
+
+      it 'if GITLAB_VALIDATE_DATABASE_CONFIG=1' do
+        stub_env('GITLAB_VALIDATE_DATABASE_CONFIG', '1')
+
+        expect { run_rake_task('gitlab:db:validate_config') }.to raise_error(match)
+      end
+
+      it 'to stderr if GITLAB_VALIDATE_DATABASE_CONFIG=0' do
+        stub_env('GITLAB_VALIDATE_DATABASE_CONFIG', '0')
+
+        expect { run_rake_task('gitlab:db:validate_config') }.to output(match).to_stderr
+      end
+    end
+
+    context 'when only main: is specified' do
+      let(:test_config) do
+        {
+          main: main_database_config
+        }
+      end
+
+      it_behaves_like 'validates successfully'
+    end
+
+    context 'when main: uses database_tasks=false' do
+      let(:test_config) do
+        {
+          main: main_database_config.merge(database_tasks: false)
+        }
+      end
+
+      it_behaves_like 'raises an error', /The 'main' is required to use 'database_tasks: true'/
+    end
+
+    context 'when many configurations share the same database' do
+      context 'when no database_tasks is specified, assumes true' do
+        let(:test_config) do
+          {
+            main: main_database_config,
+            ci: main_database_config
+          }
+        end
+
+        it_behaves_like 'raises an error', /Many configurations \(main, ci\) share the same database/
+      end
+
+      context 'when database_tasks is specified' do
+        let(:test_config) do
+          {
+            main: main_database_config.merge(database_tasks: true),
+            ci: main_database_config.merge(database_tasks: true)
+          }
+        end
+
+        it_behaves_like 'raises an error', /Many configurations \(main, ci\) share the same database/
+      end
+
+      context "when there's no main: but something different, as currently we only can share with main:" do
+        let(:test_config) do
+          {
+            archive: main_database_config,
+            ci: main_database_config.merge(database_tasks: false)
+          }
+        end
+
+        it_behaves_like 'raises an error', /The 'ci' is expecting to share configuration with 'main', but no such is to be found/
+      end
+    end
+
+    context 'when ci: uses different database' do
+      context 'and does not specify database_tasks which indicates using dedicated database' do
+        let(:test_config) do
+          {
+            main: main_database_config,
+            ci: additional_database_config
+          }
+        end
+
+        it_behaves_like 'validates successfully'
+      end
+
+      context 'and does specify database_tasks=false which indicates sharing with main:' do
+        let(:test_config) do
+          {
+            main: main_database_config,
+            ci: additional_database_config.merge(database_tasks: false)
+          }
+        end
+
+        it_behaves_like 'raises an error', /The 'ci' since it is using 'database_tasks: false' should share database with 'main:'/
+      end
+    end
+  end
+
+  %w[db:migrate db:schema:load db:schema:dump].each do |task|
+    context "when running #{task}" do
+      it "does run gitlab:db:validate_config before" do
+        expect(Rake::Task['gitlab:db:validate_config']).to receive(:execute).and_return(true)
+        expect(Rake::Task[task]).to receive(:execute).and_return(true)
+
+        Rake::Task['gitlab:db:validate_config'].reenable
+        run_rake_task(task)
+      end
+    end
+  end
+
+  def with_db_configs(test: test_config)
+    current_configurations = ActiveRecord::Base.configurations # rubocop:disable Database/MultipleDatabases
+    ActiveRecord::Base.configurations = { test: test_config }
+    yield
+  ensure
+    ActiveRecord::Base.configurations = current_configurations
+  end
+end