add e2e rake tasks

lib/tasks/e2e.rake

@@ -0,0 +1,57 @@
+class E2ETask
+  include Rake::DSL
+
+  def initialize
+    namespace :e2e do
+      task setup: :environment do
+        Rake::Task["db:reset"].invoke
+        terminate_connections_to db_config["database"]
+        drop_e2e_db_template
+        create_e2e_db_template
+      end
+
+      task :db_reset do # rubocop:disable Rails/RakeEnvironment
+        terminate_connections_to db_config["database"]
+        sh "dropdb --if-exists #{connection_config} #{db_config["database"]}"
+        sh "createdb #{connection_config} --template=#{template_db_name} #{db_config["database"]}"
+      end
+    end
+  end
+
+  private
+
+  def drop_e2e_db_template
+    disable_template_sql = "ALTER DATABASE #{template_db_name} WITH IS_TEMPLATE false;"
+    system "psql -c \"#{disable_template_sql};\" #{connection_config}"
+    sh "dropdb --if-exists #{connection_config} #{template_db_name}"
+  end
+
+  def create_e2e_db_template
+    set_template_sql = "ALTER DATABASE #{db_config["database"]} RENAME TO #{template_db_name}; ALTER DATABASE #{template_db_name} WITH IS_TEMPLATE true;"
+    create_db_sql = "CREATE DATABASE #{db_config["database"]} WITH TEMPLATE #{template_db_name};"
+    sh "psql -c \"#{set_template_sql};\" #{connection_config}"
+    sh "psql -c \"#{create_db_sql};\" #{connection_config}"
+  end
+
+  def terminate_connections_to(database_name)
+    system "psql -c \"#{terminate_connection_sql(database_name)};\" #{connection_config} #{database_name}"
+  end
+
+  def terminate_connection_sql(database_name)
+    "SELECT pg_terminate_backend(pg_stat_activity.pid) FROM pg_stat_activity WHERE pg_stat_activity.datname = '#{database_name}' AND pid <> pg_backend_pid();"
+  end
+
+  def template_db_name
+    "fti_e2e_template"
+  end
+
+  def connection_config
+    "--host=#{db_config["host"]} --port=#{db_config["port"]} --username=#{db_config["username"]}"
+  end
+
+  def db_config
+    Rails.configuration.database_configuration[Rails.env]
+  end
+end
+
+E2ETask.new