# Environment Options

In addition to the options in config/app.rb, some instance specific options in Volt can be configured with instance variables.

Name Description
VOLT_ENV Sets the value of Volt.env, which is used to control how various parts of the application.
RACK_ENV Also can be used to set Volt.env
NO_MESSAGE_BUS Disable the message bus. This will prevent updates from propagating between Volt instances, but can be useful for debugging
NO_FORKING The "Forking Server" is used in development on MRI to allow code reloading. (It forks a child process for connections, which are killed and reforked when code changes). Disabling forking prevents code reloading for Tasks, HttpControllers, Routes, and a few other things.
WEBSOCKET_PING_TIME When present, the websocket connection will send a ping every WEBSOCKET_PING_TIME seconds.
NO_WEBSOCKET_PING Websocket ping is only enabled by default on heroku (when the DYNO env is present), to prevent Heroku from killing idle connections. This forces a disable of the websocket ping
SKIP_BUNDLER_REQUIRE Disables auto-requiring files in the Gemfile. This feature is considered experimental.
POLL_FS In some situations, the listen gem Volt uses to track file system changes for auto-reloading will not detect changes correctly. In this situation, you can run with POLL_FS=true to have it poll the file system for changes. One place you might need this is sharing files over a network.
DB_NAME Same as Volt.config.db_name
DB_HOST Same as Volt.config.db_host
DB_PORT Same as Volt.config.db_port
DB_DRIVER Same as Volt.config.db_driver
DB_URI Same as Volt.config.db_uri