Reproduction steps

• Call autobahn.Connection.close on an active connection.
• Observe the following is logged:

connection closed closed {
  reason: 'wamp.error.goodbye_and_out',
  message: '',
  retry_delay: null,
  retry_count: null,
  will_retry: false
}

This can be observed in the autobahn-js tests: https://travis-ci.org/github/crossbario/autobahn-js

✔ testConnect
connection closed closed { reason: 'wamp.close.normal',
  message: '',
  retry_delay: null,
  retry_count: null,
  will_retry: false }
CLOSE closed { reason: 'wamp.close.normal',
  message: '',
  retry_delay: null,
  retry_count: null,
  will_retry: false }
auto-reconnect disabled! false undefined
connection closed closed { reason: 'wamp.close.normal',
  message: '',
  retry_delay: null,
  retry_count: null,
  will_retry: false }

Tech Details

_session.leave is called in autobahn.Connection.close. Ultimately, Transport.onclose is being called when the connection is closed and this function logs a "connection closed {reason}" as a warning, when really this would only be a warning if the connection closed were a problematic state.

My suggestion is to simply use log.debug instead, as this spams stderr needlessly and can lead users to think that something went wrong on disconnection, when everything went well.