better solution for disconnected store

[jonathanong]

migrated from senchalabs/connect#973

[Fishrock123]

Is it reasonable to just default to a cookie store for this when another store is unavailable?

(or you could just have it cache it in a temporary memory store, but that seems like a bad idea..)

[jonathanong]

naw. these sessions could be humongous

[dougwilson]

Is it reasonable to just default to a cookie store for this when another store is unavailable?

plus if it is unavailable, how would you get the data out of the store to put into the cookie? :)

[paton]

I experienced undefined req.session every so often caused by a disconnected redis store (using ElastiCache).

Here's a workaround that recreates the session middleware with a new Redis connection when the old connection disconnects.

Not sure if it would make sense to attempt a reconnect in the module itself.

app.use((function(){
  var sessionMiddleware;

  var createMiddlware = _.throttle(function() {
    var store = new RedisStore({ ... });
    store.on('disconnect', createMiddlware);

    sessionMiddleware = session({
      store: store,
      cookie: { maxAge: 60000 },
    });
  }, 2000);

  createMiddlware();

  return function(req, res, next) {
    sessionMiddleware.apply(this, arguments);
  };
})());

app.use(function(req, res, next) {
  if (req.session) return next();
  res.send(500, 'Servers are updating. Please check back soon.');
});

[dougwilson]

Not sure if it would make sense to attempt a reconnect in the module itself.

It's up to the core to reconnect; the reason this module gives undefined is because you store explicitly told us to do so--a store does not have to do that and just auto-reconnect and you won't experience that, but it's up to the store to do so.

You'll need to report the issue here: https://github.com/visionmedia/connect-redis/issues

[gireeshpunathil]

the choice of what to do when the store is unavailable is definitely the application's - based on the use case,

• one could wait for a while with timeout, if the store becomes auto-available again,
• one could return an error if the app critically session-sentitive,
• one could behave as if there was no session

but again, the choice is best left to the application, not the middleware.

I guess this can be closed.

[davidmashe]

This issue seems to be stale, was proposed for closing last year with no objections. Closing now.