Strange behaviour with throw in handlers

[qraynaud]

Hi,

I'm working on latest, so v8.6.1.

I never noticed this before so maybe it's a recent bug, but when I throw in a handler, sometimes the error is sent to the wrong request.

Here is the route that fails:

'use strict';

module.exports = {
  method: 'GET',
  path: '/api/user/_me',
  config: {
    handler: function(request, reply) {
      var user = request.session.get('user');
      if (user)
        return reply(user);
      var err = new Error('You are disconnected');
      err.status = 401;
      throw err;
    }
  }
};

This is only a test to showcase the problem, on a normal day, I would just reply the error.

I don't know if it can be related, but I have the following onPreResponse handler:

// Handle errors
server.ext('onPreResponse', function(request, reply) {
  if (!(request.response instanceof Error) && !request.response.isBoom)
    return reply.continue();

  console.error(chalk.grey('[') + chalk.red('err') + chalk.grey('] on ') +
    chalk.yellow(request.path) + (request.url.search ? chalk.blue(request.url.search) : '') + chalk.grey(':'));
  console.error((request.response.stack || request.response).toString().replace(/^/mg, chalk.grey('> ')));

  reply(_.pick(request.response, ['message', 'status']))
    .code(request.response.status || 500)
  ;
});

I make multiple simultaneous requests using my browser. Most of the time it works but sometimes another request gets the error and I never get to have an answer on the throwing route.

Here is my network stack when it works:

And here is the result once every 5 times or so (this is random):

As you can see, a random call to my i18n endpoint failed and I got no answer for my call to _me.

The failing API call response looks like:

And here we can see that the error is the one emitted by _me that got no answer…

Any ideas of what I might be doing wrong?

Another possibility might be my i18n endpoint that is using the official elasticsearch client that might or might not restore the domains properly. Could the other endpoint mess with my _me route?

[qraynaud]

Seems that the elasticsearch client is only using http.Client and http.Agent to do its job so I think domains are properly handled by it… Not the cause it seems.

[hueniverse]

Domains are shit.

You need to look into everything you are using in any extension, handler, pre, method, etc. that might have it's own client or domain context. Do you know where the error you do get comes from? It sounds like a handler is going through some async action that cross the domain boundary.

The problem is that we can't fix anything involving domains... so we need to find workarounds for you to prevent the issue from happening in the first place.

[mik01aj]

@hueniverse if "domains are shit", as you say, what would you recommend for handling request errors in a generic way? I'm struggling with similar problems.

[hueniverse]

@qraynaud any chance you are using server methods or any caching provided by hapi? We had a bug in catbox where the throw from the first request would be passed to all other pending requests and mess up the domain stack. Also, is there any overlap between the two route (common code, ext.) that uses elastic search? We need to find a place where the two domains of each request cross over with something else.

@mik01aj You just need to be very careful and have a good mapping of where your handler changes domains. It's hard. Most people don't hit the edge cases and when you do, like this, you need to dig deeper to see where you have overlapping context (such as two handlers both using the same HTTP connection and therefore crossing domains boundaries).

[qraynaud]

@hueniverse : Yes, I was using catbox indeed. And no there is no overlap (other than catbox/yar) I can see between the 2 routes.

I suppose I will update catbox asap then. Thanks for the tip.

I'll keep in touch if this fixes the problem.

[hueniverse]

This is not published yet. If you can manually try out the fix here: https://github.com/hapijs/catbox/pull/128/files before it is released, please report back if it solved your problem.

[hueniverse]

I'm going to assume this is related to the catbox issue. Once 9.0 is out please check again and if it is still not resolved, open a new issue. Thanks!

[qraynaud]

Ok thx. I'm sorry I have so little time for this right now.