Variable Cookie TTL based on master_ttl

[evantahler]

No description provided.

[bleonard]

i don't see the new cookie_ttl setting here. did you mean for the second one to be that?
Should this use the Makara::ConfigParser or ather, this logic be there ? it provides a way to do the default.

[evantahler]

As far as I can tell, we can't use the Makara::ConfigParser here. There may be many instances of Makara in play (ActiveRecord vs ActiveRabbit, so we won't know which connection to source). I also don't know how we would find the instance at the middleware level.

That's why I tried to hack it with ActiveRecord::Base...

[dreyks]

As I can see it right now, this won't solve the whole problem.
Use-case of countering replication lag as I see it:

• write to master occurred
• stick to master to the end of this request (this works already)
• all subsequent requests in the time-frame of master_ttl have to stick to master
• after master_ttl seconds passed unstick back to slave groups if no action in this time-frame naturally required master

If you just increase the cookie TTL, leaving the other mechanics as they are right now, it will stick to master only for one request during this time-frame. As soon as the next request will start, a new Context will be generated, and the cookie will be overwritten with the new context (and this new context is not in cache, so the third request will go back to slaves even though the master_ttl still haven't passed)

[bleonard]

I don't see anywhere where we delete that cookie. if it was there at the beginning of the middleware, it will write it at the end. If anything, i'd be worried that we'd keep writing it over and over forever at the moment. I don't believe Rack::Utils.set_cookie_header! will not write it if it's already there. So, I think we'd keep loading and writing the same context. Or am I missing something?

[dreyks]

It's either we are talking about different things or this really works not as you intended

This one fails

# spec/middleware_spec.rb
it 'should not overwrite existing cookie' do
  env['HTTP_COOKIE'] = '_mkra_ctxt=old_context--200; path=/; max-age=5; HttpOnly'

  status, headers, body = middleware.call(env)

  expect(headers['Set-Cookie']).to match('old_context')
end

[jeremy]

(See #159 if you'd like to simply extend the cookie's max-age or drop it entirely.)

[bleonard]

Should be replaced by this one: #194