Open Stack

On 05/03/2016 11:47 AM, Clint Byrum wrote:
> Excerpts from Monty Taylor's message of 2016-05-03 07:59:21 -0700:
>> On 05/03/2016 08:55 AM, Clint Byrum wrote:
>>>
>>> Perhaps we have different perspectives. How is accepting what we
>>> previously emitted and told the user would be valid sneaky or wrong?
>>> Sounds like common sense due diligence to me.
>>
>> I agree - I see no reason we can't validate previously emitted tokens.
>> But I don't agree strongly, because re-authing on invalid token is a
>> thing users do hundreds of times a day. (these aren't oauth API Keys or
>> anything)
>>
>
> Sure, one should definitely not be expecting everything to always work
> without errors. On this we agree for sure. However, when we do decide to
> intentionally induce errors for reasons we have not done so before, we
> should weigh the cost of avoiding that with the cost of having it
> happen. Consider this strawman:
>
> - User gets token, it says "expires_at Now+4 hours"
> - User starts a brief set of automation tasks in their system
>    that does not use python and has not failed with invalid tokens thus
>    far.
> - Keystone nodes are all updated at one time (AMAZING cloud ops team)
> - User's automation jobs fail at next OpenStack REST call
> - User begins debugging, wasting hours of time figuring out that
>    their tokens, which they stored and show should still be valid, were
>    rejected.

Ah - I guess this is where we're missing each other, which is good and 
helpful.

I would argue that any user that is _storing_ tokens is doing way too 
much work. If they are doing short tasks, they should just treat them as 
ephemeral. If they are doing longer tasks, they need to deal with 
timeouts. SO, this:


- User gets token, it says "expires_at Now+4 hours"
- User starts a brief set of automation tasks in their system
    that does not use python and has not failed with invalid tokens thus
    far.

should be:

- User starts a brief set of automation tasks in their system
that does not use python and has not failed with invalid tokens thus
far.

"Get a token" should never be an activity that anyone ever consciously 
performs.

> And now they have to refactor their app, because this may happen again,
> and they have to make sure that invalid token errors can bubble up to the
> layer that has the username/password, or accept rolling back and
> retrying the whole thing.
>
> I'm not saying anybody has this system, I'm suggesting we're putting
> undue burden on users with an unknown consequence. Falling back to UUID
> for a while has a known cost of a little bit of code and checking junk
> tokens twice.

Totally. I have no problem with the suggestion that keystone handle 
this. But I also think that users should quite honestly stop thinking 
about tokens at all. Tokens are an implementation detail that if any 
user thinks about while writing their app they're setting themselves up 
to be screwed - so we should make sure we're not talking about them in a 
primary way such as to suggest that people focus a lot of energy on them.

(I also frequently see users who are using python libraries even get 
everything horribly wrong and screw themselves because they think they 
need to think about tokens)