API doesn't specify what limit=0 means

[Brian Waldon]

An http request like /v1.1/images?limit=0 returns all images available. It should return an empty container.

[Brian Waldon (bcwaldon)]

Same goes for /servers

[Alex Meade (alex-meade)]

The comments in the code specify that if a limit=0 is given then limit will be set to the max limit. I am going to hold off until the intention is clarified or we decide to change it to return no results.

[Thierry Carrez (ttx)]

Looks like it's by design ?

[Alex Meade (alex-meade)]

I've looked over the spec and it doesn't mention anything about a zero limit. I think we should either leave it the way it is or change a limit of zero to return empty results. Either way it should be mentioned in the spec.

Let me know what you guys think

[Tom Fifield (fifieldt)]

The behaviour looks unchanged for ~10 months now.

Perhaps this can be counted as a vote for "leave it as limit=0 means no limit", and we can close this bug now?

[Brian Waldon (bcwaldon)]

It makes more sense to interpret the integer literally.

[Tom Fifield (fifieldt)]

Added it to the nova bugtracker to start the discussion there for the functionality change

[Ying Chun Guo (daisy-ycguo)]

Simply speaking, if a parameter is invalid, an error message should be returned; if the parameter can be accepted, interpret it literally.

So if the back end service can accept parameter "limit = 0", I prefer returning empty result.

[lizheming (lizheming-li)]

I agree Ying Chun Guo.
for most user, they will think that "limit=0" return empty result
but max result. this is normal if you have not pointed out.

[Sean Dague (sdague)]

It looks like limit 0 is largely implemented as empty list now

[Mark Doffman (mjdoffma)]

Sorry to try and bring this one back to life, but i'm just not sure that its really invalid. Marked https://bugs.launchpad.net/nova/+bug/1494617 as duplicate.

Seems that for the images api this now implements the empty list . However I think that for flavors and servers api Ithat the behavior is still to use limit=0 as max_limit. These should one day be consistent?

At the very least we should change the comments in http://git.openstack.org/cgit/openstack/nova/tree/nova/api/openstack/common.py#n206 to represent the new behavior.

[John Garbutt (johngarbutt)]

the images API is a proxy to glance, so generally we let glance set the limits on that API.

[Sean Dague (sdague)]

Making the proxies consistent with our usage is a bit beyond scope. I think this is a wishlist item which if someone ever wants to do, is fine, but I don't think we want an open artifact here.